DFT Study for Evaluation of the Interaction of CoordinatedMolecule to Fe(III) in Various Iron(III) Chloride Complexes

Abstract

八面体構造から四面体構造まで塩素数に応じて構造が変化する塩化鉄(III)錯体に対してDFT法を用いて理論計算を行った．使用した汎関数はBHandHLYP，wB97XD，CAM-B3LYP，LC-wPBEの4種である．基底関数には6-311+G(d,p)あるいは6-311+G(3df,2pd)を用い，PCM法による水媒体中で計算を行った．4種の汎関数を用いたDFT法は概ね錯体構造をよく再現した．2原子の塩素が配位した八面体型[Fe(III)Cl₂(H₂O)₄]⁺のcis型とtrans型の安定性，及び3原子の塩素が配位した三方両錐型の[Fe(III)Cl₃(H₂O)₂]と四面体型の[Fe(III)Cl₃(H₂O)] の安定性をエネルギー的に比較した．振動計算から得られる配位水分子の伸縮振動の波数の変化を[Fe(III)(H₂O)₆]³⁺から[Fe(III)Cl₃(H₂O)]まで調査したところ，八面体型では水分子の減少とともに伸縮振動は高波数側へシフトし，フリーの単独水分子の伸縮振動に近づく．八面体型では塩素原子の鉄への配位は鉄の極性を低下させ，その結果として水分子との相互作用を弱めると考えられる．しかし，三方両錐型([Fe(III)Cl₃(H₂O)₂])から四面体型([Fe(III)Cl₃(H₂O)])になるにつれ再び伸縮振動はやや低波数側へシフトした．配位する塩素原子数が同じ3であっても，水分子数が少ないほど鉄との相互作用は強められる．鉄－酸素間距離についても同じ傾向を示した．

Figures

Figure 1.

 Optimized geometry of [Fe(III)(H₂O)₆]³⁺ with T_h symmetry obtained by using wB97XD/6-311+G(3df,2pd) in PCM water.

Figure 2.

 Optimized geometry of [Fe(III)Cl(H₂O)₅]²⁺ with C_2v symmetry obtained by using LC-wPBE/6-311+G(3df,2pd) in PCM water.

Figure 3.

 Optimized geometry of cis-[Fe(III)Cl₂(H₂O)₅]⁺ with C_s symmetry obtained by using LC-wPBE/6-311+G(d,p). a) in PCM water and b) in vacuum.

Figure 4.

 Various optimized geometries of [Fe(III)Cl₂(H₂O)₄]⁺ in PCM water obtained by using wB97XD/6-311+G(d,p). Point group symmetry and number of imaginary frequency are indicated at upper right of each geometry.

Figure 5.

 Optimized geometry of fac-[Fe(III)Cl₃(H₂O)₃] and mer-[Fe(III)Cl₃(H₂O)₃] obtained by using wB97XD/6-311+G(d,p) in PCM water.

Figure 6.

 Optimized geometry of trigonal bipyramidal [Fe(III)Cl₃(H₂O)₂] and two types of tetrahedral [Fe(III)Cl₃(H₂O)] obtained by using LC-wPBE/6-311+G(d, p) in PCM water.

Figure 7.

 Relation of OH stretching frequency to number of H₂O in various Fe(III) chloride complexes obtained by using wB97XD/6-311+G(3df, 2pd). T.B. means trigonal bipyramid. The OH stretching for free water is indicated as (○) and (●).

Figure 8.

 Relation of Fe − O distance to number of H₂O in various Fe(III) chloride complexes obtained by using wB97Xd/6-311+G(3df, 2pd). T.B. means trigonal bipyramid.

Figure 9.

 Relation of ATP partial charge on Fe(III) to fraction of Cl in various Fe(III) chloride complexes obtained by using wB97Xd/6-311+G(3df, 2pd). T.B. means trigonal bipyramid.

Tables

Table 1.  Analysis of the optimized structures of aquated iron calculated using wB97XD with the basis function of 6-311+G(d, p) or 6-311+G(3df, 2pd).

