Late transition metal complexes of a new P-N ligand Ph₂PCH₂N(H)C₅H₃(Cl-5)N: synthesis and structural studies

A new functionalised pyridylphosphine Ph2PCH2N(H)C5H3(Cl-5)N 1 has been synthesized from Ph2PCH2OH and 2-H2NC5H3(Cl-5)N. Reaction of 1 with aqueous H2O2 gave Ph2P(O)CH2N(H)C5H3(Cl-5)N 2. The crystal structures of 1 and 2 reveal, in both cases, dimer pair formation through N-H . . .N-pyridyl or N-H . . . OP intermolecular hydrogen bonding respectively. Chloro bridge cleavage of either [{RuCl(mu -Cl)(eta (6)-p-MeC6H4Pri)}(2)], [{RhCl(mu -Cl)(eta (5)-C5Me5)}(2)] or [{Pd(C12H12N)(mu -Cl)}(2)] with two equivalents of 1 gave the mononuclear complexes [RuCl2(eta (6)-p-MeC6H4Pri)1] 3, [RhCl2(eta (5)-C5Me5)1] 4 or [PdCl(C12H12N)1] 5 (P trans to N) respectively. The chloro complexes [AuCl(1)] 6, [PtCl2(1)(2)] 7 and [PdCl2(1)(2)] 8 were prepared by substitution of tht (tetrahydrothiophene) (or cod) from [AuCl(tht)] or [MCl2(cod)] (M = Pt or Pd). In 3-8 only P-ligation of 1 was observed. Chloride abstraction from either 3-5 or 7, 8 using Ag[BF4] gave the cationic complexes [RuCl(eta (6)-p-MeC6H4Pri){Ph2PCH2N(H)C5H3(Cl-5)N-P,N}][BF4] 9, [RhCl(eta (5)-C5Me5){Ph2PCH2N(H)C5H3(Cl-5)N-P,N}][BF4] 10, [Pd(C12H12N){Ph2PCH2N(H)C5H3(Cl-5)N-P,N}][BF4] 11 and cis-[M{Ph2PCH2N(H)C5H3(Cl-5)N-P,N}(2)][BF4](2) (M=Pt 12 or Pd 13) in which 1 chelates through both P and N-pyridyl donor atoms. All complexes were characterised by a combination of multinuclear NMR, IR spectroscopy and elemental analyses. Furthermore the crystal structures of 5-7 and 12 have been determined and reveal several types of N-H . . .X (X = N, F or Cl; inter- or intra-molecular) hydrogen bonding contacts. The structure of 12 represents an extremely rare, crystallographically characterised, M-P-C-N-C-N six-membered metallacyle.