Crystal and molecular structure of 1,2-difluoroethane and 1,2-diiodoethane

A single crystal of phase 1 of 1,2-difluoroethane was grown from the melt directly on an X-ray diffractometer close to the melting point of 169 K. It crystallizes in the monoclinic space group C2/c with lattice parameters a = 7.775(4), b = 4.4973(7), c = 9.024(3) Å, = 101.73(1)°, V = 308.9(2) ų, d _calc = 1.420 g cm^–3 for Z = 4. A second phase of 1,2-difluoroethane was obtained under similar conditions which crystallizes in the orthorhombic space group P2₁2₁2₁ with the unit cell parameters a = 8.0467(16), b = 4.5086(9), c = 8.279(2) Å,V = 300.36(11) ų, d _calc = 1.461 g cm^–3 for Z = 4. In both phases the 1,2-difluoroethane molecules adopt the gauche conformation with F–C–C–F torsion angles close to 68°. Crystals of 1,2-diiodoethane C₂H₄I₂ were grown from pentane at –30°C. A platelet single crystal of the size 0.35 × 0.25 × 0.03 mm was measured with Mo K-radiation at 153 K. 1,2-Diiodoethane crystallizes in the monoclinic space group P2₁/n with a unit cell of a = 4.6051(7), b = 12.939(2), c = 4.7318(7) Å, = 104.636(3)°, V = 272.79(7) ų, Z = 2, d _calc = 3.431 g cm^–3, (MoK) = 11.353 mm^–1. In the molecule the two neighboring iodine atoms are positioned anti. The shortest intermolecular contacts occur via iodine–iodine interactions resulting in layers of molecules in the crystal.     

Crystal and molecular structure of 1,1,2-trifluorobuta-1,3-diene

A single crystal of 1,1,2-trifluorobuta-1,3-diene, m.p. –108°C, was obtained by in situ crystallization in a capillary directly on a diffractometer. 1,1,2-Trifluorobutadiene crystallizes monoclinic, space group Pc, a = 4.4030(12), b = 6.4160(16), c = 8.293(3) Å, = 91.728(14)°, V = 234.17(12) Å, d _calc = 1.5326 g cm^–3, Z = 2, wR ₂ = 0.1332. The 1,1,2-trifluorobutadiene molecules have an anti conformation, C4–C3–C2–C1 179.17(1)°. There is no fluorine substitution effect on the bond lengths of the conjugated C–C double bonds, C1–C2 1.331(3), C3–C4 1.336(4) Å. The central bond C2–C3 1.436(4) Å is shorter than a single bond because of conjugation. The C–F bond lengths of the CF₂ group are significantly shorter than the one of the CF moiety.     

Synthesis and structure of tris[2-(1-naphthalenyloxy)ethyl]amine and tris[2-(1-naphthalenyloxy)ethyl]amine perchlorate

Syntheses and crystal structures of tris[2-(1-naphthalenyloxy)ethyl]amine 1 and tris[2-(1-naphthalenyloxyl)ethyl]amine perchlorate 2 are reported. Compound 1 crystallizes in the rhombohedral system, space group R3¯ with a = 13.077(4), c = 29.011(8) Å, and D _calc = 1.233g/cm³ for Z = 6; compound 2 crystallizes in the cubic system, space group P2₁3 with lattice parameters a = 14.630(5) Å and D _calc = 1.332g/cm³ for Z = 4. In 1, three naphthalene rings make dihedral angles of 109.21, 70.78, 70.78,° respectively. In 2 they make dihedral angles of 107.3, 72.7, 72.7° respectively. Deviation of N from the plane (C(12),C(12)i,C(12)ii) in 1 is 0.3742 Å which is less than that in (2) (–0.4223 Å). The crystals structure is stabilized by van der Waals interactions in both compounds.     

