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

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.


1975 ◽  
Vol 53 (15) ◽  
pp. 2345-2350 ◽  
Author(s):  
Monique Authier-Martin ◽  
André L. Beauchamp

The title compound belongs to space group P21/c with a = 23.99(1), b = 4.245(2), c = 25.98(1) Å, β = 117.58(7)°, and Z = 8. The structure was solved by the heavy-atom method and refined by block-diagonal least squares on 2589 independent observed reflections. All non-hydrogen atoms were refined anisotropically and some of the hydrogen atoms were located but their parameters were not refined. The final values of R and Rw were 0.042 and 0.047, respectively.The two nonequivalent mercury atoms have very similar environments. Two short Hg—Cl bonds (2.34–2.38 Å) at ∼ 165° define a quasi-molecular HgCl2 unit. Overall octahedral coordination is completed with two chloride ions at 2.76–2.84 Å and two chlorine atoms at 3.19–3.26 Å on neighboring HgCl2 quasi-molecules. HgCl6 octahedra share edges to form twofold ribbons in the b direction. This pattern of octahedra is identical with the onereported for β-NH4HgCl3. The cations are pairs of N(1)-protonated adenine molecules linked by two N(10)—H(10)… N(7) hydrogen bonds and stacked in the b direction. Water molecules act as acceptors in moderately strong hydrogen bonds with acidic protons H(1) and H(9) of adeninium ions. Other generally weaker hydrogen bonds exist between the various parts of the structure.



1987 ◽  
Vol 52 (7) ◽  
pp. 1742-1747 ◽  
Author(s):  
Jiří Brynda ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová

The crystal structure of CrHPO3.2 H2O has been solved by the heavy atom method. The compound crystallizes in the orthorhombic space group P212121 with the unit cell parameters a = 679·25(8), b = 915·61(8), c = 752·2(1) pm, Z = 4. The structure was refined to the final reliability factor R = 0·043 for 1 040 observed reflexions (I > 1·96σ(I)). The structure consists of chains formed by CrO6 octahedra connected each other in vertices. The chains are interconnected by phosphite tetrahedra HPO3. Hydrogen bridges of water-phosphite tetrahedron and water-water types form space cross-linking of the whole structure. Bond distances Cr-O in the tetragonally distorted octahedron range from 201·2 to 304·9 pm. The interatomic distances P-O in phosphite tetrahedron are between 152·1 and 152·7 pm. The degree of the distorsion DISQ of HPO3 tetrahedron and CrO6 octahedron is discussed on the basis of known structures of phosphites and chromium(II) compounds.



1978 ◽  
Vol 56 (4) ◽  
pp. 560-563 ◽  
Author(s):  
Chung Chieh

Methyl,2-mercaptopyrimidinatomercury(II) was synthesized from methylmercuric hydroxide and 2-mercaptopyrimidine in aqueous solution. The crystal is orthorhombic with a = 4.063(2), b = 9.901(4), c = 18.808(15) Å, Dm = 2.88(1), Z = 4, Dc = 2.867 g cm−3, space group P212121. The structure was solved by the heavy atom method using 605 diffractometer measured reflections. The final R factor was 0.069. The key bond lengths and angles are: Hg—S, 2.39(2) Å, Hg—CH3, 2.13(6) Å, [Formula: see text] 174°. The CH3HgS— group bends out of the plane of the pyrimidine ring and the Hg atom interacts rather strongly with one of the ring nitrogens with an Hg—N distance of 2.83 Å. However, the Hg … N interaction is very labile in solution, since the two hydrogen atoms in the meta positions are equivalent from the 1H nmr spectra in both CDCl3 and DMSO solutions. The solution of the compound is not optically active.



2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.



1992 ◽  
Vol 57 (11) ◽  
pp. 2309-2314 ◽  
Author(s):  
Josef Loub ◽  
Zdeněk Mička ◽  
Jana Podlahová ◽  
Karel Malý ◽  
Jürgen Kopf

Structure of sodium hydrogen selenite-selenious acid (1:3) was solved by heavy-atom method and refined anisotropically to R = 0.098 for 1223 unique observed reflections. The title compound crystallizes in the Pc space group with a = 5.756(2), b = 4.911(2), c = 20.010(5) Å, β = 100.48(3)°, V = 556(1) Å3, T = 293 K, (a = 5.763(2), b = 4.878(1), c = 20.03(1) Å, β = 100.48(3)°, V = 554(1) Å3, T = 173 K), Z = 2. The structure consist of HSeO3- anions, molecules of selenious acid and Na+ cations which are octahedrally coordinated with oxygen atoms. The structure is stabilized by a system of hydrogen bonds.



1974 ◽  
Vol 52 (16) ◽  
pp. 2923-2927 ◽  
Author(s):  
André L. Beauchamp ◽  
Bernard Saperas ◽  
Roland Rivest

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.



1984 ◽  
Vol 62 (3) ◽  
pp. 601-605 ◽  
Author(s):  
Masood A. Khan ◽  
Clovis Peppe ◽  
Dennis G. Tuck

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.



Author(s):  
H. M. Maurer ◽  
Alarich Weiss

AbstractThe crystal structure of diamminesilver dinitroargentate, [Ag(NHThe point positions of the silver atoms were obtained by the heavy-atom method whereas those of the light atoms were found by difference Fourier syntheses. Coordinates and anisotropic temperature factors were refined by block-diagonal least-squares methods with the result



1976 ◽  
Vol 54 (19) ◽  
pp. 3001-3006 ◽  
Author(s):  
William Edward Lee ◽  
Mary Frances Richardson

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.



2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
Mohamed Ibrahim Mohamed Tahir ◽  
Karen Anne Crouse ◽  
Fiona Ni Foong How ◽  
David J Watkin

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1 , Z = 2, V = 1839.42(18) A3 and unit cell parameters a= 11.0460(6) A, b = 13.3180(7) A, c = 13.7321(8) A, a= 80.659(3)° , b= 69.800(3)° and g= 77.007(2)° with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and O130/O131 [site occupancy factor 0.3965/0.6035]. The C22-S21 and C19-S20 bond distances of1.779(7) A and 1.788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and C19-N18] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35...O16 formed between the two molecules and N28-H281...O130, N28-H281...O131 and C41-H411...O131 with the solvent molecule.



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