Crystal structure of a dimeric 1-methylcytosine mercuric chloride complex

1977 ◽  
Vol 55 (7) ◽  
pp. 1213-1217 ◽  
Author(s):  
Monique Authier-Martin ◽  
André L. Beauchamp
Keyword(s):  
Heavy Atom ◽  
Carbonyl Oxygen ◽  
Chloride Complex ◽  
R Factor ◽  
Cell Dimensions ◽  
Distorted Trigonal Bipyramid ◽  
Ring Nitrogen ◽  
Heavy Atom Method ◽  
Neighboring Molecule ◽  
Trigonal Bipyramid Geometry

Di-μ-chloro-bis[chloro(1-methylcytosine-O,N3)mercury(II)] belongs to space group P21/c with cell dimensions a = 9.932(2), b = 14.051(3), c = 9.198(2) Å, and β = 135.41(2)°. The structure was solved by the heavy-atom method and refined to an R factor of 0.027 for 1271 independent reflections. The crystal is composed of centrosymmetric dimeric molecules in which two mercury atoms are attached by a pair of symmetrical chlorine bridges. The 1-methylcytosine ligand is bidentate via N(3) and O(2). The metal atom has a (2 + 3) coordination with a very distorted trigonal bipyramid geometry. A chlorine atom at 2.322(3) Å and ring nitrogen N(3) at 2.17(1) Å form strong axial bonds with mercury. Two bridging chlorine atoms at 2.719(2) and 2.745(3) Å, and carbonyl oxygen O(2) at 2.84(1) Å form weaker equatorial bonds. The amino group is hydrogen-bonded to a bridging chlorine of the same molecule [Formula: see text] and a carbonyl oxygen of a neighboring molecule [Formula: see text]

Crystal and Molecular Structure of the Synthetic Intermediate, 2-Bromo-3-methoxy-5-hydroxy-5,6,7,8,9,10,13,14-octahydro-8-methyl-10,13-N-acetylaminomethano-phenanthrene, C19H24O3NBr

1973 ◽  
Vol 51 (16) ◽  
pp. 2637-2638 ◽  
Author(s):  
H. Lynton ◽  
P. Y. Siew
Keyword(s):  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Cell Dimensions ◽  
Ring Nitrogen ◽  
Unit Cell Dimensions ◽  
Synthetic Intermediate ◽  
Heavy Atom Method

Crystals of the synthetic intermediate, 2-bromo-3-methoxy-5-hydroxy-5,6,7,8,9,10,13,14-octahydro-8-methyl-10,13-N-acetyl aminomethano-phenanthrene, C19H24O3NBr, are monoclinic, space group P21/n, unit cell dimensions a = 10.62(1), b = 14.47(2), c = 23.88(2) Å, β = 99.4(2)°, z = 8 with two molecules in the asymmetric unit. The structure was solved by the heavy atom method and refined by full matrix least squares to R = 0.096 for 2120 observed reflections. The conformation was found to be cis at the junction between rings A and B making further cyclization to obtain an A ring nitrogen bridge not possible.

Structure cristalline et moléculaire du cis-dithiocyanatobis(phénanthroline-1,10)mercure(II), Hg(SCN)2(C12H8N2)2

1974 ◽  
Vol 52 (16) ◽  
pp. 2923-2927 ◽  
Author(s):  
André L. Beauchamp ◽  
Bernard Saperas ◽  
Roland Rivest
Keyword(s):  
Heavy Atom ◽  
Octahedral Geometry ◽  
Van Der Waals Interactions ◽  
Distorted Octahedral Geometry ◽  
Triclinic Space Group ◽  
Bond Lengths ◽  
R Factor ◽  
Distorted Octahedral ◽  
Phenanthroline Ligands ◽  
Heavy Atom Method

