Synthesis and characterisation of the six-membered cyclopalladated complexes of 2-benzylbenzothiazole

Abstract

The six-membered cyclopalladated complex di- μ-acetato-bis[2-(2′-thiazolylmethyl)phenyl- C 1, N]dipalladium(II), [{Pd( μ-O 2CMe) ( η 2-bbt)} 2] ( η 2-bbt = 2-(2′-thiazolylmethyl) phenyl- C 1, N), has been prepared by the reaction of palladium(II) acetate and 2-benzylbenzothiazole. Its di-μ-halogeno analogues [{Pd( μ-K) ( η 2-bbt)} 2], synthesised by the metathetical reaction with LiCL or NaX, undergo bridge-splitting reactions with some pyridine derivatives and thallium(I) acetylacetonate to yield corresponding mononuclear cyclopalladated complexes. The cyclopalladated feature and the six-membered structure have been confirmed by the 1H NMR spectra of the mononuclear pyridine complexes. Temperature-dependent 1H NMR spectra have been observed for [{Pd( μ-O 2CMe) ( η 2-bbt)} 2] and [Pd(acac) ( η 2-bbt)] and are attributed to inversions of acetato bridges and the boat-formed six-membered ring, respectively.