Crystal structure of (E)-5-hydroxypyrrolizidin-3-one and (Z)-5-thioketalpyrrolizidin-3-one

The crystal structures of (E)-5-hydroxypyrrolizidin-3-one (2) and (Z)-5-thioketalpyrrolizidin-3-one (3) have been determined by single-crystal x-ray diffraction techniques and refined by full-matrix least squares. Molecule2 crystallizes in the monoclinic space groupP2₁/a(No. 14) witha=7.887(3) Å,b=9.788(5) Å,c=9.316(4) Å,=100.6(1), andZ=4. Molecule 3 crystallizes in the monoclinic space groupP2₁/c witha=12.947(14) Å,b=10.553(14) Å,c=9.629(14) Å,=101.4(1), andZ=4. The calculated density for both molecules is 1.33 g cm^–1. FinalR-factors were 5.1% for2 and 8.59% for3. The x-ray results showed that a change in configuration occurred in the reaction going from2 to3.     

The crystal and molecular structures of 2-hydroxy-1-naphthalenecarboxaldehyde and 3-hydroxy-2-naphthalenecarboxaldehyde

The crystal and molecular structures of 2-Hydroxy-1-naphthalenecarboxaldehyde (I) and 3-Hydroxy-2-naphthalenecarboxaldehyde (II) were determined. Compound (I) crystallizes in the space groupP2 ₁/n witha+5.589(2),b+9.352(2), andc+15.490(3) Å, =98.14(3)°, andZ+4. Compound (II) crystallizes inP2 ₁/n witha+16.831(11),b+5.936(3), andc+8.295(3) Å =97.24(5)°. andZ+4. The structures were solved by direct methods, and refined by fullmatrix least squares toR+0.071 andR _w+0.083 forI, andR+0.047 andR _w+0.061 forII.     

Heptacoordination in MnII,NiII, and CuII complexes of 2,6-diacetylpyridine bis (acetylhydrazone)

Manganese(II), nickel(II), and copper(II) complexes of 2,6-diacetylpyridine bis (acetylhydrazone) (H₂dapac) have been synthesized and structurally characterized by X-ray diffraction methods. [Mn(H₂dapac) (OH₂)₂](NO₃)₂ crystallizes in the monoclinic space groupP2₁/c witha=11.145(3),b=10.723(4),c=17.189(2) Å, =92.81(2)° andZ=4; [Ni(H₂dapac)(OH₂)₂] (NO₃)₂·H₂O crystallizes in the monoclinic space groupP2₁ witha=9.994(3),b=14.423(4),c=7.697(2)Å, =100.37(2)°, andZ=2; [Cu(H₂dapac)(OH₂)₂](NO₃)₂·H₂O crystallizes in the orthorhombic space groupPbcn witha=20.986(5),b=14.552(3),c=6.905(1)Å andZ=4. In each case the metal atom has a slightly distorted pentagonal bipyramidal environment, the equatorial positions being occupied by three nitrogen and two oxygen atoms from the hydrazone ligand and the apices by two water molecules. The crystalline cohesion in ensured by a three-dimensional network of hydrogen bonds involving the complex cations, the nitrate anions, and, where present, the uncoordinate water molecules.     

Crystal and molecular structure analysis of benzamide neuroleptics and analogs (VIII):endo- andexo-2,3-dimethoxy-N-[8-(phenylmethyl)-8-azabicyclo[3.2.1]oct-2-y1]-benzamide hydrochloride: C23H28N2O3·HCl

The crystal structures ofendo- andexo-2,3-dimethoxy-N-[8(phenylmethyl)-8-azabicyclo[3.2.1]oct-2-y1]benzamide hydrochloride have been determined by single-crystal X-ray diffraction techniques, and refined by full-matrix least squares. The endo-compound crystallizes in the monoclinic space groupP2₁/n witha=12.389(2) Å,b=22.861(3) Å,c=8.019(2) Å,=93.58(2)°, andZ=4; the exo-compound crystallizes in the monoclinic space groupP2₁/a witha=26.295(12) Å,b=12.503(4) Å,c=6.667(7) Å,=97.80(6)°, andZ=4. The calculated densities are 1.22 and 1.27 g cm^–3 respectively. FinalR-factors are 0.04 for the endo and 0.05 for the exo-compound. Comparison with a very active analog, the tropapride, suggests that the lack of antipsychotic activity is due to a different orientation of the dimethoxyphenyl or carbonyl group for the exo- and endo-compound, respectively.     

