Crystal and Molecular Structure Determination of N,N'-Diphenylacetamidinium Trifluoroacetate

1995 ◽  
Vol 60 (4) ◽  
pp. 576-582 ◽  
Author(s):  
Jan Ondráček ◽  
Svetlana Pakhomova ◽  
Bohumil Kratochvíl ◽  
Svatava Smrčková

The structure of N,N'-diphenylacetamidinium trifluoroacetate - a model of the lactate dehydrogenase binding site - was solved by direct methods and anisotropically refined to R = 0.032 for 1 475 unique observed reflections. The compound crystallizes in the monoclinic space group P21/m, a = 5.942(1), b = 17.256(2), c = 7.817(1) Å, β = 103.05(1)°, V = 780.8(1) Å3, Z = 2, Dcalc = 1.38 g cm-3, μ(MoKα) = 0.11 mm-1, F(000) = 336.

1983 ◽  
Vol 61 (6) ◽  
pp. 1185-1188 ◽  
Author(s):  
Hans Koenig ◽  
Richard T. Oakley ◽  
A. Wallace Cordes ◽  
Mark C. Noble

The reaction of tetrasulphur dinitride with norbornadiene produces the 1:1 adduct S4N2•C7H8; X-ray crystallographic analysis of this compound reveals that olefin addition cleaves one of the sulphur–sulphur bonds of S4N2, yielding a novel eight-membered C2S4N2 ring. Crystals of S4N2•C7H8 are monoclinic, space group P21/c, a = 6.127(1), b = 17.369(1), c = 9.580(1) Å, β = 106.74(1)°, V = 1003.8(5) Å3Z = 4. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.039. The S—S—N—S—N—S fragment of the C2S4N2 ring is planar to within 0.15 Å. The S—C—C—S unit is folded out of this plane to produce a dihedral angle of 74.5°.


2014 ◽  
Vol 38 (1) ◽  
pp. 97-101
Author(s):  
Jagodish C Sarker ◽  
Md Saifur Rahman ◽  
Shariff E Kabir ◽  
Tasneem A Siddiquee

The solid-state molecular structure determination of the bimetallic osmium-tin compound [(?-H)Os2(CO)4(SnPh3)2(?-HSnPh2)(?-dppf)] (1) was carried out to determine the relative orientationof the coordinated ligands. Compound 1 crystallizes in the monoclinic space group P 21/c with a =22.366(7), b = 14.217(4), c = 25.213(8) Å, ? = 98.865(7)°, Z = 8 and V = 7921(4) Å3. It is a 34-electron bimetallic cluster with the Os-Os edge concomitantly bridged by a dppf and two HSnPh2 ligands DOI: http://dx.doi.org/10.3329/jbas.v38i1.20218 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 1, 97-101, 2014


1978 ◽  
Vol 56 (23) ◽  
pp. 2915-2921 ◽  
Author(s):  
Douglas C. Rohrer ◽  
Jean-Claude Fischer ◽  
Derek Horton ◽  
Wolfgang Weckerle

Grignard addition of phenylmagnesium bromide to 3,5-O-benzylidene-1-deoxy-D-erythro-2-pentulose (1) affords C-phenyl branched-chain pentitols having exclusively either the D-arabino (2) or D-ribo (5) stereochemistry according to the mode of substitution of 1. In order to determine the chirality of these products conclusively, the crystal and molecular structure of the unsubstituted pentitol 6 (from 2) has been determined. Crystals of 1-deoxy-2-C-phenyl-D-arabinitol (6; C11H16O4) are orthorhombic, space group P212121, with cell dimensions a = 8.9420(6), b = 18.910(1), c = 6.4263(6) Å, and Z = 4. The structure was solved by multi-solution direct methods and refined to a final discrepancy index of 5.6%. The molecule has an extended, planar zigzag conformation with the phenyl ring nearly perpendicular to this plane. Compound 6 forms one intramolecular (between 2-OH and O-4) and three intermolecular hydrogen bonds. Palladium-catalyzed hydrogenolysis of the 2-phenylcarbamate of 2 results in deoxygenation of the benzylic center with complete-inversion of configuration, as established by crystal-structure determination of the product 7. Crystals of 2(S)-4-O-acetyl-3,5-O-benzylidene-1,2-dideoxy-2-C-phenyl-D-erytro-pentitol (7; C20H22O4) are monoclinic, space group C2, with cell dimensions a = 19.102(1), b = 6.1925(5), c = 16.098(1) Å, β = 108.325(9)°, and Z = 4. The structure was solved by multi-solution direct methods and refined to a final discrepancy index of 5.9%. The molecule has an almost ideal planar, zigzag backbone conformation which incorporates the 1,3-dioxane ring. Comparison of the conformation observed in the crystal with that calculated from proton–proton coupling constants shows good agreement


