Crystal structure of μ-adeninatobis (methylmercury (II)) perchlorate monohydrate

The title compound belongs to the triclinic space groupP¯1,a= 8.189 Å,b = 9.863 Å,c = 10.726 Å, = 69.93 °, = 68.62 °, = 73.66 °, andZ = 2. The structure was refined on 1337 observed reflections to anR factor of 0.042. The crystals contain [adeninato(CH₃Hg)₂]⁺ complex cations in which mercury is linearly bonded to N(7) and N(9) of a deprotonated adenine ring. Centrosymmetrically related complex cations are paired via two N(6)-H(6) N(l) hydrogen bonds. Those planar units are stacked in the crystal with a distance of 3.4 Å between rings. The water molecule and the ClO₄ ^-ion are involved in hydrogen bonding and HgO contacts. This structure identifies N(7) as the best residual coordination site after H(9) has been substituted by CH₃Hg.     

Synthesis and molecular structure of {[Se(CH3)3][(CH3)AlCl3]}n: A novel two-dimensional layered organoaluminum-selenium polymer

The crystalline product {[Se(CH₃)₃][(CH₃)AlCl₃]}_n was prepared from reaction of SeCl₄ with A1(CH₃)₃ in heptane. The organo-main group polymer crystallizes in the monoclinic space group P2₁/c with unit cell parametersa=11.218(3) Å,b=11.119(3) Å,c=9.915(2) Å,=107.82(2)°,V=1177.4(5) ų, andD ^calcd=1.54 g cm^–3 forZ=4. Least-squares refinement based on 1195 observed reflections I>3(I) in the range 3.50°<2<45.0° led to a finalR factor of 0.036 (R ^w=0.047). The asymmetric unit contains one selenonium ion, Se(CH₃) ₃ ⁺ , and one organoaluminum anionic species, (CH₃)AlCl ₃ ^– . Secondary interactions (SeCl) serve to link the ions along two dimensions to form infinite layers. Thus, {[Se(CH₃)₃] [(CH₃)A1C1₃]}_n may be regarded as a layered organoaluminum-selenium polymer. The mean Se-C bond distance is 1.921(5) Å while the mean C-Se-C bond angle is 99.1(4)°. The independent Al-C bond distance is 1.927(8) Å while the mean Al-Cl bond distance is 2.166(7) Å.     

X-ray diffraction and vibrational spectra of the guanidine:maleic acid (1:1) complex—two crystal forms

From an equimolar mixture of guanidine and maleic acid, two different crystal modifications of guanidinium hydrogen maleate, CH₆N ₃ ⁺ ·C₄H₃O ₄ ^– , were isolated and their crystal structures determined using three-dimensional diffractometer data. Crystals of both forms are orthorhombic:Pca2₁,a=19.012(8)b=3.758(1),c=11.119(5) Å,Z=4 for form I;Fdd2,a=18.505(2),b=20.007(3),c=8.406(2) Å,Z=16 for form II. The structures were solved by direct methods and refined by full-matrix least squares to conventionalR values of 0.064 for form I and 0.043 for form II, with 488 and 605 reflections respectively. The structures consist of planar guanidinium cations C(NH₂) ₃ ⁺ and hydrogen-maleate residues C₄H₃O ₄ ^– . There are no significant differences in distances and angles within the guanidinium and hydrogen-maleate units. However, a substantial difference appears in the length and geometry of the intramolecular hydrogen bond OHO. The packing of cations and anions is also completely different in the two forms. Infrared and Raman spectra of the title compound are presented, and salient differences between them and the spectrum of the symmetrically bonded potassium hydrogen maleate are discussed briefly.     

