Rhenium trihalides

The best-known examples of noncarbonyl clusters containing three metal atoms are the rhenium trihalides [(ReO,)iJ and their derivatives. The basic structural unit is shown in Fig. 16.62a. Each rhenium atom is bunded to the other two rhenium atoms directly by metal-metal bonds and indirectly by a bridging halogen ligand. In addition. 

Fig. 16.62 Rhenium(III) clusters (a) The structural unit present in a Rellll) irinuclear cluster. The positions marked O are empty in the trihalides in the gas pha.se but have coordinating groups in other situations. [From Penfold, B. R. In Perspectives in Structural Chemistry, Dunitz, J. D. Ibers, J. A., Eds. Wiley New York, 1968 Vol. 2, p 71. Reproduced with permission.) (b) The structure of solid (RcClj).,. [From Cotton. F. A. Mague. J. T. Inorp. Client. 1964. J. 1402. Reproduced with permission.) (c) fhe IRcjCli f union. [From Bertrand, J. A. Codon. F. A. Dolla.se, W. A. I/Mr.i . Client. 196.1. 2. 1166, Reproduced with permission.)...

Rhenium (III) clusters (a) The structural unit present in a Re(III) trinuciear cluster. The positions marked O are empty in the trihalides in the gas phase but have coordinating groups in other situations. 

Reaction with Allylic Halides, Alcohols, and their Derivatives. Allylation of allyl and propargyl trimethylsilyl ethers as well as benzyl and propargylic alcohol derivatives proceeds in the presence of a catalytic amount of Lewis acids, such as ZnC, TMS(OTf), and B(C6F5)3. Direct substitutions of the hydroxyl group of allylic, ben-zylic, and propargylic alcohols are catalyzed by HN(S02F)2, a rhenium-oxo complex, and InCls (eq 27). A combination of chlorodimethylsilane and allyltrimethylsilane effectively promotes the deoxygenative allylation of aromatic ketones in the presence of a catalytic amount of an indium compound, such as indium trihalide or metallic indium (eq 28). Allylation of cyclic allylic acetates with allyltrimethylsilane can be catalyzed by molecular iodine. ... 

A 8chiff-base condensation reaction apparently results from treating the rhenium metalla-acetylacetone complex (7) with primary aromatic amines (Scheme 1). The tetracarbonylrhenium /3-diketone molecule (7) reacts with boron trihalides to give compounds (9). ... 

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