175

1040-7278/04/0600-0175/0 © 2004 Plenum Publishing Corporation

Journal of Cluster Science, Vol. 15, No. 2, June 2004 (© 2004)

Formation of Mixed Fe/W/S Complexes Bearing Oxoand Acetylide Ligands: Synthesis and Characterizationof [(g5-C5Me5)W2Fe2(CO)6(O)2(m-O)(m3-S)2

(g1:g2-CCR)] (R=Ph, (Me)C=CH2) and[(g5-C5Me5)W2Fe2(CO)6(O)(m-O)(m3-S)2

(g1:g2-CCR)(g2-RCCH)] (R=Ph, (Me)C=CH2)

Pradeep Mathur,1 , 2 Anjan K. Bhunia,1 and Shaikh Md. Mobin3

1 Chemistry Department, Indian Institute of Technology, Powai, Bombay 400076, India.2 To whom correspondence should be addressed. E-mail: mathur@iitb.ac.in3 National Single Crystal X-Ray Diffraction Facility, Indian Institute of Technology, Powai,

Bombay 400076, India.

Received December 1, 2003

Reaction of the acetylide-bearing oxo-peroxo complex [(g5-C 5Me5)W(O2)(O)(g1-CCR)] (R=Ph, (Me)C=CH2) with [Fe2W(CO)10(m3-S)2] yielded [(g5-C 5Me5)W2Fe2(CO)6(O)2(m-O)(m3-S)2(g1:g2-CCR)]. When the reaction wascarried out in presence of free acetylene, RC — CH (R=Ph, (Me)C=CH2),clusters [(g5-C 5Me5)W2Fe2(CO)6(O)(m-O)(m3-S)2(g1:g2-CCR)(g2-RCCH)] wereobtained. Structures of one of each type of cluster were determined by singlecrystal X-ray diffraction methods.

KEY WORDS: Tungsten; iron; oxo; acetylide; mixed-metal; cluster.

INTRODUCTION

Complexes containing electronically disparate ligands, strong p-acid car-bonyl and p-base oxo, have attracted considerable attention in recent times[1]. Synthesis of such complexes provides an opportunity to obtain com-plexes with both low oxidation state metal carbonyl fragment and highoxidation state metal oxide fragment in the same molecule. Although suchcluster complexes are rare, some studies of the carbonyl clusters with metalatoms bearing oxo ligands have been documented [2], a major attraction

for their study being that may provide valuable information on mechanisticdetails on their activity in various types of oxidation processes [3]. Of par-ticular interest is the elucidation of the reactivity and structural features ofoxo-bearing clusters to further our understanding of how oxo ligands arebonded to the metal atoms and how they react with adjacent hydrocarbylligands and serve as intimate reagents for oxygen transfer reactions. Com-plexes which contain a hydrocarbon ligand besides the carbonyl and oxo,serve as models for metal-mediated oxidation and other reactions in whichhigh-valent metal species are employed as catalysts [4].

The oxo metal cluster, [(g5-C 5Me5)WRe2(CO)8(O)(m-CCR)] (R=Ph,(Me)C=CH2) can be obtained by exposing a solution of [(g5-C 5Me5)WRe2(CO)9(m-CCR)] (R=Ph, (Me)C=CH 2) to an oxygen or nitrousoxide atmosphere [5]. Shapley has reported the synthesis of a tetranuclearcluster, [(g5-C 5H 5)WOs3(CO)11(m3-g2-C(O)CH 2C 6H 4-CH 3)], in which thebridging dihapto acyl ligand shows an activated C–O bond [6]. On ther-molysis, the cluster forms the oxo-alkylidyne complex, [(g5-C 5H 5)WOs3

(CO)9(m-O)(m3-CCH 2C 6H 4CH 3]. Polynuclear metal-oxo complexes canalso be synthesised by using mononuclear metal-oxo complexes as one ofthe synthons [7]. For instance, the thermal reaction of [Ru4(CO)13(m3-PNR2)] (R=i-Pr, Cyclohexyl) and [(g5-C 5Me5)W(O)2(g1-CCPh)] formsthe oxo-metal cluster, [(g5-C 5Me5)Ru4W(CO)10(m-O)2(m3-PNR2)(m4-g2-CCPh)] (R=i-Pr, Cyclohexyl) [8].

