Showing papers by "Thomas A. Hamor published in 1996"
TL;DR: The monometallic bipyridyl complexes [MoTp*(NO)X(L-L)] and their bimetallic counterparts as discussed by the authors have been synthesized and the single crystal X-ray structure of the polyene chain is in the alltrans configuration and exhibits normal bond length alternation with [rCC−rCC] = 0.092 A.
Abstract: The monometallic bipyridyl complexes [MoTp*(NO)X(L-L)] [Tp* = HB(3,5-Me2C3HN2)3; L-L = 3,3‘-bipyridine, 4,4‘-bipyridine, 1,2-bis(4-pyridyl)ethane and X = Cl; L-L = 4,4‘-NC5H4(CHCH)nH4C5N, n = 0, 1, 2, 3, 4 (all trans) and X = Cl, I] and their bimetallic counterparts [{(NO)MoTp*X}2(L-L)] have been synthesized, together with [MoTp*(NO)Cl{4-NC5H4CHCHC(Me)CHCH}]2. The single crystal X-ray structure of [{MoTp*(NO)Cl}2{4,4‘-NC5H4(CHCH)4H4C5N}] confirms that the polyene chain is in the all-trans configuration and exhibits normal bond length alternation with [rCC−rCC] = 0.092 A. The Mo−Mo distance is 20.764(3) A, and the Mo−N(pyridyl) bond distance of 2.196(6) A indicates a much lower degree of Mo−(N)ligand π bonding than that found in related amide complexes where Mo−N(amide) distances are typically some 0.3 A shorter. Cyclic voltammograms of the monometallic complexes contain a single one-electron reduction process, whereas those of the bimetallic complexes contain two one-electron processes. The separation bet...
42 citations
TL;DR: In this paper, the same yields of products are obtained in 50 min as are achieved in 15-18 h of conventional heating; however no desulfurisation of the benzothiophene ring was observed.
Abstract: The reaction of thiophene and of benzothiophene with [Fe3(CO)12] was greatly accelerated by microwave heating when carried out in the presence of Fe3O4. Thus the same yields of products are obtained in 50 min as are achieved in 15–18 h of conventional heating; however no desulfurisation of the benzothiophene ring was observed. By contrast, both tellurophene and, more importantly, dibenzotellurophene undergo detelluration reactions with [Fe3(CO)12], the latter reaction affording a dibenzoferrole C18H8Fe2O6, the structure of which has been determined. The reaction of 2-telluraindane with [Fe3(CO)12] gave a complex C19H16FeO3 in which a novel dimer of the detellurated C8H8 fragment is co-ordinated to an Fe(CO)3 unit, as determined crystallographically. The released tellurium was isolated as either FeTe or as [Fe3Te2(CO)9], depending on the reaction conditions.
26 citations
TL;DR: The structure of 2-(2-pyridyl)phenyltellurium(II) chloride (1) is triclinic and consists of discrete molecules with average bonding distances over six independent molecules as discussed by the authors.
17 citations
TL;DR: The trimeric metallocyclophanes [M(NO)(HB(3,5-Me2,C3,HN2)3(O2C6H4]4, (M = Mo, syn, syn-isomer; M = W, anti, synisomer) have been obtained from metal-directed reactions involving the octahedral precursor complexes as discussed by the authors.
15 citations
TL;DR: In this paper, the results of the reactions of Te(S2CNEt2)X with NEt4X (X = Br or I) with 1,10-phenanthroline (phen) and phen.
