Heteronuclear complexes stoichiometry

This field has developed at a rapid pace since 1968, and a wide range of heteronuclear complexes of the tri- and tetranuclear variety has been established. It will be convenient to discuss the compounds in the first instance on the basis of nuclearity and, for the tetranuclear species, to subdivide the discussion on the basis of the carbonyl stoichiometry and cluster electron count. We have excluded from the discussion the interaction with nontransition elements, such as Hg, Tl, and Cd, which form a wide range of compounds. 

Heteronuclear Complexes, Like protonation of cis-Pt (NH )2L2, binding of heterometals or of a second Pt (vide infra) occurs readily. Guay and Beauchamp have reported similar findings with Ag (54) and CH Hg (55) coordinated to N3 of 1-MeT. Among the isolated heteronuclear complexes of cis-Pt(NH ) two types of complexes have been established using X -ray crystallo- graphy complexes of Pt,M and Pt ,M stoichiometries. 

Metal carbonyls, such as Fe(CO)s and other organometallic complexes have been reported to react preferentially with metallic rather than with oxidic surfaces to the corresponding metals. Though the thus performed decomposition of suitable organometallic complexes ensures the formation of exclusively bimetallic particles, the composition of the individual particles may still vary. Preparation procedures based on the deposition of heteronuclear complexes are therefore much more attractive. The fixed stoichiometry of the complexes favours the desired uniform composition of the individual supported particles. Polynuclear metal carbonyls have proved to be very suitable for the preparation of bimetallic... 

Homo- and heteronuclear cyanide complexes are attractive precursors for the preparation of supported catalysts. First of all since the reaction with the support to an inactive compound does not proceed appreciably, and secondly, since the fixed stoichiometry of the complex cyanides results in active particles of a uniform chemical composition. 

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