77Se NMR spectroscopic and x-ray crystallographic characterization of bis(cyclopentadienyl)titanium selenide sulfide mixtures, [Ti(C5H5)2SexS5-x]

Mixed crystals of bis(cyclopentadienyl)titanium selenide sulfides, [Ti(C5H5)2SexS5-x], have been prepared by reacting [Ti(c5H5)2Cl2] with a series of lithium polyselenide and polysulfide mixtures at different molar ratios. The reaction products were studied with 77Se NMR spectroscopy and x-ray crystallography. When the initial lithium polyselenide/polysulfide mixture was either sulfur-rich or selenium-rich, mainly [Ti(C5H5)2S5] or [Ti(c5H5)2se5] were formed, respectively. However, when the initial molar ratio of selenium and sulfur was near unity, several different [Ti(c5H5)2SexSe5-x]species were formed. The product from the reaction with initial molar ratio of selenium and sulfur of 3:2 was subjected to a more detailed study. Both the crystal and molecule structures of the complex were determined and are reported. According to the 77Se NMR spectra the main selenium-containing components in the product are [Ti(C5H5)2Se5], [Ti(C5H5)2Se4S], [Ti(C5H5)2Se3S2], [Ti(C5H5)2Se3S], and [Ti(C5H5)2Se2S3]. The product also contains [Ti(C5H5)2S5]. The refined occupation factors sulfur and selenium from the crystal structure determination agree well with the relative abundance of the different molecular species as calculated from the NMR spectrum. 26 refs., 4 figs., 5 tabs