MoKα Diffractometer Data Research Articles

Crystal structure of dimethyltin bisfluorosulphate

Crystals of dimethyltin bisfluorosulphate, Me2Sn(SO3F)2, are monoclinic, a= 7·813(2), b= 8·399(2), c= 8·143(2)A, β= 117·13(2)°, Z= 2, space group P21/c. The structure was determined with Mo-Kα diffractometer data by Patterson and full-matrix least-squares methods, the final R being 0·036 for 643 observed reflexions. The structure consists of polymeric sheets parallel to (100), with the fluorosulphate groups acting as bridging ligands between linear dimethyltin units. The tin atom is octahedrally co-ordinated to two methyl groups, Sn–C 2·08(1)A, and four oxygen atoms, Sn–O 2·24(1)A. The SO3 F group does not deviate significantly from C3v symmetry, and has the mean dimensions, S–O 1·47(1), S–F 1·56(1)A, O–S–O 112, and F–S–O 107°.

Crystal structure of dichloromalonamide

Crystals of dichloromalonamide, CCl2(CONH2)2, are monoclinic, space group I2/a, a= 10·514, b= 5·985 c= 10·371 A, β= 101·44°, Z= 4, molecular symmetry, C2. The structure was determined with Mo-Kα diffractometer data by Patterson and Fourier syntheses and refined by full-matrix least-squares methods to R 0·031 for 604 observed reflexions. Hydrogen atom positions were determined.The amide group is nearly planar. The mean bond distances, after application of vibration corrections are C–Cl 1·781, C–C 1·560, C–O 1·242, and C–N 1·334 A. The molecules are held together by N–H ⋯ O hydrogen bonds (2·96 and 3·05 A); there is also one exceptionally short intermolecular Cl ⋯ Cl contact (3·10 A).

Crystal and molecular structure of chloro[dodeca(dimethylamino)-cyclohexaphosphazene-NNNN]-copper(II) dichlorocuprate(I), [N6P6(NMe2)12CuIICl]+ CuICl2 ?

Crystals of [N6P6(NMe2)12CuIICl]+Cu ICl2– are monoclinic, a= 19·352(8), b= 8·690(6), c= 14·069(7)Å, β= 91·04(4)°, Z= 2, space group P2/n. The structure was determined with Mo-Kα diffractometer data from Patterson and electron-density maps; full-matrix least-squares refinement reduced R to 0·083 for 1103 observed reflexions. The cation is situated on a crystallographic C2 axis, and has the copper(II) atom bonded to four nitrogen atoms of the phosphazene ring and to one chlorine atom, in a distorted square-pyramidal co-ordination, with the chlorine atom in the apical position. There are two distinct P–N bond distances, 1·62 and 1·55 Å, which are explicable in terms of π-bonding theory. The CuICl2+ ion is also situated on a crystallographic C2 axis, and is linear, with Cu–Cl 2·11 Å.

Crystal structure of [1,2-bis(dimethylarsino)trifluoroethane]tetracarbonylmolybdenum, (Me2AsCHF·CF2AsMe2)Mo(CO)4

Crystals of [1,2-bis(dimethylarsino)trifluoroethane]tetracarbonylmolybdenum, (Me2AsCHF·CF2AsMe2)Mo(CO)4, are orthorhombic, a= 18·26, b= 14·87, c= 12·52 A, Z= 8, space group Pbca. The structure was determined with Mo-Kα diffractometer data by Patterson, electron-density, and full-matrix least-squares methods, the final R being 0·052 for 1757 observed reflexions. The molybdenum atom has a slightly distorted octahedral co-ordination, with As–Mo–As angle 81·9(1)° and Mo–As bond distances 2·563(2) and 2·589(2)A. The five-membered ring is non-planar, with As–C–C–As dihedral angle 22°, and the hydrogen atom in an equatorial position. The C–C bond distance is extremely short, 1·30(2)A, and the axial C–F bond lengths, 1·72(3) and 1·73(2)A, are very significantly longer than the equatorial C–F bond, 1·38(2)A, and than a normal C–F bond, 1·33 A. The C–C–F-(axial) angles are very far from tetrahedral (85 and 82°). These unusual features can be explained by a contribution from an ionic resonance structure, [(Me2AsCH:CFAsMe2)Mo(CO)4]2+2F–.