The compound cis-Hg(SCN)2(Phen)2 belongs to the triclinic space group [Formula: see text] with a = 13.252(5), b = 11.077(4), c = 8.443(3) Å, α = 105.20(3), β = 83.25 (3), γ = 90.92(3)°, and Z = 2. The structure was solved by the heavy atom method and refined on 1718 independent reflections to an R factor of 0.069. The crystal contains discrete molecules, in which mercury is coordinated to four nitrogen atoms from two phenanthroline molecules and to two sulfur atoms from thiocyanate groups. These donor atoms define a distorted octahedral geometry around mercury. The Hg—N bond lengths are in the range 2.42(2)–2.52(2) Å, whereas the Hg—S bonds are equal to 2.622(8) and 2.582(8) Å. The molecules are packed in layers parallel to the (110) planes and the layers are held together by normal van der Waals interactions. Within the layers, the packing of the complex is characterized by parallel stacking of phenanthroline ligands at distances of ∼3.4 Å. The terminal nitrogen atoms of the thiocyanate groups are uncoordinated.

scholarly journals The crystal and molecular structure of the bis(N,N,N′,N′-tetramethylethanediamine) adduct of I(Br)InInBr2, In2Br3I•2C6H16N2, an indium–indium bonded molecule

1984 ◽  
Vol 62 (3) ◽  
pp. 601-605 ◽  
Author(s):  
Masood A. Khan ◽  
Clovis Peppe ◽  
Dennis G. Tuck
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Orthorhombic Space Group ◽  
Trigonal Bipyramidal ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Heavy Atom Method ◽  
Distorted Trigonal Bipyramidal

The crystal structure of the title compound has been determined by the heavy atom method. The crystals are orthorhombic, space group Pbca, with unit cell dimensions a = 22.795(3) Å, b = 17.518(2) Å, c = 12.396(3) Å, Z = 8; R = 0.0409 for 1527 unique "observed" reflections. The structure is disordered, with each halogen site (X) occupied by 75% Br, 25% I. The molecule consists of two X2(tmen)In units (tmen = N,N,N′,N′-tetramethylethanediamine) with distorted trigonal bipyramidal geometry, joined by an In—In bond 2.775(2) Å in length.

The crystal and molecular structure of thiamine iodide hydroiodide

1976 ◽  
Vol 54 (19) ◽  
pp. 3001-3006 ◽  
Author(s):  
William Edward Lee ◽  
Mary Frances Richardson
Keyword(s):  
Heavy Atom ◽  
Pyrimidine Ring ◽  
Side Chain ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Iodide Ions ◽  
Cell Parameters ◽  
Weak Hydrogen Bonds ◽  
Ring Nitrogen ◽  
Heavy Atom Method

The X-ray crystal structure of thiamine iodide hydroiodide, C12H18N4OSI2, has been determined. The unit cell parameters are: a = 13.835(7), b = 7.442(4), c = 20.243(9) Å, β = 120.52(7)°, monoclinic space group P21/c, Z = 4. A total of 1445 reflections having F2 > 2σ(F2), 2θ < 40° were collected on a Picker 4-circle diffractometer with MoKα radiation by the 2θ scan technique. The structure was solved by the heavy-atom method. The iodide and sulphur atoms were refined anisotropically; only positional parameters were refined for the hydrogen atoms. Successive full-matrix least-squares refinements yielded an unweighted R-factor of 0.054. The pyrimidine ring is protonated on the ring nitrogen opposite the amino group. The relative disposition of the pyrimidine and thiazolium rings is similar to that observed in most other thiamine structures. The β-hydroxyethyl side chain of the thiazolium ring is folded in such a way that there is a short S … O contact, 2.97 Å in length. The iodide ions are involved in a number of weak hydrogen bonds.