1977 ◽  
Vol 32 (1) ◽  
pp. 22-25 ◽  
Author(s):  
W. S. Sheldrick ◽  
W. Wolfsberger

N-(Trifluorosilyl)trimethylphosphinimine dimer crystallises in the monoclinic space group P21/n, Z = 2, with a= 6.314(2), b = 12.057(5), c = 10.936(4) Å, β = 95.45(2)°. The structure was solved by direct methods and refined to R 0.078 for 1117 independent reflections. The molecule is dimeric and centrosymmetric with an planar four-membered [SiN]2 ring containing trigonal-bipyramidal pentacoordinate silicon and trigonal nitrogen. Significant differences are observed in the bond lengths from silicon to its equatorial and axial ligands: Si-Neq 1.736(4), Si-Nax 1.857(4), Si-Feq1.606(4) and 1.607(3), Si-Fax 1.668(3) Å. The Si-Neq bond length is similar to that in tetracoordinate derivatives for which a (p →d) π bonding component has been postulated, while the Si-Nax distance is very much shorter than that observed in other pentacoordinate derivatives.


1990 ◽  
Vol 55 (4) ◽  
pp. 1010-1014 ◽  
Author(s):  
Jiří Kameníček ◽  
Richard Pastorek ◽  
František Březina ◽  
Bohumil Kratochvíl ◽  
Zdeněk Trávníček

The crystal and molecular structure of the title compound (C8H16N2NiS4) was solved by the heavy atom method and the structure was refined anisotropically to a final R factor of R = 0.029 (wR = 0.037) for 715 observed reflections. The crystal is monoclinic, space group P21/c with a = 948.3(2), b = 776.9(2), c = 1 167.4(2) pm, β = 125.14(2)°, Z = 2. The molecule contains two four-membered NiSCS rings of approximately planar configuration with the Ni atom situated at a centre of symmetry. The molecules are arranged in chains along the c-axis of the unit cell.


1981 ◽  
Vol 36 (10) ◽  
pp. 1208-1210 ◽  
Author(s):  
Hartmut Köpf ◽  
Joachim Pickardt

Abstract The molecular structure of the bridged [1]-titanocenophane 1,1'-dimethylsilylene titanocene dichloride, (CH3)2Si(C5H4)2TiCl2, has been investigated by an X-ray structure determination. Crystal data: monoclinic, space group C2/c, Z = 4, a = 1332.9(3), 6 = 988.7(3), c = 1068.9(3) pm, β = 113.43(2)°. The results are compared with the structural dimensions of similar compounds: 1,1'-methylene titanocene dichloride, CH2(C5H4)TiCl2, with the unbridged titanocene dichloride, (C5H5)2TiCl2 and the ethylene-bridged compound (CH2)2(C5H4)2TiCl2


1999 ◽  
Vol 54 (10) ◽  
pp. 1313-1317 ◽  
Author(s):  
Qianfeng Zhang ◽  
Jinxi Chen ◽  
Maochun Hong ◽  
Xinquan Xin ◽  
Hoong-Kun Fun