Primary to secondary sphere coordination of 18-crown-6 to lanthanide (III) nitrates: Structural analysis of [Pr(NO3)3-(18-crown-6)] and [M(NO3)3(OH2)3]·18-crown-6 (M=Y,Eu, Tb−Lu)

The direct reaction of hydrated lanthanide nitrate salts with 18-crown-6 in 31 CH₃CNCH₃OH has resulted in the isolation and structural characterization of [Pr(NO₃)₃(18-crown-6)] and [M(NO₃)₃(OH₂)₃]·18-crown-6 (M=Y, Eu, Tb–Lu). (The Eu and Yb analogs were confirmed with preliminary cell data only.) [Pr(NO₃)₃(18-crown-6)] is 12-coordinate icosahedral and crystallizes in the orthorhombic space group Pbca with (at 20°C)a=12.230(2),b=15.598(4),c=21.777(9)Å andD _calc=1.89 g cm^–3 forZ=8. The seven isostructural [Pr(NO₃)₃(18-crown-6)] complexes all contain 9-coordinate capped square antiprismatic metal centers hydrogen bonded via the bound water molecules to D_3d 18-crown-6 within the lattice to form hydrogen bonded polymeric chains. Each complex is orthorhombic Pnma with cell parameters as follows: M=Tb (20°C):a=15.242(6),b=14.253(11),c=11.070(6)Å,D _calc=1.83 g cm^–3 forZ=4; M=Dy (20°C):a=15.248(3),b=14.239(5),c=11.058(3)Å,D _calc=1.84 g cm^–3 forZ=4; M=Y (19°C):a=15.260(2),b=14.238(2),c=11.048(3) Å,D _calc=1.64 g cm^–3 for Z=4; M=Ho (20°C):a=15.226(4),b=14.208(15),c=11.028(3)Å,D _calc=1.86 g cm^–3 forZ=4; M=Er (20°C):a=15.250(3),b=14.208(7),c=11.028(3)Å,D _calc=1.87 g cm^–3 forZ=4; M=Tm (20°C):a=15.246(6),b=14.190(16),c=11.013(6) Å,D _calc=1.88 g cm^–3 forZ=4; M=Lu (21°C):a=15.244(9),b=14.158(6),c=10.980(7)Å,D _calc=1.90 g cm^–3 forZ=4.     

Crystal structure of 1-chloroanthraquinone

The X-ray crystal structure of 1-chloroanthraquinone is determined. The compound C₁₄H₇O₂Cl, is monoclinic in P2₁(#4) with a = 7.763(1), b = 3.973(2), c = 16.947(1) Å, = 95.13(1)°, V = 520.6(3) ų, D _calc = 1.548 g/cm³, and Z = 2. In the molecular structure, the Cl atom is obviously repelled by O(1). The major force of crystal formation comes from aromatic ring stacking and C–H-aromatic interaction.     

The crystal structures of (p-ClPh)3PO and (p-OMePh)3PO, including an analysis of the P-O bond in triarylphosphine oxides

The crystal structures of the compounds tris(para-chlorophenyl)phosphine oxide {(p-ClPh)₃PO} and tris(para-methoxyphenyl)phosphine oxide {(p-OMePh)₃PO} were determined by X-ray diffraction methods. (p-ClPh)₃PO crystallizes in the space group P-1 (no. 2) with a = 11.828(2), b = 12.645(2), c = 14.072(2) Å, = 97.90(1), = 109.45(1), = 115.43(1), V = 1692.3(2) ų and Z = 4. The mean O–P and C–P distances are 1.481(6) and 1.806(2) Å, respectively, and the mean C–P–C angle is 106.5(1.1). (p-OMePh)₃PO crystallizes in the space group P2₁/c (no. 14) with a = 18.8642 (10), b = 10.3999(5), c = 21.3462(16) Å, = 115.414(6)°, V= 3782.6(4) ų, and Z = 8. The mean O–P and C–P distances are 1.484(5) and 1.798(4) Å, respectively, and the mean C–P–C angle is 106.5(1.0). These two structures were analyzed along with the previously determined structures of triphenylphosphine oxide {Ph₃PO} and tri-p-tolylphosphine oxide {(p-MePh)₃PO}, and IR data were collected on all four compounds. Both the observed P–O distances and the IR stretching frequencies for these triarylphosphine oxides support the interpretation of the P–O bond as having substantial multiple-bond character, with a bond order between 1.7 and 1.8. The para-substituents on these triarylphosphines were shown to have a statistically insignificant effect on the P–O bond.     

