A.W. Cordes

The reaction of CpRu(PPh3)2+ with organic thiols. Synthesis and characterization of [CpRu(PPh3)2(RSH)]BF4 (R=benzyl, phenethyl) and the molecular and crystal structure of [CpRu(PPh3)2(C6H5CH2CH2SH)]BF4.CH2Cl2

Abstract The isolation and characterization of two mercaptan complexes of the general formula [CpRu(PPh3)2(RSH)]BF4, where R=benzyl and phenethyl, were undertaken to model the substrate/catalyst interaction of the hydrode-sulfurization (HDS) process. The IR data show a shift in the SH stretching frequency upon coordination. The structure of the [CpRu(PPh3)2(C6H5CH2CH2SH)]BF4 complex was determined by X-ray diffraction techniques: monoclinic space group P21/n, a=15.317(4), b=13.924(9), c=21.815(7) A, β=95.20(2)°, Z=4, R=0.057, Rw=0.073. The Ru is attached to two triphenylphosphine ligands, a cyclopentadienyl and the phenethylmercaptan. The Ru-S distance is 2.369(2) A and the S-H distance is 1.18 A.

The reaction of CpRu(PPh3)2+ with trimethylenesulfide. Synthesis and molecular and crystal structure of [CpRu(PPh3)2(SC3H6)]CF3SO3

The isolation and characterization of the trimethylenesulfide-coordinated complex, [CpRu(PPh3)2(SC3H6)]CF3SO3, is reported. The structure of [CpRu(PPh3)2(SC3H6)]CF3SO3 was determined by X-ray diffraction techniques: monoclinic space group I2/a, a=23.864(10), b=14.233(3), c=24.385(7) A, β=97.10(3)°, Z=8, R=0.046, Rw=0.065. The Ru is attached to two triphenylphosphine ligands, a cyclopentadienyl and the trimethylenesulfide. The Ru-S distance is 2.3459(20) A.

Reaction of CpRu(PPh3)2Cl with six-member cyclothioethers. Structures of the [CpRu(PPh3) x L]Y complexes (L = pentamethylene sulfide, x = 2, Y = BF4−; L = 1,3-dithiane; 1,3,5-trithiane, x = 2, Y = CF3SO3−; L = 1,4-dithiane, x = 1, Y = BF4−)

The synthesis of a series of ruthenium complexes with cyclothioether ligands is reported. The compounds were characterized by X-ray diffraction techniques. The molecular structures of [CpRu(PPh3)2(pms)]BF4 (1), [CpRu(PPh3)2(1,3-dithiane)]OTfl (2), [CpRu(PPh3)2(1,3,5-trithiane)]OTfl (3), and [CpRu(PPh3)(1,4-dithiane)]BF4 (4) show chelation occurs only when the sulfur atoms are separated by at least two C atoms, creating a ligand bite size large enough to chelate. Cell parameters: 1, space group P21/c, a = 14.601(4), b = 19.102(10), c = 14.751(7) Å, β = 98.28(3)○; 2, space group P21/c, a = 12.859(7), b = 15.576(3), c = 22.126(11) Å, β = 102.22(4)○; 3, space group P21/c, a = 12.7320(20), b = 15.571(5), c = 22.287(4) Å, β = 101.812(14)○; 4, space group Pbca, a = 11.2010(10), b = 16.321(7), c = 28.966(4) Å. Compounds 2 and 3 are X-ray isomorphous. The Ru–S bond lengths range from 2.341(3), 2.365(3) Å in compound 4 to 2.382(4) Å in compound 2. Upon chelation (compound 4), with subsequent loss of PPh3, the Ru–P bond shortens to 2.327(3) Å. This may be due to reduced steric hindrance about the Ru atom. No evidence for C–S bond lengthening is observed.

Synthesis, molecular structure and computational study of a ruthenium bis(thietane) complex

Abstract Dissolution of [CpRu(PPh 3 )(SC 4 H 8 ) 2 ]CF 3 SO 3 in thietane/CH 2 Cl 2 with stirring yields the title compound [CpRu(PPh 3 )(SC 3 H 6 ) 2 ]CF 3 SO 3 ( I ). The single crystal X-ray structure shows a disparity in the puckering of the two thietanes. One thietane ligand is near-planar, with torsion angles of ±1.5(5)° for CSCC and ±1.8(4)° for CCCS; the second thietane ligand of I has torsion angles of ±21.0(4)° for CSCC and ±25.0(3)° for CCCS. Compound I contains both the largest and the smallest torsion angles for any complex reported. Theoretical calculations were carried out for both thietane and for I using the gamess and gaussian 98 packages.

Reactions of bis[diphenyl-3-(4-methoxyphenylsydnonyl)]phosphine palladium chloride and amines and crystal analysis of its amine adducts

Abstract Reactions of bis[diphenyl-3-(4-methoxyphenylsydnonyl)]phosphine palladium chloride and amines yielded trans-amminedichloropalladium complexes, which were characterized by spectroscopic techniques (compounds 5–9) and X-ray diffraction (compounds 5 and 7). Bond lengths of PC(10), P-(16) decrease more than that of P-(1) after the complex is formed, suggesting that the phenyl rings are able to contribute more electron density to phosphorus for binding with Pd(II) than the sydnone ring. The equilibrium constants and rate constants for the reaction between complex 4 and amines depend not only on the basicity but also on the steric size of amines used.

1,1'-Diacetyl-2,2'-biimidazole

A crystallographic twofold rotation axis passes through the C-C bond joining the imidazole rings of the title compound, C10H10N4O2. The molecule crystallizes in a cis disposition. The planar acetyl group is twisted by 5.0 (3)° with respect to the imidazole ring and the two imidazole rings are tilted by 60.53 (5)° in relation to one another.