Primary to secondary sphere coordination of 15-crown-5 to lanthanide(III) chlorides: structural analysis of [MCl3(15-crown-5)] (M=La,Ce) and [Er(OH2)8]Cl3·15-crown-5

Complexes of LaCl₃·7H₂O and CeCl₃·7H₂O directly coordinated to 15-crown-5 were prepared by placing the reactants in 31 CH₃CNCH₃OH on opposite sides of a fine porosity glass frit in a U-shaped cell and passing a 10 A current through the cell. The crystal structures of the two anhydrous 8-coordinate complexes, [MCl₃(15-crown-5)] (M=La, Ce) have been determined. Each contains the lanthanide in a bicapped trigonal prismatic geometry. The two complexes are isostructural crystallizing in the monoclinic space groupP2₁/c with (at 20°C) for M=La:a=8.217(8),b=14.298(2),c=14.341(9) Å, =104.79(8)°, andD _calc=1.90 g cm^–3 forZ=4; for M=Ce:a=8.208(9),b=14.263(6),c=14.270(8) Å, =104.74(7)°, andD _calc=1.92 g cm^–3 forZ=4. Direct reaction of ErCl₃·6H₂O with 15-crown-5 in 31 CH₃CNCH₃OH resulted in the crystallization of the second sphere hydrogen bonded complex [Er(OH₂)₈]Cl₃·15-crown-5. This complex is monoclinic,P2₁/n with (at 18°C)a=9.193(3),b=17.235(9),c=15.216(5) Å, =92.48(3)°, andD _calc=1.76 g cm^–3 forZ=4. The Er³⁺ ion is dodecahedral.     

Structure of dichloroethanolaminecopper(II) and dibromoethanolaminecopper(II)

CuCl₂(NH₂CH₂CH₂OH) is monoclinic, space group C2/c, witha+11.092(2),b+10.012(2),c+6.401(1) Å, =121.71(1)°, andV=604.8(2)ų withZ+4. The structure was refined to a final value ofR+0.27 for 518 unique observed reflections with |F|>3. The ethanolamine and halide ions coordinate to the copper(II) ion forming a pseudoplanar four-coordinate monomeric CuCl₂L² complex (L²+bidentate ligand). The copper ion also interacts with the halides of neighboring complexes through the formation of semi-coordinate Cu-Cl linkages (2.926(1) Å) between oligomers. The copper thus attains a 4+2 elongated octahedral coordination geometry. In this space group, the ligand is statisticallydisordered The Cu-Cl distance is 2.267(1)Å while the Cu-N/O distances are 2.025(2)Å. The dibromide structure is isomorphous with the dichloride structure, with space group C2/c, anda+11.285(2),b+10.218(2),c+6.715(1) Å, =121.65(1)°, andV=659.2(2)ų.     

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.     

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 and molecular structure of tris-(O-isopropylxanthato)-chromium(III)

The title compound has been synthesized by the reaction of CrCl₃6H₂O with K{S₂COCH(CH₃)₂} in a 13 molar ratio in an aqueous medium. It has been characterized by elemental analysis and IR spectral studies. Crystals of Cr{S₂COCH(CH₃)₂}₃ are monoclinic, space group P2₁/n witha=10.002(2),b=10.973(1),c=18.961(6) Å,=91.78(2)°,V=2079.9 ų,Z=4,D _calc=1.46 g cm^–3, monochromatic radiation (Mo-K), =0.71069 Å,=11.2 cm^–1,F(0 0 0)=948,T=295K, finalR=0.0320 for 2641 reflections. The environment of the chromium atom is based on an octahedral geometry having six sulfur donor atoms from three symmetrically chelated ligands with average distances: Cr-S=2.396(9) Å, C-S=1.690(3) Å and C-O=1.315(3) Å. The bond distance between oxygen atom and the carbon atom of the isopropyl group (O-C_av=1.478(4) Å) suggests that the form –S ₂ ^(–) C=O⁽⁺⁾CH(CH₃)₂ contributes significantly to the structure of the isopropyl group.     