Crystal and molecular structure of the m-bromobenzoate derivative of bisnorquassin

1970 ◽  
Vol 48 (2) ◽  
pp. 307-311 ◽  
Author(s):  
H. Lynton
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Unit Cell ◽  
Anisotropic Temperature ◽  
Cell Dimensions ◽  
Final Agreement ◽  
Unit Cell Dimensions ◽  
Heavy Atom Method ◽  
Atomic Parameters

The molecular structure of the m-bromobenzoate derivative of bisnorquassin, C27H27O7Br, has been determined by the heavy atom method. The compound crystallizes in the orthorhombic system, space group P212121, with unit cell dimensions a = 20.09 ± 0.02 Å, b = 14.63 ± 0.02 Å, c = 8.06 + 0.01 Å and 4 molecules in the unit cell. Final atomic parameters have been obtained from a blockdiagonal least-squares refinement using anisotropic temperature parameters. The final agreement residual for 1665 observed reflections is R = 0.107.The structure of bisnorquassin previously proposed by Findlay and Cropp, on the basis of spectroscopic and chemical evidence, is shown to be essentially correct.

Metal binding to N(9), N(7), and N(3) of adenine. Crystal structure of μ-(adeninato-N3,N7,N9)tris(methylmercury(II)) perchlorate

1980 ◽  
Vol 58 (14) ◽  
pp. 1439-1443 ◽  
Author(s):  
Joseph Hubert ◽  
André L. Beauchamp
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Metal Binding ◽  
Heavy Atom ◽  
Individual Species ◽  
Cell Parameters ◽  
R Factor ◽  
Dimeric Unit ◽  
Adenine Ring ◽  
Heavy Atom Method

The title compound belongs to space group [Formula: see text] with the following cell parameters: a = 6.304, b = 11.925, c = 25.946 Å, α = 85.76, β = 89.78, γ = 83.57°, and Z = 4. The structure was solved by the heavy-atom method and refined on 2570 nonzero reflections to an R factor of 0.044. In the two crystallographically independent [Adeninato(CH3Hg)3]2+ ions, methylmercury groups are linearly bonded to N(3), N(7), and N(9) of a deprotonated adenine ring, forming Hg—N bonds of normal lengths (ave. 2.08 Å) for two-coordinated mercury. One half of the complex cations are associated in a dimeric unit by a pair of strong [Formula: see text] hydrogen bonds, while the others are packed as individual species in the crystal. The structure is stabilized by a number of contacts between mercury and perchlorate oxygens.

Chemistry of proximal π-bond systems. Part IV. The structure of 5,6-dimethylenebicyclo[2,2,1]hept-2-ene molybdenum tricarbonyl

1976 ◽  
Vol 54 (12) ◽  
pp. 1958-1966 ◽  
Author(s):  
Bryan F. Anderson ◽  
Glen B. Robertson ◽  
Douglas N. Butler
Keyword(s):  
Metal Atom ◽  
Heavy Atom ◽  
Least Square ◽  
Molybdenum Atom ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
R Factor ◽  
Heavy Atom Method

Crystals of 5,6-dimethylenebicyclo[2,2,1]hept-2-ene molybdenum tricarbonyl 1 (M = Mo) are monoclinic, a = 7.4451(3) Å, b = 13.5783(7) Å, c = 11.2691(4) Å, β = 92.593(3)°, Z = 4, space group P21/c. The structure was solved by the 'heavy atom' method and was refined by full-matrix least square procedures to a final R = 0.031. The weighted R factor was 0.051. Experimental bond lengths and angles are close to other reported values for bicyclo[2,2,1]hept-2-ene systems except for three major distortions in the triene ligand namely: the closing of the angles C(2)—C(1)—C(6) and C(3)—C(4)—C(5) by about 5.3°, the bending of the butadiene fragment plane C(8)—C(5)—C(6)—C(9) toward the metal atom by about 20° and the twisting of the terminal methylene hydrogens H(8i) and H(9i) out of the butadiene fragment plane (0.44 and 0.53 Å respectively) away from the molybdenum atom.

