Synthesis and structural studies of <Emphasis Type="Italic">tris</Emphasis>-2-chlorobenzylamine and <Emphasis Type="Italic">tris</Emphasis>-2-bromobenzylamine

The tris-2-chloro and 2-bromotribenzylamines are prepared from aqueous ammonia and 2-chlorobenzyl chloride and 2-bromobenzyl bromide, respectively, in ethanol. Recrystallization yielded colorless cubes of each product. The crystal structures are each solved in space group P , and are isostructural. The tris-2-chloro compound, 1, has a = 7.4226(5) Å, b = 9.0825(7) Å, c = 14.529(1) Å, = 78.279(1), = 82.389(1), = 84.661(1), and V = 948.41(12) ų with Z = 2, and d_calc = 1.368 Mg/m³. The tris-2-bromo analog, 2, has a = 7.6569(11) Å, b = 9.0922(13) Å, c = 14.614(2) Å, = 79.286(2), = 81.777(2), = 85.401(2), and V = 987.9(2) ų with Z = 2, and d_calc = 1.762 Mg/m³. Lithium–halogen exchange experiments conducted in tetrahydrofuran at –78C using n-butyl lithium revealed that no exchange occurred for the tris-2-chloro compound, but did occur for the tris-2-bromo analog to yield tribenzylamine upon quench and work-up.     

The x-ray crystal and molecular structure of glechomafuran

The X-ray crystal structure of glechomafuran (1,10,4,5-diepoxy-7,8-furanogermacrane), a natural product obtained from seeds ofSmyrnium olusatrum L., has been determined in order to establish the correct relative configuration of the molecule. Crystals are monoclinic, space groupP2₁ witha=6.785(4),b=12.325(9),c=16.390(6) Å,=97.89(4)°, and four molecules in the unit cell. The two epoxides are found to be ,-attached, and the associated methyl groups are positionedsyn to each other. The furan ring is essentially flat, and shows no evidence of any double bond delocalization.     

Synthesis and crystal structure of 3,5-di(2-propenyl)-6-phenyl-1,3,5-triazine-2,4-dione and 2-dimethylamino-4-ethoxycarbonylmethoxy-6-phenyl-1,3,5-triazine

The title compound 3,5-di(2-propenyl)-6-phenyl-1,3,5-triazine-2,4-dione has been synthesized by the reaction of 6-phenyl-1,3,5-triazine-2,4-dione with allyl bromide. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to orthorhombic, space group Pbca with the following crystallographic parameters: a = 16.282(4) Å, b = 8.888(2) Å, c = 19.281(5) Å, = 90°, = 90°, = 90°, = 0.088 mm^–1, V = 2790.1(13) ų, z = 8, Dx = 1.282 mg/m³, F(000) = 1136, T = 293(2) K, 2.11° 25.02°, the final R factor: R ₁ = 0.0430, wR₂ = 0.0981. The X-ray results demonstrate that the reaction of 6-phenyl-1,3,5-triazine-2,4-dione with allyl bromide in the presence of N,N-dimethylformamide and potassium carbonate yields the N-alkylated product. The title compound 2-dimethylamino-4-ethoxycarbonylmethoxy-6-phenyl-1,3,5-triazine has been synthesized by a new reaction, in which the solvent N,N-dimethylformamide involves. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to triclinic, space group P-1 with the following crystallographic parameters: a = 7.977(2) Å, b = 10.394(3) Å, c = 10.837(3) Å, = 111.774(5)°, = 104.050(5)°, = 99.446(5)°, = 0.093 mm^–1, V = 776.6(4) ų, z = 2, Dx = 1.293 mg/m³, F(000) = 320, T = 293(2) K, 2.14° 25.03°, the final R factor: R ₁ = 0.0582, wR ₂ = 0.1399. The distance of N(4) C(2) (1.339 Å) is much shorter than the length of normal C N (1.47 Å) and very close to that of C-N (1.33 Å), which is indicative of the significant double bond character.     

