Molecular Spectroscopic studies of Molecular Spectroscopic studies of

metal(II) [Mn(II), Co(II) and Ni(II)]metal(II) [Mn(II), Co(II) and Ni(II)]

halogen complexes with halogen complexes with methylanilinesmethylanilines Part IPart I

M. KUMRUM. KUMRU, Fatih University, Faculty of Arts and , Fatih University, Faculty of Arts and Sciences, Department of Physics, 34500 Büyükçekmece, Sciences, Department of Physics, 34500 Büyükçekmece, Istanbul, TURKEYIstanbul, TURKEY

K. GOLCUK, DeptK. GOLCUK, Dept.. of Chem of Chem.., Univ, Univ.. of Michigan, 930 N. University, of Michigan, 930 N. University, Ann Arbor, MI 48109-1055, USAAnn Arbor, MI 48109-1055, USA

A. ALTUN, MaxA. ALTUN, Max PlanckPlanck InstInstituteitute,, Kaiser-Wilhelm-PlatzKaiser-Wilhelm-Platz 1, 45470 1, 45470 Mülheim an der Ruhr, GERMANYMülheim an der Ruhr, GERMANY

Aniline and its derivatives are widely used for producing polyurethanes, rubbers, pesticides Aniline and its derivatives are widely used for producing polyurethanes, rubbers, pesticides and dyes and also found in the environment [1].and dyes and also found in the environment [1].

Recently, their toxicity effects to Recently, their toxicity effects to Daphnia magna Daphnia magna were also studied [2]. were also studied [2].

Hence, understanding of their molecular properties and the reactions they experience is very Hence, understanding of their molecular properties and the reactions they experience is very important. Besides, their metal(II)halide complexes have been interested for decades [3-9]. important. Besides, their metal(II)halide complexes have been interested for decades [3-9].

As a continuation of our previous works [10-16], we report thermogravimetric (TG) analysis, As a continuation of our previous works [10-16], we report thermogravimetric (TG) analysis, magnetic moments, electronic spectra and vibrational spectra of the pMA metal(II) [Mn(II), magnetic moments, electronic spectra and vibrational spectra of the pMA metal(II) [Mn(II), Co(II) or Ni(II)] bromide complexes in the present study. Co(II) or Ni(II)] bromide complexes in the present study.

A detailed vibrational band analysis of each metal complex is also given. A detailed vibrational band analysis of each metal complex is also given.

The spectroscopic investigations are used to obtain the local structure around each metal The spectroscopic investigations are used to obtain the local structure around each metal atoms.atoms.

Our Related Some Publications :Our Related Some Publications :

M. KumruM. Kumru, A. Aypar, Spectrochim. Acta, Vol. 4 7A, No. 12, pp.1789, , A. Aypar, Spectrochim. Acta, Vol. 4 7A, No. 12, pp.1789, 11991991

M. KumruM. Kumru, A. Aypar, Doğa- Tr. J. Physics, 16 (1992) 377 - 382., A. Aypar, Doğa- Tr. J. Physics, 16 (1992) 377 - 382.

M. KumruM. Kumru, H. Yuksel, A. Aypar, Doğa- Tr. J. Physics, 17(1993)793-799. , H. Yuksel, A. Aypar, Doğa- Tr. J. Physics, 17(1993)793-799.

M.M. KumruKumru,, Fourier Transform Infrared Spectra and Assignment of Vibrations of Hg(3-Fourier Transform Infrared Spectra and Assignment of Vibrations of Hg(3-CC77HH99N)N)22ClCl22 and Hg(3-Cand Hg(3-C77HH99N)N)22ClCl22,, DOĞA, Turkish Journal of Physics, 19(1995)662-668.DOĞA, Turkish Journal of Physics, 19(1995)662-668.

……………………....

A. Altun, K. Golcuk, A. Altun, K. Golcuk, M. KumruM. Kumru, " Vibrational and thermal studies of metal(II) [Ni(II), Zn(II) and , " Vibrational and thermal studies of metal(II) [Ni(II), Zn(II) and

Cd(II)] iodide m-methylaniline complexes ", Vibrational Spectroscopy, 31(2003) 215-225Cd(II)] iodide m-methylaniline complexes ", Vibrational Spectroscopy, 31(2003) 215-225

A. Altun, K. Golcuk, A. Altun, K. Golcuk, M. KumruM. Kumru, " Theoretical and experimental studies of the vibrational spectra of , " Theoretical and experimental studies of the vibrational spectra of

mm-methylaniline", J. Mol. Struct. ( THEOCHEM ), 625(2003)17-24-methylaniline", J. Mol. Struct. ( THEOCHEM ), 625(2003)17-24

A. Altun, K. Golcuk, A. Altun, K. Golcuk, M. KumruM. Kumru, "Structure and vibrational spectra of , "Structure and vibrational spectra of pp-methylaniline: Hartree--methylaniline: Hartree-

Fock, MP2 and density functional theory studies ", J. Mol. Struct. (THEOCHEM), 637(2003)155-169Fock, MP2 and density functional theory studies ", J. Mol. Struct. (THEOCHEM), 637(2003)155-169

A. Altun, K. Golcuk, A. Altun, K. Golcuk, M. KumruM. Kumru, "Vibrational and thermal studies of , "Vibrational and thermal studies of pp-methylaniline complexes with -methylaniline complexes with

Ni(II), Zn(II) and Cd(II) iodides", Vibrational Spectroscopy, 33 / 1-2 (2003) 63 –74 Ni(II), Zn(II) and Cd(II) iodides", Vibrational Spectroscopy, 33 / 1-2 (2003) 63 –74

K. Golcuk, A. Altun, K. Golcuk, A. Altun, M. KumruM. Kumru, "Thermal studies and vibrational analyses of m-methylaniline , "Thermal studies and vibrational analyses of m-methylaniline

complexes of Zn(II), Cd(II) and Hg (II) bromides", Spectrochimica Acta, 59A (2003) 1841-1847complexes of Zn(II), Cd(II) and Hg (II) bromides", Spectrochimica Acta, 59A (2003) 1841-1847

K. Golcuk, A. Altun, K. Golcuk, A. Altun, M. KumruM. Kumru, " Spectroscopic and thermal studies of Mn(II), Co(II) and Ni(II) , " Spectroscopic and thermal studies of Mn(II), Co(II) and Ni(II)

bromide m-methylaniline complexes ", Journal of Molecular Structure, 657 (2003) 385-393bromide m-methylaniline complexes ", Journal of Molecular Structure, 657 (2003) 385-393

