The aminophosphine-phosphinites and related ligands: synthesis, coordination chemistry and enantioselective catalysis1Dedicated to the memory of Professor Francis Petit1

Tetracarbonyl group 6B metal complexes of a N-(4-acetylphenyl)-N-(diphenylphosphino)amine ligand. Molecular structure of cis-[Cr(CO)4{4-CH3CO-C6H4-1-N(PPh2)2}]

Chemical reactions of N-(4-acetylphenyl)-N-(diphenylphosphino)amine ligand (1) with three group 6B metal hexacarbonyls produced cis-M(CO)₄[1-_k ² P,P][ M = Cr(2), Mo(3), W(4)], respectively. The novel complexes 2-4 were isolated and their structures were elucidated by multinuclear NMR spectroscopy (¹H, ¹³C, ³¹P NMR) and elemental analysis. Crystal-structure determination using single-crystal X-ray diffraction was carried out on complex 2.

P-Stereogenic N-Phosphine-Phosphite Ligands for the Rh-Catalyzed Hydrogenation of Olefins

We have identified a successful family of simple P-stereogenic N-phosphine-phosphite ligands for the Rh-catalyzed asymmetric hydrogenation of olefins. These catalysts show excellent enantiocontrol for α-dehydroamino acid derivatives and α-enamides (ee's up to >99%) and promising results for the more challenging β-analogues (ee's up to 80%). The usefulness of these catalytic systems was further demonstrated with the synthesis of several valuable precursors for pharmacologically active compounds, with ee's at least as high as the best ones reported previously (up to >99%).

Mono- and dinuclear cobalt complexes with chelating or bridging bidentate P,N phosphino- and phosphinito-oxazoline ligands: synthesis, structures and catalytic ethylene oligomerisation

Cobalt(ii) complexes of the type [CoCl(2)(P,N)], where P,N represents a heterobidentate phosphino- or phosphinito-oxazoline-type ligand, have been synthesised and characterised by infrared spectroscopy and elemental analysis. Their molecular structures were established by single-crystal X-ray diffraction in the solid state. Whereas the phosphino-oxazoline complex [CoCl(2){Ph(2)PCH(2)ox(Me2)}] (Ph(2)PCH(2)ox(Me2) = 2-[(diphenylphosphanyl)-methyl]-4,4-dimethyl-4,5-dihydro-oxazole) () and the phosphinito-oxazoline complexes [CoCl(2){Ph(2)POCH(2)ox(Me2)}] (Ph(2)POCH(2)ox(Me2) = 1-[4,4-dimethyl-2{1-oxy(diphenylphosphino)-1-methyl}]-4,5-dihydro-oxazole) () and [CoCl(2){Ph(2)POCMe(2)ox(Me2)}] (Ph(2)POCMe(2)ox(Me2) = 1-[4,4-dimethyl-2- [1-oxy(diphenylphosphino)-1-methylethyl]]-4,5-dihydrooxazole) () are mononuclear, the phosphino-oxazoline complexes [CoCl(2){micro-i-Pr(2)PCH(2)ox}](2) (i-Pr(2)PCH(2)ox = 2-[(diisopropyl-phosphanyl)-methyl]-4,5-dihydro-oxazole) () and [CoCl(2){micro-Ph(2)PCH(2)ox}](2) (Ph(2)PCH(2)ox = 2-[(diphenyl-phosphanyl)-methyl]-4,5-dihydro-oxazole) () are dinuclear compounds and contain two bridging phosphino-oxazoline ligands which form a 10-membered ring. In the course of this work, the zwitterionic complex [CoCl(3){Ph(2)PCH(2)C(O)OCH(2)CMe(2)NH(3)] () was obtained and characterised by X-ray diffraction in which the oxazoline ring has been opened. Air-oxidation of the phosphine function of the mononuclear P,N chelate complex yielded the blue N,O-bridged, centrosymmetric dinuclear complex [[upper bond 1 start]CoCl(2){micro-OPPh(2)CH(2)[lower bond 1 start]C[double bond, length as m-dash]N[upper bond 1 end]CMe(2)CH(2)O[lower bond 1 end]}](2) () which contains a 12-membered ring. All these complexes are paramagnetic and their magnetic moments in solution were measured by the Evans method. Complexes were evaluated in the catalytic oligomerisation of ethylene with AlEtCl(2) or methylaluminoxane (MAO) as cocatalysts and provided moderate activities. In the presence of AlEtCl(2) (6-14 equiv.), the selectivities for ethylene dimers were higher than 92% and complex showed the highest turnover frequency with 14 equiv. of AlEtCl(2). When MAO was used as cocatalyst, the catalytic activities were similar to those with AlEtCl(2) but significant amounts of C(6)-C(12) oligomers were produced.

Syntheses, structures, and optical properties of novel zinc(ii) complexes with multicarboxylate and N-donor ligands

Five novel coordination polymers [Zn(2)(OA)(4,4'-bipy)(H(2)O)].0.5(4,4'-bipy), [Zn(2)(OA)(dib)(H(2)O)].H(2)O, [Zn(2)(OA)(bbi)(2)].3H(2)O, [Zn(2)(OA)(phen)(2)(H(2)O)] and [Zn(4)(OA)(2)(2,2'-bipy)(2)(H(2)O)].2H(2)O were obtained by hydrothermal reactions of Zn(NO(3))(2).6H(2)O with a V-shaped multicarboxylate ligand 3,3',4,4'-oxydiphthalic acid (H(4)OA) and a series of N-donor ligands, namely 4,4'-bipyridine (4,4'-bipy), 1,4-di(1-imidazolyl)benzene (dib), 1,1'-(1,4-butanediyl)bis(imidazole) (bbi), 1,10-phenanthroline (phen), 2,2'-bipyridine (2,2'-bipy). The structures of the complexes were established by single-crystal X-ray diffraction analysis. Complex exhibits a robust 3D porous structure with uncoordinated 4,4'-bipy molecules filling the cavities. Complexes and show a complicated 3D framework, while complexes and have a 2D network and a 1D helical chain structure, respectively. The results indicate that the multicarboxylate OA(4-) ligand can adopt varied coordination modes in the formation of the complexes and the influence of the N-donor ligand on the structure of the complexes is discussed. The photoluminescence properties of H(4)OA and were studied in the solid state at room temperature. Moreover, nonlinear optical measurements showed that displayed a second-harmonic-generation (SHG) response of 0.5 times of that for urea. The results suggested that the configuration and flexibility of the ligands play a key role in directing the related properties of the complexes.