スピンクロスオーバー現象とその光・スピン・電荷

による相乗効果

Outline

(1) History of spin crossover phenomena

(2) Light induced excited state trapping (LIESST) and its related

phenomena

(3) Spin crossover transition at r.t. toward molecular devices

(4) Development of spin crossover complex film

(5) Development of assembled-metal complex exhibiting

dynamical spin equilibrium

(6) Development of mixed-valence complex exhibiting charge

transfer phase transition

Molecular structure of Fe(S2CNR2)3(R = n-CnH2n+1, etc.). Temperature dependence of inverse magnetic

susceptibility for Fe(S2CNR2)3 (R = n-CnH2n+1).

L. Cambi, L. Szegö, Ber. Deutsch. Chem. Ges. 1933, 66, 656 (1933).

L. Cambi and A. Cagnasso, Atti Accad. Naz. Lincei. 1931, 13, 809

First report of spin-crossover phenomenon

HS(S = 5/2)

LS(S = 1/2) Fe(III):3d5

K. Stahl, i. Ymén, Acta Chem. Scand.,

A 1983, 37, 729

Spin configuration of d4 – d7: It is possible that the low-spin (LS) state and the high-spin (HS) state compete with each other in the ground state.

d6d5 d7d4

P. Charpin, et al., J. Cryst.

Spectrosc. Res., 1988, 18, 429.

[Cr(II)I2(depe)2]

D.M. Halepoto, et al., J. Chem. Soc.,

Chem. Commun., 1989, 1322.

many Fe(III)

complexes

many Fe(II)

complexes

[Co(II)(H2fsa2en)(py)2]

(1)P. L. Franke, et al. Inorganica Chimica Acta, 1982, 59, 5, (2) S. Decurtins et al. Chem. Phys. Lett. 1984, 105, 1.

S = 0 S = 2

T, P, hν

LIESST

S = 0 :low-spin state

S = 2 : High-spin state

[FeII(ptz)6](BF4)2

Light Induced Excited Spin State Trapping (LIESST)

N

NN

NPr

Ptz =

eg

t2g

Wave number (cm−1)

Near-infrared and visible absorption spectra of [Fe(ptz)6](BF4)2 at 10 K: (―) before

light irradiation, (– – –) after irradiation with λ = 514.5 nm (300 mJ), (……) after

subsequent irradiation with λ = 752.7 nm (≈3000 mJ).

A. Hauser, Chem. Phys. Lett. 1986, 124, 543

LIESST (Light Induced Excited Spin State Trapping)

Colorless （HS state）

Purple （LS state)

Writing

Delete

Mechanism of LIESST and Reverse-LIESST

Tanabe-Sugano diagram Mechanism of LIESST and Reverse-LIESST

A. Hauser, Chem. Phys. Lett. 1986, 124, 543Y. Tanabe, S. Sugano, J. Phys. Soc. Jpn.1954, 9, 766.

Upper limit of LIESST

Figure 1. 7. Spin-crossover transition temperature vs

LIESST temperature. The lines represent the

correlation between the spin-crossover transition and

LIESST temperatures; T(LIESST) = T0－0.3T1/2.

J. F. Létard et al., Chem. Phys. Lett. 1999, 313, 115. .

ΔH T(LIESST)T1/2

ΔE

ΔE

Spin crossover transition of [FeII(R-trz)3]A2·nH2O

N N

N

R

1,2,4-R-triazole

R = H, NH2, CnH2n+1,etc

memory, display device

cMT vs. T for [Fe(H-trz)2.85(NH2-trz)0.15](ClO4)2

cooling

heating

J. Kröber, E. Codjovi, O. Kahn, F. Grolière, C. Jay: J. Am. Chem. Soc. 1993, 115, 9810.

Spin-transition polymers: From molecular materials toward memory devices

O. Kahn, C. Jay Martinez, Science, 1998, 279, 44.

Spin crossover transition of

[FeII(NH2trz)3](NO3)1.7(BF4)0.3

Principles of a display using a spin-

transition polymer.

bistability

http://www.sciencemag.org/content/279/5347/44/F7.large.jpghttp://www.sciencemag.org/content/279/5347/44/F7.large.jpghttp://www.sciencemag.org/content/279/5347/44/F6.large.jpghttp://www.sciencemag.org/content/279/5347/44/F6.large.jpg

T = 300 K T = 77 K

[FeII(Htrz)3]-Nafion®

T1/2 = 260 K

Nafion®

SO3-

[FeII(Htrz)3]

A. Nakamoto, N. Kojima, et al., Chem.

Lett. 2003, 32, 336.

Development of Spin-crossover complex film

A. Nakamoto, N. Kojima et al.,

Polyhedron, 2005, 24, 2909.