Synthesis and X-ray structure of [H3O+·18-crown-6] [Br−Br−Br−]; a compound containing both H3O+ and a linear and symmetrical Br 3 t- ion crystallized from aromatic solution

[H₃O⁺·18-crown-6][Br–Br–Br^–] crystallizes in the triclinic space group P 1 witha=6.105(1),b=8.658(1),c=11.072(1)Å, =71.35(1), =77.58(1), =71.09(1)⁰, andD _c=1.68 g cm^–3 forZ=1. Refinement based on 1112 observed reflections led toR=0.044. The cation exhibits a planar oxonium ion bonded symmetrically to the 18-crown-6 (O(oxonium) resides 0.092 Å out of the plane of the crown ether oxygen atoms). The anion also resides on a center of inversion with Br–Br=2.530(1)Å.     

Interaction of mercury(II) halides with tertiary phosphine betaines: synthesis and structural characterization of [HgX2{Ph3P(CH2)2CO2}] (X=Cl, I) and [HgCl(μ-Cl)-{Ph3P(CH2)3CO2}]2

Three new mercury(II) complexes containing tertiary phosphine betaine ligands Ph₃P⁺(CH₂)₂CO₂ ^? and Ph₃P⁺(CH₂)₃CO₂ ^? have been synthesized and fully characterized by single-crystal X-ray analysis: [HgCl₂{Ph₃(CH₂)₂CO₂}],1, space groupP2₁/n,a=9.819(2),b=14.966(4),c=14.973(5) Å, β=105.67(2)° andZ=4; [HgI₂{Ph₃(CH₂)₂CO₂}],2,P2₁/n,a=10.206(2),b=14.807(3),c=15.557(3) Å, β=107.11(2)° andZ=4; [HgCl(μ-Cl){Ph₃P(CH₂)₃CO₂}]₂,3, $P\bar 1$ ,a=10.813(2),b=11.975(3),c=11.180(2) Å, α=87.04(2), β=75.14(1), γ=81.95(1)° andZ=1. The isomorphous complexes1 and2 contain discrete mononuclear molecules in which the mercury(II) atom is unsymmetrically chelated by a Ph₃P⁺(CH₂)₂CO ₂ ^? ligand and coordinated by a pair of terminal halo ligands in a distorted tetrahedral environment, while3 consists of discrete centrosymmetric dinuclear molecules in which the betaine ligand Ph₂P⁺(CH₂)₃CO ₂ ^? acts in the chelate mode and the mercury(II) atoms are unsymmetrically bridged by a pair of chloro ligands.     

The crystal structure of 2-benzoylpyridine N4-methyl-N4-phenylthiosemicarbazone

2-Benzoylpyridine N4-methyl-N4-phenylthiosemicarbazone, HBz4MePh, monoclinic,P2(1)/n a=9.141(2),b=18.507(4),c=11.401(2) Å, =110.58(3)^o,V=1805.6(9) ų,Z=4, =1.655 mm^–1. HBz4MePh crystallizes in a hydrogen bonded Z isomeric conformation with respect to the C7–N2 bond. The intramolecular hydrogen bond is between N3–H...N1, and the S atom isZ to the azomethine nitrogne, N2.     

Molecular structure of tetrapropylammonium-2,3-dichloro-5,6-dicyano-p-benzoquinone compared toM + TCNQ− (M +=Rb+, K+, Cs+, or organic cations; TCNQ−=tetracyanoquinomethane) charge-transfer complexes

The crystal and molecular structure of tetrapropylammonium-2,3-dichloro-5,6-dicyano-p-benzoquinone (TPA⁺ DDQ^–) has been determined from single-crystal X-ray diffraction analysis. The crystals are monoclinic, space groupP2₁/n, witha=13.297(5),b=12.851(4),c=13.099(5) Å,=101.34(2)°, andZ=4. The compound consists of discrete (DDQ) ₂ ^2– anion dimers and two TPA⁺ cations inserted between the (DDQ) ₂ ^2– dimers, with an infinite stack running along b of the type (DDQ) ₂ ^2– [(C₃H₇)₄N⁺] (DDQ) ₂ ^2– 2[(C₃H₇)₄N⁺]The (DDQ) ₂ ^2– anion is formed by two DDQ^– anions dimerized through a crystallographic center of symmetry; each DDQ^– moiety is nearly planar and exhibits molecular dimensions similar to those found in analogous compounds. The comparison between the (DDQ) ₂ ^2– anion and a neutral DDQ molecule clearly shows that bond lengths are markedly influenced by the 2-anionic charge. Tetrapropylammomum cation assumes a distorted tetrahedral configuration as observed in TEA⁺ DDQ^– (TEA⁺=tetraethylammonium cation). The data are discussed in connection with the electrical conductivity of organic metals.     