Crystal structure of [1,2-bis(dimethylarsino)hexafluoropropane]tetracarbonylmolybdenum, Me2AsCF(CF3)CF2AsMe2·Mo(CO)4

Crystals of [1,2-bis(dimethylarsino)hexafluoropropane]tetracarbonylmolybdenum, Me2AsCF(CF3)CF2AsMe2·-Mo(CO)4, are monoclinic, a= 25·06, b= 13·27, c= 11·56 A, β= 102·8°, Z= 8, space group C2/c. The structure was determined with Mo-Kα diffractometer data by Patterson, electron-density, and full-matrix least-squares methods, the final R being 0·073 for 1510 observed (of a total of 1750) reflexions. The Mo–As bond distances being 2·572(4)A. The five-membered chelate ring is non-planar, the As–C–C–As dihedral angle being 47°, so that the ligand has a staggered conformation, with the CF3 group in an equatorial position. The two axial C–F bonds, 1·51 (3)A, are significantly longer than the equatorial C–F bond, 1·37(4)A, than the CF3 bonds, mean 1·28 A and than a normal C–F bond, 1·33 A. The C–C bond length, 1·40(4)A, is significantly less than the single-bond distance. These unusual features, and the detailed values of the valency angles in the ligand, are explicable in terms of a bonding system which involves donation of molybdenum nonbonding d electrons, via the arsenic 4d orbitals, into orbitals of the fluorocarbon group.

Crystal structure of exo-tricyclo[3,2,1,02,4]oct-6-ene–silver nitrate, and a refinement of the silver nitrate structure

Crystals of exo-tricyclo[3,2,1,02,4]oct-6-ene-silver nitrate are orthorhombic, a= 25·54, b= 6·28, c= 5·60 A, Z= 4, space group P212121. The structure was determined with Mo-Kα diffractometer data from Patterson and electron-density maps and was refined by least-squares methods to a final R of 0·105 for 322 observed reflexions. The structure contains thick layers perpendicular to a and separated by ½a; within the layers each silver ion is coordinated roughly tetrahedrally to the double bond of the hydrocarbon (in the exo-position, Ag ⋯ C 2·4 A), and to three nitrate groups (Ag ⋯ O 2·45–3·03 A). The layers are held together by van der Waals forces.The structure of silver nitrate was refined with Mo-Kα diffractometer data to R 0·067 for 404 observed reflexions. Previously observed inequalities in N–O distances have been removed, all three bond lengths in the nitrate ion being 1·26(1)A.

Crystal structure of decacarbonyl-µ-[1,2-bis(dimethylarsino)tetrafluorocyclobutene-As,As]-triangulo-triruthenium [(Me2AsCC(AsMe2)CF2·CF2)Ru3(CO)10

Decacarbonyl-µ-[1,2-bis(dimethylarsino)tetrafluorocyclobutene-As, As]-triangulo-triuthenium, [(Me2As[graphic omitted]F2)Ru3(CO)10] crystallizes in the orthorhombic space group P212121, a= 8·594, b= 18·795, c= 16·69 A, Z= 4. The structure was solved by Patterson and Fourier methods applied to Mo-Kα diffractometer data, and was refined by least-squares procedures to a final R of 0·076 for 1828 observed (of a total of 2028) reflexions. The compound is a derivative of Ru3(CO)12 in which one equatorial carbonyl group on each of two ruthenium atoms is replaced by an arsenic atom of the diarsine ligand so that the plane of the diarsine ligand is twisted 18° with respect to the plane of the ruthenium triangle. Ru–Ru bond distances are 2·831, 2·831, and 2·858 A the difference between the short and long bond lengths being significant in terms of the bonding characteristics of the ligand.

Crystal structure of shanorellin chloride (6-chloromethyl-2-hydroxy-3, 5-dimethyl-1,4-benzoquinone)

Crystals of shanorellin chloride (6-chloromethyl-2-hydroxy-3,5-dimethyl-1,4-benzoquinone) are triclinic, a= 8·250, b= 12·401, c= 4·609 A, α= 90·9°, β= 95·1°, γ= 103·5°, Z= 2, space group P. The structure was determined with Mo-Kα diffractometer data by Patterson, electron-density, and least-squares methods, the final R being 0·047 for 1031 observed reflexions. The molecule is significantly non-planar as a result of steric repulsions between the substituent groups. The bond lengths are CO 1·220, CCC 1·340, C–C(ring) 1·473, 1·503, C–C(exocyclic) 1·497, C–OH 1·354, C–Cl 1·794 A. The molecules are joined into centrosymmetrical dimers by an O–H ⋯ O hydrogen bond of 2·85 A.