7

6

5

4

3

2

1

0

吸収強度

86420距離（Å）

FeII(NH2-trz)3－Nafionβ

γI∝cos(γ+β）

r (Ǻ)

Inte

nsity

Fe-K edge EXAFS

-[CF2-CF2]x-[CF-CF2]y-

O-[CF2-CF-O]z-CF2-CF2-SO3H

CF3Nafion 117

023.0

)(exp

stnHS

2

25)(

expst

nHS

(a)

(b)

X.J. Liu, Y. Moritomo, N. Kojima, et al. Phys. Rev. B, 2013, 67, 012102-1

Photo-generated HS state of

Nafion-[Fe(Htrz)3] filmLife time of photo-generated HS state

(a) weak excitation (b) strong excitation

○:LS ●:HS

Condensed phase of photo-generated high-spin state

X.J. Liu, Y. Moritomo, N. Kojima, et al. J. Phys. Soc. Jpn. 2003, 72, 1615.

Preparation of pH-sensitive spin-crossover

complex film, [FeII(diAMsar)]-Nafion

H. Kamebuchi, N. Kojima et al., Chem. Lett. 2011, 40, 888.

Nafion 117

pH 4 pH 7 pH 10

Volume expansion due to the Coulomb

repulsion between Fe2+ and NH3+

Absence of the volume

expansion

High-spin state

(S = 2; 5T2)

Low-spin state

(S = 0; 1A1)

Manipulating the spin state by applied voltage

Coulomb repulsion

Voltage: 20 V

Current: ca.15 mA (average)

Time: 60 min

H. Kamebuchi: XXIV ICCBC, June 6, 17:10-17:20

Spin State of FeIIIO3S3

FeIII(ox)3 FeIII(dto)3

FeIII(mto)3

FeIII

Weak ligand field

HS (S = 5/2)

FeIII

Strong ligand field

LS (S = 1/2)

FeIII

Spin-Crossover?

O

O

O

O

S

O

O

O

S

S

O

O3

3

3

HS (S = 5/2) LS (S = 1/2)

t2g

eg

t2g

eg

t2g

eg

t2g

eg

hn

P, T

16

Slow spin-equilibrium at FeIIIS3O3（τ> 10−7 s）

HS

HSLS

LS

Tris(monothio-b-diketonato)iron( III)

M. Cox, et al, J. Chem. Soc. Dalton trans, 1972, 1192.

300 K

80 K

K. R. Kunze, et al, Inorg. Chem, 1977, 16, 594.

Rapid spin-equilibrium at FeIIIS3O3（τ< 10−7 s）

Tris(monothiocarbamato)iron( III)

NS

O

C2H

5

C2H

5 3

FeIII

296 K

93 K

Mössbauer spectra of Fe(Et2mtc)3

K. Kagesawa, N. Kojima, et al., Chem. Lett., 2010, 39, 872.

X-band ESR

-4 -3 -2 -1 0 1 2 3 4

0.96

0.98

1.00

Velocity [mm/s]

0.96

0.98

1.00

Rel

ativ

e T

ransm

issi

on

0.985

0.990

0.995

1.000

300 K

200 K

77 K

57Fe Mössbauer spectra

HS + LS

Rapid spin-equilibrium of FeIII in (C6H5)4P[ZnIIFeIII(mto)3]

100 200 300 400 500

Inte

nsi

ty [

a. u

.]

H [mT]

LS state (g ≈ 4.25)

HS state (g ≈ 2.05)

─ 300 K─ 77 K─ 10 K

Rapid spin equilibrium

(10-10 s < t < 10-7 s)

(τ ≈ 10-10 s)(τ ≈ 10-7 s)

HSLS

egt2g

Spin state of (C6H5)4N[MnIIFeIII(mto)3](mto = C2O3S)

O

S

O

O S

O

S

O

O

O

S

O

O

O

O

O

O

O

O

S

FeIII MnII

Effect of rapid spin

equilibrium on the

magnetic interaction

between FeIII and MnII

Rapid spin equilibrium

HSLS

Concerted phenomenon between the rapid spin

equilibrium and the succeeding magnetic phase

transitions for (Ph)4N[MnIIFeIII(mto)3].

Theoretical value

FeIII (HS), MnII (HS)→ cT = 8.75 [emu K mol-1]

FeIII (LS), MnII (HS)→ cT = 4.75 [emu K mol-1]Experimental value

cT = 6.90 [emu K mol-1] (@400K)→spin equilibrium at FeIIIO3S3

0

1

2

3

4

5

6

7

8

9

10

0 100 200 300 400

0

0.01

0.02

0.03

0.04

0.05

0.06

0 100 200 300 400

FeIII (HS), MnII (HS)

cT = 8.75 [emu K mol−1]

FeIII (LS), MnII (HS)

cT = 4.75 [emu K mol−1]

cT

[e

mu K

mol-

1]

T [K]

c[e

mu m

ol-

1]

T [K]

c[e

mu m

ol-

1]

T [K]

0.042

0.044

0.046

0.048

0.05

0.052

0 20 40 60 80

30 K

23 K

Two-dimensional Heisenberg-type

antiferromagnetic interaction

23 K

30 K

Magnetic properties of (C6H5)4P[MnIIFeIII(mto)3]

magnetic ordering ?

