Showing papers by "Kim Henrick published in 1983"
TL;DR: The first undeca-osmium cluster, [Os11C(Co)27]2−(1), has been isolated as a low-yield product of the vacuum pyrolysis of Os3(CO)12, the dianion (1) reacts with 1 equivalent of [Cu(NCMe)4][BF4] to give the monoanion (2) which has an unusual Os11core geometry with the carbido atom occupying a trigonal prismatic cavity as mentioned in this paper.
Abstract: The first undeca-osmium cluster, [Os11C(Co)27]2–(1), has been isolated as a low-yield product of the vacuum pyrolysis of Os3(CO)12, the dianion (1) reacts with 1 equivalent of [Cu(NCMe)4][BF4] to give the monoanion [Os11C(CO)27Cu(NCMe)]–(2) which has been shown by X-ray analysis to have an unusual Os11core geometry with the carbido atom occupying a trigonal prismatic cavity.
8 citations
TL;DR: In this article, minor chages in methyl substitution in a 1,4,7-triazaheptane fragment of an O2N3-macrocycle are shown to have a significant influence on the lignad.
Abstract: Apparently minor chages in methyl substitution in a 1,4,7-triazaheptane fragment of an O2N3-macrocycle are shown to have a significant influence on the lignad.
7 citations
TL;DR: In this paper, single crystal X-ray structures of the starting material and the two μ-Br products have been determined based on 1H NMR, mass spectra and IR data, and the outcome of the reactions studied is interpreted in terms of stabilising effect of the CF3 subtituents on the complexed alkene, both with respect to displacement and ligand modification.
7 citations
TL;DR: In this article, the authors used a combination of direct methods and Fourier-difference techniques and refined by blocked full-matrix least squares to R= 0.051 for 5 091 observed reflections.
Abstract: The cluster anion [Os4(CO)1 2H3]– reacts with commercial [NO][PF6] in acetonitrile via the in situ formation of orthophosphoric acid to give the neutral cluster species, [Os4(CO)1 2H4], [Os4(CO)1 2H3(µ-OPO3H2)], and [Os4(CO)1 2H3(µ-OH)]. The latter two products crystallise together in a 2 : 1 ratio in the monoclinic space group P21/c with unit-cell dimensions a= 14.315(3), b= 30.732(4), c= 15.314(3)A, β= 101.48(2)°, and Z= 4. The structure was solved by a combination of direct methods and Fourier-difference techniques and refined by blocked full-matrix least squares to R= 0.051 for 5 091 observed reflections. In each of the µ-OPO3H2 and µ-OH compounds the four osmium atoms define a ‘butterfly’ configuration with two triangles sharing a common edge but which are not coplanar, supported by the bridging oxygen linkage. The three hydrido-ligands were not located but the Os–Os bond lengths suggest that they bridge in the same arrangement as that found previously in [Os4(CO)1 2H3I] by neutron diffraction.
7 citations
TL;DR: Macrocycles containing two o-iminoanilino units undergo stereoselective C-alkylation on treatment with Grignard reagents or lithium alkyls to give the meso-dialkyl-substituted macrocyclic tetra-amines as mentioned in this paper.
Abstract: Macrocycles containing two o-iminoanilino units undergo stereoselective C-alkylation on treatment with Grignard reagents or lithium alkyls to give the meso-dialkyl-substituted macrocyclic tetra-amines.
5 citations
TL;DR: The HOMO's of these molecules to some extent reflect their ease of chemical oxidation at the 6,7-double bond; biological oxidation is less easy to correlate probably due to spatial restrictions at the active site within the mono-oxygenase.
Abstract: Comparative X-ray crystallographic structure analyses have been carried out on seven cyclopenta[a]phenanthrenes, namely 15,16-dihydocyclopenta[a]phenanthren-17-one and its 2-, 6- and 12-methyl homologues (non-carcinogens) and the 7-and 11-methyl and 1,11-methano derivatives (carcinogens). All-valence-electron molecular-orbital calculations by the CNDO/2 method, using the crystallographic parameters, have also been executed. Charge distribution and the energies of the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) have been calculated. With one exception all the molecules show only small deviations from planarity, the exception being the strongly carcinogenic 11-methyl-17-ketone in which the bay-region methyl group causes out-of-plane deformation of the benzo rings of 12.5 degrees. Among the other six compounds the two carcinogens are readily differentiated by high angle strain induced by a 7-methyl group or a 1,11-methano bridge. As expected, the HOMO's of these molecules to some extent reflect their ease of chemical oxidation at the 6,7-double bond; biological oxidation is less easy to correlate probably due to spatial restrictions at the active site within the mono-oxygenase.
4 citations
TL;DR: The reaction of Cephalosporin esters with cerium(IV) ammonium nitrate in aqueous acetic acid gave the trisubstituted thiazoles.
Abstract: Reaction of the Cephalosporin esters (1)–(3) with cerium(IV) ammonium nitrate in aqueous acetic acid gave the trisubstituted thiazoles (4)–(6).
3 citations