A FAMILY OF STABLE IRON(I) SIGMA-ALKYNYL COMPLEXES - SYNTHESIS, CHARACTERIZATION, STRUCTURE, AND ELECTRON-TRANSFER CHEMISTRY

被引:55
作者
BIANCHINI, C
LASCHI, F
MASI, D
OTTAVIANI, FM
PASTOR, A
PERUZZINI, M
ZANELLO, P
ZANOBINI, F
机构
[1] UNIV FIRENZE,DIPARTIMENTO CHIM,I-50100 FLORENCE,ITALY
[2] UNIV SIENA,DIPARTIMENTO CHIM,I-53100 SIENA,ITALY
关键词
D O I
10.1021/ja00060a022
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
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.
引用
收藏
页码:2723 / 2730
页数:8
相关论文
共 84 条
[61]   AN X-RAY CRYSTALLOGRAPHIC AND SINGLE-CRYSTAL EPR INVESTIGATION OF THE CATIONIC, IRON-CENTERED RADICAL TRICARBONYLBIS(TRIPHENYLPHOSPHINE)IRON(I), (FE(CO)3(PPH3)2+) - A THEORETICAL-EXAMINATION OF THE STRUCTURAL PREFERENCES OF 5-COORDINATED 17-ELECTRON COMPLEXES [J].
MACNEIL, JH ;
CHIVERTON, AC ;
FORTIER, S ;
BAIRD, MC ;
HYNES, RC ;
WILLIAMS, AJ ;
PRESTON, KF ;
ZIEGLER, T .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1991, 113 (26) :9834-9842
[62]  
MARCH J, 1985, ADV ORGANIC CHEM
[63]  
Mcgarvey B.R., 1966, T MET CHEM, V3, P89
[64]   STRUCTURAL FLEXIBILITY AND BONDING CAPABILITIES OF THE LIGAND NP3 TOWARD THE TRANSITION-METALS [J].
MEALLI, C ;
GHILARDI, CA ;
ORLANDINI, A .
COORDINATION CHEMISTRY REVIEWS, 1992, 120 :361-387
[65]  
MEALLI C, 1973, J CHEM SOC CHEM COMM, P886
[66]  
MOINET C, 1981, J ELECTROANAL CHEM, V121, P241, DOI 10.1016/S0022-0728(81)80582-7
[67]   REACTION OF FERROCENE WITH POLYAROMATIC MOLECULES - PI-ARENEBIS(PI-CYCLOPENTADIENYLIRON) DICATIONS .2. ELECTRONIC-STRUCTURE [J].
MORRISON, WH ;
HO, EY ;
HENDRICKSON, DN .
INORGANIC CHEMISTRY, 1975, 14 (03) :500-506
[68]   COORDINATION CHEMISTRY OF METAL ALKYNYL COMPOUNDS [J].
NAST, R .
COORDINATION CHEMISTRY REVIEWS, 1982, 47 (1-2) :89-124
[69]  
ORLANDINI A, 1975, CRYST STRUCT COMMUN, V4, P157
[70]   STRUCTURAL EFFECTS OF ONE-ELECTRON OXIDATION ON A CYCLOBUTADIENEIRON DERIVATIVE - X-RAY CRYSTAL-STRUCTURES OF [FE(CO)(P(OME)3)2(ETA-C4PH4)] AND [FE(CO)(P(OME)3)2(ETA-C4PH4)]BF4 [J].
ORPEN, AG ;
CONNELLY, NG ;
WHITELEY, MW ;
WOODWARD, P .
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1989, (09) :1751-1757