20

Temperature dependence of magnetic susceptibility

K. Kagesawa, Doctoral Thesis (Univ. Tokyo, 2011)

-10 -8 -6 -4 -2 0 2 4 6 8 100.90

0.95

1.00

Velocity [mm s-1

]

0.96

0.98

1.00

0.90

0.95

1.00

Rel

ativ

e T

ran

smis

sio

n 0.85

0.90

0.95

1.00

0.80

0.85

0.90

0.95

1.00

57Fe Mössbauer spectra of （C6H5)4P[MnIIFeIII(mto)3]

30 K

24 K

23 K

22 K

4.2 K

0.95

0.96

0.97

0.98

0.99

1

0.9

0.92

0.94

0.96

0.98

1

0.8

0.85

0.9

0.95

1

-5 -4 -3 -2 -1 0 1 2 3 4 5

300 K

200 K

77 K

HSLS

Rapid spin equilibrium

-5 -4 -3 -2 -1 0 1 2 3 4 5

Velocity (mm/s) Velocity (mm/s)

0.92

0.94

0.96

0.98

1

-10 -5 0 5 10

0.95

0.96

0.97

0.98

0.99

1

0.75

0.8

0.85

0.9

0.95

1

30 K

22 K

10 K

Velocity [mm/s]

Rel

ativ

e tr

ansm

issi

on

0 5 10 15 20 25 30 35 400

2

4

6

8

10

12

14

16

M

[cm

3 m

ol-1

G]

T [K]

57Fe Mössbauer spectra

ACχ

FCM

RM

ZFCM

Successive magnetic phase transitions in (C6H5)4P[MnIIFeIII(mto)3]

K. Kagesawa, Doctoral Thesis (Univ. Tokyo, 2011)

Rapid Spin Equilibrium and Magnetic Ordering

23 K 30 K

Mn & Fe→ order

Mn & Fe→ disorder

Mn → orderFe → disorder

T

G

0

Multi-step magnetic phase transitions induced by rapid

spin equilibrium in (C6H5)4P[MnIIFeIII(mto)3]

MnII FeIII

30 K 23 K

Antiferro (inter layer) Antiferro (Mn-Fe)

K. Kagesawa, Doctoral Thesis (Univ. Tokyo, 2011)

Crystal structure of (n-C3H7)4N[FeIIFeIII(dto)3]

FeII

FeIII

S

O

(n-C3H7)4N+

C18H28Fe2NO6S6Hexagonal P63 a = b = 10.0615(8) Å

c = 16.0424(7) Å

M. Itoi, M. Enomoto, N. Kojima, et al., Solid State Commn., 2004, 130, 415.

Honeycomb structure

a

b

0

c

Charge transfer phase transition in (n-C3H7)4N[FeIIFeIII(dto)3]

57Fe Mössbauer spectra

Charge transfer phase transition in(n-C3H7)4N[FeIIFeIII(dto)3]

S

FeIII

S

S

S

S

S

O

FeII

O

O

O

O

O

S

FeII

SS

S

S

S

O

FeIII

OO

O

O

O

FeII (S = 2)FeIII (S = 1/2)

FeII (S = 0)

e-

e-

FeIII (S = 5/2)

120 K

N. Kojima, M. Seto, Yu. Maeda, et al., Solid State Commun. 2001, 120, 165.

High Temperature Phase (HTP)S = R ln(2×5）

Low Temperature Phase (LTP)S = R ln(１×6）

Mӧssbauer spectra of (n-CnH2n+1)4N[FeIIFeIII(dto)3](n = 3 - 6)

n = 3,4: charge transfer phase transition (CTPT) n = 5,6: no CTPT

A: FeIII(S = 1/2)

B: FeII(S = 2)

C: FeII(S = 0)

D: FeIII(S = 5/2)N. Kojima, et al., Hyperfine Interactions, 2004, 156-157, 175.