	DFT method	P.G.M.S.a)	Im. Freq.b)	Fe—ODistance (pm)	Spin Densityon Fe	APT Chargeon Fe	APT Chargeon O	ν(OH)symν(OH)asym(cm−1)
[Fe(III)(H2O)6]3+	wB97XD/6-311+G(d, p)	Th	0	201.2	4.394	3.144	−0.917	3796.23880.3
	wB97XD/6-311+G(3df,2pd)	Th	0	201.0	4.472	3.112	−0.874	3807.53893.5
Exp. for[Fe(III)(H2O)6]3+		—	—	201c,d) 199e)	—	—	—	—
[Fe(II)(H2O)6]2+	wB97XD/6-311+G(d, p)	D2h	8	211.0f)209.7217.9	3.845	2.064	−0.774g)−0.817−0.775	—
	wB97XD/6-311+G(3df,2pd)	D2h	9	210.8209.0217.6	3.864	2.043	−0.737−0.778−0.738	—

a) Point group molecular symmetry

b) Number of imaginary frequency

c) Reference [8]

d) Reference [9]

e) Reference [10]

f) Due to the D_2h symmetry, the three values are overlapped with each other among six kinds of Fe—O distance.

g) Due to the D_2h symmetry, the three values are overlapped with each other among six kinds of charges on oxygen.

Table 2.  Analysis of the optimized structures of iron (III) chloro complex, [Fe(III)Cl(H₂O)₅]²⁺, calculated using wB97XD with the basis function of 6-311+G(d, p) or 6-311+G(3df, 2pd).

DFT method	P.G.M.S.a)	Im. Freq.b)	Fe—ClDistance(pm)	Fe—ODistancec)(pm)	Spin Densityon Fe	APT Chargeon Fe	APT Chargeon Cl	APT Chargeon Od)
wB97XD/6-311+G(d, p)	C2v	0	217.1	208.4204.4208.4	4.234	2.919	−0.721	−0.843−0.864−0.928
wB97XD/6-311+G(3df, 2pd)	C2v	0	216.6	208.3204.1210.9	4.337	2.904	−0.722	−0.813−0.826−0.896
Exp. for[Fe(III)Cl(H2O)5]2+	—	—	228e)226f)	200e) 205f)	—	—	—	—

a) Point group molecular symmetry

b) Number of imaginary frequency

c) Due to the C_2v symmetry, the first and the second values are overlapped among five kinds of Fe—O distance.

d) Due to the C_2v symmetry, the first and the second charges are overlapped among five kinds of charges on oxygen.

e) Reference [4]

f) Reference [13]

Table 3.  Analysis of the optimized structures of cis-[Fe(III)Cl₂(H₂O)₄]⁺, calculated using wB97XD with the basis function of 6-311+G(d, p) or 6-311+G(3df, 2pd).

DFT method	P.G.M.S.a)	Im.Freq.b)	Fe—ClDistance(pm)	Fe—ODistance(pm)	Spin Densityon Fe	APT Chargeon Fe	APT Chargeon Cl	APT Chargeon O
cis-[Fe(III)Cl2(H2O)4]+
wB97XD/            6-311+G(d, p)	C1	0	222.9222.1	210.4212.8219.1210.2	4.157	2.950	−0.875−0.859	−0.835−0.888−0.848−0.836
wB97XD/            6-311+G(3df,2pd)	C1	0	222.2221.5	210.6213.2219.4210.0	4.264	2.921	−0.865−0.852	−0.804−0.853−0.830−0.803

a) Point group molecular symmetry

b) Number of imaginary frequency

Table 4.  Analysis of the optimized structures of trans-[Fe(III)Cl₂(H₂O)₄]⁺ calculated using wB97XD with the basis function of 6-311+G(d, p) or 6-311+G(3df, 2pd).

