Crystal structure of 1β-methyl-4α-isopropylcyclohexyl-spiro-5′-hydantoin

The crystal structure of 1-methyl-4-isopropylcyclohexyl-spiro-5-hydantoin has been determined by single-crystal X-ray diffraction techniques, and refined by full-matrix least-squares methods. The molecule C₁₂H₂₀N₂O₂·H₂O crystallizes with one molecule of water in the orthorombicP2₁2₁2₁ space group, witha=15.869(5),b=14.043(4),c=6.240(2) Å, andZ=4; the finalR factor was 0.032. The X-ray results showed that both substituents (methyl and isopropyl) in the cyclohexyl ring are in thetrans configuration. The configuration of the molecule is in agreement with suggestions of organic chemists.     

Structure and conformation of 6-nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin: X-ray crystallographic determination

6-Nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin is triclinic,P¯1;a=6.604(2),b=7.678(6),c=15.201(4) Å; =91.57(5),=99.39(2), =90.50(5)°;Z=2. The structure was solved by direct methods from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer and refined by least squares to a finalR value of 0.035 using 2092 reflections.The molecule consists of a heterocycle in a distorted screw boat conformation fused to a significantly nonplanar aromatic ring. One-CCl₃ group is pseudoequatorial while the (Ar-C)CCl₃ group is pseudoaxial. The C_Ar-C-O-C side of the ring is much flatter than the C_Ar-C_Ar-O-C side, the distortion being caused by the necessity of the-C_axCl₃ group to bend away from the heterocycle. C-C_eq 1.532(4) Å; C-C_ax 1.550(4) Å; C-C(C_ax)-O 113.0(3)°; C(C_ax)-O-C(C_eq) 115.5(2)°.     

X-ray crystallographic determination of the structure and conformation of trans-2-tribromomethyl-5-trichloromethyl-1,3-dioxolan-4-one: an analogue of chloralide

trans-2-Tribromomethyl-5-trichloromethyl-1,3-dioxolan-4-one is monoclinic,P2₁/c,a=6.381(6),b=17.116(6),c=10.598(5) Å,=94.07(6)°,Z=4. The structure was solved by direct methods from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full-matrix least squares to a finalR value of 0.042 using 1274 reflections. The conformation of the molecule is very similar to that of chloralide with the 5-mem-bered ring being almost planar. Evidence is provided for a possible C-HO intermolecular interaction. The average C-Br distance is 1.931(11) Å and the average Br-C-Br angle is 109.7(9)°. A table of average C-Br bond lengths and Br-C-Br angles, with the ranges for these parameters, in compounds containing -CBr₃ groups is given. Some¹H NMR and mass spectra data are included for the title compound and for chloralide.     

Geometric alignment in the structure of 6,8-dichloro-2-trichloromethyl-4-dichloromethylene-1,3-benzdioxin consistent with incipientcis-elimination of HCl

Crystals of the title compound are monoclinic, P2₁/c, a=11.464(14),b=21.027(9),c=12.806(3) Å,=108.00(6)°,V=2935.85 ų,Z=8. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full matrix least squares to a finalR value of 0.089 using 3949 reflections. The two nonequivalent molecules are both disordered to the same extent, the ratio of the two models being 0.80.2. In the minor model the substituent hydrogen atom at the 2-position is exactly eclipsed by a chlorine atom in the 2-CCl₃ group whereas in the major model the normal staggered conformation is observed. C-Cl bond lengths and C-C-Cl angles in the major model are normal whereas those in the minor model are C-Cl(A) 1.51(3), C-Cl(B) 1.67(3), C-Cl(C) 1.95(3) Å, where Cl(C) is eclipsed, for one molecule and 1.85(3), 1.67(3), 1.94(2) Å for the other. Corresponding C-C-Cl bond angles (deg) are 115(1), 114(1), 80(1); and 120(1), 126(1), 90(1). A comparison is given with a structure which is not disordered but in which similar changes in the geometry of aCCl.CCl₃ group are found.     

