G. Vasapollo

Novel nickel catalyzed conversion of 2-bromo-1-phenyl-1,3-butadiene to an α keto lactone. An example of double carbonylation of a halodiene

Abstract Nickel cyanide and phase transfer catalyzed carbonylation of 2-bromo-1-phenyl-1,3-butadiene affords an methylene-α-keto lactone in good yield; isomerization to a ketobutenolide occurs on silica gel.

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II)

Abstract Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II) of the type M(pnp)(CONHR)Cl (pnp = 2,6-bis(diphenylphosphinomethyl)pyridine; M ue5fbPd, R ue5fb C6H5, p-CH3C6H4, p-CH3OC6H4, C6H11, t-Bu; M ue5fb Pt, R ue5fb C6H5), Pd(pnp)[CON(Pr)2]Cl (Pr = propyl), M(pnp)(COOR)Cl (M ue5fb Pd, R ue5fb C6H5, CH3; M ue5fb Pt, R ue5fb CH3), Pd(pnp)(COOCH3)2 result from reaction of M(pnp)Cl2 with carbon monoxide and amines or alkoxides at room temperature and atmospheric pressure. The carbamoyl complexes react with bases to give urethane or diphenylurea depending upon the experimental conditions.

Synthesis and reactivity toward gas molecules of chloro 2,6-di(diphenylphosphinomethyl)pyridine rhodium(I)

Abstract The synthesis of the title compound and of its adducts with O 2 , CO, CO 2 , SO 2 , tertiary phosphines is described. The reactions of the dioxygen adduct with sulfur dioxide and carbon monoxide are also reported.

Rhodium and iridium complexes containing nitrosoarene ligands

Abstract A number of new nitrosoarene complexes of rhodium(I) and iridium(I) have been prepared, and characterized by elemental analysis, IR spectroscopy and 1H NMR spectroscopy. Some reactions of the complexes have been studied.

Stereospecific nickel and phase transfer catalyzed carbonylation of vinyl bromides and chlorides

Abstract Nickel cyanide catalyzes the carbonylation of vinyl bromides and chlorides to α,β-unsaturated acids.

Olefin ligands. Syntheses and structures of 2,6-diallylpyridine (DAP) complexes of rhodium(I); crystal structures of [Rh(COD)(DAP)][RhCl2(COD)] and [Rh(COD)(DAP)][CuCl2]

Abstract The olefinic ligand 2,6-diallylpyridine (DAP) has been shown to react with various rhodium(I) compounds to give complexes of the type [RhCl(DAP)] n , RhCl(L)(DAP) (L = CO, PPh 3 ), [Rh(diene)(DAP)]Y (diene = cycloocta-1,5-diene (COD), bicyclo[2.2.1]hepta-2,5-diene (NBD); Y = [RhCl 2 (diene)], [CuCl 2 ], ClO 4 ). These complexes have been characterised by chemical and spectroscopic means. In addition, the crystal structures of [Rh(COD)(DAP)][RhCl 2 (COD)] ( 1 ) and [Rh(COD)(DAP)][CuCl 2 ] ( 2 ) have been determined by X-ray methods. Crystal of 1 are triclinic, space group P 1 , with Z = 2 in a unit cell of dimensions a 10.481(4), b 13.041(4), c 10.456(4) A, α 106.77(2), β 112.10(2), γ 79.57(1)°. Crystals of 2 are monoclinic, space group P 2 1 / c , with Z = 4 in a unit cell of dimension a 14.303(8), b 10.453(5), c 13.412(6) A, β 110.95(4)°. Both structures were solved from diffractometer data by direct and Fourier methods and refined by blocked full-matrix least-squares to R = 0.0316 (2204 observed reflections) for 1 and by full matrix least-squares to R = 0.0545 (1897 observed reflections) for 2 . The crystals consist of cationic [Rh(COD)(DAP)] + and anionic [Rh(COD)Cl 2 ] − ( 1 ) and [CuCl 2 ] − ( 2 ) complexes. The cations are similar in the two compounds, and the coordination around the Rh I atoms can be described as trigonal bipyramidal, with a “short” Rhue5f8N axial bond and four η 2 -Cue5fbC olefinic interactions. The DAP acts as a tridentate ligand.