Synthesis, characterization, and crystal structure of 1-(4-chloro-benzoyl)-3-naphthalen-1-yl-thiourea

1-(4-Chloro-benzoyl)-3-naphthalen-1-yl-thiourea has been synthesized and characterized by elemental analysis, IR spectroscopy, and mass spectrometry. The crystal and molecular structure of the title compound has been determined from single crystal X-ray diffraction data. It crystallizes in the triclinic space group P-1, with a = 6.962(1) Å, b = 10.770(3) Å, c = 11.738(2) Å, = 65.76(2)°, = 80.03(1)°, = 84.86(2)°, and D _calc= 1.432 g cm^–1 for Z = 2. The thermal behavior of the compound has been studied by DTA and TG. The antibacterial activities of the title compound were investigated for three Gram (+) and two Gram (–) bacteria by employing broth microdilution method and subsequently, inhibitory activity against yeast-like fungi was also determined.     

Crystal structure of two brom containing aza-tetracyclic fused-ring N-heterocycles including isoxazolidine ring

Crystal structure of two brom containing aza-tetracyclic fused N-heterocycles including isoxazolidine ring compounds have been determined in single-crystal X-ray diffraction studies. The compound, C₁₄H₁₉BrN₂O₃, (1), and C₁₂H₁₅BrN₂O₃, (2), were obtained from a stereospecific[3+2] 1,3-cycloaddition of oxime based tandem nitrone generation reactions. The envelope conformation of the isoxazolidine rings are different, leading the substituents to be pseudoaxial in (1) and pseudoequatorial in (2). The stereochemistry of these fused compounds are exo- and endo-stereoisomer geometry contributed by exo and endo transition state of nitrone 1,3-dipolar cycloaddition reactions. The title compound (1) crystallizes in the monoclinic space group P2 ₁/n with a = 12.6221(5)Å, b = 7.5917(4) Å, c = 16.2350(9) Å, = 112.254(5)°, V = 1439.81(12) ų, and D _calc = 1.583 Mg/m³ for Z = 4 and compound (2) crystallizes in the monoclinic space group P2 ₁/c with a = 11.6906(9) Å, b = 6.4255(7) Å, c = 17.2070(10) Å, = 109.264(5)°, V = 1220.2(2) ų, and D _calc = 1.716 Mg/m³ for Z = 4. The antibacterial activity of both compounds were investigated for three Gram (+) and two Gram (–) bacteria by employing broth microdilution method and subsequently inhibitory activity against yeast-like fungi was also determined.     

Synthesis, crystal structures, and properties of copper complexes with tripodal ligands and azide anion

Two new Cu^II complexes, (CuL¹N₃)ClO₄ (1) and (CuL²N₃)ClO₄ (2), have been synthesized and characterized in the presence of NaN₃, where L¹ = tris[2-(6-methylpyridyl)methyl]amine and L² = tris[(3,5-dimethylpyrazol-l-yl)methyl]amine, and their crystal structures have been determined by X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group P–1, with a = 8.258(2) Å, b = 11.481(2) Å, c = 14.158(3) Å, = 72.30(3)°, = 79.05(3)°, = 86.08(3)°, V = 1255.4(5) ų. Compound 2 crystallizes in the monoclinic space group C2/c, with a = 26.752(2) Å, b = 10.561(2) Å, c = 21.059(4) Å, = 120.51(3)°, V = 5126(3) ų. In both compounds, each Cu^II center is in a distorted trigonal–bipyramidal coordinated environment with four nitrogen atoms from the tripodal ligand and one nitrogen atom from the azide group. The coordination geometry around Cu^II center of 1 is axially compressed trigonal bipyramid, while that of 2 is an axially elongated trigonal bipyramid. The coordinated azide group is in the axial site in both complexes. A quasi-dimeric structure of 1 has been formed in the unit cell through hydrogen bonding. The electronic spectra of two complexes in solution have been further studied by UV–vis technique, and the coordination properties have been discussed.     