Preparation and X-ray structure of [H3O+·18-crown-6]-[(H5O 2 + )(Cl−)2], a compound containing both H3O+ and H5O 2 + crystallized from aromatic solution

The title compound was synthesized by the reaction of [H₃O⁺·18-crown-6][Cl-H-Cl^–]·3.8 C₆H₅Me with two equivalents of H₂O. Colorless crystals, which slowly deposited from the corresponding liquid clathrate, belong to the monoclinic space group P2₁/n witha=10.648(6),b=9.571(2),c=20.801(6) Å,=98.67(5)°, andD _c=1.24 g cm^–3 forZ=4. Refinement based on 1609 observed reflections led to a finalR value of 0.072. In the crystal structure the [H₃O⁺·18-crown-6]⁺ cations are packed in layers separated by puckered sheets of [(H₅O ₂ ⁺ )(Cl^–)₂]^–.     

Crystal and molecular structure of 3-dimethylaminobenzoic acid

The title compound C₉H₁₁NO₂ is triclinic, space group P¯1, with the cell dimensionsa=7.022(1),b=7.476(2),c=8.957 (1) Å,=87.02(2),=110.88(1),=99.10(1)°,V=433.8(4) ų,Z=2,M _r =165.2,Do=1.27,Dx=1.26 mg/m³,F(000)=176,T=293 K,R=0.057 for 939 observed reflections. The molecules are packed as centrosymmetric hydrogen bonded dimers with an O-HO distance of 2.626(3) Å. The COOH group is rotated by 1.7(1)° about the exocyclic C(1)-C(7) bond out of the benzene ring plane. The molecules lie on (0 2-1) plane for which thed value is found to be 3.378 Å which is very close to the mean separation between the parallel packed benezene rings [3.347(4) Å]. The entire molecule is planar except for the two methyl groups attached to the nitrogen atom. The N atom is free from any binding of either type C-HN or O-HN.N. C. L. Communication No. 4699.     

Crystal and molecular structure of benzophenone azine: evidence for an Fe(II) carbene intermediate

Benzophenone azine crystallizes in the monoclinic space groupA2/a (No. 15) witha=16.303(3) Å,b=5.4864(2) Å,c=21.973(5) Å, =85.52(2)°,V=1959.4(8) ų, andD _calc=1.22 g cm^–3 forZ=4. The structure was solved by direct methods and refined againstF to a finalR value of 0.047. The unit cell contains four molecules of the title compound; the asymmetric unit consists of half a molecule. Despite the high crystallographic symmetry, the two halves of the molecule arenot related by a center of symmetry; instead, the molecule adopts C₂ symmetry; the molecular C₂ axis is coincident with the crystallographic twofold axis. The formation of benzophenone azine from the reaction of the iron-containing Lewis acid complex [(⁵-C₅H₅)Fe(CO)₂(THF)]⁺ [BF₄]^– and diphenyldiazomethane provides strong evidence for an Fe(II) carbene intermediate.     

Crystal structure of Al(tBu)3(NH2CH2CH2Ph): A molecular “slinky”

The molecular structure of Al(^tBu)₃(NH₂CH₂CH₂Ph) is determined by the crystal packing of the phenyl rings and the pseudo spherical Al(^tBu)₃ units, and may be viewed as a layered structure consisting of double sheets of the phenyl rings and the Al(^tBu)₃ units. The Al–N–C–C linkage shows severe disorder as a result of its flexibility. The structure of Al(^tBu)₃ (NH₂CH₂CH₂Ph) can be likened to a molecular slinky, in which the rigid ends are fixed in space by molecular packing forces, leaving the interior link to adopt multiple orientations. Crystal data: orthorhombic, Cmca,a=13.282(9),b=25.01(1),c=13.210(9), Å,V=4388(10) ų,Z=4,R=0.0957,R _w=0.0957.     

