Showing papers by "Stephen Barlow published in 1996"

Molecular Mechanics Study of Oligomeric Models for Poly(ferrocenylsilanes) Using the Extensible Systematic Forcefield (ESFF)

Abstract: Molecular mechanics have been employed to study the conformations of the oligomeric metallocene species Fc[Fe(C5H4)2XMe2]nH (Fc = Fe(C5H5)(C5H4); X = Si, n = 1 (1); X = C, n = 1 (2); X = Si, n = 2 (3); X = C, n = 2 (4); X = Si, n = 4 (5)) and their cations. The calculations utilize the new generalized ESFF forcefield; they show that the neutral molecules are conformationally flexible with the lowest energy configurations having close contacts between the positively charged iron atoms of the ferrocene units and the negatively charged cyclopentadienyl rings of their neighbors. The carbon-bridged species have harder potential surfaces than their silicon analogues, but replacement of the methyl groups of the bridge with longer alkyl chains was found to have very little effect on the relative orientation of the ferrocene units. The conformations of the molecules 3, 4, and 5 in their experimental crystal structures were found to be significantly different from the calculated low energy isolated conformers. Howe...

Synthesis, Characterization, and Properties of High Molecular Weight Poly(methylated ferrocenylsilanes) and Their Charge Transfer Polymer Salts with Tetracyanoethylene

Abstract: A series of poly(ferrocenylsilanes) with methylated cyclopentadienyl (Cp) rings [Fe(η-C5MexH4-x)(η-C5MeyH4-y)SiMe2]n (2a−e) (a, x = 0, y = 0; b, x = 1, y = 1 (Cp−Me groups at random positions); c, ...

Molecular dynamics in solid bis(η-arene)molybdenum complexes studied by solid-state deuterium nuclear magnetic resonance spectroscopy

Abstract: Variable-temperature solid-state 2H NMR spectra have been recorded on microcrystalline samples of [Mo(η-C6D6)2], [Mo{η-C6D3(CD3)3-1,3,5}2] and [ZrS2{Mo[η-C6D3(CD3)3-1,3,5]2}0.15]. In the case of [Mo(η-C6D6)2] the spectra are invariant in the range 160–360 K and are consistent with rapid ring rotation at all accessible temperatures. For both [Mo{η-C6D3(CD3)3-1,3,5}2] and [ZrS2{Mo[η-C6D3(CD3)3-1,3,5]2}0.15] the η-C6D3(CD3)3 ligands were found to be static at all temperatures up to 360 K.