Low Temperature X-ray Crystallographic Structures of Two Lamotrigine Analogues: (I) 2-Methyl,3-amino, 5-imino-6-(2,3-dichlorophenyl)-1,2,4-triazine Water Solvate and (II) 2-Methyl,3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine Isethionate,Hemi-hydrate

Abstract The X-ray crystal structures of two lamotrigine derivatives (I) 2-methyl, 3-amino, 5-imino-6-(2, 3-dichlorophenyl)-1,2,4-triazine, C₁₀H₉Cl₂N₅, as the hemi hydrate and (II) 2-methyl,3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine, C₁₀H₁₀Cl₂N₅, as the isethionate-water solvate, have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are monoclinic and centrosymmetric, with (I) in space group C2/c, and (II) in space group P2₁/n. For (I) the unit cell dimensions are a = 19.5466(10), b = 7.5483(4), c = 15.7861(8) ?, β = 91.458(3)°, volume = 2328.4(2) ?³, Z = 8, density = 1.590 Mg/m³; for (II). For (II) the unit cell dimensions are a = 6.0566(2), b = 11.0084(4) c = 23.9973(9) ?, β = 92.587(3)°, volume = 1598.35(10) ?³, Z = 4, density = 1.597 Mg/m³. For (I) final R indices [I > 2sigma(I)] are R1 = 0.0356, wR2 = 0.0782 and R indices (all data) are R1 = 0.0424, wR2 = 0.0817. For (II) final R indices [I > 2sigma(I)] are R1 = 0.0380, wR2 = 0.0871 and R indices (all data) R1 = 0.0558, wR2 = 0.0949. Both structures have a molecule of water of crystallization and (II) also includes a solvated CH₃SO₃. Comparisons are made between the two structures. Structure (I) is very unusual in having a = NH group at position C5′ on the triazine ring. No other examples of this particular substitution, which is usually −NH₂, have been reported. Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry The crystal structures of (I) 2-methyl,3-amino, 5-imino-6-(2, 3-dichlorophenyl)-1, 2, 4-triazine, water solvate and (II) 2-methyl,3, 5-diamino-6-(2, 3-dichlorophenyl)-1, 2, 4-triazine isethionate water solvate are presented. The relative orientation of the two rings is shown to vary. Lamotrigine and analogues have been investigated for some time for their effects on the central nervous system. For example both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW 1003C87) are voltage-gated sodium channel blockers as well as blocking the release of the neurotransmitter glutamate [D. R. Riddall, M. J. Leach, J. Garthwaite, Mol. Pharmacol. 2006, 69 (1), 278.3], BW10003C87 (like lamotrigine) has been shown to exhibit excitatory amino acid antagonist activity similar to that of three conventional antiepileptic drugs phenytoin, carbamazepine and phenobarbital [R. Lingamaneni, H. C. Hemmings Jr., Epilepsy Res. 1993, 15, 101.]. BW 1003C87 has also been shown [B. S. Meldrum, J. H. Swan, M. J. Leach, M. H. Millan, R. Gwinn, K. Kadota, S. H Graham, J. Chen, R. P. Simon , Brain Res., 1992, 593, 1.] to reduce the release of glutamate evoked by veratrine in brain tissue, providing a therapeutic approach in both cerebral ischemia and epilepsy. This is one of a series of papers on the structures of lamotrigine analogues.      

Low Temperature X-ray Structures of Two Crystalline Forms (I) and (II) of the Pyrimidine Derivative and Sodium Channel Blocker BW1003C87: 5-(2,3,5-Trichlorophenyl)-2,4-diaminopyrimidine