K. Golcuk, A. Altun, S. Guner, K. Golcuk, A. Altun, S. Guner, M. KumruM. Kumru and B. Aktas, "Thermal, Vibrational and ESR studies of and B. Aktas, "Thermal, Vibrational and ESR studies of

Cu(II) bromide Cu(II) bromide bisbis((pp-methylaniline) and -methylaniline) and bisbis((mm-methylaniline) complexes" Spectrochimica Acta Part -methylaniline) complexes" Spectrochimica Acta Part

A, 60 (2004) 303-309A, 60 (2004) 303-309

K. Golcuk, A. Altun, K. Golcuk, A. Altun, M. KumruM. Kumru, M. Somer " Vibrational and thermal studies of [MBr2(, M. Somer " Vibrational and thermal studies of [MBr2(pp--

methylaniline)2] (M:Zn+2, Cd+2 and Hg+2) complexes", Vibrational Spectroscopymethylaniline)2] (M:Zn+2, Cd+2 and Hg+2) complexes", Vibrational Spectroscopy xxx(2005)xxx-xxx xxx(2005)xxx-xxx

BENZENAMİN-3-METHYLBENZENAMİN-3-METHYL

m-toluidine

3-amino toluene

m-amino toluene

3-methyl aniline

m-methylaniline(mMA)

. . . . . . . .

BENZENAMİN-4-METHYLBENZENAMİN-4-METHYL

p-toluidine

4-amino toluene

p-amino toluene

4-methyl aniline

p-methylaniline (pMA)

. . . . . . . .

m-methylaniline (mMA) p-methylaniline (pMA)

N

C

H

H

H

C

molecular structuresmolecular structures

ExperimentalExperimental

The ligand (L: pMA) and MBrThe ligand (L: pMA) and MBr22 (M: Mn, Co and Ni) (M: Mn, Co and Ni) were used as received from Fluka and Aldrich Co. were used as received from Fluka and Aldrich Co.

The polycrystalline complexes were prepared using The polycrystalline complexes were prepared using the method given in our previous studiesthe method given in our previous studies[10-16]. [10-16].

Composition and purity (C, H, N, and M) were Composition and purity (C, H, N, and M) were determined by microanalysisdetermined by microanalysis..

Microanalysis data, listed in Table 1, suggest that Microanalysis data, listed in Table 1, suggest that the complexes have 1:2 (MBrthe complexes have 1:2 (MBr22:L) stoichiometry.:L) stoichiometry.

Therefore, [MBrTherefore, [MBr22(pMA)(pMA)22] form is obtained for all ] form is obtained for all the complexes.the complexes.

Table 1. Analyses (%) of the metal complexesTable 1. Analyses (%) of the metal complexes

Found (Calculated) %

Compound Colour M C N H

[MnBr2(mMA)2] Pale pink 12.88 (12.80) 38.90 (39.19) 6.49 (6.53) 4.18 (4.23)

[MnBr2(pMA)2] Pale pink 12.93 (12.80) 38.72 (39.19) 6.58 (6.53) 4.11 (4.23)

[CoBr2(mMA)2] Blue 13.49 (13.61) 38.69 (38.83) 6.45 (6.47) 4.26 (4.19)

[CoBr2(pMA)2] Blue 13.53 (13,61) 38.90 (38.83) 6.49 (6,47) 4.22 (4.19)

[NiBr2(mMA)2] Light yellow 13.23 (13,56) 39.29 (38.85) 6.89 (6.47) 4.15 (4.19)

[NiBr2(pMA)2] Light yellow 13.40 (13,56) 39.60 (38.85) 6.61 (6.47) 4.17 (4.19)

Electronic spectra in EtOH were recorded on a Perkin Electronic spectra in EtOH were recorded on a Perkin Elmer Lambda 9 UV-VIS-NIR spectrometer in the range Elmer Lambda 9 UV-VIS-NIR spectrometer in the range 190–1100 nm.190–1100 nm.

Measurements of magnetic moments at room Measurements of magnetic moments at room temperature were made using the Evans method with a temperature were made using the Evans method with a Sherwood Sci. magnetic balance. Sherwood Sci. magnetic balance. **The molar The molar susceptibilities were corrected for the diamagnetism of susceptibilities were corrected for the diamagnetism of the constituent atoms using Pascal’s constants.the constituent atoms using Pascal’s constants.

Thermal analyses were made on a Mettler Toledo TG50 Thermal analyses were made on a Mettler Toledo TG50 thermobalance under Nthermobalance under N22 flow (flow rate, 30 cm flow (flow rate, 30 cm3/3/min). min). **The samples were heated in an AlThe samples were heated in an Al22OO33 crucible at a rate crucible at a rate of 10of 10CC//min.min.

The 4000-400 cm-1 region FT-IR spectra of the The 4000-400 cm-1 region FT-IR spectra of the complexes were recorded as KBr discs using a Perkin complexes were recorded as KBr discs using a Perkin Elmer Paragon 1000 FT-IR spectrometer. Elmer Paragon 1000 FT-IR spectrometer. **500-200 cm-1 500-200 cm-1 region IR spectra of the complexes were recorded on a region IR spectra of the complexes were recorded on a Mattson Instruments 2030 Galaxy Series as polyethylene Mattson Instruments 2030 Galaxy Series as polyethylene discs at room temperature. discs at room temperature.

The FT-Raman spectra were recorded on a Bruker RFS The FT-Raman spectra were recorded on a Bruker RFS 100/S FT-Raman Spectrometer in the range 3600100/S FT-Raman Spectrometer in the range 3600 –– 70 cm-70 cm-1. 1. **The 1064 nm line, provided by a 1.5 W Nd:YaG air-The 1064 nm line, provided by a 1.5 W Nd:YaG air-cooled laser, was used as excitation line. cooled laser, was used as excitation line. **A liquid A liquid nitrogen cooled Ge detector was used. nitrogen cooled Ge detector was used. **The FT-Raman The FT-Raman spectra of pMA and its complexes are shown together in spectra of pMA and its complexes are shown together in

Fig. 2.Fig. 2.