Crystal and molecular structure of a steroidal spirocyclic lactone, C29H34O4

The X-ray crystal structure of the title compound, as crystallized from methanol–methylene chloride was determined. The asymmetric unit contains two steroid molecules, which differ primarily in the orientation of the aromatic rings of the benzyl ethers. The title compound crystallizes in the noncentrosymmetric space group P2(1), with a = 7.558(2), b = 16.673(3), c = 18.735(4) Å, = 97.610(10)°, and D _calc = 1.268 g cm^–1 for Z = 4.     

Synthesis and crystal structures of 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran

The title compounds 2-amino-3-cyano-4-(2-chlorophenyl)-1,4-dihydro-2H-pyrano[3, 2-h]quinoline 1 (C₁₉H₁₂ClN₃O, M _r = 333.77) and 2-amino-3-cyano-4-(2-chlorophenyl)-8-(2-chlorobenzylidene)-1,4,5,6,7,8-hexahydrobenzo[b]pyran 2 were synthesized and crystallized. The crystals of compound 1 are triclinic, space group P-1, a = 7.488(2), b = 9.127(3), c = 12.252(3) Å, = 73.58(2), = 78.38(2)°, = 75.39(2), Z = 2, V = 769.5(4) ų; The compound 2 crystallizes in space group P2₁/n, with cell parameters a = 13.582(2), b = 8.974(1), c = 16.960(2) Å, = 103.34(1)° and D _calc = 1.352 g/cm^–3 for Z = 4. X-ray analysis reveals that atoms C(1)—C(5) and O form a pyran ring in compound 1, which adopts half-chair conformation. In compound 2 the atoms C(12)—C(16) and O form a pyran ring which adopts boat conformation, another six-membered ring (C(8)—C(13)) adopts a half-chair conformation. In addition, there are intermolecular hydrogen bonds in the crystal structures 1 and 2.     

Crystal structures of a pair of diastereomeric 3-(N,N-dimethylammonium)-1,1-diphenyl-1-butanol hydrogen tartrates

The crystal structures of a pair of diastereomeric salts of (2R, 3R)- (+)-tartaric acid and (–)-and (+)-3-N,N-dimethylamino-1,1-diphenyl-1-butanol have been determined. Crystal data: 1: (R)-(–)-C₁₈H₂₄NO⁺, , C2, a = 38.198(7), b = 5.841(2), c = 9.993(2)Å, = 102.63(1)°, V = 2175.6(1) ų, Z = 4, D _calc = 1.281 g cm^–3. 2: (S)-(+)-C₁₈H₂₄NO⁺, P2₁2₁2₁, a = 6.037(2), b = 8.5947(8), c = 39.74(1)Å, V = 2062.0(9) ų, Z = 4, D _calc = 1.351 g cm^–3. The conformations of the 3-(N,N-dimethylammonium)-1,1-diphenyl-1-butanol cations in the two salts are almost mirror images of each other, but the cation in 2 has an intramolecular hydrogen bond. The hydrogen tartrate ions adopt an extended conformation. The hydrogen bonding networks in the two salts are very different. The absolute configuration of (–)-3-(N,N-dimethylamino)-1,1-diphenyl-1-butanol (1) was established as R.     

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.     

Synthesis and crystal structure of 3,4-trans-4, 5-trans-2-amino-3-cyano-1,3-dimethyloxycarbonyl-4, 5-di(3,4-methyl-enedioxylphenyl) cyclopentene

The 3,4-trans-4,5-trans-2-amino-3-cyano-1,3-dimethyloxycarbonyl-4,5-di-(3,4-methyl-enedioxylphenyl) cyclopentene has been synthesized and characterized by IR, ¹H NMR, Elemental analysis, and X-ray crystallography. It crystallizes in the monoclinic space group P2₁/n, with a = 10.936(3) Å, b = 10.142(3) Å, c = 20.001(4) Å, = 93.81(2)°, and D _calc = 1.390 g cm^–3 for Z = 4. X-ray analysis reveals that the phenyl groups and the alkoxyl carbonyl group are in the equatorial positions. The dihedral angles between the phenyl groups and the central five-membered ring are 73.08° and 62.15°. In addition, there are intermolecular hydrogen bonds in the crystal lattices.     