Structural and spectral studies of N-trans-cinnamylidene-m-toluidine and N-trans-cinnamylidene-m-chloroaniline

N-trans-cinnamylidene-m-toluidine (1) C₁₆H₁₅N, and N-trans-cinnamylidene-m-chloroaniline (2) C₁₅H₁₂NCl form isomorphous crystals which are monoclinic, space group P2_l/c, with unit cell dimensionsa=5.967(2),b=13.793(3),c=15.048(5) Å, =91.97(3)° anda=5.868(2),b=13.788(4),c=15.191(4) Å, =91.87(3)°, respectively. The single-crystal X-ray structure determinations of the title compounds revealtrans structures. Ring (A) C_10–15 and ring (B) C_1–6, are practically planar in both structures with dihedral angels of 61.3(3) and 63.6(2)°, respectively.¹H nmr, u.v. and i.r. spectra are also reported.     

Crystal and molecular structure of 4-(N,N-dimethylamino) benzaldehyde thiosemicarbazone

4-(N,N-Dimethylamino)benzaldehyde thiosemicarbazone, C₁₀H₁₄N₄S, has been prepared. The crystal structure has been determined from X-ray diffractometer data byMultan 78. The crystals are triclinic:P¯1,a=8.532(1),b=9.391(1),c=15.592(4) Å,=73.81(2),=79.59(2), =82.85(2)°,Z=4, finalR=0.033 for 2198 observed reflections. Atomic charge densities have been calculated by the CNDO/2 method. The S and hydrazinic N atoms in both molecules in the asymmetric unit are in thetrans configuration. The crystal structure is stabilized by N-HS hydrogen bonds. The net negative charge on the hydrazinic N atom, calculated by the CNDO/2 method, is decreased as compared to those in some 4-phenylthiosemicarbazide derivatives.     

Synthesis and structure of 1-(2-amino)phenyl-2-phenyl-12H-indolo[3,2-c]carbazole ethylacetate solvate,a new indolocarbazole compound

The structure of a new indolo-carbazole compound, unique in having two indole rings with NH groupstrans-fused to a phenyl ring, has been determined by X-ray crystallography. The crystals are monoclinic, space groupP2₁/n,a=25.548(7),b=8.532(3),c=12.594(4) Å,=93.50(2)°,V _c=2740.1(2) ų,Z=4,D _k=1.240 g cm^–3, (CuK)=1.54178 Å,=5.79 cm^–1,F(000)=1080,R=0.071,R _w=0.080 for 2939 unique significant reflections measured at 298 K. The crystals retain one mole of ethyl acetate per molecule, which shows disorder. Restricted rotation of the phenyl and aminophenyl groups was detected by¹³C nmr. The title Indolo-carbazoles are easily obtained by reaction of 3-bromoindoles with 2,3-biindolyls and show an interesting planar structure which could be investigated for anticancer properties.     

Refinement of the crystal structure of malonic acid,C3H4O4

A reinvestigation of the X-ray crystal structure of malonic acid (C₃H₄O₄) has been made in the light of some observations arising from solid-state¹³C NMR studies on this compound. The unit cell parameters are:a=5.156(1),b=5.341(1),c=8.407(1) Å, =71.48^o (2), =76.12^o (2), =85.09^o (2), space group ,Z=2. The structure was solved by direct methods and refined by full-matrix least-squares refinement to a finalR value of 0.038 for 711 unique reflections withl>3. The packing of the molecules involves dimeric hydrogen bonded association of each carboxyl group with a centrosymmetrically related neighbor. The angles O–C–O (123.3^o and 124.8^o, respectively) for the two carboxyl groups agree qualitatively with the values predicted from a linear relationship relating the observed ₂₂ component of the Carbon-13 NMR chemical shielding tensor for the carboxyl carbon atom to the bond angle O–C–O at the carbon atom.Contribution No. 825.     

X-ray structural investigation of N-epimeric 1,8-cis- and 1,8-trans-5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorates,C12H24N4Ni(ClO4)2

The structures of 1,8-cis- and 1,8-trans-5, 12-dimethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-dienenickel(II) diperchlorates (I andII, respectively) have been investigated by X-ray diffracto-metric methods. CompoundI crystallizes in a monoclinic system, space group P2₁/n, with cell dimensionsa=13.732(2),b=13.526(2),c=10.658(2) Å,=99.20(2)°; compoundII crystallizes in a monoclinic system, space group C2/c, with cell dimensionsa=15.776(2),b=9.919(1),c=12.451(1) Å,=102.27(1)°. The structures were solved by heavy atommethods and refined by a full-matrix least-squares method to giveR=0.0601 and 0.0575 forIandII, respectively. Both N-epimers show the square planar Ni(II) coordination arrangements. The ligand ofI has approximate twofold symmetry (C₂ perpendicular to the coordination plane), the moleculeII is crystallographically centrosymmetric (C_i).     