Vibrational SpectroscopyVibrational Spectroscopy

The only coordination site for the ligand pMA is the The only coordination site for the ligand pMA is the nitrogen atom of the amine group. nitrogen atom of the amine group. **Hence, we pay Hence, we pay attention to –NHattention to –NH22 group vibrations upon complexation. group vibrations upon complexation. **The detailed structural and vibrational studies based The detailed structural and vibrational studies based on ab initio and DFT for free pMA were already on ab initio and DFT for free pMA were already discussed in our previous study [discussed in our previous study [1111]. ]. **Considering that Considering that pMA belongs to CpMA belongs to Css symmetry point group, the symmetry point group, the symmetry species (25Asymmetry species (25A + 20A + 20A) of the observed ) of the observed pMA vibrations are given in Table 2 and Table 3. pMA vibrations are given in Table 2 and Table 3. **All All observed vibrational bands in the spectra of metal observed vibrational bands in the spectra of metal complexes and their assignments are also given in complexes and their assignments are also given in Table 2 and 3. Table 2 and 3. **The FT-IR spectra of pMA and its The FT-IR spectra of pMA and its complexes are given together in Fig. 1. complexes are given together in Fig. 1.

As an evidence of complex formation between metal(II)bromide As an evidence of complex formation between metal(II)bromide

and pMA, it is observed that some modes originating from pMA and pMA, it is observed that some modes originating from pMA

vibrations show substantial shifts in the spectra of complexes. vibrations show substantial shifts in the spectra of complexes.

The NHThe NH22 group vibrational frequencies of pMA are much affected group vibrational frequencies of pMA are much affected

by complexation. by complexation. **This suggests that coordination occur via lone This suggests that coordination occur via lone

pair electrons of nitrogen. pair electrons of nitrogen. **The hybridization type around nitrogen The hybridization type around nitrogen

changes via electron donation from nitrogen orbitals to the metal changes via electron donation from nitrogen orbitals to the metal

atom on complex formation [12-16]. atom on complex formation [12-16]. **Hence, the N-H bond Hence, the N-H bond

strength weakens upon coordination and the strength weakens upon coordination and the NH asymmetric and NH asymmetric and

symmetric stretching bands shift toward lower wavenumbers (see symmetric stretching bands shift toward lower wavenumbers (see

Table 1). Table 1). **The change in HNH angle with coordination decreases The change in HNH angle with coordination decreases

scissoring force constant [12-16]. scissoring force constant [12-16]. **As a result, the scissoring As a result, the scissoring

frequency of the amino group downshifts up to 52 cmfrequency of the amino group downshifts up to 52 cm-1-1 upon upon

coordination.coordination.

•We have assigned the bands observed at 1267 cm–1 (IR) and

1271 cm–1 (Raman) to the CN stretching for free pMA [11].

*The C-N stretching band in the complexes has two

components (asymmetric and symmetric stretching of C-N

bonds), each of them is observed at lower frequencies

compared with the free pMA. *Vibrations of this mode occur

at lower frequencies and have two components (asymmetric

and symmetric stretching of C-N bonds) in the spectra of

complexes, in line with the decrease in the C=N double bond

character.

In m-methylaniline (mMA) and p-methylaniline (pMA), the nitrogen atom is out of the ring plane for about 2-3 and the angle between the ring and amino planes reaches to 40 [10,11,17]. *High-level ab initio and DFT calculations, which confirm non-planar geometry of pMA, show that amino group rocking, wagging and twisting vibrations are expected around 1060 cm-1, 600 cm-1 and 250 cm-1, respectively [11,17]. *Hence, we assign the IR band of the free pMA at 1074 cm-1 as the rocking mode. *We could not determine the frequency of the wagging and twisting modes from the experimental IR and Raman spectra of the free pMA due to the broadness or low intensity of the bands.

In the complexes, amino group rocking, wagging and twisting In the complexes, amino group rocking, wagging and twisting

vibrations shift towards upper frequencies. vibrations shift towards upper frequencies. **The rocking vibration The rocking vibration

has been observed in the complexes around 1080-1060 cm-1. has been observed in the complexes around 1080-1060 cm-1. **The The

wagging mode shifts upon coordination to 1065-1040 cm-1 region wagging mode shifts upon coordination to 1065-1040 cm-1 region

and appears as a strong and coordination sensitive band [18]. and appears as a strong and coordination sensitive band [18].

* *A study of normal coordinate analysis on aniline was reported A study of normal coordinate analysis on aniline was reported

and the band at 216 cm-1 in IR spectrum of aniline was assigned to and the band at 216 cm-1 in IR spectrum of aniline was assigned to

NH2 twisting mode. NH2 twisting mode. **On the other hand, this band was found at On the other hand, this band was found at

605 cm-1 in aniline-Cd complex [9]. 605 cm-1 in aniline-Cd complex [9]. **Therefore, we assign the Therefore, we assign the

635-566 cm-1 region bands of the complexes, as the NH2 twisting 635-566 cm-1 region bands of the complexes, as the NH2 twisting

vibrations, which are not observed in the spectra of free pMA. vibrations, which are not observed in the spectra of free pMA.

**The explicit metal-sensitivity can be explained directly by The explicit metal-sensitivity can be explained directly by

mechanical coupling of this mode with M–N vibrations [14-16].mechanical coupling of this mode with M–N vibrations [14-16].

The metal-ligand bands are helpful for determining the local The metal-ligand bands are helpful for determining the local structure around metal ions. structure around metal ions. **It is considered that the metal-ligand It is considered that the metal-ligand vibrations occur below 500 cm–1 [3-16]. vibrations occur below 500 cm–1 [3-16]. **Assignments of the Assignments of the (M-N) and (M-N) and (M-Br) vibrations, listed in Table 3, have been given (M-Br) vibrations, listed in Table 3, have been given carefully by considering the internal modes of mMA and carefully by considering the internal modes of mMA and comparing with literature reports [3-16]. comparing with literature reports [3-16]. **The 500-200 cm–1 The 500-200 cm–1 region IR spectra of the complexes are shown together in Fig 3. region IR spectra of the complexes are shown together in Fig 3.

For the Co (II) complex, strong and medium IR bands at 420 cm–1 For the Co (II) complex, strong and medium IR bands at 420 cm–1 and 394 cm–1 were assigned to and 394 cm–1 were assigned to (Co-N) stretching vibrations. (Co-N) stretching vibrations. **We We observed terminal Co-Br bond stretching, i.e. observed terminal Co-Br bond stretching, i.e. (Co-Br)t bands at (Co-Br)t bands at 217 cm–1 and 208 cm–1 [14]. 217 cm–1 and 208 cm–1 [14]. **In Co(II) complex, the metal ion is In Co(II) complex, the metal ion is involved in a tetrahedral N2CoBr2 skeleton. involved in a tetrahedral N2CoBr2 skeleton. **Assuming C2v Assuming C2v symmetry for this complex, both the asymmetric and symmetric symmetry for this complex, both the asymmetric and symmetric CoBr2 and CoN2 stretching vibrations are IR active [19]. CoBr2 and CoN2 stretching vibrations are IR active [19]. **Then, Then, the the (Co-Br)t and (Co-Br)t and (Co-N) stretching vibrations can be described (Co-N) stretching vibrations can be described with A1+B1 and A1+B2 representations, respectively. with A1+B1 and A1+B2 representations, respectively. **Thus, the Thus, the metal-ligand vibrational bands are consistent with previously metal-ligand vibrational bands are consistent with previously reported tetrahedral Co(II) complexes [3-6,14,19].reported tetrahedral Co(II) complexes [3-6,14,19].

