Showing papers by "Thomas A. Hamor published in 1974"
TL;DR: The crystal and molecular structure of the title compound (I) has been determined by a single-crystal X-ray analysis from three-dimensional counter data as mentioned in this paper, and the structure was established by direct methods and refined by least squares to R 3·7%.
Abstract: The crystal and molecular structure of the title compound (I) has been determined by a single-crystal X-ray analysis from three-dimensional counter data. Crystals are orthorhombic, space group Pnma, with Z= 4 in a cell of dimensions a= 11·305, b= 12·110, c= 9·075 (all ± 0·010)A. The structure was established by direct methods and refined by least squares to R 3·7% for 1066 structure amplitudes. The complex has exact Cs symmetry. The boat-like conformation of the ring and molecular dimensions (bond length σ 0·003–0·007 A) are consistent with a significant contribution to the metal–cycloheptadiene bonding of a σ–π type of interaction.
6 citations
TL;DR: The piperidine ring is in the chair conformation with the ester group oriented axially as discussed by the authors, and the acetylcholine-like portion adopts a conformation similar to, but somewhat more compact than, that of acetyl choline in crystals of the bromide salt.
Abstract: Crystals of the title compound are monoclinic, space group P21/c, with Z= 4 in a cell of dimensions a= 9·60, b= 15·46, c= 13·49 A(all ±0·01 A), β= 98·6°± 0·05°. The structure was determined by Fourier and least squares methods from three-dimensional X-ray counter-data and refined by least squares to R 6·4% for 1339 structure amplitudes. The piperidine ring is in the chair conformation with the ester group oriented axially. The acetylcholine-like portion adopts a conformation similar to, but somewhat more compact than, that of acetylcholine in crystals of the bromide salt.
3 citations
TL;DR: In this paper, X-ray crystallographic analysis of the title compound has established that there is substantial electron delocalisation involving the nitrogen atom and the ester group, with the bonds from the nitrogen atoms nearly coplanar.
Abstract: X-Ray crystallographic analysis of the title compound has established that there is substantial electron delocalisation involving the nitrogen atom and the ester group, with the bonds from the nitrogen atom nearly coplanar. The sulphur atom does not appear to be involved in the conjugation. The crystals are orthorhombic, space group P212121, with Z= 4 in a cell of dimensions a= 8·881 ± 0·005, b= 19·14 ± 0·01, c= 7·042 ± 0·005 A. The structure was determined by Patterson and Fourier methods, by use of three-dimensional counter data, and refined by least-squares to R 6·7% for 1011 structure amplitudes.
2 citations
TL;DR: The decafluoronorbornane system approximates closely to C2v symmetry as mentioned in this paper, and the bridge angle is 98·2° and the flap angle 115·7°.
Abstract: Crystals of the title compound are triclinic, space group P, with Z= 2 and cell parameters a= 7·321 ± 0·005, b= 11·566 ± 0·006, c= 13·227 ± 0·006 A, α= 110·38 ± 0·05, β= 67·18 ± 0·05, γ= 82·40 ± 0·05°. The structure was solved by direct methods and refined by least-squares to a final R of 4·9% for 2770 X-ray counter-data. Estimated standard deviations for bond lengths, bond angles, and torsion angles average ca. 0·007 A, 0·3, and 0·5°. The decafluoronorbornane system approximates closely to C2v symmetry. The bridge angle is 98·2° and the flap angle 115·7°, respectively 3 and 5° greater than the means determined by gas-phase electron diffraction studies on the parent hydrocarbon.
2 citations
TL;DR: The triclinic structure of the title compound was determined by Patterson and Fourier methods by use of three-dimensional X-ray counter data, and refined by least-squares to R 7·1% for 2219 structure amplitudes as mentioned in this paper.
Abstract: Crystals of the title compound are triclinic, space group P with Z= 2 in a unit cell of dimensions a= 7·14 ± 0·01, b= 8·32 ± 0·01, c= 17·31 ± 0·01 A, α= 90·7 ± 0·05, β= 83·9 ± 0·05, γ= 97·5 ± 0·05°. The structure was determined by Patterson and Fourier methods by use of three-dimensional X-ray counter data, and refined by least-squares to R 7·1% for 2219 structure amplitudes. The thienyl ring is planar and is oriented nearly perpendicular to the mean plane of the ester group. The cyclopentyl ring is in the envelope conformation. The acetylcholine-like system adopts a conformation similar to that of acetylcholine in crystals of the chloride salt. The molecular geometry is compared with those of certain related anticholinergic cations as determined in the solid state by X-ray crystallography. A common feature is that the previously defined ‘methyl side’ of the acetylcholine system is partially blocked by ring substituents in the acyl group and by a large cationic head.
2 citations
TL;DR: The crystal and molecular structure of the title compound (I) has been determined by a single-crystal X-ray analysis from three-dimensional counter data as discussed by the authors, and the structure was established by direct methods and refined by least squares to R 3·7%.
Abstract: The crystal and molecular structure of the title compound (I) has been determined by a single-crystal X-ray analysis from three-dimensional counter data. Crystals are orthorhombic, space group Pnma, with Z= 4 in a cell of dimensions a= 11·305, b= 12·110, c= 9·075 (all ± 0·010)A. The structure was established by direct methods and refined by least squares to R 3·7% for 1066 structure amplitudes. The complex has exact Cs symmetry. The boat-like conformation of the ring and molecular dimensions (bond length σ 0·003–0·007 A) are consistent with a significant contribution to the metal–cycloheptadiene bonding of a σ–π type of interaction.