The structures of three trimethylarsine-boron trihalide adducts: (CH3)3AsBCl3, (CH3)3AsBBr3, and (CH3)3AsBI3

An X-ray structure analysis of three trimethylarsine-boron trihalide adducts has been undertaken. Crystals of (CH₃)₃AsBCl₃ and (CH₃)₃AsBBr₃ are monoclinic with space groupP2₁/m (No. 11) withZ=2 while those of (CH₃)₃AsBI₃ are orthorhombic with space groupPnma (No. 62) withZ=4. For (CH₃)₃AsBCl₃,a=6.497(3) Å,b=10.735(3) Å,c=7.070(2) Å,=111.8(3)°,V=458.4(3) ų,R=0.0343. For (CH₃)₃AsBBr₃,a=6.672(4) Å,b=11.135(7) Å,c=7.199(4) Å,=111.5(1)°,V=497.7(5) ų,R=0.0434. For (CH₃)₃ÅsBI₃,a=13.113(7) Å,b=11.733(5) Å,c=7.387(3) Å,V=1136.5(5) ų,R=0.0329. The As-B bond lengths are 2.065(6), 2.04(1), and 2.03(1) Å, respectively, for the chloride, bromide, and iodide. These and other structural parameters are discussed with reference to previous predictions based on vibrational spectra and previous structural studies on the trimethyl-phosphine and trimethylamine adducts.     

X-ray structure and NMR assignment of 3,3′-dimethylthio-4,4′-diquinolinyl sulfide

The title compound (C₂₀H₁₆N₂S₃) is triclinic, witha=9.494(3)b=9.890(3),c=19.456(5)Å,a=90.26(3)°,°=100.47(3)°, =99.18(3)°,Z=4 and space groupP¯1. The structure was solved by direct methods and refined toR=0.045 for 6076 reflections. There are two nonequivalent molecules in the unit cell. Two pairs of sulfur atoms in ortho-positions remain in very close contact. The S-methyl groups are nearly coplanar to the quinoline moieties and turned to the orthoposition, 2. CP MAS spectrum shows two conformers in the solid state but¹H and¹³C NMR spectra in CDCl₃ solution show rapid equilibrium of the conformers giving rise to average NMR data.Part XX in the series of Azinyl Sulfides.     

Tri-(nitrato)-bis-(hexamethylenetetramine)-nona-(aquo) neodymium (III): Synthesis,crystal structure,IR and Raman spectroscopy

This paper reports the structural and spectroscopic properties of tri-(nitrato)-bis-(hexamethylene-tetramine)-nona-(aquo)neodymium (III). The crystals are monoclinic, space groupP2₁/n,Z=4, witha=17.902(4),b=9.335(2),c=18.489(4)Å, B=112.07(2)°. The crystal structure consists of one [Nd(NO₃)₂(H₂O)₆]⁺ cation, two NO ₃ ^– anions coordinated to the neodymium atom, two hexamethylene tetramine molecules, third free NO ₃ ^– anion and three water molecules. The structure was refined to a finalR index 0.039 and weightedR _w 0.039 for 6221 observed reflections. The IR and Raman spectra are fully consistent with the crystallographic results.     

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.     

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 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.     

Synthesis and characterization of a novel pentacyclic C16 diketone and derivatives

The syntheses and crystal structures of pentacyclo[9.4.1.0^5,14.0^7,13.0^12,15]hexadecane-3,9-dione (2), a novel C₁₆ diketone with potential inclusion ability, and the products of the reaction of2 withn-butyllithium andmeso-erythritol (i.e.,meso-1,2,3,4-butanetetrol) are described. Crystal data:2·H₂O, orthorhombic,Pmmn,a=10.7385(8),b=9.0188(6),c=6.8411(4)Å,V=662.55(7)ų, andR=0.039 (379 reflections);3 (product from reaction withn-butyllithium), triclinic,P¯1,a=8.7192(7),b=10.9351(8),c=12.1842(8)Å,=68.933(5),=75.850(6), =80.309(6)°,V=1047.0(1)ų, andR=0.081 (1811 reflections);4 (product from reaction with erythritol), triclinic,P¯1,a=7.7224(8),b=10.1976(8),c=10.7021(9)Å,=85.405(7),=85.766(8), =76.056(7)°,V=814.0(1)ų, andR=0.052 (1471 reflections).     