Crystal structure of diethylammonium tetrachloro(p-phenoxyphenyl)tellurate

1984 ◽  
Vol 62 (1) ◽  
pp. 32-35 ◽  
Author(s):  
Raj K. Chadha ◽  
John E. Drake ◽  
Masood A. Khan
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Heavy Atom ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
Secondary Interaction ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Heavy Atom Method ◽  
Interionic Hydrogen

The crystal structure of diethylammonium tetrachloro(p-phenoxyphenyl)tellurate has been determined by the heavy atom method. The crystals are monoclinic, space group C2/c, with unit cell dimensions a = 19.675(5), b = 7.634(3), c = 28.716(6) Å, β = 105.58(2)°, and Z = 8. For 2636 "observed" reflections (I > 3σ(I)), R = 0.030. The primary geometry about tellurium is based on a square pyramid with a secondary interaction on the vacant side of the tellurium coordination octahedron. The ions are apparently linked by weak interionic hydrogen bonding along the crystallographic b axis.

scholarly journals Crystal and Molecular Structure of the 1:1 Complex of Chloral Hydrate and 7-Bromo-2,3-dihydro-1-methyl-5-phenyl-1,4-benzodiazepin-2-one

1971 ◽  
Vol 49 (20) ◽  
pp. 3401-3404 ◽  
Author(s):  
R. F. Dunphy ◽  
H. Lynton
Keyword(s):  
Chloral Hydrate ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Unit Cell ◽  
Orthorhombic System ◽  
Cell Dimensions ◽  
Final Agreement ◽  
Unit Cell Dimensions ◽  
Heavy Atom Method ◽  
Atomic Parameters

The structure of a 1:1 complex of chloral hydrate and 7-bromo-2,3-dihydro-1-methyl-5-phenyl-1,4-benzodiazepin-2-one has been determined by the heavy atom method. The complex crystallizes in the orthorhombic system, space group Pbca, with unit cell dimensions a = 13.45(1), b = 26.74(2), c = 11.23(1) Å and 8 molecules in the unit cell. The 1:1 complex of chloral hydrate and diazepam, 7-chloro-2,3-dihydro-1-methyl-5-phenyl-1,4-benzodiazepin-2-one, is isomorphous with the above compound and has unit cell dimensions a = 13.43(1), b = 26.60(2), c = 11.20(1) Å. The final atomic parameters have been obtained from a block-diagonal least squares refinement using anisotropic thermal parameters. The final agreement residual for 575 observed reflections is R = 0.079.The structure consists of chains of chloral hydrate and Br-diazepam molecules linked by hydrogen bonds.

Flukicides. IV. Crystal and Molecular Structure of 3'-Chloro-4'(p-chlorophenoxy)-3,5-diiodo-salicylanilide (Rafoxanide)

1980 ◽  
Vol 33 (1) ◽  
pp. 203 ◽  
Author(s):  
A Sindt ◽  
M Mackay
Keyword(s):  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Carbonyl Oxygen ◽  
Aromatic Rings ◽  
Hydrogen Atoms ◽  
Molecular Hydrogen Bond ◽  
Anisotropic Temperature ◽  
Orthorhombic Crystals ◽  
Temperature Factors ◽  
Heavy Atom Method

Orthorhombic crystals of rafoxanide, C19H11Cl2I2NO3, belong to the space group Pca21 with a 23.234(2), b 8.980(2), c 9.582(2)Ǻ and Z 4. The structure was solved by the heavy-atom method from diffractometer data measured with Mo Kα radiation. Refinement with anisotropic temperature factors given to the non-hydrogen atoms converged at R 0.059 for the 2025 observed terms. The two aromatic rings of the salicylanilide moiety are almost coplanar with a dihedral angle of 11.2°, whereas they are approximately perpendicular to the plane of the phenoxy group. Weak inter-molecular hydrogen-bond-like interactions between the nitrogen and carbonyl oxygen, which involve a glide motif, link the molecules into ribbons extending along the c axis.

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