RESUMO
4,4'-(Disulfanediyl)dibutanoic acid (dtba) and 4,4'-bipyridine (4,4'-bpy) crystallize in an 1:1 ratio, leading to the title co-crystal with composition C8H14O4S2·C10H8N2. A distinctive feature of the crystal structure is the geometry of the dtba moiety, which appears to be stretched [with a 9.98â (1)â Å span between outermost carbons] and acts as an hydrogen-bonding connector, forming linear chains along [-211] with the 4,4'-bpy moiety by way of O-Hâ¯N hydrogen bonds and C-Hâ¯O interactions. The influence of the mol-ecular shape on the hydrogen-bonding pattern is analysed by comparing the title compound and two other 4,4'-bpy co-crystals with closely related mol-ecules of similar formulation but different geometry, showing the way in which this correlates with the packing arrangement.
RESUMO
The asymmetric unit of the title compound, C8H9NO2·H2O consists of an isolated 4-(ammonio-meth-yl)benzoate zwitterion derived from 4-amino-methyl-benzoic acid through the migration of the acidic proton, together with a water molecule of crystallization that is disordered over three sites with occupancy ratios (0.50:0.35:0.15). In the crystal structure, N-Hâ¯O hydrogen bonds together with π-π stacking of the benzene rings [centroid-centroid distance = 3.8602â (18)â Å] result in a strongly linked, compact three-dimensional structure.
RESUMO
The title mononuclear complex, [Nd(C5H3N2O3)3(H2O)3]·3H2O, consists of an Nd(III) cation, three 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate ligands and three aqua ligands forming the neutral complex molecule, and three solvent water molecules. The pyrimidinecarboxylate ligands act in a chelating manner, via carboxylate and keto O atoms. The NdO9 coordination polyhedron is in the form of a distorted monocapped square antiprism. The availability of numerous hydrogen-bonding donors and acceptors results in a very dense hydrogen-bonding network, the immediate effect of which is an unusually large packing index.
Assuntos
Cátions/química , Complexos de Coordenação/química , Neodímio/química , Cristalografia por Raios X , Ligação de Hidrogênio , Ligantes , Estrutura MolecularRESUMO
Tricarbonyl[9-(triphenylphosphonio)fluorenylidene]ruthenium, [Ru(C31H21P)(CO)3], (I), is mononuclear, consisting of a single Ru centre, to which three carbonyl units and a chelating µ3-9-(triphenylphosphonio)fluorenide ylide bind to generate a distorted octahedral RuC6 core. Nonacarbonyl-µ3-fluorenylidene-µ2-hydrido-triangulo-triosmium(III), [Os3H(C13H7)(CO)9], (II), is trinuclear and presents a triangular triosmium core, nine carbonyl ligands and one fluorenylidene ligand. Two of the Os(III) centres present a highly distorted hexacoordinated Os(Os2C4) core and are in turn bridged by a hydride ligand. The remaining Os(III) cation is octacoordinated, with an Os(Os2C6) nucleus. The crystal structures of both compounds are the result of nondirectional forces, much resembling the packing of weakly interacting quasi-spherical units, viz. the molecules themselves in (I) and centrosymmetric π-π-bonded dimers in (II).
RESUMO
Poly[[tetraaquadi-µ4-citrato-tetrakis(2,6-diaminopurine)tetracobalt(II)] 6.35-hydrate], {[Co4(C6H4O7)2(C5H6N6)4(H2O)4]·6.35H2O}n, presents three different types of Co(II) cations in the asymmetric unit, two of them lying on symmetry elements (one on an inversion centre and the other on a twofold axis). The main fragment is further composed of one fully deprotonated citrate (cit) tetraanion, two 2,6-diaminopurine (dap) molecules and two aqua ligands. The structure is completed by a mixture of fully occupied and disordered solvent water molecules. The two independent dap ligands are neutral and the cit tetraanion provides for charge balance, compensating the 4+ cationic charge. There are two well defined coordination geometries in the structure. The simplest is mononuclear, with the Co(II) cation arranged in a regular centrosymmetric octahedral array, coordinated by two aqua ligands, two dap ligands and two O atoms from the ß-carboxylate groups of the bridging cit tetraanions. The second, more complex, group is trinuclear, bisected by a twofold axis, with the metal centres coordinated by two cit tetraanions through their α- and ß-carboxylate and α-hydroxy groups, and by two dap ligands bridging through one of their pyridine and one of their imidazole N atoms. The resulting coordination geometry around each metal centre is distorted octahedral. Both groups are linked alternately to each other, defining parallel chains along [201], laterally interleaved and well connected via hydrogen bonding to form a strongly coupled three-dimensional network. The compound presents a novel µ4-κ(5)O:O,O':O',O'',O''':O'''' mode of coordination of the cit tetraanion.