Single crystal X-ray structure of 11-acetoxy-4-deoxyasbestinin B

The crystal structure of 11-acetoxy-4-deoxyasbestinin B (C₂₂H₃₄O₄,M _r=362.49) crystallized in the orthorhombic space groupP2₁2₁2₁ witha=10.923(5)Å,b=11.127(5)Å,c=17.047(5)Å,V=2072(3)ų,Z=4,D _x=1.163g/cm^–3. MoK radiation was used for data collection at room temperature. The finalR=0.042 for 2464 observed reflections. The stereochemical assignments of the molecule from the 2-D NMR data are verified totally by the overall geometry of the molecule obtained from the X-ray diffraction analysis.     

On the stereochemistry of lignin model compounds of the arylglycerol-β-aryl ether type: Crystal structure oferythro-1-(4-hydroxy-3,5-dimethoxyphenyl)-2-(4-hydroxymethyl-2,6-dimethoxyphenoxy)-1,3-propanediol,C20H26O9

The crystal structure of erythro-1-(4-hydroxy-3,5-dimethoxyphenyl)-2-(4-hydroxymethyl-2,6-dimethoxyphenoxy)-1,3-propanediol, C₂₀H₂₆O₉, has been determined from single-crystal X-ray diffraction data. The compound crystallizes in the triclinic space groupP¯1 witha=8.705(6),b=8.893(5),c=13.211(8) Å,=106.23(5),=93.71(5), =82.97(5)° andZ=2. The structure was solved by direct methods. Full matrix least-squares refinement of 366 structural parameters gaveR=0.039 for 1402 observed [I>3a(I)] reflexions. The molecules are held together by van der Waals forces and moderately strong hydrogen bonds. Average bond distances: C(sp ²)-O 1.370(6) Å and C(sp ³)-O 1.426(14) Å.     

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.     

Molecular structure of 3-phenyl-5-methyl-4-isoxazolyl-penicillin sulfone (oxacillin sulfone): C19H19N3O8S

The crystal structure of oxacillin sulfone has been determined by single-crystal X-ray diffraction techniques and refined by full-matrix least squares. The penicillin molecule cocrystallizes with H₂O in an orthorhombic space groupP2₁2₁2₁ witha=10.303(7) Å,b=26.735(17) Å, andc=7.384(4) Å. The calculated density is 1.526 g cm^–3, with aZ value of 4. FinalR-factor is 0.035. The oxidation of the sulfur atom is discussed in terms ofS1 conformation of the penam moiety and in terms of hydrogen-bond formation between one oxygen of the sulfur atom and the amidic hydrogen of the C₆ side-chain. A comparison with oxacillin and cloxacillin sulfoxide is also made.     

Structure and IR spectroscopic behavior of 2,4-dimethylpyridinium pentachlorophenolate

The structure of 2,4-dimethylpyridinium pentachlorophenolate (DMP PCP) has been determined by X-ray diffraction. The crystals are monoclinic, space groupP2₁,/n, witha=8.729(7),b=13.72(1),c=12.82(1) Å,=91.39(8)° andZ=4. The structure was solved by the direct methods, and refined toR=0.040 for 2375 non-zero independent reflections. The N⁺-HO^– hydrogen bond is of length 2.604(3) Å. The ionic character of the hydrogen bond has been confirmed by the IR spectra.     