Crystal and molecular structure analysis of gamma-hydroxybutyrate (GHB) analogs:trans-4-hydroxycrotonic acid (THCA),trans-4-hydroxy-4-0-chlorophenylcrotonic acid (THCCA), andtrans-4-hydroxy-4-p-nitrophenylcrotonic acid (THNCA)

The crystal structures oftrans-4-hydroxycrotonic acid (THCA), 4-o-chloro-phenyl-THCA (THCCA), and 4-p-nitrophenyl-THCA (THNCA) have been determined by single-crystal X-ray diffraction techniques, and refined by full-matrix least squares. THCA crystallizes in the monoclinic space groupCc witha=7.847(1),b=8.519(1),c=7.685(4) Å,=109.66(2)° andZ=4; THCCA is triclinic, space groupP¯1, witha=7.878(2),b=8.621(1),c=7.653(1) Å,=92.20(1)°,=114.15(2)°, =94.40(2)°, andZ=2; THNCA is orthorhombic, space groupPna2₁, witha=7.488(1),b=19.666(2),c=7.143(3) Å, andZ=4. FinalR-factors are 0.034, 0.045, and 0.031, respectively. The first two compounds present a semiextended conformation. The third structure is extended; however, for this last compound, empirical molecular mechanics calculations show that the semiextended conformation corresponds also to a low-energy state.     

Reaction of 5,5-diphenyl-2-thiohydantoin with ethyl-2,3-dibromopropionate. Crystal and molecular structure of ethyl-2-{2,3-dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one} formate

The crystal and molecular structure of the title compound, obtained by intramolecularN,S-dialkylation of 5,5-diphenyl-2-thiohydantoin with ethyl-2,3-di-bromopropionate, has been determined from X-ray diffractometer data. Ethyl-2-{2,3-dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one}formate crystallizes in space groupP2₁/c witha=12.166(4),b=10.689(2),c=15.021(6) Å,=113.63(4)°, andZ=4. The molecular structure was found with nonplanar thiazole ring. The structure was solved withR=0.051.     

Resolution of optical isomers of 4-amino-p-chlorobutyric acid lactam by co-crystallization

4-Amino-p-chlorobutyric acid lactam crystallizes as racemic crystals in the monoclinic space groupP2₁/n, witha=5.006(2),b=6.783(2),c=27.652(2) Å, =92.25(1)°,Z=4,R=0.035 for 1618 unique reflections. As both enantiomers are present in a single crystal it is not possible to effect enantiomeric separation by crystal growth inhibition. This lactam may, however, be co-crystallized with (2R,3R)-(+)-tartaric acid forming a 2:1 complex in which only the (R) enantiomer is present. The complex crystallizes in the monoclinic space groupP2₁ witha=10.074(2),b=10.132(6),c=12.238(6) Å, =99.13(2)°,Z=2,R=0.036 for 2291 unique reflections. Complex formation is effected by hydrogen bonding but enantioselectivity does not involve the chiral center of the title compound directly.     

Crystal and molecular structure of rubidium azidotrimethylaluminate,Rb[Al(CH3)3N3]

The crystal structure of rubidium azidotrimethylaluminate has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/n, witha= 10.003(5),b=7.497(4),c= 11.806(5) Å, = 108.70(3) °, andD _c= 1.58 g cm⁼³ forZ=4. The finalR factor for 922 observed reflections is 0.049. The compound is not isostructural with its cesium analog. The aluminum atom is coordinated in a tetrahedral fashion, and the Al-N bond length is 1.944(8) Å.     

Crystal structures ofN(6)-methyladenine hydrochloride andN(6),N(9)-dimethyladenine

The crystal structures ofN (6)-methyladenine hydrochloride (6-MA·HCl) and ofN (6),N (9)-dimethyladenine (6,9-DMA) were determined by the use of X-ray diffractometer data. Crystals of 6-MA·HCl are monoclinic, space groupP2₁/m, witha = 9.3450(6),b = 6.5838(4),c = 7.3142(3) Å, = 114.837(4) °, andZ = 2. Crystals of 6,9-DMA are monoclinic, space groupP2₁/c, witha = 12.045(3),b = 6.135(2),c = 23.27(1) Å, = 111.79(3), andZ = 8. The crystal structures were refined by least-squares toR = 0.053 for 6-MA·HCl andR = 0.071 for 6,9-DMA. The N(1)-protonated adenine derivative in the 6-MA·HCl crystal structure and the two crystallographically independent adenine derivatives in the 6,9-DMA structure all assume conformations in which the methyl substituent at N(6) is in or near the purine plane, and is pointing away from the imidazole moiety.     