Structure of dichloro[(2,4-dimethyl-5-oxo-2,3,4,5-tetrahydro-2-furyl)methyl]-(4-methoxyphenyl)tellurium(IV)

The crystal structure of TeCl₂(C₇H₇O)(C₇H₁₁O₂) has been determined from three dimensional, single crystal X-ray diffraction data. It crystallizes in the monoclinic space group C2/c with the lattice constantsa=24.551(5),b=11.435(2),c=12.368(2)Å,=97.33(1)° andZ=8,D _X=1.67 g cm^–3. Final least-squares refinement based on 3023 independent observed reflections yieldedR=0.026. The Te^iv ion is in a trigonal bipyramidal configuration with its lone pair of electrons at one of the equatorial positions. Distances and angles are: Te-Cl=2.495(1), 2.517(1); Te-C=2.134(3), 2.106(3)(aryl)Å; Cl-Te-Cl=173.45(4), Cl-Te-C=88.11(9), 88.60(9), 88.72(9), 86.06(9); C-Te-C=96.5(1)°. There are two secondary bonds to the tellurium: TeCl=3.824(1) and TeO(2)=3.006(1)Å. The methyl group to the carbonyl oxygen and the aryltelluro moiety exhibit atrans 2,4 relationship.     

Structure of the 2-hydroxymethyl-4-(1,1,3,3-tetramethylbutyl)phenol,C15H24O2

The title compound crystallizes in space group P2₁/c with lattice constantsa=14.792(2),b=8.4610(6),c=11.845(3) Å and =103.49(2)°. The main feature of the conformation of this molecule is that the oxygen of the alcohol group is out of the phenolic ring plane (distance 1.256(3) Å). The structure consists of infinite chains of molecules running along thec axis. In these chains, molecules are linked by hydrogen bonds in which the phenolic oxygen is the donor and the oxygen of the alcohol function is the acceptor (distance O...O:2.752(4) Å).     

Synthesis,structural, and spectroscopic study of rhenium(III) and rhenium(V) 4,6-dimethylpyrimidine-2-thiolate/triphenylphosphine mixed complexes: Crystal and molecular structure of ∥ReCl2(pymS)(PPh3)2∥·C3H6O and ∥ReOCl2(pymS)(PPh3)∥

4,6-dimethylpyrimidine-2(1H)-thione reacts with rhenium(V) precursorstrans-ReOX₃(PPh₃)₂ (X=Cl, Br) in acetone, to afford two classes of crystalline pyrimidinethiolate/triphenylphosphine mixed complexes:trans-Re^IIIX₂(C₆H₇N₂S)(PPh₃)₂·C₃H₆O and Re^vOX₂(C₆H₇N₂S)(PPh₃) (X=Cl, Br). The crystal structures oftrans-ReCl₂(C₆H₇N₂S)(PPh₃)₂·C₃H₆O (I) and ReOCl₂(C₆H₇N₂S)(PPh₃) (II) have been determined from single-crystal diffractometer data and refined toR factors of 0.0496 and 0.0365, respectively. (I) crystallizes in the triclinic space group P¯1 witha=16.875(4),b=13.969(7),c=9.510(2) Å;=81.78(2)°,=85.15(12)°, =107.97(8)° andZ=2. The coordination geometry around the rhenium center exhibit mutuallytrans phosphine groups and chloride ligands disposedtrans to the nitrogen and sulfur donors of the pyrimidinethiolate ligand which form a four-membered chelate ring with the metal. (II) crystallizes in the monoclinic space group P2₁/c witha=12.554(3),b=10.501(1),c=19.200(5) Å;=106.54(2)° andZ=4. The rhenium atom presents a very distorted octahedral configuration with a chlorine atomtrans to phosphine ligand in the axial position and the N,S-chelate ligand in the equatorial plane with the sulfur donor atomtrans the Re=O_oxo group. The compounds were characterized also by means of ir and nmr spectroscopic measurements; reaction pathways are discussed on the basis of structural data.     