The stretching vibrations of the bridging M-Br-M bonds, i.e. The stretching vibrations of the bridging M-Br-M bonds, i.e. (M-(M-Br)b, should appear below 200 cm–1 [14,20]. Br)b, should appear below 200 cm–1 [14,20]. **In Raman spectrum In Raman spectrum of Mn(II) complex (see Fig.2(c)), we could not observe of Mn(II) complex (see Fig.2(c)), we could not observe (Mn-(Mn-Br)b, bands due to broad strong Raman band around 100 cm–1 Br)b, bands due to broad strong Raman band around 100 cm–1 which is ascribed as the lattice mode of the solid complexes [21] which is ascribed as the lattice mode of the solid complexes [21] and couple with torsional mode of CHand couple with torsional mode of CH33.. In FT-Raman spectrum of Ni(II) complex (see Fig.3(d)), the 155 In FT-Raman spectrum of Ni(II) complex (see Fig.3(d)), the 155 cm–1 and 136 cm–1 bands are due to the stretching bands of cm–1 and 136 cm–1 bands are due to the stretching bands of bridging Ni-Br-Ni bonds, i.e. bridging Ni-Br-Ni bonds, i.e. (Ni-Br)b. (Ni-Br)b. **Hence, the appearance of Hence, the appearance of the the (Ni-Br)b vibrations indicates a polymeric octahedral structure (Ni-Br)b vibrations indicates a polymeric octahedral structure around metal ions with exclusively bridging bromides for around metal ions with exclusively bridging bromides for [NiBr[NiBr22(pMA)(pMA)22] complex. ] complex. **On the other hand, the nonappearance of On the other hand, the nonappearance of (Mn-Br)t bands can be concluded that the local environment of (Mn-Br)t bands can be concluded that the local environment of Mn ion consists of polymeric octahedral structure, as also proposed Mn ion consists of polymeric octahedral structure, as also proposed for [MnBrfor [MnBr22(mMA)(mMA)22] complex [14]. ] complex [14]. ********As a result, each of Mn As a result, each of Mn and Ni ions is surrounded by four bromine atoms and two nitrogen and Ni ions is surrounded by four bromine atoms and two nitrogen atoms of the ligands, having a polymeric octahedral structure atoms of the ligands, having a polymeric octahedral structure [3,5,8,14,19].[3,5,8,14,19].

The coordination number effect on metal-ligand The coordination number effect on metal-ligand vibration frequencies is known to be a substantial one vibration frequencies is known to be a substantial one [4,14]. [4,14]. **Substitution of Ni(II) by Co(II) causes to a Substitution of Ni(II) by Co(II) causes to a decrease in decrease in (M-N). Substitution of Co(II) by Mn(II) is (M-N). Substitution of Co(II) by Mn(II) is expected to lead to an increase in expected to lead to an increase in (M-N). (M-N). **This result This result arises from the bonding capacity of the metal ion being arises from the bonding capacity of the metal ion being distributed over more bands with consequently lower distributed over more bands with consequently lower metal-ligand force constants [4,14]. metal-ligand force constants [4,14]. **If the coordination If the coordination number remains unchanged, number remains unchanged, (M-N) bands follow the (M-N) bands follow the sequence Mn<Ni. sequence Mn<Ni. **The difference between the The difference between the frequencies of corresponding frequencies of corresponding (M-N) bands in each Mn-(M-N) bands in each Mn-Ni pair might be ascribed to the fact that the Ni(II) Ni pair might be ascribed to the fact that the Ni(II) complex is stabilized by crystal field splitting whereas the complex is stabilized by crystal field splitting whereas the Mn(II) complex is not [14]. Mn(II) complex is not [14].

(pMA) [MnBr2(pMA)2] [CoBr2(pMA)2] [NiBr2(pMA)2]    

IR Ra IR Raman IR Raman IR Raman Symmetry

Assignments

3416 s 3418 w 3293 s 3276 s 3311 m 3312 s A NH asym

3333 s 3337 w 3238 vs 3244 s 3226 vs 3227 m 3240 s 3232 vs A NH sym

3220 m 3224 w 3123 m 3124 m 3121 w 3120 w,br 2 x 1621 overton

3056 w 3054 s 3054 vw 3054 s 3054 vw 3057 s 3065 vw 3057 vs A CH ring

3020m, sh

3032 s 3031 m 3030 s3031 m

3032 m 3032 w 3038 s,sh A CH ring

3008 m 3013 s 3011 s 3012 m 3008 w 3014 s A CH ring

2912 m 2917 s 2920 m 2916 m 2925 m 2924 s 2911 m 2915 vs A CH3 sym

2859 m 2861m 2868 w 2863 m 2864 vw 2860 w 2857 m 2864 vs 2 x 1458 overton

2737 w 2738 w 2731 vw 2722 w 2721 w 2735 w 2 x 1380 overton

1621 vs 1617 s 1573 s 1575 m,sh 1578 vs 1576 w 1569 vs A NH2 sciss.

1619 s 1621 s 1612 w,sh 1612 s 1615 s 1616 vs A CC ring

1582 s, sh

1581 m 1596 s 1595 m A CC ring

1514 vs 1518 vs 1519 m 1512 vs 1516 vs 1518 w A CC ring

1458 w 1451 w 1455 w 1451 m,br 1449 w A CH3 asym

1441 s 1440 w,br 1430 vw,br A CC ring

1380 m 1374 w 1380 s 1380 vw 1379 m 1379 w 1377 m A CH3 sym

1324 m 1324 w 1317 m 1324 m 1327 vw 1326 vw 1327 w A CH ring

1281 m 1294 m 1295 w 1292vw, 1296 w 1293 w A CC

Table 2. Infrared and Raman frequencies of pMA and metal comlexes

(4-MA) [MnBr2(4-MA)2] [CoBr2(4-MA)2] [NiBr2(4-MA)2]    

IR Ra IR Raman IR Raman IR Raman Sim Bant Tanımları

1281 m 1243 vs 1237 m 1238 m 1250 s 1242 s A CN

1216 s 1222 s 1215 1235 s 1222 vs CN

1218 m 1205 m 1204 s 1217 w 1207 w,sh 1207 vs A CCH3

1176 s 1179 m 1160 m 1183 s 1181 m 1180 m 1179 s A CH ring

1120 s 1100 s, sh 1116 w,sh 1123 w,br A CH ring

1074 m 1074 m 1070 vs 1080 vs 1062 vs 1070 w,sh A NH2 rock.

