Department of Chemistry, University of Illinois, 600 South Goodwin Avenue, Urbana, Illinois 61801, United States.
Inorg Chem. 2012 Feb 20;51(4):2338-48. doi: 10.1021/ic202329y. Epub 2012 Feb 3.
A series of mixed-valence nickel-iron dithiolates is described. Oxidation of (diphosphine)Ni(dithiolate)Fe(CO)(3) complexes 1, 2, and 3 with ferrocenium salts affords the corresponding tricarbonyl cations (dppe)Ni(pdt)Fe(CO)(3) (1), (dppe)Ni(edt)Fe(CO)(3) (2) and (dcpe)Ni(pdt)Fe(CO)(3) (3), respectively, where dppe = Ph(2)PCH(2)CH(2)PPh(2), dcpe = Cy(2)PCH(2)CH(2)PCy(2), (Cy = cyclohexyl), pdtH(2) = HSCH(2)CH(2)CH(2)SH, and edtH(2) = HSCH(2)CH(2)SH. The cation 2 proved unstable, but the propanedithiolates are robust. IR and EPR spectroscopic measurements indicate that these species exist as C(s)-symmetric species. Crystallographic characterization of [3]BF(4) shows that Ni is square planar. Interaction of [1]BF(4) with P-donor ligands (L) afforded a series of substituted derivatives of type [(dppe)Ni(pdt)Fe(CO)(2)L]BF(4) for L = P(OPh)(3) ([4a]BF(4)), P(p-C(6)H(4)Cl)(3) ([4b]BF(4)), PPh(2)(2-py) ([4c]BF(4)), PPh(2)(OEt) ([4d]BF(4)), PPh(3) ([4e]BF(4)), PPh(2)(o-C(6)H(4)OMe) ([4f]BF(4)), PPh(2)(o-C(6)H(4)OCH(2)OMe) ([4g]BF(4)), P(p-tol)(3) ([4h]BF(4)), P(p-C(6)H(4)OMe)(3) ([4i]BF(4)), and PMePh(2) ([4j]BF(4)). EPR analysis indicates that ethanedithiolate 2 exists as a single species at 110 K, whereas the propanedithiolate cations exist as a mixture of two conformers, which are proposed to be related through a flip of the chelate ring. Mössbauer spectra of 1 and oxidized S = 1/2 [4e]BF(4) are both consistent with a low-spin Fe(I) state. The hyperfine coupling tensor of [4e]BF(4) has a small isotropic component and significant anisotropy. DFT calculations using the BP86, B3LYP, and PBE0 exchange-correlation functionals agree with the structural and spectroscopic data, suggesting that the SOMOs in complexes of the present type are localized in an Fe(I)-centered d(z(2)) orbital. The DFT calculations allow an assignment of oxidation states of the metals and rationalization of the conformers detected by EPR spectroscopy. Treatment of 1 with CN(-) and compact basic phosphines results in complex reactions. With dppe, 1 undergoes quasi-disproportionation to give 1 and the diamagnetic complex (dppe)Ni(pdt)Fe(CO)(2)(dppe) (5), which features square-planar Ni linked to an octahedral Fe center.
一系列混合价态的镍铁二硫代配合物被描述。用 ferrocenium 盐氧化 (二膦)Ni(dithiolate)Fe(CO)(3) 配合物 1、2 和 3，得到相应的三羰基阳离子 (dppe)Ni(pdt)Fe(CO)(3) (1)、(dppe)Ni(edt)Fe(CO)(3) (2) 和 (dcpe)Ni(pdt)Fe(CO)(3) (3)，其中 dppe = Ph(2)PCH(2)CH(2)PPh(2)、dcpe = Cy(2)PCH(2)CH(2)PCy(2)、(Cy = 环己基)、pdtH(2) = HSCH(2)CH(2)CH(2)SH 和 edtH(2) = HSCH(2)CH(2)SH。阳离子 2 被证明不稳定，但丙二硫醇盐是稳定的。IR 和 EPR 光谱测量表明这些物种以 C(s)-对称存在。[3]BF(4) 的晶体结构表征表明 Ni 是正方形平面的。[1]BF(4) 与 P-供体配体 (L) 相互作用，得到一系列取代衍生物类型 [(dppe)Ni(pdt)Fe(CO)(2)L]BF(4)，其中 L = P(OPh)(3) ([4a]BF(4))、P(p-C(6)H(4)Cl)(3) ([4b]BF(4))、PPh(2)(2-py) ([4c]BF(4))、PPh(2)(OEt) ([4d]BF(4))、PPh(3) ([4e]BF(4))、PPh(2)(o-C(6)H(4)OMe) ([4f]BF(4))、PPh(2)(o-C(6)H(4)OCH(2)OMe) ([4g]BF(4))、P(p-tol)(3) ([4h]BF(4))、P(p-C(6)H(4)OMe)(3) ([4i]BF(4)) 和 PMePh(2) ([4j]BF(4))。EPR 分析表明，乙二硫醇盐 2 在 110 K 下以单一物种存在，而丙二硫醇盐阳离子以两种构象的混合物存在，据推测它们是通过螯合环的翻转相关的。1 和氧化 S = 1/2 [4e]BF(4) 的 Mössbauer 谱都与低自旋 Fe(I)态一致。[4e]BF(4) 的超精细耦合张量具有较小的各向同性分量和显著的各向异性。使用 BP86、B3LYP 和 PBE0 交换相关泛函的 DFT 计算与结构和光谱数据一致，表明本类型配合物中的 SOMOs 定域在 Fe(I)中心的 d(z(2))轨道上。DFT 计算允许对金属的氧化态进行赋值，并对 EPR 光谱检测到的构象进行合理化。1 与 CN(-) 和紧凑型碱性膦反应会产生复杂的反应。用 dppe，1 经历准歧化反应，生成 1 和无磁性的配合物 (dppe)Ni(pdt)Fe(CO)(2)(dppe) (5)，其特点是 Ni 呈正方形平面，与八面体 Fe 中心相连。
