Syntheses of the Phenylchalcogenolate Complexes (η5-C5Me5)2Zr(EPh)2(E = O, S, Se, Te) and (η5-C5H5)2Zr(OPh)2: Structural Comparisons within a Series of Complexes Containing Zirconium-Chalcogen Single Bonds

Article abstract of DOI:10.1021/ic00127a031

The complete series of phenylchalcogenolate derivatives of permethylzirconocene Cp(*)2Zr(EPh)2 (Cp(*) = η5-C5Me5; E = O, S, Se, Te) has been prepared by the reactions of Cp(*)2Zr(CO)2 with PhOH and Ph2E2 (E = S,Se, Te). The molecular structures of all of the derivatives Cp(*)2Zr(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 significanily shorter than thesum 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)°] in Cp(*)2Zr(OPh)2 is effectively linear, whereas the Zr-E-C bond angles for the heavier congeners are significantly bent (113°-119°]. Comparison of the structure of Cp(*)2Zr(OPh)2 with that of the less substituted zirconocene derivative Cp2Zr(OPh)2, which possesses a bent Zr-O-C moiety [147(1)°], suggests that the linearity of Cp(*)2Zr(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 pπ-dπ lone pair donation from oxygen to the metal. Cp(*)2Zr(OPh)2 is monoclinic: C2/c (No. 15), a = 11.049(2) ?, b = 15.445(3) ?, c = 17.141(3) ?, β = 104.24(1)°, and Z = 4.Cp(*)2Zr(SPh)2 is monoclinic: C2/c (No. 15), a = 14.444(4) ?, b = 11.449(2) ?, c = 18.262(3) ?, β = 103.39(2)°, and Z =4. Cp(*)2Zr(SePh)2 is hexagonal: P61 (No. 169) a = 12.903(2) ?, c =31.923(6) ?, and Z = 6. Cp(*)2Zr(TePh)2 is monoclinic: P21/c (No. 14), a = 16.917(3) ?, b = 25.326(6) ?, c = 15.234(4) ?, β = 107.95(2)° and Z = 8. Cp2Zr(OPh)2 is orthorhombic: Aba2 (No. 41), a = 8.274(3) ?, b = 19.843(9) ?, c = 11.586(8) ?, and Z= 4.