Synthesis of copper,nickel and cobalt complexes containing a new N2S2 ligand: benzyl-N,N′-alkylbis(2-amino-1-cyclopentencarbodithioate)

The synthesis of [benzyl-N,N-alkylbis(2-amino-1-cyclopentencarbodithioate)]M^II [alkyl = ethene (L₂) and propene, (L₃) and M = Cu, Ni and Co] complexes and their characterization (u.v.–vis., FT-IR, ¹H-n.m.r., mass spectra and cyclic voltametry) are reported.     

Configurational stability in some 3-coordinate phosphorus compounds

PMR spectra of a variety of 4,4,5,5-tetramethyl-1,3,2-dioxaphospholanes, bearing different substituents at phosphorus, have been determined at different temperatures. There is no inversion at phosphorus detectable. The P-chloro compound undergoes a chemical exchange process the rate of which is concentration dependent.     

Synthesis of methyl‐2,4‐bis(cyclohexane)dispiro‐1,2,3,4,4a,5,6,7‐octahydro‐(lH,3H)quinazoline‐8‐carbodithioate derived from cyclohexanone in one step

The new compound Methyl‐2,4‐bis(cyclohexane)dispiro‐1,2,3,4,4a,5,6,7‐octahydro‐(1H,3H)‐quinazo‐line‐8‐carbodithioate has been synthesized from cyclohexanone and carbon disulfide. It has been characterized by uv‐visible, FTTR , mass spectra and a complete structure proposed based on ¹H and ¹³C NMR spectroscopy.     

Methane Conversion Over Sr2+/La2O3 Catalyst Modified with Nickel and Copper

Methane transformation over Ni and Cu modified Sr²⁺/La₂O₃ catalysts has been studied. These species favor formation of reducible mixed oxides and change the surface reactivity of the Sr²⁺/La₂O₃ system, modifying the reaction mechanism, since Sr²⁺/La₂O₃ favors methane oxidative coupling but with copper methane combustion is favored and nickel favors partial oxidation.     

Aqueous biphasic olefin hydroformylation catalyzed by water-soluble rhodium complexes

Catalysis with water-soluble rhodium complexes, RhCl(CO)(TPPMS)₂, [TPPMS = P(C₆H₅)₂(C₆H₄SO₃)] (1), RhCl(CO)(TPPDS)₂, [TPPDS = P(C₆H₅)(C₆H₄SO₃)₂] (2) and RhCl(CO)(TPPTS)₂, [TPPTS = P(C₆H₄SO₃)₃] (3) in hydroformylation of 1-hexene, 2-pentene, 2,3-dimethyl-1-butene, cyclohexene and several mixtures of these olefins have been studied, under moderate reaction conditions (T: 50–150 °C; pCO/pH₂ = 1; total p: 14–68 bar; Substrate/Catalyst: 600/1) in biphasic toluene/water media. The catalytic system shows high activity but low selectivity. The linear and branched oxygenated products obtained are equally useful in naphtha upgrading, as observed in the real El Palito naphtha tried. The catalysts can be recycled several times without significant activity loss.     

Biphasic catalysis with RuCl2(DMSO)(TPPMS)3

A mononuclear RuCl₂(DMSO)(TPPMS)₃ complex (1) (TPPMS = triphenylphosphine monosulfonate) has been synthesized. Spectroscopic analysis by i.r., u.v.–vis., ¹H-, ¹³C-, ³¹P-n.m.r., cyclic voltammetry, m.s. analysis and MO calculations were in agreement with a possible octahedral structure. Biphasic (H₂O/PhMe) catalytic studies have shown good olefin hydrogenation activity by the complex at moderate temperature and pressure.     

Synthesis and characterization of trans -Mo(CO)4( p -C5NH4SO3Na)2

Reaction between Mo(CO)₆ and p-C₅NH₄SO₃Na (1:2 (Mo: p-C₅NH₄SO₃Na) stoichiometric ratio) gave the trans-Mo(CO)₄(p-C₅NH₄SO₃Na)₂ complex, (1), in 80% yield. Complex (1) has been characterized by FTIR, ¹H and ¹³C NMR spectroscopy. Complex (1) has most likely an idealized D_4h geometry with trans N-bound p-C₅NH₄SO₃Na ligands.     

Hydroformylation reactions of the trans -Mo(CO)4( p -C5NH4SO3NA)2 complex in biphasic medium

Trans-bis(sodium pyridine-p-sulphonate)tetracarbonylmolybdenum(0) complex, (trans-Mo(CO)₄(p-PySO₃Na)₂, (1)) was used as a catalytic precursor for the 1-hexene hydroformylation reaction, in biphasic toluene/water medium (T = 100°C, syngas total pressure = 600 psi, pH₂/pCO = 1). Complex (1) showed good activity favoring the linear aldehyde. Likewise as other organic olefin substrates and with synthetic and real naphtha, good conversions to oxygenated products were obtained.     

Hydrogenation of Aromatics with [Ru(η 5-C5H5)Cl(TPPDS)2] in Biphasic Medium

[Ru(η⁵-C₅H₅)Cl(TPPDS)₂], [TPPDS=P(C₆H₅)(C₆H₄SO₃⁻)₂] in biphasic (n-heptane/water) medium hydrogenates toluene, benzene and m-xylene (105 °C, 1400 psig H₂, substrate/catalyst=600:1, 4 h) and in toluene hydrogenation gives methylcyclohexane. Catalytic activity increases with temperature, H₂ pressure, ionic strength, and pH lower than 10. The catalytic water solution can be reused several times with little activity loss.