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···Npyridyl or N–H···OP intermolecular hydrogen bonding respectively. Chloro bridge cleavage of either [{RuCl(μ-Cl)(η6-p-MeC6H4Pri)}2], [{RhCl(μ-Cl)(η5-C5Me5)}2] or [{Pd(C12H12N)(μ-Cl)}2] with two equivalents of 1 gave the mononuclear complexes [RuCl2(η6-p-MeC6H4Pri)1] 3, [RhCl2(η5-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(η6-p-MeC6H4Pri){Ph2PCH2N(H)C5H3(Cl-5)N-P,N}][BF4] 9, [RhCl(η5-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 Npyridyl 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.