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Trans-Pd(PPh3)2Cl2 reacts with Li(p-RC6H4N NC6H4R-p) (R = CH3O, CH3, H and Cl) in THF yielding the deeply colored complexes Pd(PPh3)2 (p-RC6H4NCH=NC6H4R-p)Cl (I), stable in the solid state. The main decomposition products in EtOH were identified when R = CH3, as trans-Pd(PPh3)2Cl2 and [Pd(p-CH3C6H4N NC6H4CH3-p)2]2(II). Dimeric complexes of type (II) can be synthesized also by reacting Li(p-CH3C6H4N NC6H4CH3-p) with Pd(NCCH3)2Cl2 in THF. The structures of all the new complexes are proposed on the basis of u. v., i.r. and n.m.r. data.

This paper reports a study of the hydrogenation of nitric oxide to hydroxylamine in aqueous sulfuric acid in the presence of platinum supported on high-surface-area active carbon as catalyst. Industrially relevant catalysts (low Pt content and finely divided carbon particles) were used. In particular, conditions for the kinetic regime have been investigated. Measurements in the range 15–55 °C and on catalysts with platinum contents approximately from 1 to 11 wt% have been carried out. An activation energy of 11.8 Kcal/mol has been calculated.

The compound [Re(CO)3(PPh3)2Cl] reacts with Li(OCHNAr) (Ar = C6H5, p-CH3C6H4, p-ClC6H4, p-CH3OC6H4, p-NO2C6H4, o-CH3C6H4) in boiling tetrahydrofuran or toluene to yield new complexes of ReI of the type [Re(CO)2(ArNCH O)(PPh3)2]. The IR spectra suggest that the ligand is chelated and that the two CO groups are in cis positions. The crystal structure of the tittle compound was determined by X-ray analysis using counter data. The compound crystallizes in the triclinic system, space group P 1 , with a = 10.26(1), b = 12.91(1), c = 16.73(1) A, α = 111.27(3)°, λ = 75.78(3)°, and γ = 107.12(3)° for Z = 2. The structure was refined to R = 0.049. The rhenium atom is in a distorted octahedral co-ordination with two aixal PPh3, two cis-CO groups, and the bidentate ligand forming a four-membered ring with the metal.

The complex [PdCl3(PPh3)]−[Ph3P(CH2CH2COCH3)]+ (I) was prepared by reacting trans-[PdCl2(PPh3)2] with CH3COCH2CH2Cl in boiling ethanol. The i.r. spectrum of (I) shows a band of strong intensity at 1717 cm−1 for v(CO) and bands attributable to v(PdCl) at 343(s), 301(w) and 277(m) cm−1. The crystal and molecular structure of complex (I) has been determined from three-dimensional X-ray diffractometer data. The complex crystallizes in the monoclinic space group P21/n. Cell parameters are as follows: a = 18.849(9), b = 21.301(9), c = 9.156(7) A, β = 92.8(1)°, Z = 4. Full-matrix least-squares refinement converged at R = 0.063 (Rw = 0.055). The anion [PdCl3(PPh3)]− has approximately square planar geometry. The cation [Ph3P(CH2CH2COCH3)]+ shows the usual angular distortions from the tetrahedral value at the phosphorus atom.

The hydrocarboalkoxylation of N-vinylphthalimide catalyzed by palladium tertiary phosphine complexes occurs with high selectivity towards the linear isomer when the alcohol is used also as the solvent but towards the branched isomer in the presence of an additional solvent. When triphenylphosphine is employed as the ligand, the yield and the regioselectivity towards the branched isomer increase with increasing pco or decreasing concentration of the phosphine. Reaction in the presence of molecular hydrogen leads to higher yields, with minor changes in regioselectivity. High regioselectivities towards either the linear or the branched isomer are observed also in the presence of chiral di- or mono-phosphines, but the degree of asymmetric induction is very low.

The major products of the reaction of Ru 3 (CO) 12 with cis -bicyclo[6.2.0]- deca-2,4,6-triene are (7-10-η-tricyclo[4.4.0.0 2,5 ]deca-7,9-diene)tricarbonyl- ruthenium and (the fluxional) cis -bicyclo(2,6,7-η, 3-5-η-bicyclo[6.2.0]deca-2,4,6- triene)hexacarbonyldiruthenium(RuRu).

The structure of the title compound has been determined by counter data. In this square-planar iridium complex the triazenido-ligand is unidentate and trans to the carbonyl group. The Ir–N(1) distance is 2.16(1) and the Ir–C(26)(carbonyl) 1.79(1)A. The complex crystallizes in the monoclinic system, space group C2/c, with unit-cell dimensions a= 22.121(3), b= 19.190(3), c= 10.111(2)A, and β= 92.77(5)°. The structure is refined to a conventional R index of 0.032.

Reactions of allylpalladiumchloride dimer with neutral ligands (L = RNCHNHR, R = C6H5CH2, p-CH3C6H4, p-ClC6H4; L = RNNNHR, R = p-CH3C6H4, p-ClC6,H4) afford bridge splitting products of the type PdClL(1,3-η-C3H5). Variable temperature 1H and 13C NMR spectra show two dynamic processes in solution. The first one, operating at room temperature, involves the dissociation of the neutral ligand L; the second one, which has a lower activation energy, is concentration dependent and involves chloride-L exchange, probably via a pentacoordinated chloro bridged species. The influence of the basicity of the ligands on the activation energies of the processes is discusseed.

The structure of the title compound has been determined by counter data. In this square-planar iridium complex the triazenido-ligand is unidentate and trans to the carbonyl group. The Ir–N(1) distance is 2.16(1) and the Ir–C(26)(carbonyl) 1.79(1)A. The complex crystallizes in the monoclinic system, space group C2/c, with unit-cell dimensions a= 22.121(3), b= 19.190(3), c= 10.111(2)A, and β= 92.77(5)°. The structure is refined to a conventional R index of 0.032.

The preparation of new hydrido-cationic species of the general formula [Pt(PEt3)2LH]X is reported (L = As Ph3 SbPh3, thiourea, isopropylamine, 3-chloropyridine, 3-methylpyridine, 2,6-dimethylpyridine, and 4-cyanopyridine), together with the reaction of trans-[Pt(PEt3)2(H)Cl] with 1,2-diarsinoethane. Equilibrium indices for the reactions trans-[Pt(PEt3)2HCl]+ L trans-[Pt(PEt3)2LH]++ Cl– in ethanol (L = PPh3, AsPh3, SbPh3, pyridine, 4-cyanopyridine, isopropylamine, and thiourea) have been also measured. The greater the equilibrium index of the cationic hydrido-species the lower is the stretching frequency of the Pt–H bond.

Aryldiazonium cations react with polyhydrido-complexes mer-IrH3(PPh3)3 and RhH2Cl(PPh3)2(S)(S = solvent) to yield simple insertion products in the former case and hydrazine derivatives in the latter.