Abstract The X-ray crystal structures of two crystalline forms of 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine, C₁₀H₇Cl₃N₄ (code name BW1003C87) (I) and (II), have been carried out at liquid nitrogen temperature. A detailed comparison of the two structures is given. Both are centrosymmetric, with structure (I) in the triclinic space group P unit cell a = 6.4870(10), b = 9.216(2), c = 12.016(2) ?, α = 75.78(3)°, β = 89.95(3)°, γ = 83.45(3)°, V = 691.5(2) ?³, Z = 2 and density (calculated) = 1.544 Mg/m3; and (II) in the monoclinic space group P2₁/c, unit cell a = 12.000(2), b = 7.518(2), c = 13.450(3) ?, β = 97.87(3)°, V = 1202.0(5) ?³, Z = 4, Density (calculated) = 1.600 Mg/m3. Structure (I) includes a solvated CH₃OH in the lattice. Final R indices [I > 2sigma(I)] are R1 = 0.0427, wR2 = 0.1075 for (I) and R1 = 0.0487, wR2 = 0.1222 for (II). R indices (all data) are R1 = 0.0470, wR2 = 0.1118 for (I) and R1 = 0.0623, wR2 = 0.1299 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine), have been investigated for some time for their effects on the central nervous system. Both lamotrigine and 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine (code name BW1003C87), the subject of the present study, are anticonvulsant as well as neuroprotective in models of brain ischaemia and in a model of white matter ischaemia. BW1003C87 is a sodium channel blocker which also reduces the release of the neurotransmitter glutamate. The three dimensional structures reported here form part of a newly developed data base for the detailed investigation of members of this drug family and their biological activities. Index Abstract Rex A. Palmer, Brian S. Potter, Michael J Leach and Babur Z. Chowdhry 5-(2,3,5-trichlorophenyl)-2,4-diaminopyrimidine occurs in two crystalline forms whose X-ray structures are described here. The molecular conformations in (I) and (II) are quite distinct as illustrated, the ring linkage torsion angle differing by 23.5 deg. (I) has a methanol solvate molecule in the lattice.      

Central Nervous System Drugs: Low Temperature X-ray Structures of (I) the Base 5-(2,3-Dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine (4030W92) and (II) 5-(2,6-Dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine methanesulphonic acid salt (227C89)

Abstract  The X-ray crystal structures of (I), the base 4030W92, 5-(2,3-dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine, C₁₁H₉Cl₂FN₄, and (II) 227C89, the methanesulphonic acid salt of 5-(2,6-dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine, C₁₁H₁₁Cl₂N₄ · CH₃O₃S, have been carried out at low temperature. A detailed comparison of the two structures is given. Structure (I) is non-centrosymmetric, crystallizing in space group P2₁ with unit cell a = 10.821(3), b = 8.290(3), c = 13.819(4) ?, β = 105.980(6)°, V = 1191.8(6) ?³, Z = 4 (two molecules per asymmetric unit) and density (calculated) = 1.600 mg/m³. Structure (II) crystallizes in the triclinic space group with unit cell a = 7.686(2), b = 8.233(2), c = 12.234(2) ?, α = 78.379(4), β = 87.195(4), γ = 86.811(4)°, V = 756.6(2) ?³, Z = 2, density (calculated) = 1.603 mg/m³. Final R indices [I > 2sigma(I)] are R1 = 0.0572, wR2 = 0.1003 for (I) and R1 = 0.0558, wR2 = 0.0982 for (II). R indices (all data) are R1 = 0.0983, wR2 = 0.1116 for (I) and R1 = 0.1009, wR2 = 0.1117 for (II). 5-Phenyl-2,4 diaminopyrimidine and 6-phenyl-1,2,4 triazine derivatives, which include lamotrigine (3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine), have been investigated for some time for their effects on the central nervous system. The three dimensional structures reported here form part of a newly developed data base for the detailed investigation of members of this structural series and their biological activities. Index Abstract  Low temperature X-ray structures of (I): the base 5-(2,3-dichlorophenyl)-2,4-diamino-6-fluoromethyl-pyrimidine (4030W92); and (II): 5-(2,6-dichlorophenyl)-1-H-2,4-diamino-6-methyl-pyrimidine methanesulphonic acid salt (227C89) are presented. Both drugs act on the central nervous system. (I) crystallizes in non-centrosymmetric space group P2₁ with two molecules A and B per asymmetric unit cell and (II) is triclinic in space group . The absolute configuration of (I) is determined.      