Structures of bis(salicylaldoximato)- and bis(5-chlorosalicylaldoximato)nitrosylcobalt,examples of nitrosyls containing a bent Co-N-O group

The crystal and molecular structures of [Co(NO)(salox)₂] and [Co(NO)(5-Clsalox)₂], where saloxH is salicylaldoxime and 5-ClsaloxH is its 5-chloro derivative, have been determined. The unsubstituted nitrosyl crystallizes in the orthorhombic system,a=11.557,b=15.333,c=8.245 Å,Z=4, space groupPna2₁. The structure was determined by theDIRDIF difference structure factors method, using MoK diffractometer data, and refined by full-matrix least squares toR=0.055 for 685 observed reflexions. The 5-chloro analogue crystallizes in the monoclinic system,a=8.553,b=12.510,c=15.702 Å, =102.84°,Z=4, space groupP2₁/c. This structure was determined by the heavy-atom method, using MoK diffractometer data, and refined by full-matrix least squares toR=0.043 for 2107 observed reflections. In both compounds, the molecule excluding the nitrosyl group is approximately planar. The cobalt atom is 5-coordinate in an essentially square pyramidal arrangement with the basal plane defined bytrans bidentate oximato ligands between which are strong hydrogen bonds. The nitrosyl group occupies the apical position, and the Co-N-O angles and the N-O bond lengths are 116(2)° and 1.48(3) Å ([Co(NO)(salox)₂]), and 123.4(3)° and 1.070(5) Å ([Co(NO)(5-Clsalox)₂]). The more acute angle and unusually long N-O bond of [Co(NO)(salox)₂] may be due to disorder and/or an interaction between the NO oxygen atom and one of the oxime groups.     

Refinements of the crystal structures of 1,4-diphenylbutadiyne and its complex with two moles of Co2(CO)6

1,4-diphenylbutadiyne, C₁₆H₁₀, crystallizes in monoclinic space group P2₁/n witha=6.6152(6),b=6.0768(7),c=14.634(1) Å, =100.981(8)⁰,V=577.5(2) ų,Z=2. The structure was refined toR=0.077 andR _w=0.069 for 1007 observed reflections with CuK radiation. The molecule lies on an inversion center. Our determination represents and increase in precision of a factor of approximately three over the original determination. The 21 cobalt complex, C₁₆H₁₀[Co₂(CO)₆]₂, also crystallizes in monoclinic space group P2₁/n witha=8.9568(12),b=17.7057(10),c=18.5671(12) Å, =90.606(12)^o,V=2944.3(5) ų,Z=4. The structure was refined toR=0.032 andR _w=0.031 for 4312 observed reflections. The diphenylbutadiyne triple bonds elongate to 1.346(3) Å and the angles at the diyne C atoms decrease to 134.1(3)–144.9(3)^o upon complexation. The Co-Co distance is 2.4580(4)Å. Our data represent an increase in precision by a factor of 2–3 over the original determination.     

Molecular structure of an extremely crowded iron(II) dihydride complex: FeH2(PMePh2)4

The crystal structure of FeH₂(PMePh₂)₄ shows this to exist as thecis isomer in the solid state with major distortions of the FeP₄ skeleton:cis P-Fe-P angles 98.1(1)–107.2(1)° andtrans P-Fe-P angle 143.3(1)°. All hydrogen atoms were refined, and the mean Fe-H separation is 1.59 Å. Long Fe-P distances, 2.187(3)–2.251(3) Å, emphasize the crowding in this molecule. Crystallographic data:a=11.684(4) Å,b=37.793(17),c=9.765(3),=90.81(1)°, andZ=4 in space groupP2₁/n (No. 14).R(F)=6.3% andR _w (F)=6.0% for 2585 observed reflections collected at —162°C.     

