Transition metal complexes metallaboranes

In contrast to other transition metal compounds of boron such as borides or metallaboranes, the class of transition metal complexes of boron, e.g. borane (I), boryl (II), and borylene (Ilia, b) complexes (Figure I), are characterized by two-center-two-electron bonds between the metal center and boron. 

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... 

Metallaborane cluster complexes of the post-transition metals 167... 

This section reviews the developments in the chemistry of monoborane complexes of the transition metals especially borohydride and hydridoborate complexes. Although such complexes are not strictly metallaboranes in the sense that they are not cluster species, they are included here as they share many similarities with polyborane species of the transition metals such as three-center two-electron bonding. Additionally, as will be shown in Section 3.04.3.1 borohydride species can also be intermediates in the formation of larger M By clusters. In this chapter, three-coordinate monoborane species, which are best considered as cr-complexes between a transition metal and HBR2 or metal-boryl (M-B) species, are not considered. 

Some examples of complexes of metallaboranes of post-transition metals are given in Table 14. 

Metallaboranes, and /-Block metallaboranes, overview, 3,133-174 Metallacarboranes 7-block metal characteristics, 3, 200 deblock metal overview, 3, 175-264 early transition elements, 3, 201 /-block metal characteristics, 3, 246 /-block metal overview, 3, 175-264 late transition elements, 3, 221 linked cage and multi-decker complexes, 3, 245 mid-transition elements, 3, 214 Metallacarbynes, molybdenum, and palladium complexes, 8, 211... 

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