Recently, a polynuclear metal-oxo complex, [(g5-C 5H 5)2Mo2WFe2

(O)2(m-S)2(CO)9(m-CCPh)2] has been obtained from the aerial reactionof [Fe2W(CO)10(m3-S)2] and [(g5-C 5H 5)Mo(CO)3(g1-CCPh)] [9a]. Thesame methodology has been extended to synthesise a range of metalclusters with hydrocarbyl and oxo ligands in the same molecule by carefulcontrol of oxygen usage [9b]. In this paper we report the reactivity ofchalcogen-bridged mixed-metal cluster, [Fe2W(CO)10(m3-S)2] towardsoxo-peroxo metal acetylides, [(g5-C 5Me5)W(O2)(O)(g1-CCR)] (R=Ph,(Me)C=CH2).

RESULTS AND DISCUSSION

Synthesis and Characterisation of [(g5-C5Me5)W2Fe2(CO)6(O)2(m-O)(m3-S)2(g1:g2-CCR)] (R=Ph, 1 and R=(Me)C=CH2, 2) and[(g5-C5Me5)W2Fe2(CO)6(O)(m-O)(m3-S)2(g1:g2-CCR)(g2-RCCH)](R=Ph, 3 and R=(Me)C=CH2, 4)

The oxo-peroxo acetylide complexes, [(g5-C 5Me5)W(O2)(O)(g1-CCR)](R=Ph, (Me)C=CH 2) were obtained by the reported method of reaction

176 Mathur, Bhunia, and Mobin

Scheme 1.

of [(g5-C 5Me5)W(CO)3(g1-CCR)] (R=Ph, (Me)C=CH 2,) with acidicsolution of hydrogen peroxide [10] (Scheme 1).

Thermolysis at 75°C for 15 min of a toluene solution containing[Fe2W(CO)10(m3-S)2] and [(g5-C 5Me5)W(O2)(O)(g1-CCR)] (R=Ph,

Scheme 2.

Formation of Mixed Fe/W/S Complexes Bearing Oxo and Acetylide Ligands 177

Scheme 3.

(Me)C=CH2) afforded two new types of clusters, [(g5-C 5Me5)W2Fe2

(CO)6(O)2(m-O)(m3-S)2(g1:g2-CCR)] (R=Ph, 1 and R=(Me)C=CH 2), 2)as major products and [(g5-C 5Me5)W2Fe2(CO)6(O)(m-O)(m3-S)2(g1:g2-CCR)(g2-RCCH)] (R=Ph, 3 and R=(Me)C=CH 2, 4) in minor amounts(Scheme 2).

Clusters 3 and 4 were obtained in improved yields, as the sole productswhen the thermolysis was carried out in presence of RC — CH (Scheme 3).

Compounds 1–4 were characterised by IR and 1H NMR spectroscopy.The IR spectra show bands in the terminal CO region. 1H NMR spectraof all four compounds display a single peak at d 2.00–2.28 ppm for theC 5Me5 protons. A singlet at d 8.69 (3) and at d 10.34 ppm (4) can beassigned to the coordinated acetylenic proton in each case; this signal was

178 Mathur, Bhunia, and Mobin

not seen when deuterated toluene was used as solvent, thus confirming thatthe coordinated acetylene originates by abstraction of a proton fromthe solvent by the acetylide group of [(g5-C 5Me5)W(O2)(O)(g1-CCR)].Abstraction of proton from the solvent by an acetylide group has beenpreviously observed in the formation of [(g5-C 5H 5)2W2Fe3(CO)7(m3-S)2

(m3-g2-CCPh)(m3-g1-CCH 2Ph)] from the reaction of [Fe3(CO)9(m3-S)2]and [(g5-C 5H 5)W(CO)3(g1-CCR)] [11]. Alkene protons of 2 resonate astwo different signals at d 6.19 and 5.94 ppm. For compound 4, two signalsat d 5.10 and 5.20 ppm can be attributed to the alkene protons of coor-dinated metal enyne moiety, {MC — CC(=CH2)CH 3} and two othersignals at d 5.43 and 5.53 ppm can be assigned to the alkene protons ofcoordinated enyne moiety, {HC — CC(=CH2)CH 3}. Compounds 1 and 3display multiplets for the phenyl groups in the expected region.

