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The synthesis of two new aminoalcohol functionalized tertiary phosphines o-Ph2PCH2N(H)C6H4(OH) (I) and o-Ph2PCH2N(H)C6H4(CH2OH) (II) are reported. Oxidation with aqueous H2O2 gave the corresponding phosphine oxides o-Ph2P(O)CH2N(H)C6H4(OH) (III) and o-Ph2P(O)CH2N(H)C6H4(CH2OH) (IV) (31P NMR evidence only). The ligating ability of I, II and, in several cases, the known ligand 2,3-Ph2PCH2N(H)C5H3N(OH) (V), was investigated with a range of late transition-metal precursors. Accordingly, reaction of 2 equiv of I (or II) with [MCl2(cod)] (M = Pd or Pt, cod = cycloocta-1,5-diene) gave the corresponding dichloro metal(II) complexes [MCl2(I)2] (M = Pd 1; M = Pt 2) and [MCl2(II)2] (M = Pd 3; M = Pt 4) in which I (and II) P-coordinate. Solution NMR studies reveal that 2 and 4 are exclusively cis whereas 1 and 3 are present as a mixture of cis and (or) trans isomers [4.7:1 (for 1); 2.2:1 (for 3)]. Reaction of 2 equiv of II with [Pt(CH3)2(cod)] gave the neutral complex [Pt(CH3)2(II)2] (5) whose X-ray structure confirmed a cis disposition of "hybrid" ligands. In contrast, reaction of I with [Pt(CH3)2(cod)] gave initially [Pt(CH3)2(I)2] (6) which, upon standing, afforded several products possibly reflecting an increased acidity of the phenolic groups of ligated I. Chloro bridge cleavage reactions of [{Ru(µ-Cl)Cl(p-cymene)}2] or [{Rh(µ-Cl)Cl{C5(CH3)5}}2] with I (or II) proceeds smoothly and gave the mononuclear complexes [RuCl2(p-cymene)I] (7), [RuCl2(p-cymene)II] (8), [RhCl2{C5(CH3)5}I] (9), and [RhCl2{C5(CH3)5}II] (10) in good yield. X-ray crystallography confirms both ruthenium complexes bear P-coordinated I (or II) ligands. Molecules of 7 are linked into linear chains via O-H···Clcoord intermolecular hydrogen bonding, a feature absent in the closely related compound 8. Reaction of [AuCl(tht)] (tht = tetrahydrothiophene) with 1 equiv of I (or II) gave the corresponding gold(I) complexes [AuCl(I)] (11) and [AuCl(II)] (12). Bridge cleavage of the cyclometallated palladium(II) dimers [{Pd(µ-Cl)(C~N)}2] [C~N = C,N-C6H4CH2N(CH3)2, C,N-C10H6N(CH3)2, C,N-C6H4N=NC6H5] with V (or I) gave the neutral complexes [PdCl(C~N)V] (13-15) (or [PdCl(C9H12N)I] (16)), respectively. Chloride abstraction from 13 (or 15) with Ag[BF4] gave the cationic complexes [Pd(C~N)V][BF4] (17) (or 18) in which V P,N pyridyl-chelates to the palladium(II) metal centre. The X-ray structures of 13 and 18 have been determined and confirm the expected coordination environments. An array of intra- and intermolecular H-bonding contacts are also observed. All compounds have been characterized by a combination of spectroscopic and analytical studies.Key words: phosphines, crystal structures, alcohols, precious metals.

N pyridyl complexes were characterised by a combination of multinuclear NMR, IR spectroscopy and elemental analyses. Furthermore the crystal structures of 5È7 and 12 have been determined and reveal several types of NÈHÉ É ÉX (X \ N, F or Cl ; inter-or intra-molecular) hydrogen bonding contacts. The structure of 12 represents an extremely rare, crystallographically characterised, MÈPÈCÈNÈCÈN six-membered metallacyle.

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The two-step synthesis of a new unsymmetrical ligand 2-[Ph2PC6H4C(H)=N]C6H4[N(H)COCH2N(H)CO2Bz], 2.HH, via acid-catalyzed Schiff base condensation of 2-(H2N)C6H4[N(H)COCH2N(H)CO2Bz], 1, with 2-Ph2PC6H4(CHO) in refluxing EtOH is reported. The multidentate ligand 2.HH, isolated in ca. 60% yield, exhibits an array of ligation modes, as exemplified by coordination studies with NiII, PdII, PtII, and AuI mononuclear metal precursors. Hence, reaction of 2.HH with AuCl(tht) (1:1 molar ratio, tht = tetrahydrothiophene) affords AuCl(2.HH), 3, in which the ligand behaves as a classic, neutral two-electron phosphorus donor. In contrast, reaction with MCl2(cod) (M = Pt, Pd; cod = cycloocta-1,5-diene) affords the corresponding dichloro complexes MCl2(2.HH) (4a M = Pt; 4b M = Pd) in which kappa2-P/N-chelation through both P and imino N-donor atoms is observed. Likewise, treatment of Pd(CH3)Cl(cod) with 2.HH gave Pd(CH3)Cl(2.HH), 4c, in which the imino nitrogen is trans to the methyl ligand. Cycloocta-1,5-diene elimination from, and single methyl protonation of, Pt(CH3)2(cod) with 1 equiv of 2.HH in toluene at ambient temperature affords the neutral complex Pt(CH3)(2.H-), 5a, in which 2.H- functions effectively in a kappa3-PNN' coordination mode. The dichloro compounds 4a or 4b undergo smooth N(H) deprotonation with tBuOK to give 6a\6a' and 6b\6b' in which 22- acts as a dianionic kappa4-PNN'N' ' ligand. The corresponding square-planar, diamagnetic, nickel(II) complex 6c\6c' was prepared in excellent yield from NiCl2.6H2O, 2.HH, and tBuOK. Variable-temperature NMR experiments confirm 6a\6a' and 6b\6b' exist, in solution, as a pair of conformational (anti and syn) isomers due to restricted rotation about the N-CO2Bz group. This feature is also borne out by single-crystal X-ray studies of anti-6a.CHCl3, syn-6a'.H2O, anti-6b.CHCl3, and anti-6c.CH2Cl2. To the best of our knowledge, we believe these constitute the first examples of crystallographically characterized conformers of a tetradentate ligand incorporating a P-donor center. All new compounds reported have been fully characterized by a combination of spectroscopic (NMR, FT-IR, ES-MS) and analytical methods. Furthermore, single-crystal X-ray studies have also been undertaken on compounds 2.HH, 3, 4a, and 5a.Et2O.