Crystal and molecular structure of chlorotris(triphenylarsine)Cu(1),C54H45As3CuCl

The title compound crystallizes in the monoclinic space groupP2₁/n, witha=28.494(2),b=10.148(5),c=32.172(2) Å,=94.57(1)°, andZ=8 (with two independent molecules in the asymmetric unit). The structure was solved by direct methods and refined by block-diagonal least-squares methods toR=0.057 for 12286 observed reflections. The dimensions and conformations of the two independent molecules are closely similar. The coordination around the copper and arsenic atoms is approximately tetrahedral, although distortion is considerable. Some important mean bond distances and angles with their rms standard deviations are: Cu-Cl=2.270(4), Cu-As=2.419(4), As-C=1.953(2) Å, Cl-Cu-As=105.4(1.2), and As-Cu-As=113.3(8)°.     

Crystal structure oftrans-tetrachlorobis[2-(2-1H-imidazolyl)-1H-imidazolium]cadmium(II), [Cd(H3biim)2Cl4]

The reaction between cadmium(II) chloride and 2,2'-bi-1H-imidazole (H₂biim) in an acidic solution affords [Cd(H₃biim)₂Cl₄] (H₃biim=2-(2-1H-imidazolyl)-1H-imidazolium) in 63% yield. The compound crystallizes in the triclinic space groupP1, wherea=8.072(2),b=8.100(2),c=8.593(2) Å, =75.89(2), =62.94(2), =63.29(1)°,V=446.4(2) ų, andZ=1. The central Cd atom exhibits an octahedral geometry composed of a Cl₄N₂ core. The Cd-N bond distance is 2.392(2) Å. Cd–Cl distances are 2.5919(9) and 2.671(1) Å.     

Crystal structure ofcis-diaqua bis(2,2′-bipyridyl)chromium(III) nitrate, [Cr(bipy)2(H2O)2] (NO3)3

cis-Diaquabis(2,2-bipyridyl)chromium(III) nitrate crystallizes in the mono-clinic system, space groupP2₁/c, witha=16.102(6),b=10.792(5),c=15.076(6) Å,=112.90(5)°, andZ=4. The saltlike structure was determined from X-ray crystallography and refined toR=7.5% for 3342 observed reflections. The Cr atom is octahedrally surrounded by twocis water molecules and by two chelated 2,2-bypiridyl ligands forming two nearly orthogonal planes. Selected bond distances are: Cr-O, 2.00(1) and 1.98(1) Å, Cr-N, 2.04 Å (mean).     

Crystal structure of bromofluoroacetic acid: a chiral molecule

The crystal structure of bromofluoroacetic acid has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/c, witha = 8.529(4),b = 5.632(3),c = 9.500(4) Å, = 105.52(4) °, andD _x = 2.37 g cm^–3 forZ = 4. The finalR factor for 654 independent observed reflections is 0.081. The compound exists as hydrogen-bonded dimers in the solid state.     

NMR and crystallographic evidence for polymorphism of the N-phenyl-N′-[1-(3-(phenyl-4-piperazinyl)propan-2-ol)]urea

NMR spectroscopy and single-crystal X-ray analysis have been used to characterize polymorphism of the racemate of the N-phenyl-N-[1-(3-(phenyl-4-piperazinyl)propan-2-ol)urea displaying an analgesic activity. The crystal structures of the monoclinic form,R _m witha=4.788(1),b=9.432(7),c=40.791(5) Å, =90.93(1)°, space groupP2₁/n,Z=4 and of the orthorhombic form,R _o witha=10.948(3),b=8.896(3),c=38.857(6) Å, space groupPbca,Z=8, have been determined. In addition, the crystal structure of an enantiomer orthorhombic,E _o, isolated from a conglomerate, witha=4.787(3),b=9.461(2),c=40.809(10) Å, space groupP2₁2₁2₁, Z=4, has also been determined. The three conformations have been compared when the molecules have the same relative configurations.     

Crystal and molecular structure of trans-(tricarbonyl)bis(trans-2,2,3,4,4-pentamethyl-1-phenylphosphetane)iron

The title compound crystallizes in the monoclinic space groupP2₁/a witha=13.092(2) Å,b=15.853(2) Å,c=15.406(3) Å,=103.00(1)°,V=3116(1) ų, andD _calc=1.237 g cm^–3 forZ=4. The structure was solved by direct methods, and refined to a finalR value of 0.057. The phosphetane ligands adopt a nonlinear trans relationship. The four-membered rings are non-planar and have different flap angles of 6.1 and 20.3°. Virtual coupling is evident in the¹³C NMR spectrum of the title compound. Comparison of the¹³C NMR spectral data of this molecule with the parent phosphine ligand, the ligand oxide, and the mono-phosphine iron complex is provided.     

