Electronic Structure of Mononuclear Bis(1,2-diaryl-1,2-ethylenedithiolato)iron Complexes Containing a Fifth Cyanide or Phosphite Ligand: A Combined Experimental and Computational Study
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- 作者：Apurba K. Patra ; Eckhard Bill ; Eberhard Bothe ; Krzysztof Chlopek ; Frank Neese ; Thomas Weyhermü ; ller ; Keira Stobie ; Michael D. Ward ; Jon A. McCleverty ; Karl Wieghardt
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：September 18, 2006
- 年：2006
- 卷：45
- 期：19
- 页码：7877 - 7890
- 全文大小：588K
- 年卷期：v.45,no.19(September 18, 2006)
- ISSN：1520-510X
文摘
A series of mononuclear square-based pyramidal complexes of iron containing two 1,2-diaryl-ethylene-1,2-dithiolateligands in various oxidation levels has been synthesized. The reaction of the dinuclear species [FeIII2(1L
bull.gif">)2(1L)2]0,where (1L)2- is the closed shell di-(4-tert-butylphenyl)-1,2-ethylenedithiolate dianion and (1Lbull.gif">)1- is its one-electron-oxidized 
fchars/pi.gif" BORDER=0 >-radical monoanion, with [N(n-Bu)4]CN in toluene yields dark green crystals of mononuclear [N(n-Bu)4][FeII(1Lbull.gif">)2(CN)] (1). The oxidation of 1 with ferrocenium hexafluorophosphate yields blue [FeIII(1Lbull.gif">)2(CN)] (1ox), andanalogously, a reduction with [Cp2Co] yields [Cp2Co][N(n-Bu)4][FeII(1Lbull.gif">)(1L)(CN)] (1red); oxidation of the neutral dimerwith iodine gives [FeIII(1Lbull.gif">)2I] (2). The dimer reacts with the phosphite P(OCH3)3 to yield [FeII(1Lbull.gif">)2{P(OCH3)3}] (3),and [FeIII2(3Lbull.gif">)2(3L)2] reacts with P(OC6H5)3 to give [FeII(3Lbull.gif">)2{P(OC6H5)3}] (4), where (3L)2- represents 1,2-diphenyl-1,2-ethylenedithiolate(2-). Both 3 and 4 were electrochemically one-electron oxidized to the monocations 3oxand 4ox and reduced to the monoanions 3red and 4red. The structures of 1 and 4 have been determined byX-ray crystallography. All compounds have been studied by magnetic susceptibility measurements, X-band EPR,UV-vis, IR, and Mössbauer spectroscopies. The following five-coordinate chromophores have been identified: (a)[FeIII(Lbull.gif">)2X]n, X = CN-, I- (n = 0) (1ox, 2); X = P(OR)3 (n = 1+) )3ox, 4ox) with St = 1/2, SFe = 3/2; (b) [FeII(Lbull.gif">)2X]n,X = CN-, (n = 1-) (1); X = P(OR)3 (n = 0) (3, 4) with St = SFe = 0; (c) [FeII(Lbull.gif">)(L)X]n 
f"> [FeII(L)(Lbull.gif">)X]n, X =CN- (n = 2-) (1red); X = P(OR)3 (n = 1-) (3red, 4red) with St = 1/2, SFe = 0 (or 1). Complex 1ox displays spincrossover behavior: St = 1/2 f"> St = 3/2 with intrinsic spin-state change SFe = 3/2 f"> SFe = 5/2. The electronicstructures of 1 and 1ox have been established by density functional theoretical calculations: [FeII(1Lbull.gif">)2(CN)]1- (SFe= 0, St = 0) and [FeIII(1Lbull.gif">)2(CN)]0 (SFe = 3/2, St = 1/2).
bull.gif">)2(1L)2]0,where (1L)2- is the closed shell di-(4-tert-butylphenyl)-1,2-ethylenedithiolate dianion and (1Lbull.gif">)1- is its one-electron-oxidized fchars/pi.gif" BORDER=0 >-radical monoanion, with [N(n-Bu)4]CN in toluene yields dark green crystals of mononuclear [N(n-Bu)4][FeII(1Lbull.gif">)2(CN)] (1). The oxidation of 1 with ferrocenium hexafluorophosphate yields blue [FeIII(1Lbull.gif">)2(CN)] (1ox), andanalogously, a reduction with [Cp2Co] yields [Cp2Co][N(n-Bu)4][FeII(1Lbull.gif">)(1L)(CN)] (1red); oxidation of the neutral dimerwith iodine gives [FeIII(1Lbull.gif">)2I] (2). The dimer reacts with the phosphite P(OCH3)3 to yield [FeII(1Lbull.gif">)2{P(OCH3)3}] (3),and [FeIII2(3Lbull.gif">)2(3L)2] reacts with P(OC6H5)3 to give [FeII(3Lbull.gif">)2{P(OC6H5)3}] (4), where (3L)2- represents 1,2-diphenyl-1,2-ethylenedithiolate(2-). Both 3 and 4 were electrochemically one-electron oxidized to the monocations 3oxand 4ox and reduced to the monoanions 3red and 4red. The structures of 1 and 4 have been determined byX-ray crystallography. All compounds have been studied by magnetic susceptibility measurements, X-band EPR,UV-vis, IR, and Mössbauer spectroscopies. The following five-coordinate chromophores have been identified: (a)[FeIII(Lbull.gif">)2X]n, X = CN-, I- (n = 0) (1ox, 2); X = P(OR)3 (n = 1+) )3ox, 4ox) with St = 1/2, SFe = 3/2; (b) [FeII(Lbull.gif">)2X]n,X = CN-, (n = 1-) (1); X = P(OR)3 (n = 0) (3, 4) with St = SFe = 0; (c) [FeII(Lbull.gif">)(L)X]n f"> [FeII(L)(Lbull.gif">)X]n, X =CN- (n = 2-) (1red); X = P(OR)3 (n = 1-) (3red, 4red) with St = 1/2, SFe = 0 (or 1). Complex 1ox displays spincrossover behavior: St = 1/2 f"> St = 3/2 with intrinsic spin-state change SFe = 3/2 f"> SFe = 5/2. The electronicstructures of 1 and 1ox have been established by density functional theoretical calculations: [FeII(1Lbull.gif">)2(CN)]1- (SFe= 0, St = 0) and [FeIII(1Lbull.gif">)2(CN)]0 (SFe = 3/2, St = 1/2).