In order to establish the structures unambiguously, representativestructural analyses by single crystal X-ray diffraction methods were carriedout on one of each of the two types of clusters. Molecular structure of 2,shown in Fig. 1, can be described as consisting of an open {Fe2S 2} but-terfly unit in which the sulfur atoms are attached to the tungsten atomof {W(=O)(g5-C 5Me5)W(=O)(m-O)(g2-m-CC(Me)C=CH2)} unit. Twoterminal oxo groups in 2 prefer to adopt a trans geometry, similar to theterminally bonded oxo groups in the Te-bridged trans [Cp2Mo2(O)2(m-O)(m-Te)] [12]. Each iron atom has three terminal carbonyl groups.

Fig. 1. Molecular structure of [(g5-C 5Me5)W2Fe2(CO)6(O)2(m-O)(m3-S)2(g1:g2-CCC(=CH 2)Me)], 2.

Formation of Mixed Fe/W/S Complexes Bearing Oxo and Acetylide Ligands 179

W(1)–W(2) distance of 2.8535(7) Å is slightly shorter than that of W–Wbond (2.941(1) Å) in [Cp2W2Ru3(CO)13] [13], and substantially shorterthan the W–W distance in the alkyne complex [Cp2W2Os(CO)7(C 2Tol2)](3.016–3.158 Å) [14]. Terminal W–O double bond distances of 1.708 (9) Å(W(1)–O(2)) and 1.707(9) Å (W(2)–O(1)) in 2 are comparable with theW–O (terminal) double, bond 1.709 (5) Å in [(g5-C 5Me5)W(O)2Ru4

(CO)10(m4-PPh)(CCPh)] [15], where the W–Ru bond is unsymmetricallybridged by an oxo group. Unsymmetrically bridging O atom with aW(2)–O(3) distance of 1.869(8) Å is similar to the W–O double bond dis-tance, 1.822(2) Å in [(g5-C 5H 5)2MoWFe2(O)2(S)2(CO)9(CCPh)2] [9]. TheW(1)–O(3) single bond distance of 2.013(7) Å is slightly shorter than W–Obridging single bond distance of 2.153(7) Å in [W3O3Cl 5(CH 3CO2)(PBu3)3 ·0.5C 7H 8] [16].

Acetylide carbon atoms, C(11)–C(12) form a shorter bond of1.272(19) Å than in a similarly bonded acetylide group (1.34(2) Å) in theother known example of a mixed-metal cluster containing both an oxoand an acetylide moiety, [(g5-C 5Me5)Re(O)(m-C 2Ph)W(CO)2Cp] complex[17]. The bond distance of 1.39(3) Å for C(13)–C(15)A reflects its olefinicnature. An electron count of 16 each can be assigned to high valent W(1)and W(2) atoms if it is assumed that a W(2) Q W(1) donor-acceptor bondexists; the two Fe atoms being electron precise. Crystal data and structuralrefinement parameters, and selected bond angles and bond lengths aregiven in Tables I and II, respectively.

The molecular structure of 4 is depicted in Fig. 2, and can be describedas a WFe2S 2 distorted square pyramid, in which the apical site is occupiedby one of the iron atoms. Both iron atoms bear three terminal carbonyls;the tungsten atom bears a {g2-C(H)CC(Me)=CH 2} and a (g5-C 5Me5)(O)W} unit (W(1)–W(2) bond distance of 2.8575(5) Å). The W–W bond isbridged by a {(g1,g2-CCC(=CH 2)CH 3)} group and a four electron donoroxo ligand, as seen in 2. All W–O bond distances {W(1)–O(1)=1.701(6),W(1)–O(2)=2.028(5) and W(2)–O(2)=1.858(5) Å} are comparable withthat of 2. The Fe(1)–W(2) bond distance, 2.9235(12) Å, is comparableto the Fe–W, 2.982(2) Å reported for the S-bridged, acetylide bearingmixed Fe/W cluster, [(g5-C 5H 5)2W3Fe2S 2(CO)12(CCPh)2] [18]. Both theacetylide bond distances, C(12)–C(11) (1.299(11) Å) and C(17)–C(16)(1.289(12) Å) are comparable to that of 2. On the basis of the 18-electronrule, the electron count for the two Fe atoms and W(1) atom are satisfiedwhile W(2) falls short by two electrons. Crystal data and structuralrefinement parameters, and selected bond angles and bond lengths aregiven in Tables I and III, respectively.

