Bruce R. Bender

[(η2-C2H4)Os(CO)4] as a vibrational model for type I′ ethene chemisorbed as a metallacyclopropane on metal surfaces

A comprehensive vibrational assignment of the hydrocarbon features in the infrared and Raman spectra of (η2-C2H4)Os(CO)4 has been achieved with the help of data from the (13C2H4) and (C2D4) isotopologues. Close analogies with the vibrational spectra of thiirane (ethene sulfide) assist in the assignment and emphasize the metallacyclopropane nature of the (C2H4Os) group. Comparisons are made with analogous spectra from (η2-C2H4)Fe(CO)4 and from Zeises salt, K[(η2-C2H4)PtCl3].Taking into account the metal–surface selection rule associated with on-specular vibrational electron energy loss or reflection–absorption infrared spectra, good agreement is found between the wavenumber/intensity pattern from the a1 modes of the complex and from ethene chemisorbed on metal surfaces previously designated Type I′.

The photochemistry of dinuclear osmium carbonyl complexes; characterisation of Os2(CO)8 using matrix isolation

Abstract UV photolysis of Os 2 (CO) 9 or ((μ-C1,C2)CH 2 CH 2 )Os 2 (CO) 8 ( 1 ) isolated in argon matrices causes ejection of a CO or C 2 H 4 ligand respectively, and formation of Os 2 (CO) 8 , which has a structure with only terminal CO groups. Long wavelength irradiation of matrix isolated Os 2 (CO) 8 in the presence of potential 2 electron donor ligands leads to production of Os 2 (CO) 8 L (L = CO, N 2 or C 2 H 4 ), each containing a bridging CO group and a terminally bound ligand L. Photolysis using plane polarised light provides confirmation of the C 2 v structure of Os 2 (CO) 9 , and gives evidence favouring a D 2 h structure for Os 2 (CO) 8 . Prolonged UV photolysis of Os 2 (CO) 9 in CO matrices leads to cleavage of the OsOs bond and production of Os(CO) 5 .

[Os2(CO)8(µ2-η2-C2H4)] as a vibrational model for 1,2-di-σ chemisorbed ethylene on metal surfaces

A vibrational assignment has been made for [Os2(CO)8(µ2-η2-C2H4)] and its deuteriated and 13C analogues: this complex is shown to be a vibrational model for molecular ethylene chemisorption, confirming the (1,2-di-σ) bonding mode.