1065 vs 1065 s 1038 1046 vs A NH2 wag.

983 w 998 m 1016 998 s 1000 s A CCC ring

953 w 956 w 650 vw 960 vw,sh A CH3; CCH3; CCC

931 w 936 w 932 vw 938 s 830 vw A CH ring; CCC ring

844 s 836 m 837 s 841 s 837 s 835 m 830 vs A CCC ring; CN

812 vs 812 vs 810 vs 813 s 810 m A CH ring; CCC ring

806 vs 806 vs 809 m 810 vs A CH ring; CCC ring

720 m 739 s 743 w 741 s 739 w 733 s 742 m A Breathing

702 s 702 vw 707 m 705 w 705 s 709 vw A CCC ring

645 s 661 s 660 s 649 s 645 m 647 s 650 vw A CCC ring

566 s 556 m 634 s 635 m 607 vs 610 m A NH2 twist.

504 vs 510 vs 521 w 507 s 524 m 523 vs 518 vw A CCC ring

4-MA [MnBr2(4-MA)2] [CoBr2(4-MA)2] [NiBr2(4-MA)2]    

IR Ra IR Raman IR Raman IR Raman Simetri Bant Tanımları

470 466 s 466 s 474 s 472 m 472 vs 476 m 476 m A CCC ring

406 m 405 m 420 s 421 m 412 m 410 m (M-N)

361 m 365 394 m 395 w 386 m 386 m (M-N)

335 m 300 s 307s 303 s 299 vs 308 s 315 w A CCH3; CCC; CN

297 s 285 vs

278 w 260 277 vw 273 m,sh A CN; CCH3

255 s 227 m 234 m NMN deformation

217 220

247 s 213 s (M-Br)t

208 s 211 vs (M-Br)t

155 vs (M-Br)b

Table 2. (Continued)Table 2. (Continued)

KeyKey :: , stretching;, stretching; , in-plane deformation; , in-plane deformation; , out-of-plane deformation; , out-of-plane deformation; s, strong; s, strong; vs, very strong;vs, very strong; m, medium; m, medium; w, weak; w, weak; vw, very weak; vw, very weak; sh, shoulder; sh, shoulder; br, broad.br, broad.

(a) FTIR and (b) FT-Raman Spectra of pMA

FT-IR spectra of (a) [MnBr2(4-MA)2], (b) [CoBr2(4-MA)2] and (c) [NiBr2(4-MA)2] complexes

FT- Raman spectra of (a) [MnBr2(3-MA)2] and (b) [NiBr2(3-MA)2] complexes

FT-Raman spectra of (a) [MnBr2(4-MA)2] and (b) [NiBr2(4-MA)2] complexes

FT-Raman spectra of (a) [CoBr2(4-MA)2] and (b) [CoBr2(3-MA)2] complexes

IR spectra of (a) [NiBr2(3-MA)2], (b) [MnBr2(3-MA)2] and (c) [CoBr2(3-MA)2] complexes in the range of 500–200 cm–1

IR spectra of (a) [NiBrIR spectra of (a) [NiBr22(4-MA)(4-MA)22], (b) [MnBr], (b) [MnBr22(4-MA)(4-MA)22] and ] and (c) [CoBr(c) [CoBr22(4-MA)(4-MA)22] complexes in the range of 500–200 cm–1] complexes in the range of 500–200 cm–1

Electronic (UV-VIS) SpectroscopyElectronic (UV-VIS) Spectroscopy

The electronic spectral data and magnetic moment The electronic spectral data and magnetic moment values of the complexes are given in Table values of the complexes are given in Table 44. . **The UV-The UV-vis spectrum of [MnBr2(pMA)2] complex gives only vis spectrum of [MnBr2(pMA)2] complex gives only one band around 23809 cm–1. one band around 23809 cm–1. **This band corresponds This band corresponds to 6A1g(S) → 4A1g(G), 4Eg(G) spin forbidden d-d to 6A1g(S) → 4A1g(G), 4Eg(G) spin forbidden d-d transition. transition. **The spectrum band and the value of The spectrum band and the value of magnetic moment (magnetic moment (eff = 5.56 B.M.) are consistent eff = 5.56 B.M.) are consistent with those predicted six coordinated polymeric with those predicted six coordinated polymeric octahedral Mn(II) complexes [5,14,19]. octahedral Mn(II) complexes [5,14,19]. **The magnetic The magnetic moment value of the complex is lower than spin-only moment value of the complex is lower than spin-only value of a Mn(II) ion, showing Mn-Mn interaction [22].value of a Mn(II) ion, showing Mn-Mn interaction [22].

The electronic absorption spectrum of [CoBrThe electronic absorption spectrum of [CoBr22(pMA)(pMA)22] ] complex shows some overlapping bands at 14837 cm-1, complex shows some overlapping bands at 14837 cm-1, 15625 cm-1, 16007 cm-1 and 16649 cm-1. 15625 cm-1, 16007 cm-1 and 16649 cm-1. **The band at The band at 14837 cm-1 arises from spin allowed 4A2(F) → 4T1(P) 14837 cm-1 arises from spin allowed 4A2(F) → 4T1(P) electronic transition. electronic transition. **The bands at 15625 cm-1, 16007 The bands at 15625 cm-1, 16007 cm–1 and 16649 cm–1 are due to spin forbidden cm–1 and 16649 cm–1 are due to spin forbidden transitions and assignable to 4A2(F) → 2E(G), 4A2(F) → transitions and assignable to 4A2(F) → 2E(G), 4A2(F) → 2T1(G) and 4A2(F) → 2T2(G), respectively, indicating 2T1(G) and 4A2(F) → 2T2(G), respectively, indicating fine structures due to pseudo-tetrahedral structure. fine structures due to pseudo-tetrahedral structure. Magnetic moment value was found as 4.72 B.M. and Magnetic moment value was found as 4.72 B.M. and consistent with high spin tetrahedral Co(II) complexes consistent with high spin tetrahedral Co(II) complexes [14,23,24]. [14,23,24]. **Therefore, the proposed tetrahedral structure Therefore, the proposed tetrahedral structure consists of Nconsists of N22CoBrCoBr22 coordination sphere. coordination sphere.

