Cationic and neutral palladium(ii) methyl complexes of di-N-heterocyclic carbenes

Abstract

Cationic and neutral methyl complexes of Pd(II) incorporating di-N-heterocyclic carbenes, ^tBuCC^meth and ^tBuCC^eth (where ^tBuCC^meth = 1,1′-methylene-3,3′-di-tert-butyldiimidazol-2,2′-diylidene and ^tBuCC^eth = 1,2-ethylene-3,3′-di-tert-butyldiimidazol-2,2′-diylidene), have been prepared. The complexes [Pd(^tBuCC^meth)Me₂] (1) and [Pd(^tBuCC^eth)Me₂] (2) have been isolated and 2 has been characterised by single crystal X-ray diffraction. When 1 and 2 are dissolved in deuterated methanol in the presence of pyridine or bipyridine the four coordinate cations [Pd(^tBuCC^meth)Me(py)]⁺ (3), [Pd(^tBuCC^eth)Me(py)]⁺ (4), [Pd(^tBuC(D)-η-C^meth)Me(η²-bipy)]⁺ (5), and [Pd(^tBuC(D)-η-C^eth)Me(η²-bipy)]⁺ (6), are observed spectroscopically.