Formation of 1–4 involves removal of all four carbonyls on thetungsten atom of the starting material, [Fe2W(CO)10(m3-S)2]. The

180 Mathur, Bhunia, and Mobin

Table I. Crystal Data and Structure Refinement Parameters for[(g5-C 5Me5)W2Fe2(CO)6(O)2(m-O)(m3-S)2(g1:g2-CCC(=CH 2)Me)], 2 and

[(g5-C 5Me5)W2Fe2(CO)6(O)(m-O)(m3-S)2(g1:g2-CCC(=CH 2)CH 3)(g2-(H)CCC(=CH 2)Me)], 4

2 4

Empirical formula C 21H 20Fe2O9S 2W2 C 26H 26Fe2O8S 2W2

Formula weight 959.89 1009.99Temperature (K) 293(2) 293(2)Wavelength (Å) 0.70930 0.70930Crystal system, space group Monoclinic, P21/c Triclinic, P(−1)Unit cell dimensions:

a (Å) 9.7421(8) 9.9430(7)b (Å) 14.4653(10) 13.7130(13)c (Å) 19.6894(19) 14.0840(13)a (º) 116.465(8)b (º) 93.293(7) 94.508(7)c (º) 109.455(7)

Volume (Å3 ) 2770.1(4) 1561.2(2)Z, calculated density (Mg/m3) 4, 2.302 2, 2.149Absorption coefficient (mm−1) 9.500 8.432F(000) 1800 956Crystal size (mm) 0.35 × 0.25 × 0.20 0.25 × 0.15 × 0.10h range of data collection (º) 1.74 to 24.92 1.67 to 27.41Index ranges 0 [ h [ 11, 0 [ h [ 12,

0 [ k [ 17, −17 [ k [ 16,−23 [ l [ 23 18 [ l [ 18

Reflection collected/unique [I > 2s(I)] [R(int)=0.0000] 4477/4477 6416/6416

Completeness to 2h=24.92 88.1%2h=27.41 89.8%

Absorption correction Y-scan Y-scanMax. and min. transmission 1.000 and 0.852 1.000 and 0.926Refinement method Full-matrix least Full-matrix least

squares on F2 squares on F2

Data/restraints/parameters 4477/0/331 6416/0/393Goodness-of-fit on F2 1.112 1.167Final R indices [I > 2s(I)] R1=0.0632, R1=0.0383,

wR2=0.1566 wR2=0.1023R indices (all data) R1=0.0700, R1=0.0515,

wR2=0.1649 wR2=0.1095Largest diff. peak and hole (e. Å−3) 3.231 and −5.752 3.331 and −2.634

Formation of Mixed Fe/W/S Complexes Bearing Oxo and Acetylide Ligands 181

Table II. Selected Bond Lengths (Å) and Bond Angles (º) of[(g5-C 5Me5)W2Fe2(CO)6(O)2(m-O)(m3-S)2(g1:g2-CCC(=CH 2)Me)], 2

Bond lengths

W(1)–W(2) 2.8535(7) W(2)–O(1) 1.707(9)W(1)–O(2) 1.708(9) W(2)–O(3) 1.869(8)W(1)–O(3) 2.013(7) W(1)–S(2) 2.418(3)Fe(1)–Fe(2) 2.524(3) W(1)–S(1) 2.428(3)C(11)–C(12) 1.272(19) C(13)–C(15) 1.39(3)Fe(1)–S(1) 2.289(4) Fe(2)–S(2) 2.250(4)Fe(1)–S(2) 2.286(4) C(12)–C(13) 1.468(19)Fe(2)–S(1) 2.262(4)

Bond angles

Fe(2)–S(1)–Fe(1) 67.36(12) W(2)–C(11)–W(1) 86.4(4)S(2)–W(1)–S(1) 72.89(11) S(2)–W(1)–W(2) 146.07(9)W(1)–C(12)–C(11) 74.4(8) O(1)–W(2)–W(1) 117.0(4)O(3)–W(1)–S(1) 78.0(2) O(2)–W(1)–W(2) 108.0(3)C(14)–C(13)–C(15) 126.1(16) Fe(1)–Fe(2)–S(1) 56.83(11)Fe(1)–S(2)–Fe(2) 67.61(11) Fe(2)–Fe(1)–S(2) 55.51(11)

W(1)–O(3)–W(2) 94.6(3)

Fig. 2. Molecular structure of [(g5-C 5Me5)W2Fe2(CO)6(O)(m-O)(m3-S)2(g1:g2-CCC(=CH 2)Me)(g2-(H)CCC(=CH 2)Me)], 4.