DFT method	P.G.M.S. a)	Im.Freq.b)	Fe—ClDistance(pm)	Fe—ODistance(pm)	Spin Densityon Fe	APT Chargeon Fe	APT Chargeon Cl	APT Chargeon O
trans-[Fe(III)Cl2(H2O)6]+
wB97XD/          6-311+G(d, p)	D2h	4	227.1	210.7206.4	4.196	3.265	−1.027	−0.852−0.862
	D4h	4	225.5	208.8	4.185	3.205	−1.000	−0.845
	C2v	2	226.6	208.6209.0	4.192	3.191	−0.994	−0.862−0.845
	C1	0	225.9226.7	211.2208.9209.1208.8	4.189	3.169	−0.990−0.998	−0.828−0.847−0.840−0.844
wB97XD/          6-311+G(3df, 2pd)	C1	0	225.3226.2	211.4208.8209.0208.6	4.196	3.129	−0.982−0.995	−0.801−0.814−0.809−0.812
Exp. for[Fe(III)Cl2(H2O)6]+	—	—	230c) 229d)	204c)208d)	—	—	—	—

a) Point group molecular symmetry

b) Number of imaginary frequency

c) Reference [4]

d) Reference [19]

Table 5.  Energy difference between cis-[Fe(III)Cl₂(H₂O)₄]⁺ and trans-[Fe(III)Cl₂(H₂O)₄]⁺.

DFT method	Conformer	P.G.M.S.a)	Cl-Fe-Cl(o)	Relative Energyb)(kJ/mol)
in water
wB97XD/      6-311+G(d, p)	cis	C1	104.19	−11.24
	trans	C1	173.52	0
wB97XD/      6-311+G(3df,2pd)	cis	C1	104.27	−9.84
	trans	C1	173.09	0
in vacuum
wB97XD/      6-311+G(d,p)	cis	C1	108.83	+9.68
	trans	C1	180.0	0
wB97XD/      6-311+G(3df,2pd)	cis	C1	108.82	+10.32
	trans	C1	180.0	0

a) Point group molecular symmetry

b) Values are obtained as the energy of the trans form is assumed to be zero

Table 6.  Analysis of the optimized structures of iron (III) chloro complex, [Fe(III)Cl₃(H₂O)₃]⁺, calculated using wB97XD with the basis function of 6-311+G(d, p) or 6-311+G(3df, 2pd).

DFT method	P.G.M.S.a)	Im. Freq.b)	Fe—ClDistance(pm)	Fe—ODistance(pm)	Spin Densityon Fe	APT Chargeon Fe	APT Chargeon Cl	APT Chargeon O
fac-[Fe(III)Cl3(H2O)3]
wB97XD/          6-311+G(d, p)	C1	0	226.5226.3226.4	220.4220.7220.8	4.076	2.983	−0.925−0.921−0.920	−0.846−0.844−0.846
wB97XD/          6-311+G(3df,2pd)	C1	0	225.9225.9225.9	220.7220.5221.3	4.186	2.959	−0.916−0.914−0.913	−0.829−0.829−0.822
mer-[Fe(III)Cl3(H2O)3]
wB97XD/          6-311+G(d, p)	C1	0	230.9230.8227.0	220.2214.0212.4	4.133	3.145	−1.004−1.005−0.931	−0.843−0.834−0.835
wB97XD/          6-311+G(3df,2pd)	C1	0	230.3230.3226.2	221.0214.0212.3	4.231	3.106	−1.009−1.008−0.922	−0.825−0.809−0.805

a) Point group molecular symmetry

b) Number of imaginary frequency

Table 7.  Analysis of the optimized structures of [Fe(III)Cl₃(H₂O)₂], calculated using wB97XD with the basis function of 6-311+G(d, p) or 6-311+G(3df, 2pd).

DFT method	P.G.M.S. a)	Im. Freq.b)	Fe—ClDistance(pm)	Fe—ODistance(pm)	O − Fe − OAngle(o)	Spin Densityon Fe	APT Chargeon Fe	APT Chargeon Cl	APT Chargeon O
wB97XD/6-311+G(d, p)	C1	0	224.3221.5225.4	213.6214.0	169.23	4.105	2.825	−0.925−0.858−0.925	−0.836−0.826
wB97XD/6-311+G(3df, 2pd)	C1	0	223.7220.6224.6	213.8214.5	168.85	4.226	2.775	−0.919−0.844−0.917	−0.801

a) Point group molecular symmetry

b) Number of imaginary frequency

Table 8.  Analysis of the optimized structures of [Fe(III)Cl₃(H₂O)], calculated using wB97XD with the basis function of 6-311+G(d, p) or 6-311+G(3df, 2pd).

