Cleavage of homometallic and formation of heterometallic M-M bonds. Serendipitous syntheses of bimetallic MnPd(μ-PPh2)-(CO)4(η2-P-P) (P-P = dppm, dppe, dppf) and polymetallic Mn2Pd2Ag(μ-Cl)(μ-PPh2)2 (μ-dppm)(CO)8

Abstract

Condensation of [Mn2(CO)8(μ-PPh2)]- with Pd(II) assisted by Ag(I) leads to cluster disproportionation, viz. Mn2Pd2Ag(μ-Cl)(μ-PPh2)2 (μ-dppm)(CO)8 and MnPd(μ-PPh2)(CO)4(η2-P-P) (P-P = dppm, dppe, dppf). The former shows a distorted bow-tie structure with two heterometallic triangles {AgPdMn} sharing an Ag center. The unexpected phosphide migration across different metals holds the key to the cleavage and formation of metal-metal bonds. The bimetallic complexes are stabilized by all common diphosphines whereas the polymetallic structure is isolated only when supported by dppm. The latter shows three different types of heterometal-metal bonds Ag-Mn (2.6938(4) Å), Ag-Pd (2.7637(1) Å) and Mn-Pd (2.8183(9) Å) (average values).