Synthesis, characterization and crystal structures of two cis/trans pyridine-cyclopalladated ferrocenylimine complexes

Abstract

Two new pyridine-cyclopalladated ferrocenylimine complexes (2a) and (2b) have been easily prepared from the reaction of halogen-bridged palladacyclic dimer (1a) and (1b) with pyridine in high yields. They were fully characterized by elemental analysis, M.s.-e.s.i., I.r., 1 H-n.m.r. and single-crystal X-ray analysis. Complex (2a) adopts a trans geometry in the solid state, while (2b) is cis. There are altogether four different types of intermolecular hydrogen bonds in their crystals. The impressing features include those intermolecular ClÁ Á ÁCl interactions in (2a) and CHÁ Á ÁPd hydrogen bonds in (2b).

Tri-p-tolylphosphine-cyclopalladated ferrocenylpyrimidine complexes: synthesis, crystal structures, catalytic activity, and a palladacycle cocrystallization adduct

“…The catalytic loadings could be lowered to 0.1 mol% without loss of activity (entry 7). Similar to the results for bromobenzene, good yields were also obtained in the case of 4-bromotoluene and 2-bromotoluene (entries [8][9]. Pd(dppf)Cl 2 [bis(diphenylphosphino)ferrocene] is a well known pre-catalyst that effectively catalyzes the reaction between 4-bromoacetophenone and phenyl boronic acid in toluene giving 94% yield [29].…”

“…For example, in palladium-catalyzed carbon-carbon bond formation reactions, palladacycles have shown superiority in many respects, due to their ready preparation and modification, high activity, and comparative stability [3][4][5][6]. In this respect, we have reported a variety of cyclometalated complexes containing N-donor ferrocenyl ligands and found that some cyclopalladated complexes are efficient catalysts for such coupling reactions [7][8][9][10][11][12]. In the cyclopalladation reactions of ferrocenylpyrimidines, owing to the poor solubility of the dimers, they were usually subjected to a bridge-splitting reaction with monophosphines to produce the corresponding monomers [10,12].…”