In the UV-vis spectrum of [NiBrIn the UV-vis spectrum of [NiBr22(pMA)(pMA)22] complex, ] complex, two bands were observed at 12820 cm–1 and two bands were observed at 12820 cm–1 and 23809 cm–1. The absorption band at 12820 cm–1 23809 cm–1. The absorption band at 12820 cm–1 arises from 3A2g(F) → 3T1g(F) transition, while arises from 3A2g(F) → 3T1g(F) transition, while the absorption band at 23809 cm–1 corresponds to the absorption band at 23809 cm–1 corresponds to 3A2g(F)→ 3T1g(P) transition. 3A2g(F)→ 3T1g(P) transition. **The positions of The positions of the d-d transitions indicate that the Ni ion is in a the d-d transitions indicate that the Ni ion is in a polymeric octahedral environment with bridging polymeric octahedral environment with bridging bromides [5]. bromides [5]. **The magnetic moment value (The magnetic moment value (eff eff = 3.15 B.M.) of the complex, which shows the = 3.15 B.M.) of the complex, which shows the presence of two unpaired electrons, lies in the presence of two unpaired electrons, lies in the region expected for octahedral Ni complexes [3].region expected for octahedral Ni complexes [3].

Electronic transitionsElectronic transitions

TransitionMulliken

representation (nm)

* N V <200

* N V 200–500

n * N Q 160–260

n * N Q 250–600

UV- VIS spectrum of pMAUV- VIS spectrum of pMA

291 nm de görülen bant n→ *, 237 nm de görülen bant → * 207 nm de görülen bant ise n→ * geçişlerine karşılık gelmektedir.

UV- VIS spectrum of mMAUV- VIS spectrum of mMA

287 nm de görülen bant n→ *, 237 nm de görülen bant → * ve 203 nm de görülen bant ise n→ * geçişlerini göstermektedir..

Electronic Transitions of Transition metal complexesElectronic Transitions of Transition metal complexes

Geçiş metal komplekslerinin soğurmaları genellikle dolu olmayan d Geçiş metal komplekslerinin soğurmaları genellikle dolu olmayan d orbitallerine geçişlerden veya yük transferi geçişlerinden kaynaklanmaktadır. orbitallerine geçişlerden veya yük transferi geçişlerinden kaynaklanmaktadır.

Serbest iyondaki d orbitallerinin (a) oktahedral ve (b) tetrahedral alanda yarılmalarıyla meydana gelen enerji-seviye diyagramları

420 nm de bir soğurma bandı gözlenmiştir. Bu soğurma, elektronun 6A1g(S) → 4T2g(G) enerji seviyeleri arasındaki spin yasaklı geçişinden kaynaklanmaktadır.

UV-VIS spectrum of [MnBr2(4-MA)2]

412 nm görülen band 6A1g(S) → 4A1g(G), spin yasaklı geçişine ve 546 nm görülen band ise 6A1g(S) → 4T1g(G) spin yasaklı geçişine karşılık gelmektedir.

UV-VIS spectrum of [MnBr2(3-MA)2]

UV-VIS spectra of (a) [CoBr2(4-MA)2] and (b) [CoBr2(3-MA)2] complexes.

670 nm gözlenen bantlar 4A2(F) → 4T1(P) geçişine karşılık gelmektedir.640 nm640 nm, , 622622 nm ve nm ve 590590 nm de görülen omuzlar Co(II) metali etrafında meydana gelen pseudo-tetrahedral nm de görülen omuzlar Co(II) metali etrafında meydana gelen pseudo-tetrahedral (tetrahedralimsi) yapının bir sonucudur. Ayrıca ortaya çıkan bu ince yapılar spin yasaklı geçişlerin de bir (tetrahedralimsi) yapının bir sonucudur. Ayrıca ortaya çıkan bu ince yapılar spin yasaklı geçişlerin de bir sonucu olup; sonucu olup; 44AA22(F) temel seviyesinden (F) temel seviyesinden 22E(G), E(G), 22TT11(G) ve (G) ve 22TT22(G) seviyelerine olan geçişleri göstermektedir. (G) seviyelerine olan geçişleri göstermektedir.

UV-VIS spectra of (a) [NiBr2(3-MA)2] and (b) [NiBr2(4-MA)2] complexes

780 nm de gözlenen band 3A2g(F) → 3T1g(F) elektronik geçişini,420 nm deki bant ise 3A2g(F) → 3T1g(P) elektronik geçişini gösterir.

Complexes max (nm) Electronic Transitions

[MnBr2(4-MA)2] 420 6A1g(S) → 4A1g(G)

[MnBr2(3-MA)2] 412 6A1g(S) → 4A1g(G)

546 6A1g(S) → 4T1g(G)

[CoBr2(4-MA)2] 340 CT

590 4A2(F) → 2T2(G)

622 4A2(F) → 2T1(G)

640 4A2(F) → 2E(G)

674 4A2(F) → 4T1(P)

[CoBr2(3-MA)2] 340 CT

590 4A2(F) → 2T2(G)

620 4A2(F) → 2T1(G)

640 4A2(F) → 2E(G)

670 4A2(F) → 4T1(P)

[NiBr2(4-MA)2] 420 3A2g(F) → 3T1g(F)

780 3A2g(F)→ 3T1g(P)

[NiBr2(3-MA)2] 420 3A2g(F) → 3T1g(F)

780 3A2g(F)→ 3T1g(P)

EElelecctronitronicc absorptionabsorption spe specctrtrumum results of complexesresults of complexes

Thermal analysesThermal analyses

Thermal decomposition data of the metal complexes are listed in Table 5. *As an example, TG and DTG traces for [MnBr2(pMA)2] complex are shown in Fig. 4. *In the TG-DTG curves of Mn(II) complex no weight changes are observed until 103C, where an initial weight loss is observed. In the temperatures between 226C and 290C, the rest of the pMA is removed immediately from the complex, leaving the intermediate MnBr2. *The metal salt starts to decompose at 295C. *The residual weight is in good agreement with the value required for MnO.

The Co(II) and Ni(II) complexes decompose in a two-step

mass loss reaction. *The first step (140-273C range) for

the Co(II) complex corresponds to the loss of 2 moles of

pMA. *The second decomposition stage registered

between 275-750C matches the decomposition of CoBr2

finally to CoO. *The Ni(II) complex loses 2 moles of pMA

in 120-273C temperature. *The observed weight losses

for the decomposition processes in each of the compounds

compare favorably with the theoretical values listed in

Table 5.