Choline sodium 4-amino-1-β-d-ribofuranosyl-2-(1H)-pyrimidionone diphosphate tetrahydrate (Sodium cytidine diphosphocholine,C14H33N4NaO15P2)

This communication presents a preliminary report on the crystal structure of this important nucleotide, involved in lecithin synthesis in animal tissues. The crystallographic data were recorded using a four-circle diffractometer with Cu-K x-radiation. Crystal data: orthorhombic, space groupP2₁2₁2₁ (No. 19),Z = 4,a = 6.98 pm,b = 123.6 pm,c = 292.3 pm,U = 2.522 nm³. The structure was solved by means of a Patterson and electron-density maps and refined by several cycles of least-squares using isotropic temperature factors toR = 0.14.The torsion angles associated with the furanosyl ring are, in general, at the very extreme of the range commonly observed for C(2) endopuckering (Altona and Sundaralingam, 1972); their values are 1 = 319 °, 2 = 47 °, 3 = 326 °, 4 = 13 °, 5 = 18 °. The phase angle of pseudorotation, calculated from these values using the formula given by Altona and Sundaralingam (1972) is 139 °. This shows the ribose ring to be slightly nearer to the C(1) exopuckering than the C(2) endopuckering conformation, but remote from being a C(3) endo-conformer. The sugar ring, in fact, is very close to being an idealized twist conformer. This is supported by a four-atom least-squares planes study, and is consistent with the high value of 237 ° (Sundaralingam, 1973).Backbone torsion angles associated with the structure are = 57 °, = 133 °, = 174 °, and = 291 °. is some 7 ° less than the preferred minimum value for C(2) endopuckering.     

Structure of the dipeptide L-lysine-L-leucine·Acetate, 0.5 acetic acid hemihydrate

2(C₁₂H₂₆O₃N₃·C₂H₃O₂)·C₂H₄O₂·H₂O,M _r =350.44, triclinic, P1,a=5.576,b=12.574(3),c=14.946(2) Å, =107.80(2), =96.34(2), =89.89(2)°.B=991.04(6) ų,Z=2,D _x =1.201 g/cm³, (KCu)=1.5418, Å, =7.4 cm^–1, room temperature.R=0.074 for 2645 observed reflections. In the unit cell there are two peptide molecules, three acetic acid molecules, two of them likely to be present as acetate anions, and one water molecule. Each peptide exists in zwitterionic form with the carboxylic group deprotonated, and with positive charges both in the amino terminal and -amino groups of lysine. The two peptide molecules have almost identical conformations. The dipeptide backbone is folded.     

Crystal structure and characterization of 1,2-N,N-disallicydene-phenylamineato nickel(II) complex

A new complex has been synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray analysis. The crystal is orthorhombic and the space group is chiral (P2₁2₁2₁) with a = 6.620(3) Å, b = 17.300(4) Å,, c = 5.450(1) Å,, = 90°, = 90°, = 90°, z = 4. In the crystal lattice, the molecules create a two-dimensional network structure through hydrogen bonds. The C–HO intermolecular hydrogen bonds connect the title complex to form a supermolecular structure.     

Polymeric and mixed carboxylate compounds: Crystal structure of [Zn(tiglate)0.54 (benzoate)1.46]x

The crystal structure of [Zn(O₂CC(CH₃)CHCH₃)_0.54(O₂CC₆H₅)_1.46]_x has been determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P2₁/c witha=10.311(1),b=13.170(1),c=19.000(2) Å,=91.895(7)°,V=2578.7 ų,Z=4,D _x=1.525g cm^–3, (Mo K)=0.71073 Å,=1–95 mm^–1, F(000)=1206,T=295K,R=0.046 for 4548 unique reflections. The two different carboxylates are randomly scrambled along a one dimensional polymer, made up of binuclear units connected by a syn-anti carboxylate bridge. Each binuclear unit contains three syn-syn carboxylates which bridge two zinc atoms. Vibrational data indicate that [Zn(O₂CC(CH₃)CHCH₃)₂]_x has the same polymeric structure; orientation of tiglate is the same as for the mixed ligand compound. Recrystallization of mixed carboxylate species produces either an alteration in carboxylate ligand ratio, or a total separation of the two carboxylates, giving two different compounds.     

Synthesis and crystal structure of 1-(1′,3′-dimethyl-5′-chloropyrazol-4′-carbonyl′-3-(2′-chlorophenyl)-5-amino-4-cyanopyrazole

The title compound 1-(1,3-dimethyl-5-chloropyrazol-4-carbonyl)-3-(2-chlorophenyl)-5-amino-4-cyanopyrazole (C₁₆H₁₂Cl₂N₆O) has been synthesized and characterized by X-ray diffraction: Triclinic, space group P1, with a = 8.6712(8) Å, b = 9.5091(10) Å, c = 11.2170(11) Å = 71.531(2)°, = 84.683(2)°, = 74.099(2)° Z = 2; V = 843.7(14) ų. C(10), O(1), C(11), and N(2) atoms are coplanar with the average deviation of 0.0071 Å, which form 11.03° and 43.93° dihedral angles with pyrazole planes (I) and (II), respectively.     

