Synthesis and properties of amido- and alkoxopalladium(II) complexes with tmeda ( N, N, N′, N′-tetramethylethylenediamine) ligand

Abstract

PdCl 2(tmeda) reacts with NaN(SiMe 3) 2 to give PdCl[N(SiMe 3) 2](tmeda) ( 1). Single crystal X-ray analysis shows the structure of 1 which has a slightly distorted square planar coordination around the Pd center with PdN(amido) bond distance of 2.043(6) Å and PdN(amine) bond distances of 2.104(7) and 2.102(7) Å, respectively. Reactions of complex 1 with 1,1,1,3,3,3-hexafluoro-2-propanol and with phenol cause substitution of the amido ligand to give the corresponding alkoxide and phenoxide palladium complexes, PdCI(OR)(tmeda) ( 2: R  CH(CF 3) 2, 3: R  C 6H 5, respectively). Reactions of dimethylpalladium complex, PdMe 2(tmeda), with the fluoro alcohol and with phenol give PdMe(OCH(CF 3) 2)(tmeda) ( 4) and PdMe(OC 6H 5)(tmeda) ( 5), respectively. Complex 5 reacts further with HOPh to give PdMe(OC 6H 5)(tmeda) · (HOPh) ( 6) whose 1H NMR spectrum shows the OH hydrogen peak at extremely low magnetic field position (10.3 ppm) due to strong OH … O hydrogen bonding between the phenoxide ligand and phenol. The tmeda ligand in complex 4 is easily displaced by addition of phosphine ligands such as dppm (bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)ethane), and dppp (1, 3-bis(diphenylphosphino)propane) to give the corresponding palladium alkoxide complexes with the phosphine ligand, PdMe(OCH(CF 3) 2)(L) ( 7: L = dppm; 8: L = dppe; 9: L = dppp).