Reactions of H2Os3(CO)10 with triallylboranes: formation of novel triosmium boron-containing olefin clusters

Abstract

H 2 Os 3 (CO) 10 (1) reacts with triallylborane B(CH 2 CHQCH 2 ) 3 at 25 1C to form the cluster [Os 3 (CO) 10 (m-Z 2 :Z 2 -trans-MeHCQCH) 2 BC 3 H 7 ] (2). Reaction of 1 with a mixture of triallylboranetrimethallylborane (1 : 3) gives a mixture of clusters 2, [Os 3 (CO) (3) and {Os 3 (CO) 10 [m-Z 2 :Z 2 -(trans-MeCHQCH)(Me 2 CQCH)]BC 3 H 7 } (4). The reaction results in the B-C bond cleavage and the isomerization of two allyl fragments into substituted vinyl groups coordinated to the osmium atoms in an Z 2 -fashion, and reduction of the third fragment to a propyl group. The mechanism of the reaction is discussed based on isotope labelling and influence of the boron substituent ligand on the reaction path and product identity. Clusters 2, 3, 4 are characterized by spectroscopic means as well as by X-ray studies.

Acyclic boron-containing π-ligand complexes: η2- and η3-coordination modes

“…The 13). 90 The divinylborane ligand in 19 is tightly coordinated via both vinyl groups, and may also engage in some degree of Os-B bonding, given that the B-Os(1) and B-Os(2) distances {2.78(1) and 2.79(1) A ˚} lie well within the sum of the van der Waals radii. 91 The reported 11 B NMR chemical shift of 7 ppm is consistent with 4-coordinate boron and/or substantial B-C multiple bond character.…”

Boron, aluminium, gallium, indium and thallium

“…The reaction of the tri-allylborane, B(CH 2 CHQCH 2 ) 3 with the tri-osmium cluster H 2 Os 3 (CO) 10 results in the formation of several new clusters containing coordinated allyl-borane units. 69 A series of 2,5-bis(dimesitylboryl)-1,4-bis(arylethynyl)benzenes that contain various p-substituents on the terminal benzene rings, including NPh, OMe, Me, H, CF 3 , and CN groups, have been synthesised, and the effects of the p-substituents on the absorption and fluorescence properties investigated both in solution and in the solid state. In addition the fluoride ion binding properties of these systems have also been described.…”