No abstract

No abstract

No abstract

Gas-phase electron diffraction data of Cp*Al = (C&fe5)Al, Me = CH3, recorded with reservoir and nozzle temperatures of 139 f 4 "C, show that the gas consists of monomeric (q5-Cp*)Al units. Least-squares refinements of a molecular model of C5, symmetry yield the bond distances AI-C = 238.8(7), C-C(endocyc1ic) = 141.4(5), and C-C(exocyc1ic) = 152.9(5) p m and a perpendicular metal-to-ring distance of 206.3(9) p m .

The molecular structures and thermodynamic functions of seven dialkyl zinc compounds, R 2 Zn, R = Me, Et, i-Pr, t-Bu, n-Pr, neopentyl and the silaneopentyl Me 3 SiCH 2 , of the parent hydrocarbons RH and of the radicals R have been determined by density functional theory calculations at the B3LYP/SDD level. The molecular structures of the i-Pr, t-Bu, neo-Pe and Me 3 SiCH 2 derivatives have been determined by gas electron diffraction. Me 2 Zn, Et 2 Zn, t-Bu 2 Zn and neo-Pe 2 Zn have been studied by photoelectron spectroscopy and the ionisation energies calculated. Both experimental and calculated Zn-C bond distances were found to increase in the orderCalculated mean bond rupture enthalpies indicate that the strength of the Zn-C bonds decrease in the same order, viz.Both bond lengths and bond strengths were found to be strongly correlated with the inductive Taft constant I, indicating that the bond strength increases and the bond length decreases with increasing electron withdrawing power of the alkyl group. Evidence from the literature indicates that bond strengths and bond lengths in homoleptic alkyl derivatives of the main group metals in Groups 12, 13 and 14 and of the transition elements in Group 4 vary in the same manner.D a l t o n T r a n s . ,