Metal complexes of benzodiazepines. Part 1. Synthesis, crystal structure, and characterization in solid and solution of trans-dichloro(7,8-dichloro-2,3-dihydro-2,2,4-trimethyl-1H-1,5-benzodiazepine)(tri-n-propylphosphine)-palladium(II)

Abstract

The complex, [PdCl₂L(PPrⁿ₃)], which to our knowledge is the first example of a metal complex of 1,5-benzodiazepines, is easily obtained by cleavage of the bridged complex [Pd₂Cl₄(PPrⁿ₃)₂] with 7,8-dichloro-2,3-dihydro-2,2,4-trimethyl-1H-1,5-benzodiazepine (L) in CH₂Cl₂. Proton and ¹³C n.m.r. spectra in CDCl₃ of the complex suggest that the ligand is co-ordinated through N(5). Single-crystal analysis confirms that the benzodiazepine is indeed co-ordinated through this nitrogen atom and the geometry around palladium is square planar with the two chlorides trans to each other. Co-ordination affects bond distances and angles without changing the boat conformation of the ligand.