ExperimentalParameters

[MnBr2(3-MA)2]

[MnBr2(4-MA)2]

[CoBr2 (3-

MA)2]

[CoBr2 (4-

MA) 2][NiBr2(3-MA)2]

[NiBr2(4-MA)2]

[CuBr2(3-MA)2]

[CuBr2(4-MA)2]

m (g) 0,0575 0,0985 0,0850 0,0788 0,1079 0,1390 0,0705 0,0601

L (cm) 2 2,5 2,3 2,5 2,4 2,5 2,3 2,2

Rd 942 1213 780 659 408 515 34 29

Rb -32 -32 -33 -33 -31 -32 -33 -33

Mw (gmol–1) 429,05 429,05 433,05 433,05 432,81 432,81 437,66 437,66

g g x 10x 10-6-6 32,1843 30,0431 20,8988 20,8566 9,2763 9,0297 1,9630 2,1570

m m x 10x 10-3-3 13,8087 12,8899 9,0502 9,0319 4,0149 3,9081 0,8591 0,9443

d d x 10x 10-6-6 -232,64 -232,64 -232,64 -232,64 -232,64 -232,64 -232,64 -232,64

A A x 10x 10-3-3 14,0413 12,8901 9,2828 9,2645 4,2475 4,1407 1,0918 1,1769

T (K) 298 298 298 298 298 298 298 298

eff (BM) 5,80 5,56 4,73 4,72 3,20 3,15 1,62 1,68

nn 5 5 3 3 2 2 1 1

Spin statesHigh spin

High spin

High spin

High spin

MMaagneticgnetic su succecceptibilitptibilityy results of complexesresults of complexes

Termogravimetrik Analiz Sonuçları Termogravimetrik Analiz Sonuçları

Termal analizler Termal analizler Mettler Toledo TG50Mettler Toledo TG50 termobalansı kullanılarak, 35– termobalansı kullanılarak, 35–900900C aralığında, 30 cmC aralığında, 30 cm33/dak. lık akış hızına sahip N/dak. lık akış hızına sahip N22 dinamik dinamik atmosfer gazı altında yapılmıştır. atmosfer gazı altında yapılmıştır.

Toz haldeki numunelerden yaklaşık 10 mg civarında alınarak, 70 Toz haldeki numunelerden yaklaşık 10 mg civarında alınarak, 70 l l lik standart alüminyum oksit (Allik standart alüminyum oksit (Al22OO33) kaplar içinde 10) kaplar içinde 10C/dak. lık C/dak. lık ısıtılma oranına sahip termobalansa yerleştirilmiştir. ısıtılma oranına sahip termobalansa yerleştirilmiştir.

Her bir numune için TG eğrilerinin yanında kısmen örtüşmüş termal Her bir numune için TG eğrilerinin yanında kısmen örtüşmüş termal ayrışma reaksiyonlarını ortaya çıkarmak ve sonuçları daha iyi ayrışma reaksiyonlarını ortaya çıkarmak ve sonuçları daha iyi yorumlayabilmek için DTG eğrileri de kaydedilmiştir. Böylece bu yorumlayabilmek için DTG eğrileri de kaydedilmiştir. Böylece bu sıcaklıklar arasında numunede meydana gelen termal ayrışma sıcaklıklar arasında numunede meydana gelen termal ayrışma reaksiyonları ortaya konularak her bir numunenin termal reaksiyonları ortaya konularak her bir numunenin termal karakterizasyonu yapılmıştır.karakterizasyonu yapılmıştır.

ThThermal ermal SperationSperation rea reactions ofctions of CompCompompleomplexesxes

Complexes Thermal Seperation Reactions

Temperature Range (C)

DTGpics (C)

% mass loose

Experimental

Theoretical

[MnBr2(4-MA)2] [MnBr2(4-MA)2] → [MnBr2(4-MA)0,4]

[MnBr2(4-MA)0,4] → MnBr2

MnBr2→MnO

103–226226–290295-770

203270680

31,0019,0034,22

30,0020,4537,66

[MnBr2(3-MA)2] [MnBr2(3-MA)2] → [MnBr2(3-MA)0,4]

[MnBr2(3-MA)0,4] → MnBr2

MnBr2→MnO

115–183183–310350–750

178202670

29,1219,8333,39

26.6817.7835.93

[CoBr2(4-MA)2] [CoBr2(4-MA)2] → CoBr2

CoBr2→CoO

140–273275-750

240685

48,8340,25

49,6136,86

[CoBr2(3-MA)2] [CoBr2(3-MA)2] → CoBr2

CoBr2 → Co

97–350390–700

250690

49,4033,29

47.7036.62

[NiBr2(4-MA)2] [NiBr2(4-MA)2] → NiBr2 120–273 257 46,65 50,38

[NiBr2(3-MA)2] [NiBr2(3-MA)2] → NiBr2

NiBr2 → NiO

90–380400–720

235685

50,3333,08

49.3134.88

[CuBr2(4-MA)2] [CuBr2(4-MA)2] → [CuBr2(4-MA)]

[CuBr2(4-MA)2] → CuBr2

85–200200-340

140250

21,1225,82

24.4824.48

[CuBr2(3-MA)2] [CuBr2(3-MA)2] → CuBr2 50–370 110 46,02 48.97

[ZnBr2(4-MA)2] [ZnBr2(4-MA)2] → ZnBr2 112–305 222 47,32 48,92

[ZnBr2(3-MA)2] [ZnBr2(3-MA)2] → ZnBr2 110–310 230 46,56 48,84

[CdBr2(4-MA)2] [CdBr2(4-MA)2] → [CdBr2(4-MA)]

[CdBr2(4-MA)] → CdBr2

70–175175–240

170190

21,7821,78

21,992199

[CdBr2(3-MA)2] [CdBr2(3-MA)2] → CdBr2 80–200 170 43,29 44,10

[HgBr2(4-MA)2] [HgBr2(4-MA)2] → [HgBr2(4-MA)]

[HgBr2(4-MA)] → HgBr2

56–118118–170

107133

16,3816,38

18,6518,65

[HgBr2(3-MA)2] [HgBr2(3-MA)2] → HgBr2 55–162 150 37,26 37,33

[MnBr[MnBr22(3-MA)(3-MA)22] için TG-DTG eğrileri] için TG-DTG eğrileri

TG-DTG curvers for

[CoBr2(3-MA)2]