Structure of 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazine isethionate solvate (lamotrigine isethionate)

The crystal and molecular structure of lamotrigine isethionate, C₉H₈Cl₂N₅ ⁺ .HOC₂H₄SO₃ ^– has been determined by direct methods. The compound crystallizes in the tetragonal space group I4₁/a. The isethionate moiety forms multiple hydrogen bonds to the lamotrigine nucleus, three from one isethionate, two from a symmetry related isethionate and a further two from two different symmetry related molecules. Protonation of N(2) in the triazine ring, not observed in the native lamotrigine structure is presumably associated with the interaction of the isethionate moiety. Both rings in the lamotrigine moiety are essentially planar, with a dihedral angle of 66.08(7)° compared to 80.70° in native lamotrigine. The connecting bond length C(1)—C(6) = 1.493(3) Å also correlates well with values in related compounds (1.480(3) Å) in the native structures.     

Co-crystal structures of 2,4-diamino-6-phenyl-1,3,5-triazine – 4-chlorobenzoic acid/4-methoxybenzoic acid: Synthesis,structural and Hirshfeld surface analysis

The co-crystal structure of 2,4-diamino-6-phenyl-1,3,5-triazine with 4-chlorobenzoic acid/4-methoxybenzoic acid molecules are explain the link between the dimension and shape of their hydrogen-bonded assembly. The co-crystal structure of 2,4-diamino-6-phenyl-1,3,5-triazine with 4-chlorobenzoic acid/4-methoxybenzoic acid forming a cyclic R₂²(8) ring motif via N–H?O and O–H?N hydrogen bonding interactions, to form a supramolecular heterosynthon. In both the co-crystal structures, self-association of 2,4-diamino-6-phenyl-1,3,5-triazine moieties are connected via N-H^….N base pairs with cyclic R₂²(8) motif form a supramolecular homosynthon. In co-crystal II, the centrosymmetrically paired methoxy group of 4-methoxy benzoic acid form a supramolecular homosynthon via weak intermolecular C-H^….O hydrogen bonds, generating R₂²(6) ring motif. Both the co-crystal structures are stabilized by weak aromatic π-π and C—Cl???π stacking interactions. Hirshfeld surface and fingerprint plots were used to study the intermolecular interactions both of the crystal structures.     

Synthesis and structure of p-chlorophenylhydrazone of 3-(methylthio)-5-propanoyl-1,2,4-triazine

The reaction of 3-(methylthio)-5-propanoyl-1,2,4-triazine with p-chlorophenylhydrazine hydrochloride is completed within 5 min at room temperature in ethanol leading to p-chlorophenylhydrazone of 3-(methylthio)-5-propanoyl-1,2,4-triazine 1 in good yield. Title compound, 1 (R = C₂H₅, R₁ = Cl, Z = SCH₃), C₁₃H₁₄N₅SCl, crystallizes in the monoclinic system, space group P2₁/n, with cell constants a = 12.5206(6) Å, b = 9.3122(8) Å, c = 12.8524(9) Å, and = 98.822(5)°, Z = 4, T = 293 K, D_cal = 1.381 g cm^–3. The structure was solved by direct methods and refined to R value of 0.0671 for 1,679 reflections. The molecule as a whole has an almost planar conformation and possesses (E) configuration with respect to the C=N double bond. The crystal structure is stabilized by a weak N(13)–H(13)···N(2) intermolecular hydrogen bond and significant stacking, characteristic for -electron systems.     