Tris(triphenylphosphine)rhodium cyano and triphenylcyanoborate complexes: Structures and a DFT study

The structures of [Rh(CN)(PPh₃)₃](EtOH) (1), [Rh(NCBPh₃)(PPh₃)₃] (2), and [Rh(CNBPh₃)(PPh₃)₃] (3) are reported together with a density functional theory (DFT) study of the model compounds [Rh(NCBH₃)(PH₃)₃] and [Rh(CNBH₃)(PH₃)₃]. Compound 1 crystallizes in space group Pc with a = 10.4798(15) Å, b = 12.5410(18) Å, c = 19.974(3) Å and = 112.215(6)°; compound 2 crystallizes in space group with a = 12.929(2) Å, b = 14.362(2) Å, c = 17.575(3) Å and = 92.544(3)°, = 90.214(3)°, = 113.831(3)°; compound 3 crystallizes in space group with a = 12.915(2), b = 14.296(2), c = 17.664(3) Å and = 92.469(3)°, = 90.088(3)°, = 113.768(3)°. All three complexes show slight tetrahedral distortion from ideal square planar geometry (largest for 1). Differences in the reactivity and stability of 2 and 3 are interpreted according to the results of a density functional theory study.     

Coordination complexes of 2,6-diarylpyrazines with copper(II) acetate

The coordination chemistry of a series of 2,6- and 2,3-diarylpyrazines with copper(II) acetate is reported. The 2:2 coordination complexes formed between two 2,6-diarylpyrazines and copper(II) acetate are characterized by X-ray crystallography. The structure (2,6-bis(3,5-dimethylphenyl)pyrazine)copper(II) acetate acetonitrile solvate, (C₄₈H₅₂Cu₂N₄O₈) (C₂H₃N) is triclinic, P 1, with a = 7.9685(10), b = 13.1893(16), c = 13.8267(17) Å, = 107.585(3)°, = 103.921(3)° and = 96.759(3)°. The structure of (2-(2,6-dimethylphenyl)-6-(3,5-dimethylphenyl)pyrazine)copper(II) acetate, C₄₈H₅₂Cu₂N₄O₈, is monoclinic, P2₁/c, with a = 8.2196(7), b = 12.5174(11), c = 21.7325(19) Å and = 96.201(2)°.     

Hydrogen-bonded coordination network in crystal structures of [Cu(3-PM)4Cl2] and [Cu(4-PM)4Cl]Cl, (PM = pyridylmethanol)

The crystal and molecular structures of [Cu(3-PM)₄Cl₂] (1) and [Cu(4-PM)₄Cl]Cl (2) have been determinated by X-ray crystallography. Complex 1 crystallizes in the triclinic system, space group P–1, with lattice parameters a = 7.972(2) Å, b = 8.293(2) Å, c = 10.707(2) Å, = 105.73(3)°, = 90.04(3)°, = 110.38(3)°, and Z = 1 at 100 K. The coordination geometry of each Cu atom is approximately octahedral formed by four nitrogen atoms of pyridine rings of 3-pyridylmethanol molecules in the equatorial plane and two chlorine atoms occupying the axial positions. The O—HsO, C—HsCl, and O—HsCl intermolecular hydrogen bonds and s stacking link the molecules in 3-D hydrogen-bonded coordination network. Complex 2 crystallizes in the tetragonal system, space group P4/n, with lattice parameters a = 10.464(1) Å, c = 11.339(2) Å, and Z = 2 at 217 K and a = 10.352(1) Å, c = 11.201(2) Å, and Z = 2 at 293 K. The coordination geometry of Cu atom in the [Cu(4-PM)₄Cl]⁺ ion is approximately square pyramidal formed by four nitrogen atoms of pyridine rings of 4-pyridylmethanol molecules in equatorial plane and one chlorine atom in axial position. The O—HsCl and C—HsCl intermolecular hydrogen bonds link the molecules in 2-D hydrogen-bonded coordination network.     

