Structure of the monosodium salt of D-glucose 6-hydrogenphosphate

Na+.C6H12O 9P-, Mr=282.1,monoclinic,P21,a=5·762([), b=7·163(2), c=12.313 Å, β=99.97(1)0, U=500.5Å3 ,Z=2,Dm=1.86,Dx=1.87 Mgm-3,Cu Ka,λ=1.5418Å,μ=3.3mm-1, F(OOO) = 292, T = 300 K, final R for 922 observed reflections is 0·042. The phosphate ester bond P-O(6), is 1·575 (5) Å, slightly shorter than the P-O bond in monopotassium phosphoenolpyruvate [1.612(6)Å] [Hosur & Viswamitra (1981). Acta Cryst. B37, 839-843]. The pyranose sugar ring takes a 4C1 chair conformation. The conformation about the exocyclic C(5)-C(6) bond is gauche-trans. The endocyclic C-O bonds in the glucose ring are nearly equal with C(5)-O(5) = 1.436(9)Å. The sodium ion has seven near neighbours within a distance of 2·9 Å. The crystal structure is stabilized by hydrogen bonds between the 0 atoms of symmetry­ related molecules

The crystal and molecular structure of magnesium hexa-antipyrine perchlorate

The structure of magnesium hexa-antipyrine perchlorate, Mg(C11H12ON2)6(ClO4) 2, has been solved by isomorphous difference-Patterson and trial-and-error methods. The compound crystallizes in the hexagonal system, space group P3̅, with one formula unit in a unit cell of dimensions a = 14.06, c = 9.76 Å. The positional and anistropic thermal parameters of the atoms were refined by the method of least squares to an R value of 0.132 for 1184 observed reflexions. In the structure, the six 3 equivalent antipyrine molecules are coordinated octahedrally to the central Mg2+ ion through their lone carboxyl oxygen atoms. The pyrazolone and the phenyl rings in the antipyrine group are planar and are inclined to each other by 62.3°. The non-equivalent Cl-O distances in the structure are 1.448 and 1.437 Å

A refinement of the structure of calcium hexaantipyrine perchlorate and a comparative study of some metal hexaantipyrine perchlorates

Calcium hexa-antipyrine perchlorate, Ca(C11H12ON2)6(CIO4) 2, is isomorphous with the corresponding magnesium and lead compounds and crystallizes in trigonal space group P3̅ with one formula unit in an elementary cell of dimensions a = 14.33 and c = 9.78 Å. The structure was refined by structure-factor least-squares method to an R value of 0.118 to 1131 observed refexions. The structural features of magnesium, calcium and lead hexa-antipyrine perchlorates are compared. The coordination of antipyrine oxygen atoms around the metal ion is octahedral in all three cases; thie octahedron becomes clongated along the 3̅ axis as the size of the metal ion increases. The nature of metal-oxygen bonds is discussed on the basis of the known electronegativivity coefficients of the relavant atoms and the observed metal-oxygen distances. In the antipyrine molecule, both the phenyl and the pyrazolone rings are planar and are inclined with respect to each other by angles varying from 62 to 68 °. An attempt has been made to explain the observed bond lengths in the pyrazolone ring in terms of the major canonical structures proposed

The crystal and molecular structure of lead hexa-antipyrine perchlorate

Lead hexa-antipyrine perchlorate is isomorphous with a series of metal hexa-antipyrine perchlorates, M(C11H12ON2)6(CIO4) 2, where M = Mg2+, Ca2+ or Zn2+ and crystallizes in a hexagonal unit having dimensions a = 14.33 (±0.03), c = 9.75 (±0.03) Å and space group P3̅ (C⅔t). The solution of the structure in the c-axis projection was facilitated by the heavy-atom method using (hki0) reflexions. A knowledge of the z coordinates obtained previously from a study of the magnesium compound was utilized to work out the complete structure and the refinement was done three-dimentional least-squares method to an agreement index of 0.079 for 736 observed reflexions. In structure, each Pb2+ ion is surrounded by six antipyrine oxygen atoms in a slightly distorted octahedral form with Pb-O(6) = 2.446 (±0.016) Å. The five-membered pyrazolone ring is planar and is inclined at an angle of 68° to the phenyl ring. The tetrahedral ClO4 ions occupy viods provided by the adjacent antipyrine groups. The two non-equivalent Cl-O bonds, Corrected for effects of thrmal oscillation, have lengths 1.453 (I) and 1.457 Å(3) respectively

Unit cell, space group and refractive indices of Al(NO<SUB>3</SUB>)<SUB>3</SUB>.9H<SUB>2</SUB>O and Cr(NO<SUB>3</SUB>)<SUB>3</SUB>.9H<SUB>2</SUB>O

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Molecular and crystal structure of deoxyguanosine 5'-phosphate

Recent crystallographic studies of the dinucleosides ApU (ref. 1) and GpC (ref. 2) have given experimental proof for the base pairing arrangement proposed by Watson and Crick for the DNA double helix. Another striking feature of this structure relates to the torsional angle about the C5′-C4′ bond in the phosphate–sugar backbone chain. In the Crick and Watson model, this conformation is gauche–trans (GT). Crystal structures of 5′-nucleotides, dinucleosides and dinucleotides so far studied, however, have shown only the gauche–gauche (GG) conformation about this bond. The GG conformer is also the only one found in the refined models of the proposed structure of the double helical nucleic acids and polynucleotides. The only nucleotide with a GT conformation is 6-azauridine-5′-phosphate which is not a normal monomer unit of nucleic acids. It is also reported that 5′-dGMP assumes preferentially GT conformation in solution

The structure of monopotassium phosphoenolpyruvate

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