RESUMO
The title compound, C17H11F5N4O, is described and compared with two closely related analogues in the literature. There are two independent molecules in the asymmetric unit, linked by N-H···O hydrogen bonds and π-π interactions into dimeric entities, presenting a noticeable noncrystallographic C2 symmetry. These dimers are in turn linked by a medium-strength type-I C-F···F-C interaction into elongated tetramers. Much weaker C-H···F contacts link the tetramers into broad two-dimensional substructures parallel to (101).
Assuntos
Hidrazinas/química , Pirazolonas/química , Cristalografia por Raios X , Ligação de Hidrogênio , Estrutura MolecularRESUMO
The title compound, C(17)H(10)F(5)N(5)O(2), is described and compared with its 4-nitrophenyl isomer [Bustos, Sánchez, Schott, Alvarez-Thon & Fuentealba (2007). Acta Cryst. E63, o1138-o1139]. The title molecule presents its nitro group split into two rotationally disordered components, which in conjunction with the rotation of the `unclamped' rings constitute the main molecular differences. Packing is directed by a head-to-tail type `I' C-F...F-C interaction, generating double-chain strips running along [100]. These substructures are interlinked by a variety of weak F...F, O...F, F...π and O...π interactions.
Assuntos
Hidrocarbonetos Fluorados/química , Nitrocompostos/química , Pirazóis/química , Cristalografia por Raios X , Ligação de Hidrogênio , Estrutura MolecularRESUMO
The title ionic compound, (C(7)H(8)N(3))(2)[Ho(2)(C(4)H(5)O(2))(8)], is constructed from two almost identical independent centrosymmetric anionic dimers balanced by two independent 2-amino-1H-benzimidazol-3-ium (Habim(+)) cations. The asymmetric part of each dimer is made up of one Ho(III) cation and four crotonate (crot or but-2-enoate) anions, two of them acting in a simple η(2)-chelating mode and the remaining two acting in two different µ(2):η(2) fashions, viz. purely bridging and bridging-chelating. Symmetry-related Ho(III) cations are linked by two Ho-O-Ho and two Ho-O-C-O-Ho bridges which lead to rather short intracationic Ho···Ho distances [3.8418 (3) and 3.8246 (3) Å]. In addition to the obvious Coulombic interactions linking the cations and anions, the isolated [Ho(2)(crot)(8)](2-) and Habim(+) ions are linked by a number of N-H···O hydrogen bonds, in which all N-H groups of the cation are involved as donors and all (simple chelating) crot O atoms are involved as acceptors. These interactions result in compact two-dimensional structures parallel to (110), which are linked to each other by weaker π-π contacts between Habim(+) benzene groups.
Assuntos
Benzimidazóis/química , Hólmio/química , Íons/química , Compostos Organometálicos/química , Cristalografia por Raios X , Ligação de Hidrogênio , Estrutura MolecularRESUMO
The title compound, C(9)H(8)N(2), presents two almost identical independent molecules in the asymmetric unit, both of them exhibiting an extremely planar isoquinoline core (maximum r.m.s. deviation = 0.014 Å). The most significant deviation is found in the -NH(2) groups, which present a noticeable pyramidalization around the N atom, a feature also present in related structures containing the molecule as a ligand. The supramolecular structure is based on pairs of parallel hydrogen-bonded chains formed by just one molecular type each, defined by the strongest hydrogen bonds in the structure, which are of the N-H···N type. These parallel chains are linked into pairs (or strips) via weaker C-H···N hydrogen bonds. Related strips generated by the c-glide plane define two families running along [110] and [110], giving rise to an interesting system of interwoven chains stabilized by a number of weaker contacts of the C-H···π type.