Nitrosyltris(triphenylphosphine)rhodium and nitrosyltris(triphenylphosphine)cobalt as nitrosyl transfer reagents

Abstract Intermolecular transfer of the nitrosyl ligand in RhNOP 3 and CoNOP 3 to NiCl 2 P 2 , CoCIP 3 CoCl 2 P 2 , Co(dpe) 2 (ClO 4 ) 2 , FeCl 2 dpe [P = PPh 3 ;dpe= 1,2-bis-(diphenylhosphino)ethane] readily occurs atroom temperature. On treating RhNOP 3 with trityl and silver perchlorate, the cationic species [RhP 3 )(Me 2 - CO)] + and [Rh(NO) 2 P 2 ] + have been obtained. IR spectroscopic evidence of the formation of a nitrosyl bridge is cited.

NO bond length/stretching frequency realtionships in C-nitroso compounds and their coordination complexes

The mode of coordination of monomeric C-nitroso compounds to metals is discussed. In contrast to previous studies it is proposed that an understanding of the v(Nue5f8O)/r(Nue5f8O) and r(Cue5f8N)/r(Nue5f8O) relationships in the non-coordinated nitrosocompounds is of primary importance for assesment of the coordination mode. It is concluded that both v(Nue5f8O)/R(Nue5f8O) and r(Cue5f8N)/r(Nue5f8O) have linear interrelationships in C-nitroso compounds that the coordination compounds of RNO have the same v(Nue5f8O)/r(Nue5f8O) relationship as the non-coordinated monomers. Previous correlations of Δv(Nue5f8O) with coordination mode are therefore correlations of r(Nue5f8O) with coordination mode. σ-N and σ-O complexes of aromatic RNO conform to the same R(Cue5f8N)/r(Nue5f8O) equation (within a very small error) as the non-coordinated monomers. The extent of deviation from the r(Cue5f8N)/(r(Nue5f8O) relationship for complexes of aliphatic RNO is of a similar order of magnitude to that which occurs when C-nitroso monomers form the trans-dimer. The coordination mode of aliphatic RNO is, with one exception, σ-N. Nitrosobenzene has a variety of coordination modes to transition metals but does not display σ-O coordination. p-Nitrosodimethylaniline undergoes σ-O coordination to d10 metals.

2,6-Bis(diphenylphosphinomethyl)pyridine complexes of nickel(II), cobalt(II), iron(II)

Abstract Some new 2,6-bis(diphenylphosphinomethyl)pyridine (pnp) complexes of nickel(II), cobalt(II) and iron(II) were prepared and their physical properties were determined and compared with those of some previously described nickel(II) complexes. A pentaco-ordinate molecular structure (distorted tirgonal bipyramidal), instead of the previous square-planar, is now suggested for [Ni(pnp) 2 ] 2+ . For Ni(pnp)-(NCS) 2 , previously described as a mixture of low-spin and high-spin forms of a five-co-ordinated molecule, the interallogon formulation [Ni(pnp)NCS] [Ni(pnp)-(NCS) 3 ], which receives strong support from the experimental data, is suggested. The hexa-co-ordinated Ni(pnp)(NO 3 ) 2 , the penta-co-ordinated high spin Co(pnp)(NO 3 ) 2 and Fe(pnp)(NO 3 ) 2 , and the hexaco-ordinated low-spin [Co(pnp) 2 ](ClO 4 ) 2 and [Fe(pnp) 2 ](ClO 4 ) 2 are also described. The equilibrium constant for the hydration reaction of Ni(pnp)Cl 2 in n-BuOHue5f8H 2 O solution is determined.

Carbonylation of nitrosobenzenes to carbamate esters catalyzed by palladium and cupric acetates under ambient conditions

Abstract Palladium acetate and cupric acetate are effective catalysts for the reaction of nitrosobenzenes with carbon monoxide and alcohol at room temperature and one atmosphere.