Advances in Transition Metal Seleno‐ and Tellurocarbonyl Chemistry

Abstract

In contrastt ot he ubiquity of transition-metal carbonyl, and (to al esser extent) thiocarbonyl complexes,t ransition-metal complexes of carbon monoselenide L n MCSe and monotellurideL n MCTer emain scarce. The last few years, however,h ave seen notable steps towards expanding this chemistry,specifically with regards to new systematic studies on homologous sets of chalcocarbonyl complexes L n MCE (E = O, S, Se, Te), the first reports of new bi-and polynuclear CSe and CTeb ridging complexesa nd ac onfluence with metal carbidoc hemistry.H erein the properties, syntheses and reactions of these rare but fundamentally intriguing compounds are discussed.

C–H activation in bimetallic rhodium complexes to afford N-heterocyclic carbene pincer complexes

“…Additionally, while CO dissociation is plausible, dissociation of CS via cleavage of a Rh–CS bond seems unlikely due to the strong degree of multiple bond character and high energy of the free molecule, indeed this has rarely been inferred for any chalcocarbonyl complexes. 28 A second possibility of hydride migration to the carbonyl group followed by reductive elimination was considered, however formaldehyde was not observed by 1 H NMR spectroscopy, and the intimate mechanism may well be more complicated, involving multi-metallic pathways.…”

Pnictogen‐Functionalised C1 Ligands: MC‐ARn (n=0, 1, 2, 3)

“…Firstly, there is a gradual increase in the strength of the metal–carbon bond (Löwdin bond order 0.94 to 1.17), which contracts down the group (2.094 to 2.034 Å). This might be traced, as in the case of heavier chalcocarbonyls, [70c] to increasingly more effective retrodonation from ruthenium to the CA ligand, a supposition that is supported by the gradual decrease in the negative natural charge for ruthenium, which is accompanied by an increase in the negative charge for the carbon.…”

Fluorocarbyne complexes via electrophilic fluorination of carbido ligands

“…11 Alternatively, lithium/halogen exchange with n BuLi affords, in situ , the lithiocarbynes [M(CLi)(CO) 2 (Tp*)] (M = Mo, W) that allow the introduction of carbyne substituents in electrophilic form. 9,12 This latter approach has allowed the synthesis of carbyne ligands that bear substituents based on boron and all the elements of groups 14–16 as well as a range of transition metals. 11,12…”