Abstract: The reactions of (diethyldithiocarbamato)halogenotellurium(II) with thiourea, benzimidazole-2-thiol, halides (Cl–, Br–, I–) and 1,10-phenanthroline (phen) have been studied. The products were principally characterized by elemental analyses, IR and 1H NMR spectroscopies. Novel anionic (diethyldithiocarbamato)dihalogenotellurate(II) complexes resulted from the reactions of Te(S2CNEt2)X (X = Br or I) with NEt4X (X = Br or I) and phen. The crystal structures of the complexes [NEt4][Te(S2CNEt2)I2], [H(phen)2][Te(S2CNEt2)I2] and [H(phen)2][Te(S2CNEt2)Br2] have been determined. In the anions tellurium is co-ordinated to two sulfur atoms of the dithiocarbamate in an almost isobidentate manner and to two halides in an overall planar trapezoidal geometry. In [NEt4][Te(S2CNEt2)I2] the two iodides are almost equidistant to tellurium with distances of 3.079(1) and 3.072(1)A, whereas in [H(phen)2][Te(S2CNEt2)I2] the two Te–I distances are 3.151(1) and 3.038(1)A and in [H(phen)2][Te(S2CNEt2)Br2] the two Te–Br distances are 2.911(1) and 2.986(1)A. In [H(phen)2]+ the proton is bound to one of the nitrogen atoms of a phenanthroline group and the two phen groups are held together by three hydrogen bonds, of which two are of the interesting type C–H ⋯ N.
4 citations
TL;DR: The title compound, C 24 H 18 Te, consists of discrete molecules with the Te atom two-coordinate, Te-C 2.105 (5) and 2.125(5)A, and angle C-Te-C 96.2(2)° as mentioned in this paper.
Abstract: The title compound, C 24 H 18 Te, consists of discrete molecules with the Te atom two-coordinate, Te-C 2.105 (5) and 2.125(5)A, and angle C-Te-C 96.2(2)°. The biphenyl residues have their phenyl rings steeply inclined to each other, with dihedral angles of 66.5 (2) and 74.3 (3)°. The inter-ring bond lengths are 1.497 (7) and 1.480(8)A.
3 citations
TL;DR: In this article, the authors postulate that the compound responsible for this UV spectrum is the intermediate formed following attack of hydroxide ion at C-6 followed by breakage of the N 1 → C 6 bond to yield an α, β-unsaturated aldehyde.
2 citations
TL;DR: In this paper, it was shown that in the crystal and in aqueous solution (analysed by 2D NMR techniques), the conformation of this nucleoside has a syn-glycosidic and C4′-exo (4E) sugar pucker conformation.
Abstract: 5-Cyclohexyl-2′-deoxyuridine (I) is an example of a 5-substituted pyrimidine 2′-deoxynucleoside which exhibits no antiviral activity and which is not a substrate for either cellular or viral (herpes) kinases. Despite the fact that a cursory inspection of NMR spectra of the compound, taken in DMSO-d 6 solution, suggested that the compound had a normal conformation, we here show that in the crystal and in aqueous solution (analysed by 2D NMR techniques), the conformation of this nucleoside has a syn-glycosidic and C4′-exo (4E) sugar pucker conformation.
1 citations
TL;DR: In this article, the authors postulate that the compound responsible for this UV spectrum is the intermediate formed following attack of hydroxide ion at C-6 followed by breakage of the N 1 → C 6 bond to yield an α, β-unsaturated aldehyde.
Abstract: Photoirradiation of 5- t -butyl-1-methyluracil at 254 nm results in the production of a 1,2-dihydro-1-methyl-pyrimidin-2-one in high yield. The structure was confirmed by X-ray analysis. When subjected to alkaline conditions, a bathochromic shift in the UV spectrum accompanied by an increase in molar absorptivity, typical of 1,2-dihydro-1-substituted pyrimidin-2-one, was observed. For the first time we can postulate that the compound responsible for this UV spectrum is the intermediate formed following attack of hydroxide ion at C-6. followed by breakage of the N-1 → C-6 bond to yield an α, β-unsaturated aldehyde.
TL;DR: The structure of C 14 H 12 INTe consists of discrete molecules in which the Te atom is three-coordinate with Te-C and Te-I distances of 2.102(5) and 2.936(1)A, respectively, and a Te???N interaction of2.230(4)A as mentioned in this paper.
Abstract: The structure of C 14 H 12 INTe consists of discrete molecules in which the Te atom is three-coordinate with Te-C and Te-I distances of 2.102(5) and 2.936(1)A, respectively, and a Te???N interaction of 2.230(4)A. The I atom is trans to the N atom [I-Te...N 170.3 (1)°].