182 Mathur, Bhunia, and Mobin

Table III. Selected Bond Lengths (Å) and Bond Angles (º) for[(g5-C 5Me5)W2Fe2(CO)6(O)(m-O)(m3-S)2((g1:g2-CCC(=CH 2)Me)(g2-(H)CCC(=CH 2)Me)], 4

Bond lengths

W(1)–O(1) 1.701(6) W(1)–W(2) 2.8575(5)W(1)–O(2) 2.028(5) Fe(1)–Fe(2) 2.5326(18)W(2)–O(2) 1.858(5) C(12)–C(11) 1.299(11)W(1)–C(11) 2.148(9) C(17)–C(16) 1.289(12)Fe(1)–S(1) 2.305(3) C(17)–C(18) 1.458(12)Fe(2)–S(1) 2.264(2) W(1)–C(12) 2.179(8)Fe(1)–S(2) 2.290(3) W(2)–C(17) 2.101(9)W(2)–Fe(1) 2.9235(12) W(2)–C(16) 2.057(9)Fe(2)–S(2) 2.281(2)

Bond angles

W(2)–O(2)–W(1) 94.6(2) Fe(2)–Fe(1)–W(2) 84.17(5)W(2)–C(12)–W(1) 86.2(3) Fe(1)–S(1)–W(2) 75.79(7)W(2)–C(16)–C(17) 73.8(5) Fe(1)–S(1)–Fe(2) 67.32(7)W(1)–C(11)–C(12) 73.8(5) Fe(1)–W(2)–W(1) 149.49(3)W(1)–W(2)–Fe(1) 149.49(3) Fe(2)–Fe(1)–S(1) 55.58(7)Fe(1)–S(2)–Fe(2) 67.28(7) W(1)–O(2)–W(2) 94.6(2)Fe(1)–Fe(2)–S(1) 57.10(7) W(1)–C(12)–W(2) 86.2(3)W(2)–C(16)–C(17) 73.8(5) W(2)–C(17)–C(16) 70.1(5)

{Fe2WS 2} square pyramid core transforms into the open-type core, seenin compounds such as [Fe2(CO)6(m3-E)2M(PPh3)2] [19] (E=S, Se, Te;M=Pd, Pt), leading to formation of 1 and 2. On the other hand, in 3and 4, there is isomerisation of the {Fe2WS 2} square pyramid with W inthe apical site to one in which the W sits on one of the basal positions. Inboth types of compounds, 1/2 and 3/4, addition of a single {(g5-C 5Me5)W(C — CR)} unit occurs. Also, in both types of compounds there are fourother ligands, in 1/2, three ‘‘O’’ and one acetylide groups whereas in 3/4,there are two ‘‘O,’’ one acetylide and one acetylene groups. A significantdifference between the two structure types is in the bonding of one of theoxo groups which formally acts as a four-electron bridge. In 1/2, this oxoformally retains its double bond character to the {(g5-C 5Me5)W} unitwhile forming a coordinate bond to the W atom of the {Fe2S 2W} core.In 3/4, however, the bridging oxo is formally double-bonded with theW atom of the {Fe2S 2W} core and it forms a coordinate bond to the{(g5-C 5Me5)W} unit. Reaction of 1/2 with the free alkyne did not givecompounds 3/4. Under the same reaction conditions, Se- and Te-ana-logues of [Fe2W(CO)10(m3-S)2] did not show any reactivity towards [(g5-C 5Me5)W(O2)(O)(g1-C — CR)] (R=Ph, (Me)C=CH2).

Formation of Mixed Fe/W/S Complexes Bearing Oxo and Acetylide Ligands 183

EXPERIMENTAL

Reaction of [Fe2W(CO)10(m3-S)2] with[(g5-C 5Me5)W(O2)(O)(C — CR)]

