A FAMILY OF STABLE IRON(I) SIGMA-ALKYNYL COMPLEXES - SYNTHESIS, CHARACTERIZATION, STRUCTURE, AND ELECTRON-TRANSFER CHEMISTRY
A FAMILY OF STABLE IRON(I) SIGMA-ALKYNYL COMPLEXES - SYNTHESIS, CHARACTERIZATION, STRUCTURE, AND ELECTRON-TRANSFER CHEMISTRY
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DOI：
10.1021/ja00060a022
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发表时间：
1993-04-07
影响因子：
15
通讯作者：
ZANOBINI, F
中科院分区：
文献类型：
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作者：
BIANCHINI, C;LASCHI, F;ZANOBINI, F
合成了通式为[（PP 3）Fe（C=CR）]n+（n = 1，0）的Fe（II）和Fe（I）σ-炔基配合物[R = Ph，SiMe 3，n-C3 H 7，n-C5 H 11，CMe 3; PP 3 = P（CH 2CH 2 PPh 2）3]。所有化合物都经历电子转移反应，包括金属的Fe（0）、Fe（I）、Fe（II）和Fe（III）氧化态。测定了16电子和17电子配合物[（PP_3）Fe（C=CPh）] BPh_4·C_4 H_8 O和[（PP_3）Fe（C=CPh）]的X射线晶体结构。Fe（II）化合物的空间群为P2（1）/c，其阳离子呈现几乎规则的三角双锥结构，炔基配体反式位于PP 3的桥头磷原子上（P4-Fe-C7键角= 177.2（6）度）。Fe（I）化合物在空间群P2（1）/n中结晶，并呈现强烈扭曲的三角双锥结构，P4-Fe-C7键角为170.3（3）度，赤道键角为143.9（1）度、102.4（1）度和111.1（1）度。从Fe（II）到Fe（I）的Fe-P键距离的减小被解释为显著的金属->磷π-背键。相比之下，从IR、结构和电化学数据的细读中，没有显著的dpi（金属）-> pi*（炔基）相互作用发生。所有化合物都是顺磁性的，并已通过X-波段ESR光谱（粉末，冷冻溶液，流体溶液）进行了表征。用S = 1/2和菱形g张量解释了Fe（I）炔基化合物的粉末和冷冻溶液光谱。流体溶液光谱表明，该化合物存在于四氢呋喃溶液中的两个异构体的形式表现出扭曲的三角双锥结构的比例，取决于温度。的Fe（II）的衍生物（粉末和冷冻溶液）的ESR光谱显示未解决的线形与S = 1的哈密顿量在室温下具有显着的零场分裂效应一致。
Fe(II) and Fe(I) sigma-alkynyl complexes of the general formula [(PP3)Fe(C=CR)]n+ (n = 1, 0) have been synthesized as BPh4- salts or neutral molecules and characterized by chemical, spectroscopic, X-ray, and electrochemical techniques [R = Ph, SiMe3, n-C3H7, n-C5H11, CMe3; PP3 = P(CH2CH2PPh2)3]. All of the compounds undergo electron-transfer reactions that encompass Fe(0), Fe(I), Fe(II), and Fe(III) oxidation states of the metal. X-ray crystal structures of the 16- and 17-electron complexes [(PP3)Fe(C=CPh)]BPh4.C4H8O and [(PP3)Fe(C=CPh)] have been determined. The Fe(II) compound crystallizes in the space group P2(1)/c, and the cation assumes an almost regular trigonal-bipyramidal structure with the alkynyl ligand trans to the bridgehead phosphorus atom of PP3 (P4-Fe-C7 bond angle = 177.2(6)degrees). The Fe(I) compound crystallizes in the space group P2(1)/n and assumes a strongly distorted trigonal-bipyramidal structure with the P4-Fe-C7 bond angle of 170.3(3)degrees and equatorial bond angles of 143.9(1)degrees, 102.4(1)degrees, and 111.1(1)degrees. A decrease in the Fe-P bond distances on going from Fe(II) to Fe(I) is interpreted in terms of significant metal --> phosphorus pi-back-bonding. In contrast, from a perusal of IR, structural, and electrochemical data, no significant dpi (metal) --> pi* (alkynyl) interaction occurs. All compounds are paramagnetic and have been characterized by X-band ESR spectroscopy (powder, frozen solution, fluid solution). The powder and frozen solution spectra of the Fe(I) alkynyls are interpreted in terms of S = 1/2 and a rhombic g tensor. The fluid solution spectra show that the compounds exist in tetrahydrofuran solution as two isomeric forms exhibiting distorted trigonal-bipyramidal structures in a ratio that depends on the temperature. The ESR spectra of the Fe(II) derivatives (powder and frozen solution) display unresolved line shape consistent with a S = 1 Hamiltonian with noticeable zero-field splitting effects at room temperature.