DFT method	P.G.M.S.a)	Im. Freq.b)	Fe—ClDistance(pm)	Fe—ODistance(pm)	Cl − Fe − ClAngle (o)	Spin Densityon Fe	APT Chargeon Fe	APTChargeon Cl	APT Chargeon O
wB97XD/6-311+G(d, p)               Type A	C1	0	219.3219.4219.9	205.2	115.0113.6114.1	4.056	2.643	−0.876−0.883−0.882	−0.837
Type B	C1	0	219.4219.7220.1	205.1	114.9114.8113.5	4.056	2.630	−0.874−0.868−0.881	−0.840
wB97XD/6-311+G(3df, 2pd)               Type A	C1	0	218.8218.8218.9	205.3	115.0113.6114.1	4.150	2.577	−0.858−0.863−0.859	−0.793
Type B	C1	0	219.0219.1219.2	205.1	115.0113.6114.1	4.150	2.565	−0.854−0.850−0.859	−0.795

a) Point group molecular symmetry

b) Number of imaginary frequency

Table 9.  Complexation energy and frequency of the optimized structures of [Fe(III)Cl₃(H₂O)₂] and [Fe(III)Cl₃(H₂O)] (TypeA), calculated using wB97XD/6-311+G(3df, 2pd).

DFT method	BSSE corrected complexation energy(kJ/mol)	νsym(OH)(cm−1)	νasym(OH)(cm−1)	ω(H−O−H)(cm−1)
[Fe(III)Cl3(H2O)2]
wB97XD/6-311+G(3df, 2pd)	−186.7a)	3832.8(0.986)b)3833.5(0.986)	3923.4(0.986)b)3923.6(0.986)	1615.7(0.996)b)1624.3(1.001)
[Fe(III)Cl3(H2O)]
wB97XD/6-311+G(3df, 2pd)	−132.2c)	3826.5(0.984)	3911.9(0.983)	1637.3(1.010)
H2O in PCM water
wB97XD/6-311+G(3df, 2pd)	—	3887.3	3978.5	1621.9

a) complexation energy according to the equation: 2H₂O + [Fe(III)Cl₃] → [Fe(III)Cl₃(H₂O)₂]

b) ratio to the respective wave number of H₂O in PCM water

c) complexation energy according to the equation: H₂O + [Fe(III)Cl₃] → [Fe(III)Cl₃(H₂O)]

Table10.  Analysis of the optimized structures of [Fe(III)Cl₄]^-, calculated using wB97XD with the basis function of 6-311+G(d) or 6-311+G(3df).

DFT method	P.G.M.S.a)	Im. Freq.b)	Fe—ClDistance(pm)	Spin Densityon Fe	APT Chargeon Fe	APT Chargeon Cl	ν3(Fe-Cl) (cm−1)	ν4(Cl-Fe-Cl) (cm−1)
wB97XD/6-311+G(d)	Td	2	223.2	4.081	2.642	−0.910	384.3	—
wB97XD/6-311+G(3df)	Td	0	222.4	3.993	2.561	−0.890	386.5	101.4
Exp.	—	—	220.4c)	—	—	—	379d)376e)	137d)135e)

a) Point group molecular symmetry

b) Number of imaginary frequency

c) Cambridge Structural Database version 5.25, November 2003.

d) Reference [23].

e) Reference [24]