Synthesis and Crystal Structure of 2-Amino-4-(4-hydroxyphenyl)-5-propylthiazole Ethanol Solvate 0.25 Hydrate

Abstract  

2-Amino-4-(4-hydroxyphenyl)-5-propylthiazole was synthesized by the reaction of α-bromo-1-(4-hydroxyphenyl)-1-pentone with thiourea. The crystal structure of its ethanol solvate 0.25 hydrate, C₁₂H₁₄N₂OS···C₂H₅OH···0.25·H₂O, was determined by X-ray diffraction analysis. The crystal belongs to monoclinic system, space group C2/c with a = 20.9046(10), b = 10.1057(5), c = 30.0017(15) ?, β = 105.5850(10)°, Z = 8, M _r = 569.77, V = 6105.0(5) ?³, D _c = 1.240 g/cm³, μ = 0.214 mm⁻¹, F(000) = 2440, the final R = 0.0598 and wR = 0.1825 for 5,911 observed reflections [I > 2σ(I)]. Compound (1) is composed by two non-coplanar ring systems of phenol and thiazole. The structure displays extensive O–H···N, N–H···O and O–H···O intermolecular hydrogen bonds.     

Crystal structures of copper(II) and nickel(II) nitrate and chloride complexes with 4-bromo-2-[(2-hydroxyethylimino)-methyl]phenol

The crystal structures of {4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo}aquacopper(II) nitrate hemihydrate (I), chloro-{4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo}copper hemihydrate (II), and chloro-{4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo}aquanickel (III) are determined using X-ray diffraction. Crystals of compound I are formed by cationic complexes, nitrate ions, and solvate water molecules. In the cation, the copper atom coordinates the singly deprotonated molecule of tridentate azomethine and the water molecule. The copper complexes are joined into centrosymmetric dimers by the O _w -H···O hydrogen bonds. The crystal structure of compound II is composed of binuclear copper complexes and solvate water molecules. The copper atom coordinates the O,N,O ligand molecule and the chlorine ion, which fulfills a bridging function. The coordination polyhedron of the metal atom is a distorted tetragonal bipyramid in which the vertex is occupied by the chlorine atom of the neighboring complex in the dimer. Compound III is a centrosymmetric dimer complex. The coordination polyhedra of two nickel atoms related via the inversion center are distorted octahedra shared by the edge.     

The Zolmitriptan-Pyridine (1:1) and Zolmitriptan-Propiophenone (3:2) Inclusion Complex

Abstract  

The crystal structures of zolmitriptan with pyridine (I) and propiophenone (II) solvates have been determined by single crystal X-ray diffraction studies. Compound (I) crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 8.5610(5) ?, b = 12.2709(7) ?, c = 19.6201(12) ?, V = 2061.1(2) ?³, and Z = 4, while compound (II) crystallizes in the monoclinic space group P2₁ with a = 15.085(1) ?, b = 19.656(12) ?, c = 21.0860(13) ?, β = 92.068(1)°, V = 6248(4) ?³ and Z = 4. The asymmetric unit of (I), C₁₆H₂₁N₃O₂·C₅H₅N, contains one zolmitriptan molecule and one pyridine solvate, while the asymmetric unit of (II), 3(C₁₆H₂₁N₃O₂)·2(C₉H₁₀O) comprises six zolmitriptan molecules and four propiophenone solvates. In both structures, the N–H···N hydrogen bonds, form an infinite helical chain and generate a C(11)-type motif in (I) and a D₂²(13)-type motif in (II). Both the complexes have layer structures, the layers being constructed from rings (cavity) of four zolmitriptan molecules, hydrogen bonded through N–H···N and N–H···O bonds, where the pyridine (I) and propiophenone (II) solvates are included in an R₄⁴(33) ring.     

Structure of 2-(1-phenylimidiazolidin-2-ylidene)- malononitrile and 2-(hexahydropyrimidinyl-2-ylidene)- malononitrile

The crystal structure of 2-(1-phenylimidazolidin-2-ylidene)-malononitrile, I, and 2-(hexahydropyrimidin-2-ylidene)-malononitrile, II, were determined with crystal data (I: Monoclinic, P2₁/n, a=8.116(3) ?, b=7.650(3) ?, c=17.399(7) ?, β=93.065(6)°, R _all=0.0980; II: Monoclinic, P2₁/n, a=9.169(2) ?, b=8.103(2) ?, c=10.337(3) ?, β=99.853(4)°, R _all=0.0877). N−H···N hydrogen bonds were responsible for the formation of centrosymmetric dimers of I and one-dimensional zigzag molecular chains of II.     

