58178-09-9Relevant academic research and scientific papers
New κ3-PNN′- and κ4-PNN′O- polydentate ligands: Synthesis, coordination and structural studies
Elsegood, Mark R.J.,Sanchez-Ballester, Noelia M.,Smith, Martin B.
experimental part, p. 115 - 121 (2012/02/02)
The three-step synthesis of new mixed P/N/N′/O-donor ligands C 6H3(OH){2-NHC(O)CH2NCHC6H 4PPh2}(4-CH3) 3a·HH and C 6H4(OH){3-NHC(O)CH2NCHC6H 4PPh2} 3b·HH, by Schiff base condensation of the 1° amines C6H3(OH){2-NHC(O)CH2NH 2}(4-CH3) 2a or C6H4(OH){3-NHC(O) CH2NH2} 2b with C6H4(CHO)(2-PPh 2) in refluxing EtOH, is described. Reaction of 1 equiv. of 3a·HH or 3b·HH with MCl2(cod) (M = Pt, Pd; cod = cycloocta-1,5-diene) affords the κ2-PN-chelate complexes MCl2(3a·HH) (M = Pd 4a; M = Pt 4b) and MCl 2(3b·HH) (M = Pt 4c). The dichlorometal(II) complexes 4d and 4e, bearing instead a pendant 4-phenolic group, were similarly prepared (in >90% yield). Chloro-bridge cleavage of [Pd(μ-Cl)(η3-C 3H5)]2 with 3a·HH or 3b·HH gave the monocationic κ2-PN-chelate complexes [Pd(η3- C3H5)(3a·HH)]Cl 5a or [Pd(η3-C 3H5)(3b·HH)]Cl 5b, respectively. Elimination of cod, and single CH3 protonation, from Pt(CH3) 2(cod) upon reaction with 1 equiv. of 3a·HH or 3b·HH in C7H8 at room temperature afforded the neutral complexes C6H3(OH){2-NC(O)CH2NCHC6H 4PPh2Pt(CH3)}(4-CH3) 6a and C 6H4(OH){3-NC(O)CH2NCHC6H 4PPh2Pt(CH3)} 6b, respectively bearing a monoanionic (3a·H- or 3b·H-) κ3-PNN′-tridentate ligand. Amide and phenol deprotonation were readily achieved, using KOtBu as base, to give high yields of the κ4-PNN′O-tetradentate complexes C6H 3(O){2-NC(O)CH2NCHC6H4PPh 2Pd}(4-CH3) 7a and C6H3(O){2-NC(O) CH2NCHC6H4PPh2Pt}(4-CH3) 7b bearing the dianionic ligand 3a2-. All new compounds have been characterised by multinuclear NMR, FTIR, mass spectroscopy and microanalysis. Single crystal X-ray studies have been performed on compounds 1b·1.5CH2Cl2, 3b·HH·0.5Et 2O, 6b·CHCl3 and 7b·0.5Et2O.
