Acta crystallographica. Section C, Crystal structure communications最新文献

In the title compound, [Ni(C14H8N2O5)(H2O)2]n, the Ni(II) cation is six-coordinate with a slightly distorted octahedral coordination geometry and the 4-(isonicotinamido)phthalate ligand links the Ni(II) centres into a three-dimensional structure with sra topology. The structure is also stabilized by N-H···O hydrogen bonding between the uncoordinated amide groups of the ligand and extensive O-H···O hydrogen bonding between the two coordinated water molecules. The magnetic and thermal stability properties of the title compound are also discussed.

Crystal structures are reported for four related diethyl [(arylamino)(4-ethynylphenyl)lmethyl]phosphonate derivatives, namely diethyl [(4-bromoanilino)(4-ethynylphenyl)methyl]phosphonate, C19H21BrNO3P, (I), diethyl ((4-chloro-2-methylanilino){4-[2-(trimethylsilyl)ethynyl]phenyl}methyl)phosphonate, C23H31ClNO3PSi, (II), diethyl ((4-fluoroanilino){4-[2-(trimethylsilyl)ethynyl]phenyl}methyl)phosphonate, C22H29FNO3PSi, (III), and diethyl [(4-ethynylphenyl)(naphthalen-2-ylamino)methyl]phosphonate, C23H24NO3P, (IV). The conformation of the anilinobenzyl group is very similar in all four compounds. The P-C bond has an approximately staggered conformation, with the aniline and ethynylphenyl groups in gauche positions with respect to the P=O double bond. The two six-membered rings are almost perpendicular. The sums of the valence angles about the N atoms vary from 344 (2) to 351 (2)°. In the crystal structures, molecules of (I), (III) and (IV) are arranged as centrosymmetric or pseudocentrosymmetric dimers connected by two N-H···O=P hydrogen bonds. The molecules of (II) are arranged as centrosymmetric dimers connected by C(methyl)-H···O=P hydrogen bonds. The N-H bond of (II) is not involved in hydrogen bonding.

The title compound, [Zn(SiF6)(C12H8N2)2]·CH3OH, contains a neutral heteroleptic tris-chelate Zn(II) complex, viz. [Zn(SiF6)(phen)2] (phen is 1,10-phenanthroline), exhibiting approximate molecular C2 point-group symmetry. The Zn(II) cation adopts a severely distorted octahedral coordination. As far as can be ascertained, the title complex represents the first structurally characterized example of a Zn(II) complex bearing a bidentate-bound hexafluorosilicate ligand. A density functional theory study of the isolated [Zn(SiF6)(phen)2] complex was undertaken to reveal the influence of crystal packing on the molecular structure of the complex. In the crystal structure, the methanol solvent molecule forms a hydrogen bond to one F atom of the hexafluorosilicate ligand. The hydrogen-bonded assemblies so formed are tightly packed in the crystal, as indicated by a high packing coefficient (74.1%).

The mixed-amide phosphinates, rac-phenyl (N-methylcyclohexylamido)(p-tolylamido)phosphinate, C20H27N2O2P, (I), and rac-phenyl (allylamido)(p-tolylamido)phosphinate, C16H19N2O2P, (II), were synthesized from the racemic phosphorus-chlorine compound (R,S)-(Cl)P(O)(OC6H5)(NHC6H4-p-CH3). Furthermore, the phosphorus-chlorine compound ClP(O)(OC6H5)(NH-cyclo-C6H11) was synthesized for the first time and used for the synthesis of rac-phenyl (benzylamido)(cyclohexylamido)phosphinate, C19H25N2O2P, (III). The strategies for the synthesis of racemic mixed-amide phosphinates are discussed. The P atom in each compound is in a distorted tetrahedral (N(1))P(=O)(O)(N(2)) environment. In (I) and (II), the p-tolylamido substituent makes a longer P-N bond than those involving the N-methylcyclohexylamido and allylamido substituents. In (III), the differences between the P-N bond lengths involving the cyclohexylamido and benzylamido substituents are not significant. In all three structures, the phosphoryl O atom takes part with the N-H unit in hydrogen-bonding interactions, viz. an N-H···O=P hydrogen bond for (I) and (N-H)(N-H)···O=P hydrogen bonds for (II) and (III), building linear arrangements along [001] for (I) and along [010] for (III), and a ladder arrangement along [100] for (II).

4-Hydroxypyridine-2,6-dicarboxylic acid (chelidamic acid, hypydc[H]H2) reacts with MnCl2·2H2O in the presence of piperazine in water to afford the title complex, {[Mn3(C7H2NO5)2(H2O)8]·3H2O}n or {[Mn3(hypydc)2(H2O)8]·3H2O}n. This compound is a one-dimensional coordination polymer, with the twofold symmetric repeat unit containing three metal centres. Two different coordination geometries are observed for the two independent Mn(II) metal centres, viz. a distorted pentagonal bipyramid and a distorted octahedron. The 4-oxidopyridine-2,6-dicarboxylate anions and two of the water molecules act as bridging ligands. The zigzag-like geometry of the coordination polymer is stabilized by hydrogen bonds. O-H···O and C-H···O hydrogen bonds and water clusters consolidate the three-dimensional network structure.