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 structures of 5,7-dimethyl-1,8-naphthyridine-2-ol (=LH) and of its mercury (II) complex HgL2 and synthesis of some lanthanide/HgL2 heterometallic complexes

The crystal structures of the title compounds have been determined by single crystal diffraction methods. Crystals of 5,7-dimethyl-1,8-naphthyridine-2-ol (1) are monoclinic, space groupP2₁/n witha=7.336(2),b=8.989(2),c=13.125(3)Å,=95.72(3)°,V=861.2(4)ų,Z=4,D _c =1.34 g cm^–3, finalR=0.052. The molecules are linked in pairs by two N-HO hydrogen bonds, and these dimers are stacked in a discontinuous, stepped fashion. Crystals of HgL₂ (2) are monoclinic space groupP2₁,/c witha=4.044(2),b=12.147(2),c=18.093(5)Å,=93.32(2)°,V=887.3(4)ų,Z=2,D _c =2.05 g cm^–3, finalR=0.051. In2 the mercury binds to N(1) to form a linear N-Hg-N coordination geometry, and the HgL₂ molecules form a continuous stacked structure. The syntheses of the compounds ML₄(NO₃)₃·H₂O (M=Nd, Gd, and Er), PrHg₂L₄(NO₃)₃, andM ₂Hg₃L₆(NO₃)₆ (M=Gd, Er) are also reported.     

Crystal structure of bis-N,N′-p-chlorosalicylideneamine-1,2-diaminobenzene

The crystal structure of the title compound, C₂₀H₁₄N₂O₂Cl₂, has been determined by single crystal X-ray diffraction techniques. It crystallizes in the orthorhombic system witha=7.532(3)Å,b=18.563(2)Å,c=25.089(3)Å, space groupPbca,V=3507.9(3)ų,Z=8,F(000)=1584.D _x =1.459 g cm^–3,M=385.3 a. m. u., (MoK)=0.7107 Å, =3.35 cm^–1,T=297°K,R=0.086,R _w =0.049 for 2119 unique diffractometer data. The molecules are linked by van der Waals forces.     

Synthesis,spectroscopic characterization of thiosemicarbazone complexes of nickel(II) and X-ray structures of anisaldehyde thiosemicarbazone (ATSZH) and bis(tolualdehyde thiosemicarbazonato)nickel(II)

Complexes of nickel(II) with anisaldehyde (ATSZH), tolualdehyde (TTSZH), and vanillin (VTSZH) thiosemicarbazones have been synthesized and characterized by means of UV-Visible, I.R., Raman,¹H and¹³C NMR spectroscopy. The thiosemicarbazones have been found to exist in the thione form.¹H and¹³C NMR as well as electronic spectral data support a square planar structure for Ni(ATSZ)₂ and Ni(TTSZ)₂ complexes.¹H and¹³C NMR spectra indicate that the structure of Ni(VTSZ)₂ complex differs from the other two nickel(II) complexes and it may possibly consist of mixtures of isomers. The X-ray structures of Ni(TTSZ)₂ and ATSZH were determined: the nickel complex is monoclinic witha=26.412(6),b=12.135(3),c=6.888(1)Å,=95.41(5)°,Z=4,R=0.0647, space groupC2/c. The structure consists of discrete Ni(TTSZ)₂ molecules in which the metal, located on a symmetry centre, is N,S-chelated by two ligands forming two five-term chelate rings. The structure of ATSZH is also monoclinic:a=7.859(1),b=13.481(3),c=10.028(3) Å,=106.32(4)°,Z=4,R=0.0412, space groupP2₁/c. The molecules, connected by NO hydrogen bonds, reveal a considerable tilting of the aromatic ring in respect to the thiourea moiety if compared with the nickel structure.     

Crystal and molecular structures of the 4-(1H)-pyridone (=L) lanthanide complexes {[GdL(NO3)3(H2O)]·CH3OH}2 and [DyL4(NO3)2](NO3) and of L2HNO3