Crystal structures of two 1,2-bis-(1-aryl-3-methyltriazene-3-yl-)ethanes with aryl substituents of opposite polarity

The crystal and molecular structure of 1,2-bis-{1-(2-cyanophenyl)-3-methyltriazen-3-yl-}ethane (1) and 1,2-bis-{1-(2-methoxyphenyl)-3-methyltriazen-3-yl-}ethane (2) have been determined by single crystal X-ray diffraction analysis. Bis-triazene (1) exists as the staggered conformation in the solid state, with an anti-anti configuration around the N2–N3 bond of the triazene units, whereas 2 assumes a gauche conformation with the syn-syn configuration in the triazene units. Crystal data: 1 C₁₈H₁₈N₈, triclinic, space group P –1, a = 6.108(2), b = 8.118(3), c = 9.600(4)Å, = 101.37(7)°, = 96.47(7)°, = 102.71(5)°, V = 449.1(3)ų, Z = 2; 2 C₁₈H₂₄N₆O₂, monoclinic, space group P 2₁/n, a = 13.119(5), b = 7.745(2), c = 19.201(2)Å, = 96.47(7)°, V = 1910.3(9)ų, Z = 4.     

A new monoclinic crystal phase of [Bu4N][Ni(dmit)2]

The crystal structure of the title compound, tetrabutylammonium bis(2-thioxo-1,3-dithiole-4,5-dithiolato)nickelate(III), [N(C₄H₉)₄][Ni(C₃S₅)₂], is the fourth known phase of this polymorphous compound. It is monoclinic space group P2₁/c, with a = 20.040(2) Å, b = 13.1151(17) Å, c = 12.1093(15) Å, = 105.456(15)°, and V = 3067.5(6) ų with Z = 4, for D _calc = 1.503 g cm^–3. The [Ni(dmit)₂] anion packing arrangement consists of arrays of side-on touching anions and these arrays are connected via head-to-tail close S S contacts.     

1-(Ethoxymethyl)-6-(phenylselenyl)-5-ethyl uracil: a nucleoside analog

The compound, 1-(ethoxymethyl)-6-(phenylselenyl)-5-ethyl uracil, crystallizes in the monoclinic space group P2₁/n with unit cell parameters a = 5.304(1), b = 21.261(4), c = 13.996(4) Å, = 94.30(2)°, and Z = 4. The acyclic chain C1, O4, C4, C5 is in fully extended form and nearly perpendicular to the uracil base. The molecules are held together by van der Waal's forces.     

Crystal and molecular structure of cesium isothiocyanatotrimethylaluminate,Cs[Al(CH3)3NCS]

The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/c, witha = 8.849(4),b = 13.798(5),c = 7.943(4) Å, = 102.98(3) °, andD _x = 1.85g cm^–3 forZ = 4. The finalR factor for 1283 observed reflections is 0.046. The aluminum atom is bonded to the nitrogen atom of the thiocyanate ligand, where the Al-N bond length is 1.94(1) Å. The SCN is linear, and the CN-Al angle is 175(1) °. The cesium ion exhibits four contacts less than 3.60 Å: Cs C(thiocyanate) = 3.39(1) Å, Cs C(methyl) = 3.52(1) Å, Cs C.(methyl) = 3.56(1) Å, and Cs N = 3.575(9) Å. The closest Cs S is 3.772(3) Å.     

Synthesis and structural characterization of 2,6-bis-(N-methylenemorpholino)-4-ter-butylphenol

The crystal and molecular structure of the title compound, C₂₀H₃₂N₂O₃, has been determined from X-ray diffraction data using CuK radiation (=1.5418 Å). The compound crystallizes in triclinic space groupP1^¯ with a=8.828(1),b=18.680(1),c=6.272(2)Å, =93.42(1), =0.24(2), =77.93(1)°,V=1009.4(2)ų, andZ=2. The structure was solved by direct methods and the full-matrix least-squares refinement leads the finalR-factor to 0.065 for 3481 observed reflections withI3(I). The phenyl ring is planar and the morpholino rings assume perfect chair conformation. The molecules are held together by van der Waals forces.DCB Contribution No. 810.     

