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

被引:36
作者
MACNEIL, JH
CHIVERTON, AC
FORTIER, S
BAIRD, MC
HYNES, RC
WILLIAMS, AJ
PRESTON, KF
ZIEGLER, T
机构
[1] QUEENS UNIV, DEPT CHEM, KINGSTON K7L 3N6, ONTARIO, CANADA
[2] UNIV CALGARY, DEPT CHEM, CALGARY T2N 1N4, ALBERTA, CANADA
[3] NATL RES COUNCIL CANADA, STEACIE INST MOLEC SCI, OTTAWA K1A 0R9, ONTARIO, CANADA
关键词
D O I
10.1021/ja00026a019
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The X-ray crystal structure of the 17-electron complex [Fe(CO)3(PPh3)2][PF6].1/2CH2Cl2 has been determined; the compound crystallizes in the space group P1BAR, and the cation assumes essentially a distorted square-pyramidal structure with trans basal phosphines, a P-Fe-P bond angle of 163.4 (1)-degrees, a (basal CO)-Fe-(basal CO) bond angle of 162.0 (6)-degrees, and (axial CO)-Fe-(basal CO) bond angles of 101.4 (6)-degrees and 96.6 (5)-degrees. The EPR spectrum of the cation {Fe(CO)3(PPh3)2+} has been measured in single crystals of [Co(CO)3(PPh3)2][PF6].CH2Cl2 at 77 K, the g and P-31 hyperfine interaction matrices being established in an orthogonal axis system of the monoclinic host. X-ray diffraction was used to determine the host crystal structure (space group P2(1)/n) and to establish the geometry of the diamagnetic cobalt cation as trigonal bipyramidal with axial phosphines (P-Co-P bond angle 176.5 (1)-degrees) and equatorial carbonyl groups (OC-Co-CO bond angles 117.8 (4)-degrees. 119.5 (4)-degrees, and 122.7 (5)-degrees). The radical {Fe(CO)3(PPh3)2+} has a 2A1 ground state, g (2.0091, 2.0898, 2.0795) being nearly axial with a unique component that lies almost in the equatorial plane of the host cation and having a value close to that of a free spin. The two P-31 hyperfine interaction tensors are coparallel and axially symmetric with unique components directed along the host P-Co bonds. The similarity of the principal values of g to those of {Fe(CO)5+} and their disposition with respect to the host cation show beyond any reasonable doubt that {Fe(CO)3(PPh3)2+} has a geometry approaching square pyramidal, as in crystalline [Fe(CO)3(PPh3)2]PF6.1/2CH2Cl2, and a 2A1 ground state (in C2-nu symmetry) with the unpaired electron principally located in the iron 3d(z)2 orbital. The phosphine ligands, axial in the host cation structure, occupy trans equatorial positions in the square-pyramidal structure of the cation radical. LCAO-HFS calculations for {M(CO)3L2} (M = Mn, Fe+; L = CO, PH3) are consistent with the finding that {Fe(CO)3(PPh3)2+} assumes a square-pyramidal (C2-nu structure and a 2A1 ground state rather than a trigonal-pyramidal (D3h) structure; other bipyramidal isomers are proximate in energy, but have not been observed.
引用
收藏
页码:9834 / 9842
页数:9
相关论文
共 77 条
  • [1] ATKINS PW, 1967, STRUCTURE INORGANIC, P269
  • [2] Self-consistent molecular Hartree-Fock-Slater calculations - I. The computational procedure
    Baerends, E. J.
    Ellis, D. E.
    Ros, P.
    [J]. CHEMICAL PHYSICS, 1973, 2 (01) : 41 - 51
  • [3] BAERENDS EJ, 1975, THESIS VRIJE U AMSTE
  • [4] ELECTROCHEMICAL ELECTRON-SPIN RESONANCE INVESTIGATION OF REACTIONS OF 17-ELECTRON IRON CARBONYL RADICAL CATION COMPLEXES
    BAGCHI, RN
    BOND, AM
    HEGGIE, CL
    HENDERSON, TL
    MOCELLIN, E
    SEIKEL, RA
    [J]. INORGANIC CHEMISTRY, 1983, 22 (21) : 3007 - 3012
  • [5] BAIRD MC, 1989, ORGNAOMETALLIC RADIC, pCH2
  • [6] REDUCTION-OXIDATION PROPERTIES OF ORGANOTRANSITION-METAL COMPLEXES .8. FORMATION AND REACTIVITY OF THE RADICAL CATIONS [FE(CO)3L2]+, AND THE MECHANISM OF THE OXIDATIVE ELIMINATION-REACTION OF [FE(CO)3L2] WITH HALOGENS
    BAKER, PK
    CONNELLY, NG
    JONES, BMR
    MAHER, JP
    SOMERS, KR
    [J]. JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1980, (04): : 579 - 585
  • [7] RE-EVALUATION OF MOLECULAR-STRUCTURE OF IRON PENTACARBONYL
    BEAGLEY, B
    SCHMIDLI.DG
    [J]. JOURNAL OF MOLECULAR STRUCTURE, 1974, 22 (03) : 466 - 468
  • [8] A MULTICENTER NUMERICAL-INTEGRATION SCHEME FOR POLYATOMIC-MOLECULES
    BECKE, AD
    [J]. JOURNAL OF CHEMICAL PHYSICS, 1988, 88 (04) : 2547 - 2553
  • [9] DENSITY FUNCTIONAL CALCULATIONS OF MOLECULAR-BOND ENERGIES
    BECKE, AD
    [J]. JOURNAL OF CHEMICAL PHYSICS, 1986, 84 (08) : 4524 - 4529
  • [10] BELFORD RL, 1979, 21ST EPR S ROCK MOUN