LTP HTP

FeII (S = 2)

FeIII (S = 1/2)

3.8 K

FeII (S = 0)

FeIII (S = 5/2)

4.2 K

FeII (S = 0) FeIII (S = 5/2) FeIII (S = 1/2) FeII (S = 2)

57Fe Mӧssbauer spectra in the ferromagnetic phase of

(n-CnH2n+1)4N[FeIIFeIII(dto)3](n = 3, 5)

n = 3 n = 5

●:fcm

■:rm

▲:zfcm

H = 30 G

n = 4n = 3

n = 5 n = 6

Ferromagnetism of (n-CnH2n+1)4N[FeIIFeIII(dto)3]

(SP)[FeIIFeIII(dto)3]

Photochromic spiropyran (SP)

Cation

Iron mixed valence complex with

[FeIIFeIII(dto)3]−

∞ 2D- honeycomb layers

Anion SOO S

S

OO

S

S

OO

S

Fe3+

SO

O S

S

OO

S

S

OO

S

Fe3+

S

OO

S

SO

O S

S

OO

S

S

OO

S

Fe3+

SO

O S

S

OO

S

Fe2+

Fe2+

Fe2+

・Reversible photo-isomerization

・Long life time in solids

(several days in r.t.)

・Charge tarnsfer phase transition

・Ferromagnetic transition

UVN

ON+

I- I

Nd+

N

Od-

+-

Vis or D

N. Kida, N. Kojima, et al., J. Am. Chem. Soc., 2009, 131, 212.

Organic-inorganic hybrid system with photochromic cation

Photo-isomerization of spiropyran in (SP)[FeIIFeIII(dto)3]

300 KUV (350 nm) irradiation After UV, Vis. (550 nm) irradiation

1.2

1.0

0.8

0.6

0.4

0.2

0.0800700600500400300

UV 60 minvis 10 minvis 30 min

1.2

1.0

0.8

0.6

0.4

0.2

0.0

Ab

sorb

ance

800700600500400300

UV 60 minUV 30 minUV 20 minUV 10 minUV 0 min

N. Kida, N. Kojima, et al., J. Am. Chem. Soc., 2009, 131, 212.

Photoinduced effect on the ferromagnetism

T (K)T (K)

N

ON+

I-

I

Nd+

N

Od-

+-

UVVis or D

LTP HTP

Photo-isomerization of SP

1.00

0.95

0.90

0.85

0.801050-5-10

1.00

0.98

0.96

0.94

0.92

0.90

1050-5-10

6 K 6 K

HTP

HTP

LTPFeIII (S = 5/2)

FeIII (S = 1/2)

FeII (S = 0) FeIII (S = 1/2)FeII (S = 2)

FeII (S = 2)

UV

I

Nd+

N

Od-

+-

N

O

N+

I-

Closed form Open form

Velocity (mm/s)Velocity (mm/s)

N. Kida, N. Kojima, et al., Polyhedron, 2009, 28, 1694.

Tra

nsm

issi

on (

a.u.)

Tra

nsm

issi

on (

a.u.)

Expansion of the unit cell volume

due to the photo-isomerization of SP

Before UV irradiationAfter UV irradiation

UV

Disappearance of LTP under UV irradiation

Schematic diagram of spin states transition by photo-irradiation

T / K75

HTP(A)

HTP(B)

LTP(A)

HTP(B)

B phase

A phase

B phase

hν hν

A phase Thermal charge transfer occurs

B phase No thermal charge transfer phase transition

black

deep purple

UVVis.

or D

KBｒ pellet

5 22

Ferromagnetic phase

charge transfer phase transition

TC shifts from 5 to 22 K by UV irradiation

Photoinduced charge transfer phase transition at 70 K

Me N

O

N

Me N

O

N

Me N

O

N

Me N

O

N

SP type

Me N

δ+

NO

δ-

Me N

δ+

NO

δ-

Me N

δ+

NO

δ-

Me N

δ+

NO

δ-

e-

High TC (22 K) ferromagnetismLow TC (5 K) ferromagnetism

e- e- e-

hν1

hν2

LTP HTP

FeIII (S = 5/2)FeII (S = 0)

FeII (S = 2)

FeIII (S = 1/2)

MC type

N. KIda, et al., J. Am. Chem. Soc., 2009, 131, 212.

Structure of rhodopsin

cis-trans photoisomerization of retinal

Photo-isomerization of retinal in visual cell

cone

rod

light

retinal

http://www.kiriya-chem.co.jp/q&a/q52.html

Summary

(1)Development of transparent spin crossover complex film, [Fe(Htrz)3]-Nafion

and observation of LIESST

(2) Development of pH sensitive spin crossover complex film, [FeII(diAMsar)]-

Nafion and the direct observation of proton flow in Nafion

(3) Concerted phenomenon between the rapid spin equilibrium and the

successive magnetic phase transitions for (n-CnH2n+1)4N[MnIIFeIII(mto)3]

(mto = C2O3S)

(4) Charge transfer phase transition (CTPT) for iron mixed- valence complex,

(CnH2n+1)4N[FeIIFeIII(dto)3] (dto = C2O2S2)

(5) Concerted phenomenon between the photo-isomerization and charge

transfer phase transition in a photo-reactive organic-inorganic hybrid

complex, (SP)[FeIIFeIII(dto)3](SP = Spiropyran)