Synthesis and crystal structure of charge-transfer salt (BEDT-TTF) [Pt(mnt)2]

The synthesis and crystal structure of the title organic charge-transfer salt (BEDT-TTF)[Pt(mnt)₂] (BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene; mnt = cis-3,4-dimercapto-2-butenedinitrile) is described. The salt crystallizes in the P1 space group with a = 6.728(2) Å, b = 7.371(2) Å, c = 13.596(4) Å, = 97.904(5)°, = 90.114(5)°, and =108.147(5)°. The stoichiometry between BEDT-TTF and [Pt(mnt)₂] is 1:1. The bond length of the central C=C bond in a BEDT-TTF ion is 1.398 (16) Å, indicating an oxidation state of +1 in BEDT-TTF ion. The structure consists of layers of BEDT-TTF and Pt(mnt)₂ along the c axis. Within each layer, both BEDT-TTF and Pt(mnt)₂ ions form segregated stacks. The stacking is not in a face-to-face manner, but instead, is through a side-by-side arrangement along the a axis, with closest SS contacts of 3.461(3) Å between neighboring BEDT-TTF ions. The structure is consistent with the semiconducting behavior found in the solid.     

Structures of Z-(nitrostilbene)chromium tricarbonyl complexes: The effect of metal coordination on the nonplanarity of the stilbene system

The structures of the nitrostilbene complexes Z-(4-R–C₆H₄–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃ (R=Me₂N,1; H,2; F₃C,3), are reported. The copounds were prepared as part of a study of the synthesis of organometallic complexes with potential nonlinear optics applications. For Z-(4-Me₂N–C₆H₄–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃,1, triclinic, ,a=7.214 (3) Å,b=7.340 (3) Å,c=17.238 (9)Å, =88.23 (5)°, =88.76 (4)°, =87.66 (3) °,Z=2. For Z-(C₆H₅–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃,2, monoclinic, P2₁/C,a=12.255 (3) Å,b=9.415 (1) Å,c=13.579 (4) Å, =105.60 (2)°,Z=4. For Z-(4-F₃C–C₆H₄–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃,3, triclinic, ,a=7.094 (2) Å,b=8.057 (5) Å,c=17.295 (9) Å, =87.95 (5)° =85.94 (4)°, =64.24 (5)°,Z=2. The structural data show that the Z isomers exhibit bond lengths and angles similar to those observed in the E isomers, but the stilbene fragment is considerably more nonplanar. As a consequence, these molecules are unlikely to behave as NLO materials.     

Crystal structure of bis[dihydrobis(3,5-dimethy-1-pyrazolyl)borato]cadmium(II)

The structure of [H₂B(3,5-Me₂pz)₂]₂Cd shows the four nitrogen donor atoms form a pseudotetrahedral arrangement about the cadmium(II). The intraligand N—Cd—N angles are restricted to an average of 91.4° by the chelate rings forcing the interligand N—Cd—N bond angles to average 119.4°. The Cd—N bond distances average 2.21 Å with a range of 0.04 Å. The crystal is in the triclinic space group, P with a = 7.6793(2) Å, b = 8.5992(2) Å, c = 25.0874(4) Å, = 91.0791(2)°, = 97.9769(4)°, = 110.2344(6)°, and Z = 2.     

A novel class of naturally occurring halogenated pyrroles, 1,1′-dimethyl-3,3′,4,4′,5,5′-hexabromo-2,2′-bipyrrole, 5,5′-dichloro-1,1′-dimethyl-3,3′,4,4′-tetrabromo-2,2′-bipyrrole, and 1,1′-dimethyl-3,3′,4,4′,5,5′-hexachloro-2,2′-bipyrrole

Crystal structure determinations of the three title hexahalogenated bipyrroles, (I) C₁₀H₆Br₆N₂, (II) C₁₀H₆Br₄Cl₂N₂, and (III) C₁₀H₆Cl₆N₂, reveal essentially planar pyrrole rings having dihedral angles of 64.7, 65.1, and 64.2° between the least-squares planes, favoring in each case a closer methyl–halogen conformation. All three complexes crystallize in the orthorhombic space group Pbcn with the following cell dimensions: (I) a = 12.654(3) Å, b = 8.853(2) Å, c = 13.753(3) Å, = = = 90°, Z = 4; (II) a = 12.438(6) Å, b = 8.753(6) Å, c = 13.696(3) Å, = = = 90°, Z = 4; (III) a = 12.088(6) Å, b = 8.566(4) Å, c = 13.486(8) Å, = = = 90°, Z = 4.