Douglas R. Powell

Synthesis, solid-state structure, and reduction of 1,1-dichloro-2,3,4,5-tetramethylsilole

Abstract The previously unknown 1,1-dichloro-2,3,4,5-tetramethyl-1-silacylopenta-2,4-diene ( 3 ) was prepared in a three-step synthesis starting from zirconocene dichloride, 2-butyne, and n-butyllithium via bis(cyclopentadienyl)-2,3,4,5-tetramethyl-1-zirconacyclopenta-2,4-diene ( 1 ) and 1,4-diiodo-1,2,3,4-tetramethylbuta-1,3-diene ( 2 ). 3 was characterized by NMR spectroscopy and single-crystal X-ray diffraction. Reaction of the new silole 3 with 4 equivalents of lithium in THF gives the corresponding dianion 4 . 1 H-, 13 C-, and 29 Si-NMR chemical shifts of 4 compared with 3 indicate some aromatic character for the ionic species. Trapping of 4 with Me 3 SiCl gives 1,1-bis(trimethylsilyl)-2,3,4,5-tetramethysilole ( 5 ) in quantitative yield.

Linear 2,2-diaryl-substituted trisilanes: Structure and photolysis to disilenes

Abstract Synthesis of the new disilene, E/Z-IsMesSi=SiIsMes (1) is reported; the isomer Is2Si=SiMes2 (2) was obtained by photolysis of a mixture of Mes2Si(SiMe3)2 (3) and Is2Si(SiMe3)2 (5). Isomerization of 1 2 does not take place up to 80°C. X-Ray crystal structures are reported for trisilanes 3, IsMesSi(SiMe3)2 (4), and 5.

The monocation and monoanion of Re2(µ-Cl)2(µ-dppm)2Cl4(dppm = Ph2PCH2PPh2). An unusual pair of complexes possessing metal–metal bond orders of 1.5 that differ in electronic configuration

The one-electron oxidation and one-electron reduction of Re2(µ-Cl)2(µ-dppm)2Cl4(dppm = Ph2PCH2PPh2) can be accomplished using NOPF6 and cobaltocene as the oxidant and reductant, respectively, to give paramagnetic ions that possess metal–metal bond orders of 1.5.

The unusual bioctahedral dirhenium(II,III) complex [Re2(µ-Cl)(µ-CNHBut)(µ-dppm)2Cl2(CNBut)2]PF6[dppm = bis(diphenylphosphino)methane]: a product of the non-cleavage reaction between Re2Cl4(dppm)2 and t-butyl isocyanide

A product from the reaction of the triply bonded complex Re2Cl4(dppm)2[dppm = bis(diphenylphosphino)methane] with two equivalents of t-butyl isocyanide is the novel paramagnetic µ-iminyl dirhenium(II,III) complex [Re2(µ-Cl)(µ-CNHBut)(µ-dppm)2Cl2(CNBut)2]PF6, a species which is different structurally from the complex [Re2Cl3(dppm)2(CNBut)3]PF6 which is formed when three equivalents of isocyanide ligand are used.

The reaction of tetramesityldisilene with cyclohexene oxide and cyclohexene sulfide

Reaction of tetramesityldisilene, 1, with Cyclohexene oxide in benzene at 80 °C gives silyl enol ether, 2, as the major product along with the products of epoxide deoxygenation, Cyclohexene and the known tetramesityldisilaoxirane,3; reaction of 1 with Cyclohexene sulfide occurs rapidly at room temp, to give the known tetramesityldisilathiirane, 6, and Cyclohexene.