Reaction of a DMF solution of Cu(S2CNC4H8) with [Ph4P]2[WSe4] affords [Ph4P]2[WSe4- (CuS2CNC4H8)3] (1) and [Ph4P][Cu(SeS2CNC4H )(S2CN2C4H8)] (2) in which a Se atom from the decomposition of the WSe42- anion has reacted with the pyrrolidyldithiocarbamate (C4H8dtc) ligand anion to form the new ligand anion SeS2CNC4H8⊖. Complex 2 crystallizes with four formula units in the monoclinic space group P21/c in a cell of dimensions a = 10.5824(2), b = 18.7575(3), c = 18.3268(4) Å and ß = 109.0980(10)°. 6055 independent reflections above background were measured with a diffractometer and the structure was refined anisotropically to R =0.073. The anion contains a three-coordinated copper(I) atom. The C4H8dtc⊖ ligand is bonded to the Cu+ cation in a terminal fashion, while SeS2CNC4H8⊖ chelates the Cu+ cation. The Se-S bond length is 2.231 (4) Å.


2015 ◽  
Vol 70 (3) ◽  
pp. 191-196 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

AbstractThe new compounds LiK[C(CN)3]2 and Li[C(CN)3]·½ (H3C)2CO were synthesized and their crystal structures were determined. Li[C(CN)3]·½ (H3C)2CO crystallizes in the orthorhombic space group Ima2 (no. 46) with the cell parameters a=794.97(14), b=1165.1(2) and c=1485.4(3) pm, while LiK[C(CN)3]2 adopts the monoclinic space group P21/c (no. 14) with the cell parameters a=1265.7(2), b=1068.0(2) and c=778.36(12) pm and the angle β=95.775(7)°. Single crystals of K[C(CN)3] were also acquired, and the crystal structure was refined more precisely than before corroborating earlier results.


1985 ◽  
Vol 63 (12) ◽  
pp. 3374-3377 ◽  
Author(s):  
C. Faerman ◽  
S. C. Nyburg ◽  
G. Punte ◽  
B. E. Rivero ◽  
A. A. Vitale ◽  
...  

The crystal and molecular structure of the title compound, C15H14O3, is described. Crystals are monoclinic, space group P21/n, a = 9.893(5), b = 10.719(5), c = 12.136(3) Å, β = 90.56(3)°. The molecule has a twist conformation and interactions between oxygen atoms of the methoxyl groups are thought to play some part in this.


1976 ◽  
Vol 54 (20) ◽  
pp. 3130-3141 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter

Crystals of B,B-bis(p-tolyl)boroxazolidine, 1c, are trigonal, a = 25.1028(9), c = 12.4184(7) Å, Z = 18, space group [Formula: see text]. And crystals of B,B-diphenylboroxazolidine, 1a, are orthorhombic, a = 17.6420(4), b = 14.2527(3), c = 10.205(1) Å, Z = 8, space group Pbca. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.057 and 0.040 for 2230 and 1828 reflections with I ≥ 3σ(I) respectively. Both molecules have structures similar to related compounds and feature intermolecular N—H … O hydrogen bonds (N … O = 2.982(2) for 1c and 2.896(2) Å for 1a). Bond lengths are: for 1c; O—C, 1.413(3), O—B, 1.478(3), N—C, 1.488(3), N—B, 1.657(3), C(sp3)—C(sp3), 1.501(4), B—C, 1.616(3) and 1.623(3), mean C—C(ar), 1.395, N—H, 0.93(2) and 0.94(2), mean C(sp3)—H, 1.00, and mean C(ar)—H, 1.00 Å; for 1a; O—C, 1.409(2), O—B, 1.476(2), N—C, 1.489(2), N—B, 1.655(2), C(sp3)—C(sp3), 1.507(3), B—C, 1.613(2) and 1.620(2), mean C—C(ar), 1.391, N—H, 0.93(2) and 0.92(2), mean C(sp3)—H, 1.00, and mean C(ar)—H, 0.98 Å. A statistical analysis of the phenyl C—C distances in compounds 1a, 1b, and 1c has provided an example of statistically significant substituent-induced bond length variation in the phenyl rings.


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