Alkylidyne carbaborane complex

PROTONATION REACTIONS OF ALKYLIDYNE (CARBABORANE) COMPLEXES OF THE GROUP 6 METALS... 

Similar protonation treatment of the alkylidyne(carbaborane) salts of type 1 yields two types of product, depending on the cage-carbon atom substituents, the particular phosphine, and the substituent on the alkylidyne-carbon atom. Hence the ylid zwitterion complexes 31 and the chelated species 32 are produced as follows (38). Protonation of la with HBF4-Et20 in the presence of dppm yields [closo-1,2-Me2-3,3-(CO)2-3,3- P(Ph)2CH2P(Ph)2C(H)(C6H4Me-4) -3,l,2-WC2B9H9] 31a, while simi-... 

Several types of dimetal product have been obtained by this method. Thus, treatment of equimolar mixtures of the (alkynyl-alkylidyne)metal complexes 4g or 4h and the alkylidyne(carbaborane)metal salts la or lb, with HBF4-Et20 in the combinations shown in Scheme 7, yields the compounds 45 (44). In these products, the icosahedral cage from the precursors 1 adopts the form familiar from protonation reactions described... 

The scope of this area of investigation is illustrated by the observation that numerous primary journal articles have stemmed from the study of essentially two types of cage system (12- and 13-vertex), utilizing only two metals (W and Mo). Extensions of the research into synthetic methods for alkylidyne(carbaborane)metal complexes based on alternative metal centers and/or new cage systems would appear to offer the prospect of dramatic new developments in future years. 

As will be seen in later sections, the complexes in which the heteronuclear metal-metal bonds are bridged by agostic B—H—- metal interactions are intermediates in a variety of reactions involving the carbaborane cages and the /i-alkylidyne ligands. 

Boron atoms in transition metal clusters Denuding the boron atom of B-H interactions in transition metal boron clusters Transition metal boride clusters at the molecular level Recent advances in the chemistry of carborane metal complexes incorporating d and /block elements The interplay of alkylidyne and carbaborane ligands at metal centres. I. Synthesis of electronically unsaturated mixed-metal complexes. II. Proton-mediated reactions... 

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