Synthesis and Reactivity of Triangular Heterometallic ComplexesContaining Zn-Zn Bond br
Résumé
This work provides a facile access to a series oftriangular [Zn2M] (M = group 10 and 11 metals) clusters.Treatment of Zn-Zn-bonded compounds [LZn-ZnL](L=CH3C(2,6-iPr2C6H3N)CHC(CH3)(NCH2CH2PR2); R = Ph,iPr)with zero-valent transition-metal reagents selectively afforded thecorresponding triangular clusters [Zn2M], where M = Ni(0),Pd(0), and Pt(0). Notably, the isoelectronic triangular clusters[Zn2M]+, where M = Ag(I) and Cu(I), could also be obtained byreactions of [LZn-ZnL] with AgOTf and CuOTf, respectively.The [Zn2Ag]+complex containing elusive Zn-Ag bonds wasinvestigated by density functional theory analysis, showing a 3c-2ebonding feature in the metallic ring. The electrochemical behaviorsof [Zn2M] complexes were examined and revealed the donation ofelectron density from the Zn-Zn Sigma-bond to the metal centers. Reaction of the [Zn2Ni] complex with isocyanide gave heterometallicspecies by coordination of isocyanide to the nickel center, keeping the trimetallic ring core structure intact. In contrast, the Zn-Znbond was rapidly cleaved upon treatment of the [Zn2Ni] complex with dihydrogen or phenyl acetylene, generating the hydride- oracetylide-bridged heterotrimetallic complex