György Bor

AsCo3(CO)9, its cyclic trimer, As3Co9(CO)24 and the phosphorus-containing analog P3Co9(CO)24☆

The AsCo3(CO)9 trigonal pyramidal cluster, its cyclic “trimer” As3Co9(CO)24 and the phosphorus-containing analog of the latter, P3Co9(CO)24 have been prepared and characterized. A reversible equilibrium between the arsenic-containing monomer and trimer was found to depend on p(CO). Such an equilibrium could not be observed in the case of P3Co9(CO)24.

The anti-syn equilibria of the organothio bridged derivatives of iron carbonyl, (μ-RS)2Fe2(CO)6, and of their monosubstitution products with some phosphines, (μ-RS)2Fe2(CO)5(PR′3)

Abstract The pure anti and syn forms of the compounds (μ-RS) 2 Fe 2 (CO) 6 (R = CH 3 , C 2 H 5 ) isomerize to equilibrium mixtures having the K = [anti]/[syn] values of 3.2 and 3.6, respectively. If R = C 6 H 5 or C 6 F 5 no evidence for “pure” isomers has been found, but anomalies of the IR spectra point to differences in the ring orientations. The new derivative R = C 6 Cl 5 has been prepared by photochemical reaction. The two isomers of the R = alkyl derivatives react with different rates (k syn >k anti ) with phosphines to give the monosubstituted derivatives (μ-RS) 2 Fe 2 (CO) 5 PR′ 3 (R′ = n-Bu, Ph) which have also two distinct isomers. The K = [ anti ]/[ syn ] value changes in favour of the syn isomers in the substituted compounds.

Infrared spectroscopic studies on metal carbonyl compounds : XIV. Assignments in the CO stretching region of the authentic infrared spectra of the compounds MCo(CO)9 (M = Mn or Re) and of the monosubstituted derivative MnCo(CO)8P(C6H5)3

Abstract Reported for the first time are the infrared spectra and their assignments in the Cue5f8O stretching region for the compounds MCo(CO)9 (M = Mn, Re). We also report the preparation and the IR spectrum of the new monosubstituted compound MnCo(CO)8P(C6H5)3. The three compounds have also been characterized by their mass spectra.

Infrared spectroscopic studies on metal carbonyl compounds. Part XVII. A comparative study of the vibrational spectrum of ditechnetium decacarbonyl and of the decacarbonyls of manganese and rhenium in the C–O stretching region

The i.r. spectra of the M2(CO)10 carbonyls (M = Mn, Tc, or Re) have been reinvestigated in the C–O stretching region with special emphasis on the weak isotopic bands. In the case of the Mn compound the effects of isotopic enrichment have also been examined. The i.r.-inactive (A1, E2, and E3) fundamentals were calculated from the isotopic satellites and the results agree within ±1 cm–1 with recent Raman data. For the technetium compound no Raman study seems to exist and thus the A1(2123 and 1999·5 cm–1), E2(2029 cm–1), and E3(1990·5 cm–1) frequencies reported here are the first data on these i.r.-inactive modes. The force and interaction constants of all three decacarbonyls have been calculated in a C–O factored force field without a priori neglections.Both the equatorial and the axial C–O force constants of Tc2(CO)10[16·642 and 16·316 mdyn A–1, respectively (1 mdyn A–1= 102 N m–1)], are the highest in the triad, whereas most of its interaction constants have intermediate values between those of Mn2(CO)10 and Re2(CO)10. For Re2(CO)10 the effect of the eclipsed configuration (D4h) on the eq ⋯ eq′ interaction constants has also been studied.

Infrared spectroscopic studies on metal carbonyl compounds : XVI. Analysis of the CO stretching region of the trimeric thiolatocobalt carbonyl complexes Co3(CO)4(SR)5. The question of terminal-bridging coupling in force constant calculations☆

The analysis of the infrared spectrum of Co3(CO)4(SCH3)5 in the Cue5f8O stretching region shows that not even the use of the 13Cue5f8O isotopic frequencies can provide proof that the interactions between terminal and bridging CO ligands have non-zero values. Thus the neglect of these interactions in force constant calculations is a justified procedure.

An exceptionally electron-rich carbonyl cluster consisting of a hexacobalt octahedron encompassed by an octa(μ3-sulphido) cube: X-ray diffraction analysis of the structure of Co6(μ3-S8)(CO)6·3S8

Cristallisation dans le groupe C2/c avec a=20,456, b=12,385 et c=17,600 A, β=90,94°, Z=8. Affinement jusqua R=0,048

X-Ray diffraction analysis of the disordered crystal and molecular structure of [{Co3(CO)9C}2SCO] : its identity with the previously reported ‘[{Co3(CO)9(CS)}2]’

The title compound, obtained from the reaction of [Co2(CO)8] with CS2, has been fully characterized by X-ray diffraction analysis. The incorrectness of the previously reported formulation, [{Co3(CO)9(CS)}2], is ascribed to the disordered –S–C(O)– chain joining the two CCo3(CO)9 entities. The compound is triclinic, space group P, with a= 8.794(4), b= 12.576(4), c= 8.113(4)A, α= 105.14(3), β= 113.32(4), γ= 95.61(1)°, and Z= 1. The cobalt atoms were located by the conventional Patterson method and the C, O, and S atoms by subsequent Fourier-difference maps. The final R value was 0.046 for 2 021 reflections with I > 3σ(I). The central part of the molecule, C–S–C(O)–C, is planar, with large π-electron delocalization and with different orientations with respect to the two Co3 triangles. Its vibrational modes correspond to the i.r. bands at 1 642 [ν(C–O)], 1 137 [ν(C–C)], and 924 and 768 cm–1[ν(S–C)].

Crystal and molecular structure of [Co8(CO)21(µ5-CS2)(µ5-C2S)]: a thiocarbonyl group as a six-electron donor

The compound [Co8(CO)21(µ5-CS2)(µ5-C2S)], a minor product of the reaction between [Co2(CO)8] and CS2, has been characterized by X-ray diffraction analysis. The crystals are monoclinic, space group Cc, with a= 9.208(4), b= 15.864(6), c= 25.36(1), β= 96.39(3)°, and Z= 4. The Co atoms were located by the Patterson method, the S, C, and O atoms by Fourier difference maps. The final R was 0.0899 for 3 206 reflections with F > 6σ(F). The structure consists of an assembly of three cobalt clusters, the central one being the most interesting part of the complex, as it shows an unprecedented Co2(µ-SC) fragment. The compound is formally derived from a previously reported one by isolobal substitution of a Co(CO)3 group by a C–R group [R = CCo3(CO)9].

Preparation and infrared spectroscopic characterization of some (Oxydiacetato)thorium(IV) complexes

Polymeric complexes, [UO2(oda)]n(oda = oxydiacetate, O2CCH2OCH2CO22–, n=∞), have been prepared, from the reaction of uranyl(VI) ions and oxydiacetic acid or its disodium salt, and characterized, mainly by i.r. spectroscopy. The complex Na2[UO2(oda)2],nH2O (n= 2 or 3) was obtained when an excess of the ligand was used in the reaction. In the presence of pyridine N-oxide(Opy), both monomeric [UO2(oda)(Opy)2] and polymeric [UO2(oda)-(Opy)]n(n=∞) complexes were obtained.