Crystal and molecular structures oftrans-dichloro-(ethylene) (4-methylpyridine)platinum(II) andtrans-dichloro(ethylene) (2,4,6-trimethylpyridine)platinum(II)

The crystal and molecular structures oftrans-[PtCl₂(C₂H₄)(4-MeC₅H₄N)] (I) andtrans-[PtCl₂(C₂H₄)(2,4,6-Me₃C₅H₂N)] (II) have been determined by single-crystal x-ray methods.I crystallizes in space groupP2₁/c witha= 4.991(1), b=21.658(3), c=10.675(3) Å, =110.17(2) °,Z=4;II is orthorhombic (Pbca) witha=10.295(6),b=12.393(8),c=20.370(10) Å,Z=8.Full-matrix least-squares refinements have given finalR factors of 0.053 (1520 reflections) forI and 0.042. (1412 reflections) forII. The intensities were recorded by counter methods, and only those reflections havingI>3(I) were used in the analyses.In both complexes, platinum is four-coordinate with the two chlorine atoms, the double bond of the ethylene, and the nitrogen atom of the substituted pyridine. The two structures are discussed in terms of the arrangement of the pyridine ligand with respect to the PtCl₂(C₂H₄) moiety.     

Triaquocalcium(18-crown-6) heptaiodopentacuprate(I), triaquostrontium(18-crown-6) heptaiodopentacuprate(I), and triaquozinc(18-crown-6) heptaiodopentacuprate(I)

Ca(H₂O)₃(18-crown-6)Cu₅I₇ (I), Sr(H₂O)₃(18-crown-6)Cu₅I₇ (II), and Zn(H₂O)₃(18-crown-6)Cu₅I₇ (III) are isostructural solids with a polymeric array of Cu₅I₇ stoichiometry. The repeat unit may be understood as a distorted tetrahedron of four copper(I) atoms, bridged on two faces and three edges by iodide atoms, bridged on an additional edge by an I–Cu–I sequence and linked in polymeric series by this copper atom and one of the face-bridging iodide atoms. The three solid materials display no emission in the visible when excited in the ultraviolet. Comparison with other polymeric cuprous iodide materials that do emit suggests that the quenching of the expected emission may stem from short Cu–Cu interactions (2.4–2.5 Å) that represent a bonding interaction.     

3-(benzo[d]thiazol-2-YL)phenol and 4-(benzo[d]thiazol-2-YL)phenol: Crystal Structure Determination,DFT Calculations and Visualizing Intermolecular Interactions Using Hirshfeld Surface Analysis

This article describes the synthesis and X-ray crystal structure analysis of 3-(benzo[d]thiazol-2-yl) phenol (I) and 4-(benzo[d]thiazol-2-yl)phenol (II), crystallized in centrosymmetric triclinic and orthorhombic space groups respectively. The packing in the unit cell of these two positional isomers are different resulting difference in various types of intermolecular interactions (C-H…S, O-H…O_w and O-H…N) connect the molecules into 2D frameworks. Due to presence of lattice water in compound (I), H-bonding interactions are strong and melting point of (I) is comparatively higher than (II). The DFT optimized molecular geometries in (I) and (II) agree closely with those obtained from crystallographic studies.     

Synthesis and X-ray diffraction study of (Cs0.5Ba0.25)[UO2(CH3COO)3] and Ba0.5[UO2(CH3COO)3]

Uranyl triacetate complexes (Cs_0.5Ba_0.25)[UO₂(CH₃COO)₃] (I) and Ba_0.5[UO₂(CH₃COO)₃] (II) are synthesized for the first time and their structures are determined by X-ray diffraction. Both compounds crystallize in the cubic crystal system. The crystal data are as follows: a = 17.3289(7) ?, V = 5203.7(4) ?³, space group I2₁3 and Z = 16 (I); a = 17.0515(8)?, V = 4957.8(4) ?³, space group I $ \bar 4 $ \bar 4 3d, and Z = 16 (II). In I and II, as in all uranyl triacetates studied earlier, the coordination polyhedron of the uranium atom is a hexagonal bipyramid whose vertices are occupied by the oxygen atoms of the uranyl and three acetate groups. The uranium-containing group belongs to the AB ₃⁰¹ (A = UO₂²⁺, B ⁰¹ = CH₃COO⁻) crystal chemical group of uranyl complexes. It was found that compound II is isostructural to the (Rb_0.50Ba_0.25)[UO₂(CH₃COO)₃] studied earlier.     