TG-DTG curves for

[CoBr2(4-MA)2]

TG-DTG curves for [NiBr2(3-

MA)2]

TG-DTG curves for [NiBr2(4-

MA)2]

TG-DTG curves for [MnBr2(4-

MA)2]

TG-DTG curves for [MnBr2(4-

MA)2]

TG-DTG curves for 4-MA

TG-DTG curves For 3-MA

ConclusionConclusion

The spectroscopic studies of [MnBrThe spectroscopic studies of [MnBr22(pMA)(pMA)22], ], [CoBr[CoBr22(pMA)(pMA)22] and [NiBr] and [NiBr22(pMA)(pMA)22] complexes show that ] complexes show that metal-ligand coordination occurs via nitrogen atom of the metal-ligand coordination occurs via nitrogen atom of the pMA. pMA. **The vibrational spectra reveal the type of the The vibrational spectra reveal the type of the coordination around each metal ion. coordination around each metal ion. **The information The information referring to the geometry of the studied complexes is also referring to the geometry of the studied complexes is also obtained from the electronic spectra and from the values of obtained from the electronic spectra and from the values of magnetic moments. magnetic moments. **The spectroscopic and magnetic data The spectroscopic and magnetic data suggest that the Co(II) complex has a tetrahedral structure, suggest that the Co(II) complex has a tetrahedral structure, with the cobalt ion bonded to two bromide ions and two with the cobalt ion bonded to two bromide ions and two nitrogen atoms from two different pMA ligand, while the nitrogen atoms from two different pMA ligand, while the Mn(II) and Ni(II) complexes have the metal ions in a Mn(II) and Ni(II) complexes have the metal ions in a polymeric octahedral environment with bridging bromides.polymeric octahedral environment with bridging bromides.

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Tetrahedral Co(II) kompleksleri metal Tetrahedral Co(II) kompleksleri metal iyonu etrafında lokal olarak Ciyonu etrafında lokal olarak C2v2v simetrisine sahiptir. CoBrsimetrisine sahiptir. CoBr22 ve CoN ve CoN22 antisimetrik ve simetrik gerilmeleri IR antisimetrik ve simetrik gerilmeleri IR aktif ve Raman aktiftir. Co(II) aktif ve Raman aktiftir. Co(II) komplekslerinin 420–399 cmkomplekslerinin 420–399 cm–1–1 deki IR deki IR bantları bantları (Co-N) gerilmelerinden, 230–(Co-N) gerilmelerinden, 230–210 cm210 cm–1–1 de görülen bantları da terminal de görülen bantları da terminal Co–Br bağ gerilme titreşimlerinden Co–Br bağ gerilme titreşimlerinden kaynaklanmaktadır. kaynaklanmaktadır.

Cu(II) komplekslerinin titreşim Cu(II) komplekslerinin titreşim spektrumlarında sırasıyla 237-251 cmspektrumlarında sırasıyla 237-251 cm–1–1 ve 202–207 cmve 202–207 cm–1–1 aralığında gözlenen aralığında gözlenen terminal Cu–Br antisimetrik ve simetrik terminal Cu–Br antisimetrik ve simetrik bağ gerilemeleri metal atomu etrafındaki bağ gerilemeleri metal atomu etrafındaki tetragonal yapıyı gösterir. 200 cmtetragonal yapıyı gösterir. 200 cm–1–1 in in altında gözlenen bantlar eksenel zayıf altında gözlenen bantlar eksenel zayıf Cu-Br etkileşimlerinden Cu-Br etkileşimlerinden kaynaklanmaktadır.kaynaklanmaktadır.

Cu(II) kompleksleri için metal atomu Cu(II) kompleksleri için metal atomu etrafındaki muhtemel yapı yandaki etrafındaki muhtemel yapı yandaki şekilde verilmektedir. (N: 3-MA veya 4-şekilde verilmektedir. (N: 3-MA veya 4-MA nın azot atomu; noktalı çizgi zayıf MA nın azot atomu; noktalı çizgi zayıf Cu-Br etkileşmesini temsil eder).Cu-Br etkileşmesini temsil eder).

Br

–z

Br

Br

–z

+z

Cu

N

N

Br

Br

Br

–z

+z

Cu

N

N

Zn(II) kompleksleri için metal–ligand ve Zn(II) kompleksleri için metal–ligand ve terminal metal–bromür titreşimleri terminal metal–bromür titreşimleri tetrahedral bir çevre için öngörülen tetrahedral bir çevre için öngörülen değerlerde çıkmaktadır. Buna göre Zn(II) değerlerde çıkmaktadır. Buna göre Zn(II) kompleksleri, Nkompleksleri, N22ZnBrZnBr22 koordinasyon koordinasyon küresiyle Cküresiyle C2v2v simetrisine sahip tetrahedral simetrisine sahip tetrahedral bir çevrede bulunmaktadır. bir çevrede bulunmaktadır.

Cd(II) ve Hg(II) komplekslerinin titreşim Cd(II) ve Hg(II) komplekslerinin titreşim spektrumlarında (uzak-IR ve Raman) 200 spektrumlarında (uzak-IR ve Raman) 200 cmcm–1–1 in üzerinde görülen bantlar terminal in üzerinde görülen bantlar terminal Cd–Br ve Hg–Br bağ gerilmesine ve 200 Cd–Br ve Hg–Br bağ gerilmesine ve 200 cmcm–1–1 altında ortaya çıkan bantlar altında ortaya çıkan bantlar (Hg-(Hg-Br)Br)b b titreşimlerine karşılık gelir. Buna göre titreşimlerine karşılık gelir. Buna göre kompleksler 5-koordinatlı dinükleer kompleksler 5-koordinatlı dinükleer yapılardan veya bir tane terminal M–Br yapılardan veya bir tane terminal M–Br bağına sahip brom köprülü 5-koordinatlı bağına sahip brom köprülü 5-koordinatlı polimerik yapılardan meydana polimerik yapılardan meydana gelmektedir.gelmektedir.

Cd(II) ve Hg (II) kompleksleri için metal Cd(II) ve Hg (II) kompleksleri için metal atomu etrafındaki muhtemel yapı yandaki atomu etrafındaki muhtemel yapı yandaki şekilde verilmektedir. (M: Hg veya Cd; şekilde verilmektedir. (M: Hg veya Cd; Br’: köprü yapmış Br atomu; N: 3-MA Br’: köprü yapmış Br atomu; N: 3-MA veya 4-MA nın azot atomu). veya 4-MA nın azot atomu).

Br

Br’

Br’

Br

NN

NN

M M