Intramolecular hydrogen bonding and tautomerism in N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine

N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine (C₁₆H₁₂N₂O) was studied by elemental analysis, IR, ¹H NMR, and UV–visible techniques and X-ray diffraction methods. The UV–visible spectrum of the compound was investigated in solutions effect polarity. The polarity of the some solvents was modifierly the additional (CF₃COOH) and [(C₂H₅)₃N]. The compound is in tautomeric equilibrium (phenol-imine O–H···N and keto-amine O···H–N forms) in polar and nonpolar solvents. The keto-amine form is observed in basic solutions of DMSO, ethanol, chloroform, benzene, cyclohexane, and in acidic solutions of chloroform and benzene, but not in acidic solutions of DMSO and ethanol. The compound crystallizes in the monoclinic, space group P2₁/a with a = 7.010(5) Å, b = 13.669(4) Å, c = 12.764(4) Å, = 101.23(4)°, V = 1199.6(10) ų, Z = 4, D _c = 1.375 g/cm³, (Mo K) = 0.088 mm^–1, R = 0.045 for 1658 reflections [I > 2(I)]. The title compound is not planar two Schiff base moieties A [C1–C11, O1] and B [N1, C12, C13, N2, C14, C15, C16] are inclined at an angle of 27.4(1)° reflecting mainly the twist about C12–N1 [C11–C12–N1–C13, 29.7(2)°]. There is a strong intramolecular hydrogen bond (O–H···N) of 2.529(2) Å.     

New sulfur derivatives of 2,3-dichloropyrrolo[1,2-a] benzimidazol-1-one. Demonstration of regioselective thiolate addition and X-ray diffraction structures of 2-chloro-3-methylthiopyrrolo[1,2-a]benzimidazol-1-one and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one

The reaction of thiols with the heterocyclic compound 2,3-dichloropyrrolo[1,2-a] benzimidazol-1-one (1) has been investigated as a route to new redox-active, bidentate sulfur ligands. Treatment of 1 with either methylthiol or benzylthiol in the presence of pyridine affords monosulfide compounds 2-chloro-3-methylthiopyrrolo[1,2-a] benzimidazol-1-one (2) and 2-chloro-3-benzylthiopyrrolo[1,2-a]benzimidazol-1-one (3) and the disulfide derivatives 2,3-di(methylthio)pyrrolo[1,2-a]benzimidazol-1-one (4) and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one (5). The substitution of the first chlorine group in 2,3-dichloropyrrolo[1,2-a]benzimidazol-1-one (1) occurs regioselectively at C-3 to produce 2-chloro-3-methylthiopyrrolo[1,2-a]benzimidazol-1-one (2) and 2-chloro-3-benzylthiopyrrolo[1,2-a]benzimidazol-1-one (3), followed by replacement of the remaining chlorine group to furnish the disulfide compounds 4 and 5. The new thiols have been isolated by column chromatography and characterized in solution by spectroscopic methods. The molecular structures of 2-chloro-3-methylthiopyrrolo[1,2-a]benzimidazol-1-one and 2,3-di(benzylthio)pyrrolo[1,2-a]benzimidazol-1-one have been determined by X-ray crystallography. Compound 2 crystallizes as two independent molecules in the monoclinic space group P2₁/c, a = 13.221(2) Å, b = 18.478(2) Å, c = 8.948(1) Å, = 100.088(3)°, V = 2152.3(5) ų, Z = 8, and d_calc = 1.547 Mg/m³; R = 0.0354, R_w = 0.0739 for 2820 reflections with I > 2(I). Compound 5 crystallizes in the triclinic space group P-1, a = 5.180(1) Å, b = 11.494(2) Å, c = 17.243(3) Å, = 86.024(3)°, = 88.606(4)°, = 81.235(3)°, V = 1012.1(4) ų, Z = 2, and d_calc = 1.360 Mg/m³; R = 0.0354, R_w = 0.0692 for 2655 reflections with I > 2(I). The redox properties of the disulfide compounds 4 and 5 have been explored by cyclic voltammetry, where a one-electron reduction at ca. –1.10 V has been observed for each compound. The site of electron accession in has been established by carrying out molecular orbital calculations at the extended Hüuckel level on the model compound 2,3-di(thio)pyrrolo[1,2-a]benzimidazol-1-one.     