A toluene solution (50 mL) of [Fe2W(CO)10(m3-S)2] (134 mg,0.21 mmol) and [(g5-C 5Me5)W(O2)(O)(C — CR)] (70 mg, 0.15 mmol, whenR=Ph; 65 mg, 0.15 mmol, when R=(Me)C=CH 2) was heated at 75°C for15 min under argon. The solvent was removed under vacuum and theresidue was subjected to chromatographic work up using silica gel TLCplates. On elution with hexane-dichloromethane mixture (60/40, v/v),some unreacted [Fe2W(CO)10(m3-S)2] eluted first followed by a majordeep orange band of 1 (57 mg, 38%) or 2 (52 mg, 36%) and minor lightorange band of 3 (9 mg, 6%) or 4 (6 mg, 4%). 1: IR (hexane) n cm−1 (ter-minal CO): 2066 (vs), 2028 (vs), 1997 (m), 1986 (m), 1971 (m); 1H NMR(CDCl 3): d 8.19 (m, C 6H 5), 7.58–7.66 (m, C 6H 5), 2.27 (s, 15H); Anal.Calc. for C 24H 20O9S 2W2Fe2: C, 28.90; H, 2.00. Found.: C, 28.00; H, 1.70.Mp(ºC): 191–193 (dec.). 2: Anal. Calc. for C 21H 20O9S 2W2Fe2: C, 26.27; H,2.08. Found C, 25.90; H, 1.85. IR (hexane) n cm−1 : 2064 (vs), 2027 (vs),1997 (m), 1986 (m), 1971 (m); 1H NMR (CDCl 3): d 6.19 (s, 1H, alkene),5.94 (s, 1H, alkene), 2.43 (s, 3H, CH 3), 2.28 (s, 15H, C 5Me5). Mp(ºC):183–185 (dec.). 3: Anal. Calc. for C 32H 26O8S 2W2Fe2.: C, 35.48; H,2.40. Found C, 35.39; H, 2.31. IR (hexane) n cm−1: 2064 (vs), 2024 (vs),2000 (vs), 1978 (m), 1969 (m); 1H NMR (CDCl 3): 8.69 (s, 1H, alkyne), d

7.17–7.10 (m, 10H, 2 x C 6H 5), 2.00 (s, 15H, C 5Me5). Mp (ºC): 175–177(dec.). 4: Anal. Calc. for C 26H 26O8S 2W2Fe2: C, 30.89; H, 2.57. Found.: C,31.20; H, 2.65. IR (hexane) n cm−1 : 2065 (vs), 2026 (vs), 1998 (vs), 1975(m), 1967 (m); 1H NMR (CDCl 3): d 10.34 (s, 1H, alkyne), 5.10 (s, 1H,alkene), 5.20 (s, 1H, alkene), 5.43 (s, 1H, alkene), 5.53 (s, 1H, alkene), 2.44(s, 6H, CH 3), 2.14 (s, 15H, C 5Me5). Mp(ºC): 189–191 (dec.)

Reaction of [Fe2W(CO)10(m3-S)2] with[(g5-C 5Me5)W(O2)(O)(C — CR)] in presence of RC — CH

A toluene solution (40 mL) of [Fe2W(CO)10(m3-S)2] (130 mg,0.20 mmol) and [(g5-C 5Me5)W(O2)(O)C — CR] (68 mg, 0.15 mmol, whenR=Ph; 66 mg, 0.15 mmol, when R=(Me)C=CH 2) and HC — CR(0.015 mL, 0.15 mmol, when R=Ph; 0.014 mL, 0.15 mmol, when R=(Me)C=CH 2) was heated at 75°C for 15 min under argon. Chroma-tographic work-up as above yielded trace amount of unreacted [Fe2W(CO)10(m3-S)2], followed by a major light orange band of compound 3(56 mg, 33%) or 4 (52 mg, 34%).

184 Mathur, Bhunia, and Mobin

Crystal Structure Determination of 2 and 4

Crystals of compounds 2 and 4 suitable for X-ray diffraction analyseswere grown from hexane-dichloromethane solvent mixtures by slow eva-poration of the solvents at 4°C. Data were collected on a Nonius MACH3four-circle diffractometer (graphite-monochromatised Mo-K a radiation).Unit cell parameters were derived and refined by using randomly selected25 reflections in the h range 7.4100–10.0300º (compound 2) and 7.4000–8.2300º (compound 4). Structures were solved by direct methods using theSHELXS97 program [20] and refined by using SHELXL97 [21] software.Non-hydrogen atoms were refined with anisotropic thermal parameters. Allthe hydrogen atoms were generated and refined using riding model forcompound 2. For compound 4, hydrogen atoms were geometrically fixedand refined using a riding model. Absorption correction was employedusing psi scans [22].

