SYNTHESES OF THE PHENYLCHALCOGENOLATE COMPLEXES (ETA(5)-C(5)ME(5))(2)ZR(EPH)(2) (E=O,S,SE,TE) AND (ETA(5)-C5H5)(2)ZR(OPH)(2) - STRUCTURAL COMPARISONS WITHIN A SERIES OF COMPLEXES CONTAINING ZIRCONIUM-CHALCOGEN SINGLE BONDS [Review]

摘要

The complete series of phenylchalcogenolate derivatives of permethylzirconocene Cp*Zr-2(EPh)(2) (Cp* = eta(5)-C-5-Me(5); E = O, S, Se, Te) has been prepared by the reactions of Cp*Zr-2(CO)(2) with PhOH and Ph(2)E(2) (E = S, Se, Te). The molecular structures of all of the derivatives Cp*Zr-2(EPh)2 have been determined by X-ray diffraction, thereby providing evidence that the nature of the bonding varies as a function of the chalcogen. Specifically, the structure of the phenoxo derivative is notably distinct from those of its heavier congeners. For example, whereas the Zr-S, Zr-Se, and Zr-Te bond lengths are comparable to the sum of their respective covalent radii, the Zr-O bond length is significantly shorter than the sum of the covalent radii, as would be anticipated due to an increased ionic contribution to the bonding. In addition, the Zr-O-C bond angle [172.7(2)degrees] in Cp*Zr-2(OPh)(2) is effectively linear, whereas the Zr-E-C bond angles for the heavier congeners are significantly bent [113 degrees-119 degrees]. Comparison of the structure of Cp*Zr-2(OPh)(2) with that of the less substituted zirconocene derivative Cp(2)Zr(OPh)(2), which possesses a bent Zr-O-C moiety [147(1)degrees], suggests that the linearity of Cp*Zr-2(OPh)(2) may be attributed to steric factors. Thus, short M-OR bond lengths and linear M-O-R angles are not necessarily a consequence of strong p pi-d pi lone pair donation from oxygen to the metal. Cp*Zr-2(OPh)2 is monoclinic: C2/c (No. 15), a = 11.049(2) Angstrom, b = 15.445(3) Angstrom, c = 17.141(3) Angstrom, beta = 104.2(1)degrees, and Z = 4. Cp*2Zr(SPh)(2) is monoclinic: C2/c (No. 15), a = 14.444(4) Angstrom, b = 11.449(2) Angstrom, c = 18.262(3) Angstrom, beta = 103.39(2)degrees, and Z = 4. Cp*Zr-2(SePh)(2) is hexagonal: P6(1) (No. 169), a = 12.903(2) Angstrom, c = 31.923(6) Angstrom, and Z = 6. Cp*Zr-2(TePh)2 is monoclinic: P2(1)/c (No. 14), a = 16.917(3) Angstrom, b = 25.326(6) Angstrom c = 15.234(4) Angstrom, beta = 107.95(2)degrees, and Z = 8. Cp(2)Zr(OPh)(2) is orthorhombic: Aba2 (No. 41), a = 8.274(3) Angstrom, b = 19.843(9) Angstrom, c = 11.586(8) Angstrom, and Z = 4. [References: 109]