参考文献

• [1]   W. Liu, B. Etschmann, J. Brugger, L. Spiccia, G. Foran, B. McInnes, Chem. Geol., 231, 326 (2006). doi:10.1016/j.chemgeo.2006.02.005
• [2]   A. Stefánsson, T. M. Seward, Chem. Geol., 249, 227 (2008). doi:10.1016/j.chemgeo.2007.12.006
• [3]   B. R. Tagirov, I. I. Diakonov, O. A. Devina, A. V. Zotov, Chem. Geol., 162, 193 (2000). doi:10.1016/S0009-2541(99)00150-3
• [4]   K. Asakura, M. Nomura, H. Kuroda, Bull. Chem. Soc. Jpn., 58, 1543 (1985). doi:10.1246/bcsj.58.1543
• [5]   K. Murata, D. E. Irish, G. E. Toogood, Can. J. Chem., 67, 517 (1989). doi:10.1139/v89-079
• [6]   C. J. Cramer, D. G. Truhlar, Phys. Chem. Chem. Phys., 11, 10757 (2009). doi:10.1039/B907148B
• [7]  [ Gaussian 09, Revision D.01, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J. A. Montgomery, Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N. Staroverov, T. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klene, J. E. Knox, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma, V. G. Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S. Dapprich, A. D. Daniels, O. Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski, and D. J. Fox, Gaussian, Inc., Wallingford CT, 2013.
• [8]   D. Harris, G. H. Loew, A. Komornicki, J. Phys. Chem. A, 101, 3959 (1997). doi:10.1021/jp963296x
• [9]   G. J. Herdman, G. W. Neilson, J. Phys. Condens. Matter, 4, 649 (1992). doi:10.1088/0953-8984/4/3/006
• [10]   H. Ohtaki, T. Radnai, Chem. Rev., 93, 1157 (1993). doi:10.1021/cr00019a014
• [11]   T. K. Sham, J. B. Hastings, M. L. Perlman, J. Am. Chem. Soc., 102, 5904 (1980). doi:10.1021/ja00538a033
• [12]   P. J. Stephens, K. J. Jalkanen, R. W. Kawiecki, J. Am. Chem. Soc., 112, 6518 (1990). doi:10.1021/ja00174a011
• [13]   Y. Inada, S. Funahashi, Z.Naturforsch., 54b, 1517 (1999).
• [14]   M. D. Lind, J. Chem. Phys., 47, 990 (1967). doi:10.1063/1.1712067
• [15]   D. L. Wertz, M. L. Steele, Inorg. Chem., 19, 1652 (1980). doi:10.1021/ic50208a044
• [16]   D. L. Wertz, M. D. Luter, Inorg. Chem., 20, 3118 (1981). doi:10.1021/ic50223a075
• [17]   C. Bordeleau, D. R. Wiles, Inorg. Chim. Acta, 41, 195 (1980). doi:10.1016/S0020-1693(00)88454-6
• [18]   A. Stefánsson, K. H. Lemke, T. M. Seward, ICPWS XV (15th International Conference on the Properties of Water and Steam) PREPRINT, Berlin, September 8–11, (2008)
• [19]   M. Magini, T. Radnai, J. Chem. Phys., 71, 4255 (1979). doi:10.1063/1.438233
• [20]   P. S. Hill, E. A. Schauble, A. Shahar, E. Tonui, E. D. Young, Geochim. Cosmochim. Acta, 73, 2366 (2009). doi:10.1016/j.gca.2009.01.016
• [21]   M. Fukuda, H. Kawai, N. Yagi, O. Kimura, T. Ohta, Polymer (Guildf.), 31, 295 (1990). doi:10.1016/0032-3861(90)90122-F
• [22]   I. Eto, H. Fujiwara, M. Akiyoshi, T. Matsumoto, J. Comput. Chem. Jpn., 7, 9 (2008). doi:10.2477/jccj.H1919
• [23]   D. Wyrzykowski, T. Maniecki, A. Pattek-Janczyk, J. Stanek, Z. Warnke, Thermochim. Acta, 435, 92 (2005). doi:10.1016/j.tca.2005.05.007
• [24]   M. C. Smith, Y. Xiao, H. Wang, S. J. George, D. Coucouvanis, M. Koutmos, W. Sturhahn, E. E. Alp, J. Zhao, S. P. Cramer, Inorg. Chem., 44, 5562 (2005). doi:10.1021/ic0482584
• [25]   J. Shamir, J. Raman Spectrosc., 22, 97 (1991). doi:10.1002/jrs.1250220209
• [26]   M. Magini, J. Chem. Phys., 76, 1111 (1982). doi:10.1063/1.443078
• [27]  [ Z. Akdeniza and M. P. Tosiac, Z. Naturforsch. 54a, 477–481 (1999)d