The crystal structures of the title compounds have been determined by single crystal diffraction methods. Crystals of the dysprosium compound are monoclinic, space groupP2₁/c witha=14.133(4),b=13.438(5),c=14.401 (4)Å,=103.98(2)°,V=2654(1)ų,Z=4,D _c =1.82 g cm^–3, finalR=0.035. The Dy atom is eight-coordinate with a distorted dodecahedral coordination geometry involving two bidentate nitrate groups and four pyridone oxygen atoms. An erbium complex with analogous stoichiometry was also prepared but not structurally characterized. Crystals of the Gd compound are monoclinic, space groupP2₁/n, witha=11.226(2),b=9.075(2),c=16.737(3)Å,=93.88(3)°,V=1701(1)ų,Z=2,D _c =1.91 g cm^–3, finalR=0.042. Each Gd atom is bonded to one pyridone oxygen atom, a water molecule and three bidentate nitrate groups. An oxygen atom of one of the bidentate nitrates additionally serves to bridge pairs of Gd atoms so as to form a dinuclear complex in which each Gd atom is nine-coordinate with a tricapped trigonal prismatic geometry. Crystals of L₂HNO₃ are monoclinic, space groupI2/a witha=12.479(4),b=6.535(2),c=14.297(6)Å,=96.07(3)°,V=1159(1)ų,Z=4,D _c =1.45 g cm^–3, finalR=0.057. The pyridones are linked in pairs by very short (2.44 Å) symmetrical OHO hydrogen bonds. Each pair is further linked via a nitrate ion by means of N-HO(nitrate)H-N hydrogen bonds, so as to form an extended chevron-like pyridone-pyridone-nitrate-pyridone-pyridone array. Adjacent chains are linked via weak C-HO(NO₃) interactions.     

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.     

An infrared,Raman, and single-crystal x-ray study of cesium hexafluorophosphate

CsPF₆:M,=277.87, cubic,Fm3m-O _h ⁵, witha 8.228(5) Å,V 557(1) ų,Z=4,D _x =3.31 Mg m^–3, X(MoK)=0.7107 Å,(MoK)=6.85 mm^–1 F(000)=496,R=0.0327 for 114 reflections. The PF₆ ion exhibits orientational disorder; infrared and Raman spectra show that its point symmetry is lower thanm3m-O _h , in agreement with the equilibrium atomic positions found in the X-ray study. The rule of mutual exclusion is not obeyed in the spectra of CsPF₆; this can be explained if the disorder also involves a small shift of the P atom away fromm3m-O _h site symmetry. Such an effect could not be modelled in the X-ray study. The deviation from octahedral symmetry of PF₆ is small and, from a consideration of the vibrational spectra of the MPF₆ series, it is concluded that both the reorientational and other motions such as librational and torsional oscillations contribute toward the breadth of some vibrational modes.     

Crystal and molecular structure of di(μ 3-oxo-tri-μ-oxotrichlorohexakis(pyridine)-triangulotritungsten(IV))hexatungstate(VI)-6-pyridine, [W3(O)O3Cl3(C5H5N)6]2W6O19·6C5H5N

[W₃(O)O₃Cl₃(C₅H₅N)₆]₂W₆O₁₉·6C₅H₅N, the side product of the reaction between WCl₄(C₅H₅N)₂ and pyridine, crystallizes in the rhombohedral space groupR¯3 (No. 148), witha=14.044(1) Å,=87.70(1)°, andZ=1. The structure was solved by the heavy-atom method, and refined to the unweighted and weighted residuals of 0.068 and 0.055, respectively. The tungsten atoms define an equilateral triangle with a capping and three bridging oxygen atoms. Two pyridines in thecis position and a chlorine atom form, together with the oxygens, a distorted octahedron around the tungsten atoms; three octahedra are connected through common edges. Important bond lengths are: W-W (single bond) 2.532(1), W-O (tricapped) 2.09(1), W-O (bridging) 1.92(1) and 1.94(1), W-C1 2.424(5), and W-N (pyridine) 2.23(1) and 2.26(1) Å. In W₆O ₁₉ ^2– , six WO₆ octahedra have one common central oxygen, twelve bridging and six terminal oxygen atoms. Corresponding W-O bond lengths are: 2.323(1) (central oxygen), from 1.90 to 1.94(1) (bridging oxygens), and 1.70(2) Å (terminal oxygens). Lattice pyridine molecules have no important contacts with either anion or cation.