Triply Bridged Borylene Complexes

Metallaborane and borylene complexes are related to some extent because both types possess direct metal-boron bonds however, the nature of these interactions is varied. In metallaborane clusters, the framework is made up by nonclassical, electron-deficient, multicenter two-electron bonds, while the borylene ligand (BR) is related to one or more transition metal centers by classicrJ, electron-precise, two-center two-electron (2c-2e) bonds [280 -283]. Since the discovery of various bridged and terminal borylene complexes by Braunschweig and Aldrige, the chemistry of this subarea of transition metal complexes of boron has received significant attention from both structure/bonding and 

Chart 5.3 Different types of triply bridged borylene molecules. 

Cotton, F.A., Murillo, C.A., and Walton, R.A. (2005) Multiple Bonds Between Metal Atoms, John Wiley Sons, Inc., New York. 

Cotton, EA. (1981) in Transition Metal Chemistry, Proceedings Conference (eds A. Muller and E. Diemann), Verlag Chemie, Weinheim, p. 451. 

Kepert, D.L. (1972) The Early Transition Metals, Academic Press, London. 

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Table 5.8 Structural parameters and chemical shift values of triply bridged borylene complexes.

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