SUPPLEMENTARY MATERIALS AVAILABLE

Crystallographic data for the structural analyses have been depositedwith the Cambridge Crystallographic Data Centre, CCDC Nos. 225487and 225486 for compounds 2 and 4 respectively. Copies of this informationmay be obtained free of charge from The Director, CCDC, 12 UnionRoad, Cambridge CB2 1EZ, United Kingdom (fax: +44 1223 336033;e-mail: deposit@ccdc.cam.ac.uk; www: http://www.ccdc.cam.ac.uk).

ACKNOWLEDGMENTS

We thank the Department of Science and Technology, Government ofIndia, for financial support for this work.

REFERENCES

1. (a) M. J. Almond (1994). Chem. Soc, Rev. 309. (b) F.-M. Su, C. Cooper, S. J. Geib, A. L.Rheingold, and J. M. Mayer (1986). J. Am. Chem. Soc. 108, 3545. (c) F.-M. Su, J. C.Bryan, S. Jang, and J. M. Mayer (1989). Polyhedron 8, 1261. (d) S. G. Feng, L. Laun,P. White, M. S. Brookhart, J. L. Templeton, and C. G. Young (1991). Inorg. Chem. 30,2582. (e) C. G. Young, R. W. Gable, and M. F. Mackay (1990). Inorg. Chem. 29, 1777.(f ) W. A. Howard, T. M. Trnka, and G. Parkin (1995). Organometallics 14, 4037.(g) S. Thomas, E. R. T. Tiekink, and C. G. Young (1996). Organometallics 15, 2428.

2. (a) A. Colombié, J.-J. Bonnet, P. Fompeyrine, G. Lavigne, and S. Sunshine (1986). Orga-nometallics 5, 1154. (b) C. P. Gibson, J.-S. Huang, and L. F. Dahl (1986). Organometallics5, 1676. (c) A. Bertolucci, M. Freni, P. Romiti, G. Ciani, A. Sironi, and V. G. Albano

Formation of Mixed Fe/W/S Complexes Bearing Oxo and Acetylide Ligands 185

(1976). J. Organomet. Chem. 113, C61. (d) R. J. Goudsmit, B. F. G. Johnson, J. Lewis,P. R. Raithby, and K. H. Whitmire (1983). Chem. Commun. 246. (e) V. A. Uchtman andL. F. Dahl (1969). J. Am. Chem. Soc. 91, 3763. (f ) A. Ceriotti, L. Resconi, R. Demartin,G. Longoni, M. Manassero, and M. Sansoni (1983). J. Organomet. Chem. 249, C35. (g)C. P. Gibson, A. D. Rae, D. R. Tomchick, and L. F. Dahl (1988). J. Organomet. Chem.340, C23. (h) C. K. Schauer, E. J. Voss, M. Sabat, and D. F. Shriver (1989). J. Am. Chem.Soc. 111, 7662. (i) C. K. Schauer and D. F. Shriver (1987). Angew. Chem., Int. Ed. Engl.26, 255.

3. (a) W. Adam, W. Malisch, K. J. Roschmann, C. R. Saha-Möller, and W. A. Schenk(2002). J. Organomet. Chem. 661, 3. (b) T. Katsuki and K. B. Sharpless (1980). J. Am.Chem. Soc. 102, 5974. (c) K. B. Sharpless, M. G. Finn, and J. D. Morrison, AssymmetricSynthesis (Academic Press, New York, 1985), Vol. 5, Chap. 8. (d) P. Pitchen, E. Dunach,M. N. Deshmukh, and H. B. Kagan (1984). J. Am. Chem. Soc. 106, 8188. (e) S. H. Zhao,O. Samuel, and H. B. Kagan (1987). Tetrahedron 43, 5135. (f ) J.-M. Brunel, P. Diter,M. Duetsch, and H. B. Kagan (1995). J. Org. Chem. 60, 8086. (g) F. DiFuria, G. Modena,and R. Seraglia (1984). Synthesis 325. (h) W. Zhang, J. L. Loebach, S. R. Wilson, andE. N. Jacobsen (1990). J. Am. Chem. Soc. 112, 2801.