Structure of dibenzothiophen

Crystals of dibenzothiophen are monoclinic, a= 8·67 ± 1, b= 6·00 ± 1, c= 18·70 ± 2 A, β= 113·9°, Z= 4, space group P21/c. The structure was determined with Mo-Kα diffractometer data by Patterson, electron-density, and least-squares methods, the final R being 0·083 for 1176 observed reflexions. The molecule is slightly folded, the dihedral angles between the five-membered ring and the six-membered rings being 0·4 and 1·2°(σ∼ 0·2°). The bond distances and valency angles are similar to those in related molecules. The C–S bond length is 1·740(8)A, and the C–S–C angle is 91·5(4)°.

Crystal structure of octacarbonylbis-µ-[bis(dimethylarsino)tetrafluorocyclobutene-AsAs]-triangulo-triruthenium

Crystals of octacarbonylbis-µ-[bis(dimethylarsino)tetrafluorocyclobutene-AsAs]-triangulo-triruthenium, [graphic omitted] (CO)8, are orthorhombic, space group Pbcn, a= 9·07, b= 18·53, c= 21·81 A, Z= 4 (one-half molecule per asymmetric unit). The structure was determined with Mo-Kα diffractometer data by direct and Fourier methods, and was refined by least-squares procedures to a final R of 0·078 for 1507 observed (of a total of 1712) reflexions. The molecule lies on a crystallographic two-fold rotation axis, and is best described as a derivative of Ru3(CO)12 in which two carbonyls on one ruthenium atom and one carbonyl on each of the other ruthenium atoms are replaced by the arsenic atoms of the bidentate diarsine ligands, in such a way that each ligand bridges two ruthenium atoms, and one Ru–Ru bond remains unbridged. This unbridged Ru–Ru bond (2·785 A) is significantly shorter than the bridged bonds (2·853 A) and than those of the parent Ru3(CO)12(average 2·848 A). The skeletons of the diarsine ligands do not deviate significantly from planarity, the plane of each ligand being twisted 18° with respect to the plane of the ruthenium triangle. The mean Ru–As bond length is 2·407 A.

Crystal structure of malonamide

Crystals of malonamide, CH2(CONH2)2, are monoclinic, space group P21/c, a= 13·07, b= 9·45, c= 8·04 A, β= 73·0°, Z= 8 (two molecules in the asymmetric unit). The structure was determined with Mo-Kα diffractometer data by the symbolic addition procedure, and refined by least-squares methods, to R 0·05 for 941 observed reflexions. Hydrogen atom positions were determined.The two symmetry-unrelated molecules have different orientations in the crystal, but have similar conformations and dimensions. The amide groups are rotated out of the central CCC plane, one group in each molecule by about 65°, and the other group by 40°. The mean bond distances, after applying rotational oscillation corrections, are C–C 1·507, C–N 1·334, C–O 1·253 A(σ 0·004 A); there are no significant deviations from these mean values. The molecules are held together by a system of eight N–H ⋯ O hydrogen bonds (2·89–3·14 A) involving all the amino-hydrogen atoms, with each oxygen atom acting as an acceptor in two hydrogen bonds.

Crystal structure of triethylenethiophosphoramide

Crystals of triethylenethiophosphoramide are monoclinic, a= 11·02, b= 7·32, c= 11·89 A, β= 99·8°, Z= 4, space group P21/c. The structure was determined with Mo-Kα diffractometer data from Patterson and electron-density maps and refined by least-squares methods. The intensity data were of limited accuracy, because of decomposition of the crystal and a high proportion of weak and unobserved reflexions; the final R value was 0·16 for 453 observed reflexions (of a total of 1294 possible). The mean bond distances (and standard deviations of the means) are P–S 1·91 (0·015), P–N 1·64 (0·02), N–C 1·50 (0·02), C–C 1·48 (0·035)A. The conformations about two of the P–N bonds are staggered, but that about the third P–N bond is between the staggered and eclipsed position. The intermolecular distances correspond to van der Waals interactions.