Crystal structures of 3-[1-Benzenesulfonyl-3-phenylsulfanyl-1H-indol-2-yl]-1-[4-(methyl (I)/methoxy (II) phenyl)]-2-phenyl-propane-1-one

The compounds 3-(1-Benzenesulfonyl-3-phenylsulfanyl-1H-indol-2-yl)-1-[4-methyl (I)/methoxy (II)phenyl)]-2-phenyl-propane-1-one crystallize in triclinic space group P . The details are: compound I a = 11.941(6) ?, b = 12.154(7) ?, c = 13.006(7) ?, α = 63.124(8)°, β = 84.464(9)°, γ = 64.810(8)°, V = 1519.7(14) ?³, Z = 2, D _cal = 1.284 Mg m⁻³, and R = 0.0382 (wR = 0.0978); compound II a = 11.897(6) ?, b = 12.268(6) ?, c = 13.001(7) ?, α = 61.919(8)°, β = 83.480(8)°, γ = 64.676(7)°, V = 1504.0(14) ?³, Z = 2, D _cal = 1.333 Mg m⁻³, and R = 0.0422 (wR = 0.1049). The indole ring system in both the molecules I and II are not strictly planar and the dihedral angles formed by the pyrrole and benzo planes are 4.0(7)° and 3.5(8)°, respectively. The C–HO, C–Hπ and ππ types of interactions stabilize the molecules in the unit cell in addition to van der Waal's forces in I and II.     

Crystal and molecular structure of 3,5-bis(N,N-diethylimonium)-1,2,4-trithiolane-tetraiododi-μ-iododiinercurate(II)

The crystal and molecular structure of 3,5-bis(N,N-diethylimonium)-1,2,4-trithiolane-tetraiododi--iododimercurate(II), (S₃C₂N₂(C₂H₅)₄)Hg₂I₆, has been determined from a single-crystal X-ray diffraction study. The monoclinic unit cell, space groupP2₁/c, witha = 12·574(3),b = 15·777(4),c = 14·560(4) Å, and = 90·83(4) °, contains four formula-units. Three-dimensional intensity data were collected on an automatic diffractometer. Atomic parameters were refined by full-matrix least-squares methods to a conventionalR value of 0·05 for 1380 independent non-zero reflexions. The structure consists of (3,5-bis(N,N-diethyl-imonium)-1,2,4-trithiolane)²⁺ and Hg₂I ₆ ^2– ions. The cation contains a five-membered ring, S-S-C-S-C, which can be formed by oxidation of dithiocarbamato and thiuramdisulfide complexes.     

Crystal structure and vibrational spectra of polyamine-copper(II) complexes

The structures of [Cu(en)(H₂O)₂]SO₄ (I), [Cu(en)₂](NO₃)₂ (II) and [Cu(trien)I]I (III) have been determined by single crystal X-ray diffraction. ComplexI is monoclinic, space group C2/c, with unit cell parametera=7.232(1),b=11.725(2),c=9.768(1), =105.50(1)°, andZ=4. ComplexII is also monoclinic, space group P2₁/a, witha=7.978(2),b=9.982(4),c=8.218(3), =111.11(2)°, andZ=2. ComplexIII is orthorhombic, space group P2₁2₁2₁, witha=8.098(1),b=11.902(1),c=13.682(2), andZ=4. The structures were solved by direct methods and refined by full-matrix least-squares to finalR values of 0.031, 0.043 and 0.036 for complexesI, II, andIII, respectively. ComplexesI andII show an octahedral coordination geometry. ComplexIII shows a square pyramidal coordination geometry. ComplexI forms infinite monodimensional chains where the SO ₄ ^2– ions acts as a bridge between two neighboringen molecules. The vibrational spectra of these complexes agree well with their crystal structures. Structure and stability of seven other related Cu(II) complexes of (trien), (dien)₂, (en)₂ and (en) are inferred in this study.     