4. (a) W. A. Nugent and J. M. Mayer, Metal-Ligand Multiple Bonds (Wiley-Interscience,New York, 1988). (b) L. M. Atagi, D. E. Over, D. R. McAlister, and J. M. Mayer (1991).J. Am. Chem. Soc. 113, 870. (c) D. A. Dobbs and R. G. Bergman (1993). J. Am. Chem.Soc. 115, 3836. (d) P. Legzdins, E. C. Philips, S. J. Rettig, J. Trotter, J. E. Veltheer, andV. C. Yee (1992). Organometallics 11, 3104. (e) M. S. Rau, C. M. Kertz, L. A. Mercando,G. L. Geoffroy, and A. L. Rheingold (1991). J. Am. Chem. Soc. 113, 7420. (f ) Y. Chi,L.-S. Hwang, G.-H. Lee, and S.-M. Peng (1988). Chem. Commun. 1456.

5. Y. Chi, P.-S. Cheng, H.-L. Wu, D.-K. Hwang, P.-C. Su, S.-M. Peng, and G.-H. Lee(1994). Chem. Commun. 1994, 1839.

6. J. T. Park, J. R. Shapley, M. R. Churchill, and C. Bueno (1983). Inorg. Chem. 22, 1579.7. (a) W.-J. Chao, Y. Chi, C. Chung, A. J. Carty, E. Delgado, S.-M. Peng, and G.-H. Lee

(1998). J. Organomet. Chem. 565, 3. (b) J. H. Yamoto, G. D. Enright, and A. J. Carty(1998). Polyhedron 17, 2971. (c) C.-W. Shiu, Y. Chi, A. J. Carty, S.-M. Peng, and G.-H.Lee (1997). Organometallics 16, 5368. (d) P. Blenkiron, A. J. Carty, S.-M. Peng, G.-H.Lee, C.-J. Su, C.-W. Shiu, and Y. Chi (1997). Organometallics 16, 519.

8. J. H. Yamamoto, G. D. Enright, and A. J. Carty (1999). J. Organomet. Chem. 577, 126.9. (a) P. Mathur, S. Mukhopadhyay, M. O. Ahmed, G. K. Lahiri, S. Chakraborty, and

M. G. Walawalkar (2000). Organometallics 19, 5787. (b) P. Mathur, S. Mukhopadhyay,G. K. Lahiri, S. Chakraborty, and C. Thöne (2002). Organometallics 21, 5209.

10. C.-W. Shiu, C. J. Su, C.-W. Pin, Y. Chi, S.-M. Peng, and G. H. Lee (1997). J. Organomet.Chem. 545, 151.

11. P. Mathur, M. O. Ahmed, J. H. Kaldis, and M. J. McGlinchey (2002). J. Chem. Soc.,Dalton Trans. 619.

12. P. Mathur, S. Ghose, M. M. Hossain, P. B. Hitchcock, and J. F. Nixon (1997). J. Orga-nomet. Chem. 542, 265.

13. Y. Chi, S.-M. Peng, G.-H. Lee, and C.-J. Su (2001). Organometallics 20, 1102.14. M. R. Churchill, C. Bueno, and H. J. Wasserman (1982). Inorg. Chem. 21, 640.15. P. Blenkiron, A. J. Carty, S.-M. Peng, G.-H. Lee, C.-J. Su, C.-W. Shiu, and Y. Chi

(1997). Organometallics 16, 519.16. F. A. Cotton, T. R. Felthouse, and D. G. Lay (1981). Inorg. Chem. 20, 2219.17. N.-S. Lai, W.-C. Tu, Y. Chi, S.-M. Peng, and G. H. Lee (1994). Organometallics 13, 4652.18. P. Mathur, S. Mukhopadhyay, M. O. Ahmed, G. K. Lahiri, S. Chakraborty, V. G.

Puranik, M. M. Bhadbhade, and S. B. Umbarkar (2001). J. Organomet. Chem. 629, 160.

186 Mathur, Bhunia, and Mobin

19. P. Mathur, M. M. Hossain, A. K. Das, and U. C. Sinha (1993). Chem. Commun. 46.20. G. M. Sheldrick, G. M. SHELXS 93, Program for Crystal Structure Solution and Refine-

ment (University of Göttingen, 1993).21. G. M. Sheldrick, G. M. SHELXS 97, Program for Crystal Structure Solution and Refine-

ment (University of Göttingen, 1997).22. A. C. T. North, D. C. Philips, and F. S. Mathews (1968). Acta Crystallogr. A24, 351.

Formation of Mixed Fe/W/S Complexes Bearing Oxo and Acetylide Ligands 187