Molecular structure and hydrogen bonding of 4-dimethylaminopyridinioacetate in its crystalline dihydrate and hydrochloride trihydrate,L·2H2O and [L2H]Cl·3H2O (L=p-Me2NC5H4N+CH2CO2 −)

The crystalline dihydrate and hydrochloride trihydrate of a new betaine, namely, L·2H₂O (1) and [L₂H]Cl·3H₂O(2) (L=p-Me₂NC₅H₄N⁺CH₂CO₂), have been synthesized and characterized by X-ray crystallography. Molecule L in compound1 [space groupPbcn, witha=15.732(3),b=7.894(2),c=18.304(4) Å, andZ=8] possesses approximateC _s symmetry. The formation of hydrogen bonds by water molecules bridging neighboring carboxy oxygen atoms leads to an infinite two-dimensional network composed of a packing of two different kinds of 12-membered rings. In compound2 [space group PT witha=7.341(2),b=9.543(2),c=17.010(4) Å, =82.43(2)°, =80.34(2)°, =74.05(2)°, andZ=2], the carboxylate groups of a pair of betaine molecules are bridged by a proton to form a dimeric cation L₂H⁺ with a very strong asymmetric hydrogen bond of length 2.464(7) Å. The crystal structure features a hydrogen-bonded corrugated ribbon comprising an alternate arrangement of edge-sharing centrosymmetric (H₂O)₄(Cl^–)₂ and (H₂O)₄ rings running parallel to thea axis.     

Crystal and molecular structure of 2,6-dihydroxybenzoic acid

The crystal and molecular structure of 2,6-dihydroxybenzoic acid has been determined by single crystal X-ray diffraction. The crystals are monoclinic witha=5.4084(5),b=5.2240(7),c=22.986(4) Å, =94.69(3)°, space group P2₁/c,Z=4,V=647.27(16) ų,d _c =1.58Mg m^–3, The acid crystallizes as hydrogen bonded carboxylic dimers which pack to generate a herringbone motif of the type typically encountered in polycyclic aromatic compounds.     

The crystal structures of NaAlR4, R=methyl,ethyl, and n-propyl

The crystal structures of the title compounds have been determined from diffractometer data and refined by full-matrix least squares. NaAlMe₄ is orthorhombic,Cmcm,a=9.234(3),b=9.221(3),c=8.303(2) Å,Z=4,D _c=1.03 g cm^–3,R=0.029 for 278 data. NaAlEt₄ is monoclinic,P2₁/c (No. 14),a=13.900(2),b=13.207(2),c=14.443(1) Å,=117.43(1)°,Z=8,D _c=0.94 g cm^–3,R=0.056 for 2747 data. NaAl(n-Pr)₄ is monoclinic,C2/c,a=9.802(5),b=15.336(4),c=21.611(10) A,=98.34(4)°,Z=8,D _c=0.92 g cm^–3,R=0.072 for 899 data. Coordination of Al is essentially tetrahedral in all structures, and closest contacts to Na⁺ involve-carbon atoms of alkyl groups.     

The crystal structure of LiBr·(CH3OCH2CH2OCH3)2

The crystal structure of LiBr·(CH₃OCH₂CH₂OCH₃)₂ has been determined from counter data and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupC2/c (C _2h ⁶ , No. 15) witha=13.518(4),b=8.007(3),c=12.252(4) Å,=98.08(2)°, andD _calc=1.35 gcm^–3 forZ=4. The finalR value for 489 observed reflections is 0.033. The lithium and bromine atoms lie on a crystallographic two-fold axis. The structure consists of discrete LiBr·(CH₃OCH₂CH₂OCH₃)₂ units. The Li-Br separation is 2.57(1) Å. The two DME molecules are coordinated to the lithium atom through the four oxygen atoms at an average LiO separation of 2.09(3) Å.