Crystal and molecular structure of dichlorotetrakis(propanol-2) titanium (III) chloride,C12H32Cl3O4Ti

The crystal and molecular structure of dichlorotetrakis(propanol-2)titanium (III) chloride, C₁₂H₃₂Cl₃O₄Ti, has been determined by X-ray methods. The complex crystallizes in the monoclinic system:a = 15.968(4),b = 11.610(5),c = 11.90(5) Å, = 94.15(2) °, space groupC2/c andZ = 4. The positions of all non-hydrogen atoms have been refined by least squares to giveR = 0.126 for 1211 observed structure factors. The crystal structure consists of {TiCl₂(HOCH(CH₃)₂)₄}⁺ cations and Cl^– anions. From the space-group symmetry, it follows that the complex cation has 2(C ₂) symmetry. The 2 chlorine and 4 oxygen atoms of the inner coordination sphere are arranged in the form of a distorted octahedron around the central Ti atom. Two chlorine atoms, with the interatomic distance Ti—Cl of 2.32 Å, are in acis-conformation. The interatomic distances Ti—O, two oxygen atoms opposite to the chlorine atoms, are 2.10 Å. The pair oftrans-oriented oxygen atoms are at distances Ti—O= 2.09 Å. The Cl^– ions occupy positions at symmetry centres. Each of them is in contact with four oxygen atoms, the paired Cl—O distances being 3.04 Å and 3.12 Å.     

Structure oftrans-methyl 2-phenylhexahydro-2H-isoxazolo (2,3-a)-pyridine-3-carboxylate

The title compound, a 1,3-dipolar cycloaddition product, crystallizes in the monoclinic space groupP2₁/c, witha=8.199(3),b=16.908(1),c=10.248(2)Å,=93.58(2)° andZ=4. The structure was solved by direct methods and refined by full matrix least squares methods toR=0.038 for 1687 observed reflections. The stereochemistry of this compound was found to have the ee conformation in the solid state as well as in solution. The piperidine ring in the molecule is in the chair form and the isoxazolidine ring adopts an envelope conformation.     

Crystal and molecular structure of 2-chloro-4-methyl-6-[[(4-)2,2,6,6,-tetramethylpiperidinyl]amino]-3-pyridinecarbonitrile hydrochloride

The compound C₁₆H₂₄N₄Cl₂ crystallizes in the monoclinic space groupP2 ₁/c witha=16.299(2),b=7.801(1),c=14.780(2) Å,=109.89(1)° andZ=4. The structure was determined by direct methods, and refined by full-matrix least squares toR=0.046 andR _w=0.050 for 2309 reflections. The resulting structure permitted the determination of the main direction of substitution during the synthesis of this compound, and correction of a previously postulated formulae of the dyes formed. The influence of salt formation on the protonation of the N atom and on the formation of hydrogen bonds is analyzed. The influence of substituents on the geometry of pyridine and piperidine ring is discussed.     

Investigation of 2-(3,4-dimethoxyphenyl)-5,6-dimethoxy-1H-indene by X-ray crystallography and NMR spectroscopy

2-(3,4-Dimethoxyphenyl)-5,6-dimethoxy-1H-indene (obtained by acid treatment of 1,2-bis(3,4-dimethoxyphenyl)-1,3-propanediol) crystallizes in space groupP2₁/c witha=6.836(6),b=28.631(9),c=16.344(6) Å, =95.73(5)°, andZ=8. There are two molecules in the asymmetric unit; the conformations of these molecules exhibit minor differences. In the crystals the double bond in the five-membered ring of the compound is disordered over two positions. The nature of the bonds in the five-membered ring could be ensured by¹H-NMR and¹³C-NMR spectral examinations.     

Crystal and molecular structure of 4-bromo-2,2,3,3-tetramethyl-1-benzyl-1-phenylphosphetanium bromide

The title compound crystallizes in the monoclinic space groupP2₁/n, witha=8.881(1),b=17.718(1),c=13.077(8) Å,=99.17(2)° andZ=4. The structure was solved by the heavy-atom method and refined to a finalR value of 0.059. The four-membered ring is nonplanar, with a puckering angle of 22.0°. The Br and phenyl are in pseudoaxial positions and aretrans to each other in the solid state.