Structural characterization of oxidized lumiflavin hydrochloride hydrate: Comparison with the hydrogen bonding at the cofactor of flavoproteins

In order to examine the possibility of hydrogen bonding around the flavin ring, an X-ray diffraction study of the title compound was undertaken. Crystals of lumiflavin hydrochloride hydrate [2(C₁₃H₁₂N₄O₂) 4 HCl 7 H₂O] are triclinic, space group ,Z=2,a=11.064(1),b=17.903(1),c=9.891(1)Å, =111.9(6), -96.4(8), =91.6(7)°. We present the crystal structure of this compound and compare it with other flavin derivatives and with the structure of the active site of some flavoproteins.     

Crystal and molecular structure of 3,5-diiodo-3′,4′-dichlorosalicylanilide

Monoclinic crystals of the salicylanilide, C₁₃H₇Cl₂I₂NO₂, a potent flukicide, belong to the space groupC ₂ witha=42.649(25),b=4.695(2),c=7.697(2) Å, =95.14(2) °, andZ=4. The structure was solved by the heavy-atom method, from intensity data measured on a diffractometer with MoK radiation. Refinement with anisotropic temperature factors given to the I and Cl atoms and isotropic given to C, N, and O has yielded a reliability index of 0.049 for the 1421 observed terms. The two aromatic rings,A andB, in the molecule are almost coplanar with a dihedral angle of 4.1 °, whereas they are inclined at 29.4 and 33.5 °, respectively, to the plane of the amide group. Molecular dimensions indicate that there is an intramolecular hyrdogen bond between the hydroxyl group and the carbonyl oxygen, the O . . . O distance being 2.65 Å.     

Structural studies of two tetracyclines: 4-dedimethylaminotetracycline hydrate and 6-methylene-5-oxytetracycline hydrochloride

The crystal structures of two tetracycline derivatives, 4-dedimethylaminotetracycline hydrate and 6-methylene-5-oxytetracycline hydrochloride (methacycline·HCl), were determined using X-ray intensity data measured on a diffractometer. The first compound crystallizes with two chemical formula and one water molecule per asymmetric unit. The monoclinic crystal [a=7.174(5),b=12.029(9),c=21.117(15) Å,=93.16(6)°] shows the space groupP2₁. Crystals of methacycline hydrochloride are orthorhombic, space groupP2₁2₁2₁,a=9.472(1),b=11.921(3),c=18.945(4)Å, with one molecule in the asymmetric unit.     

Isomerism in some 1-oxa-3,5-dithians and the X-ray structure determination of 2,6-bis(trichloromethyl)-4-dichloromethylene-1-oxa-3,5-dithian

2,6-bis (trichloromethyl)-4-dichloromethylene-1-oxa-3,5-dithian is triclinic,P¯1,a=10.125(3),b=10.294(3),c=14.631(10) Å,=92.84(5),=96.51(5), =96.18(2)°,V=1503 ų,Z=4. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least squares to a finalR value of 0.035 using 3961 reflections. The conformation of the molecules is twist-boat, one molecule being almost symmetrically twisted about the O-C(Cl₂) direction. The range of endocyclic O-C-S angles is 111.8(3) to 115.1(3)° and data are given which support the possibility of there being a correlation between the endocyclic O-C(X)-S angle, the C-O-C(X)-C(Cl₃) torsion angle, and the C-S-C(X)-C(Cl₃) torsion angle. The -CCl₃ groups are in pseudoequatorial positions. Average bond lengths (Å) for the two molecules are C-O 1.405, C(sp ³)-S 1.822, C(sp ²)-S 1.759, C-C_eq 1.529 and average endocyclic angles (°) are O 117.3, C (sp ³) 113.5, S 97.4, C(sp ²) 119.3, the esds on the individual bond lengths and angles being in the ranges of 0.003–0.004 Å and 0.2–0.4° respectively.     

The structure of N,N′-bis(2-hydroxyphenyl)butanediamide

The structure of N,N-bis(2-hydroxyphenyl)butanediamide has been determined. The molecule consists of two 2-hydroxyphenyl moieties which are attached (at the 2 position) to the two nitrogens of the butanediamide. The compound C₁₆H₁₆N₂O₄ crystallizes in the monoclinic space group P2₁/c witha=5.576(1),b=4.8853(6),c=25.397(6) Å and =90.58(1)°.