2-(1-Methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2] octan-3-one: Acid-catalyzed isomerization of the Z isomer to the E isomer

Crystals of (Z)-2-(1-methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2]octan-3-one (I) were obtained from a condensation reaction of 1-methyl-1H-indole-3-carboxaldehyde with 1-aza-bicyclo[2.2.2]octan-3-one and subsequent crystallization of the product from methanol. The isomeric (E)-2-(1-methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2] octan-3-one hydrochloride (II) was obtained by treating a methanolic solution of I with a 1M solution of hydrogen chloride diethyl ether, followed by crystallization of resultant product from methanol. Crystal data: I, is monoclinic, P2₁, a = 5.7440(10), b = 11.102(2), c = 10.708(2) Å, = 91.751(10)°, and V = 682.5(2) ų with Z = 2, for D _cal= 1.296 mg/m³ and II, is monoclinic, P2₁/c, a = 8.8510(2), b = 17.4990(5), c = 20.4300(5) Å, = 101.3620(12)°, V = 3102.26(14) with Z = 8, for D _cal= 1.316 mg/m³.     

Structures of mixed-ligand Manganese(II) compounds [Mn(Heida)(Phen)]2 · 7H2O and [Mn2(Edta)(Phen)] · 4H2O

The crystal structures of [Mn(Heida)(Phen)]₂ · 7H₂O (I) and [Mn₂(Edta)(Phen)] · 4H2O (II) are studied by X-ray diffraction [R ₁ = 0.0375 (0.0283) and wR ₂ = 0.0954 (0.0662) for 5449 (3176) observed reflections in I (II), respectively]. Structure I contains mononuclear mixed-ligand complexes [Mn(Heida)(Phen)] and [Mn(Heida)(Phen)(H₂O)]. In structure II, the [Mn(Edta)]²⁻ anionic complexes and the [Mn(Phen)(H₂O)₂]²⁺ cationic complexes are linked by the bridging carboxyl groups into the tetramers with C ₂ symmetry. In both compounds, two independent Mn atoms have different coordination numbers (6 and 7). __________ Translated from Kristallografiya, Vol. 47, No. 2, 2002, pp. 280–285. Original Russian Text Copyright ? 2002 by Polyakova, Sergienko, Poznyak.     

X-ray structural investigation of two optically active 1N-epimers of 2,5,7,10,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorate. A novel conformation of the macrocyclic ligand

The structures oftrans-1NH,8NH- (I) andcis-1NH,8NH-(II)-2,5,7,10,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorates have been investigated by X-ray diffractometric methods. CompoundI crystallizes in a monoclinic system, space groupP2₁,Z=4,a=11.225(1),b=13.710(1),c=15.898(2) Å,=109.22(1)°. CompoundII crystallizes in an orthorhombic system, space groupP2₁2₁2₁,Z=4,a=15.529(2),b=14.129(2),c=10.621(1) Å. The structures were solved by the heavy-atom method followed by a series of Fourier syntheses, and refined by full-matrix least squares to give forI andII R=0.051 (for 3787 independent reflections) andR=0.048 (for 1494 reflections), respectively. Conformational analysis of chelate rings and of the macrocyclic ring was performed forI andII, and the results were compared with those of some known 1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel (II) complexes. A novel conformation of the macrocycle was found in cationI. Conformations of the methyl groups are forI andII 2(a),7(e),10(a),14(e) and 2(a),7(e),10(a),14(a), respectively, with a 1,3-syn-axial interaction of the 2,14-methyl groups inII. The absolute configuration of cationI is 1N(S), 2(R), 7(R), 8N(S), 10(R), 14(S), and differs from that of cationII by 1N(R) exclusively (1N-epimeric compounds).