Bis-dicarbollide complex

Synthesis and characterization of the first dicarbollide thorium complexes have been reported in 1997. A THF suspension of ThCl4 or a THF solution of ThCl4(TMEDA)2 was reacted with 2 equiv. of lithium dicarbollide (Li2C2B9Hn) to form the anionic bis(dicarbollide) complex [Th(775-G2B9H11)2C12]2 (Scheme 73). By fractional... 

The compounds in which Ln atom is T -bonded with carborane, closo-lanthanoid-carboranes, can be obtained from the interaction of nido-7,8-dicarbollide dianion with lanthanoid halides [19, 24]. Samarium and ytterbium diiodides form a neutral monocage compound whereas trivalent lanthanoids give bis(dicarbollide) complexes [(C2B9H )2Gd] M (THF) (M = Na, BU4N). 

Even the addition of 4 equiv. of dimethylzinc to a bis(dicarbollide)tantalum dichloride, Scheme 23, produced only the monomethyl complex 26 in an isolated yield of 75%.63 In these reactions, the oxidation state of the transition metal and the steric bulk of its ligands obviously play a role in the degree of alkylation. 

Fig. 8-14. The structures of some bis(dicarbollide) metal complexes, (a) The symmetrical structure, (b) The slipped structure.

Recently, some other boron carriers were used to deliver polyhedral boranes into tumor cells. One of the most interesting and new direction is developments in the BNCT driven by nanotechnology [142-147]. This subject will not be discussed here since a special chapter is planned in this book. Carboranylquinazolines [148], carboranyl aminoalcohols [149], carboranyl-a-acyloxy-amides [150], carboranyl glycophosphonates [151], conjugates of icosahedral dicarboranes with cobalt bis(dicarbollide) [152], and platinum complexes containing carborane [153] have been obtained as potential candidates for BNCT. 

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