The preparation, characterization, and X-ray structural analysis of dichlorobis[1-methyl-3-(2-propyl) -2(3H)-imidazolethione]mercury(II)

A new compound of mercury(II) chloride complexed to 1-methyl-3-(2-propyl) -2(3H)-imidazolethione (mipit) has been prepared and characterized via standard methods and X-ray crystallography. The structural significance of this study is that it shows one of the few monomeric examples of a mercury(II) chloride thione complex reported to date. The compound crystallizes in space group P2₁/c with a = 17.143(6) Å, b = 17.047(6) Å, c = 14.759(5) Å, = 105.899(5)°, V = 4148(2) ų, Z = 8. The coordination sphere is distorted tetrahedral with Hg–S bonds and Hg–Cl bond distances falling within the normally expected ranges. Bond angles ranged from 108.11(4)° to 115.51(4)° with the widest angle being observed for the S–Hg–S linkage. Ligand bond distances and angles including the C=S distance are within the normally expected values observed for this compound.     

Solid-state conformational heterogeneity of the 2,2,5,5-tetramethyl-3,4-hexandione monohydrazone: X-ray diffraction and MAS NMR experiments

The X-ray diffraction study of the 2,2,5,5-tetramethyl-3,4-hexandione mono-hydrazone 1 shows a solid solution of two screwed conformers in the crystal. In each of these conformers, the conjugated C=O and C=N double bonds have an approximately perpendicular orientation with = 101.1°(2) and –93.4°(2), respectively. AM1 theoretical calculations give the same result for the isolated molecule. The calculated rotational barrier around the central single bond of the conjugated moiety is about 45.98 kJ mol^–1 which is higher than the classical values observed for 1,3 conjugated systems (28.42 kJ mol^–1 in the 1,3-butadiene). Variable temperature ¹³C CPMAS NMR experiments show hindered rotation around the COC(CH₃)₃ tert-butyl group in the solid state. 1 crystallizes in the triclinic space group P ₁ with a = 10.106(1)Å, b = 11.698(1)Å, c = 12.313(1)Å, = 62.108(1)° = 70.517(1)° = 66.052(1), V = 1157.0(3)ų, D _calc = 1.06 with Z = 4.     

Structure of 5-methyl-7-methoxy-isoflavone

The structure of 5-methyl-7-methoxy-isoflavone was determined by X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/c, with cell dimensions of a = 10.321(3) Å; b = 11.290(5) Å; c = 11.979(8) Å; = 107.00(5)°; V = 1334.9(11) ų and D_calc. = 1.325 Mg/m³ for Z = 4. The structure was solved by direct methods and refined to an R value of 0.0409. As expected ring A and ring B in 5-methyl-7-methoxy-isoflavone are coplanar, while ring C is rotated to a dihedral angle of 59.42 (7)°. Intermolecular C–HO hydrogen bonds link molecules related by the screw axis and glide-planes to form a loosely connected layer structure.     

Formation and crystal structure of 1-methyl-2-phenylindolizine-3-acetonitrile

1-Methyl-2-phenylindolizine-3-acetonitrile was unexpectedly obtained in the reaction of 1-methyl-2-phenylindolizine-3-thioaldehyde with cyanide ions. Its structure was determined by IR, ¹H NMR, MS, elemental analyses, and X-ray crystallography. Colorless regular prism shaped crystals of C₁₇H₁₄N₂ crystallize in the space group C2/c with cell dimensions a = 12.956(3) Å, b =10.516(2) Å, c = 20.429(4) Å, and = 90°, = 104.98(3)°, = 90°, V =2688.7(9) ų, D _calc =1.217 Mg/m³, and Z = 8.