The asymmetric unit in the crystal structure of the title compound, [Zn2(C16H14N2S2)2]2·0.18C2H6OS·0.82CH3OH, consists of two ordered bis{μ-2,2'-[(butane-2,3-diylidene)bis(azanylylidene)]dibenzenethiolato}dizinc(II) molecules and a disordered solvent combination at the same location which refined to 18.1 (7)% dimethyl sulfoxide and 81.9 (7)% methanol. The compound has a metallic cluster structure formed by the joining together of two zinc(II) complex molecules, forming a rhomboidal Zn2S2 arrangement. This complex was previously suggested on the basis of nonstructural evidence to be a monomer [Jadamus, Fernando & Freiser (1964). J. Am. Chem. Soc. 86, 3056-3059]. Each Zn(II) atom is five-coordinated and exhibits distorted trigonal bipyramidal geometry. The structure may be of interest with respect to zinc-thiolate bonds, the coordination chemistry of Schiff bases and the folding of proteins. The structure displays weak intermolecular C-H···S, C-H···O and C-H···N interactions, and contains a unique bonding arrangement of the ligands around the Zn2S2 rhomboid.

2-{1-[(Pyrazin-2-ylformamido)methyl]cyclohexyl}acetic acid (Pyr-Gpn-OH), C14H19N3O3, is an N-protected derivative of gabapentin (Gpn). The compound crystallizes in the triclinic space group P1 and the molecular conformation is stabilized by intramolecular five- (C5) and seven-membered (C7) hydrogen-bonded rings. The packing of the molecules reveals intermolecular O-H···O and C-H···N hydrogen bonds, together with π-π interactions.

The structures of the 1:1 hydrated proton-transfer compounds of isonipecotamide (piperidine-4-carboxamide) with oxalic acid, 4-carbamoylpiperidinium hydrogen oxalate dihydrate, C6H13N2O(+)·C2HO4(-)·2H2O, (I), and with adipic acid, bis(4-carbamoylpiperidinium) adipate dihydrate, 2C6H13N2O(+)·C6H8O4(2-)·2H2O, (II), are three-dimensional hydrogen-bonded constructs involving several different types of enlarged water-bridged cyclic associations. In the structure of (I), the oxalate monoanions give head-to-tail carboxylic acid O-H···O(carboxyl) hydrogen-bonding interactions, forming C(5) chain substructures which extend along a. The isonipecotamide cations also give parallel chain substructures through amide N-H···O hydrogen bonds, the chains being linked across b and down c by alternating water bridges involving both carboxyl and amide O-atom acceptors and amide and piperidinium N-H···O(carboxyl) hydrogen bonds, generating cyclic R4(3)(10) and R3(2)(11) motifs. In the structure of (II), the asymmetric unit comprises a piperidinium cation, half an adipate dianion, which lies across a crystallographic inversion centre, and a solvent water molecule. In the crystal structure, the two inversion-related cations are interlinked through the two water molecules, which act as acceptors in dual amide N-H···O(water) hydrogen bonds, to give a cyclic R4(2)(8) association which is conjoined with an R4(4)(12) motif. Further N-H···O(water), water O-H···O(amide) and piperidinium N-H···O(carboxyl) hydrogen bonds give the overall three-dimensional structure. The structures reported here further demonstrate the utility of the isonipecotamide cation as a synthon for the generation of stable hydrogen-bonded structures. The presence of solvent water molecules in these structures is largely responsible for the non-occurrence of the common hydrogen-bonded amide-amide dimer, promoting instead various expanded cyclic hydrogen-bonding motifs.

2,5-Bis[4-methyl-3-(pyridin-3-yl)phenyl]-1,3,4-oxadiazole (L), C26H20N4O, forms one-dimensional chains via two types of intermolecular π-π interactions. In catena-poly[[dichloridozinc(II)]-μ-2,5-bis[4-methyl-3-(pyridin-3-yl)phenyl]-1,3,4-oxadiazole], [ZnCl2(C26H20N4O)]n, synthesized by the combination of L with ZnCl2, the Zn(II) centres are coordinated by two Cl atoms and two N atoms from two L ligands. [ZnCl2L]n forms one-dimensional P (plus) and M (minus) helical chains, where the L ligand has different directions of twist. The helical chains stack together via interchain π-π and C-H···π interactions.

The disproportionation of AlCl(THF)n (THF is tetrahydrofuran) in the presence of lithium amidinate species gives aluminium(III) amidinate complexes with partial or full chloride substitution. Three aluminium amidinate complexes formed during the reaction between aluminium monochloride and lithium amidinates are presented. The homoleptic complex tris(N,N'-diisopropylbenzimidamido)aluminium(III), [Al(C13H19N2)3] or Al{PhC[N(i-Pr)]2}3, (I), crystallizes from the same solution as the heteroleptic complex chloridobis(N,N'-diisopropylbenzimidamido)aluminium(III), [Al(C13H19N2)2Cl] or Al{PhC[N(i-Pr)]2}2Cl, (II). Both have two crystallographically independent molecules per asymmetric unit (Z' = 2) and (I) shows disorder in four of its N(i-Pr) groups. Changing the ligand substituent to the bulkier cyclohexyl allows the isolation of the partial THF solvate chloridobis(N,N'-dicyclohexylbenzimidamido)aluminium(III) tetrahydrofuran 0.675-solvate, [Al(C19H27N2)2Cl]·0.675C4H8O or Al[PhC(NCy)2]2Cl·0.675THF, (III). Despite having a twofold rotation axis running through its Al and Cl atoms, (III) has a similar molecular structure to that of (II).