RESUMO
The asymmetric unit of the title compound, {[La(C(4)H(5)O(2))(3)(H(2)O)(2)]·C(5)H(5)N(5)·H(2)O}(n), consists of an La(III) cation, three crotonate (but-2-enoate) anions and two coordinated water molecules forming the neutral complex, completed by an external adenine molecule and one hydration water molecule. The LaO(10) coordination polyhedra, connected through the sharing of a single edge, form isolated chains running along the [100] direction. These one-dimensional structures are characterized by two different centrosymmetric La(2)O(2) loops, with La...La distances of 4.5394 (6) and 4.5036 (6) Å. The unbound adenine and water solvent molecules form a highly planar hydrogen-bonded array parallel to (110) (r.m.s. deviation from the mean plane < 0.10 Å) which intersects the isolated La-crotonate chains in a slanted fashion to form an extremely connected hydrogen-bonded three-dimensional structure.
RESUMO
The asymmetric unit of the title dimeric compounds, [Ln(2)(C(4)H(5)O(2))(6)(H(2)O)(4)]·C(5)H(5)N(5)·7H(2)O, with Ln = Dy, (I), and Sm, (II), consists of an Ln(III) cation, three crotonate (but-2-enoate) anions and two coordinated water molecules forming the neutral complex, cocrystallized with half of an external adenine molecule and 3.5 water molecules. The metal complex has crystallographic inversion symmetry. The LnO(9) coordination polyhedra are connected through the sharing of a single edge to form isolated dimeric units, with Ln...Ln separations of 4.1766 (12) Å for (I) and 4.2340 (12) Å for (II). The unbound adenine molecule and one of the solvent water molecules are disordered around an inversion centre into two overlapping, equally populated, units. The structure is sustained by a complex hydrogen-bonding scheme involving all possible O-H and N-H groups as donors, and crotonate and water O and adenine N atoms as acceptors. The system is compared with recently published related compounds.
RESUMO
There are two independent mol-ecules, A and B, in the asymmetric unit of the title compound, C(19)H(20)N(4), in each of which the N=N double bond has an E conformation. The dihedral angles between the pyrazole ring and the p-tolyl rings in the 1- and 4-positions are 22.54â (8) and 35.73â (7)°, respectively, in mol-ecule A. The corresponding dihedral angles in mol-ecule B are 28.13â (8) and 22.18â (8)°. In the crystal, the A and B mol-ecules are linked by weak C-Hâ¯π inter-actions, leading to inversion dimers in each case.
RESUMO
There are two independent mol-ecules, A and B, in the asymmetric unit of the title compound, C(16)H(12)ClN(5)O(3). The relative orientations of the chloro-phenyl ring with respect to the pyrazole ring in the two crystallographically independent mol-ecules are different, and their corresponding dihedral angles are -53.3â (2) and 114.09â (18)° in mol-ecules A and B, respectively. There are two strong intramolecular N-Hâ¯O hydrogen bonds, and two weak intramolecular C-Hâ¯O and C-Hâ¯Cl hydrogen bonds. The crystal packing is constructed by weak C-Hâ¯O and N-Hâ¯O inter-actions, and two π-π stacking inter-actions [centroid-centroid distances = 3.7894â (9) and 3.5719â (10)â Å], forming a mol-ecular ladder along the a axis.
RESUMO
The title compound, [Co(C(5)H(7)N(6))(2)(H(2)O)(4)](C(10)H(2)O(8))·4H(2)O, is an ionic structure comprising a [Co(Hdap)(2)(H(2)O)(4)](4+) cation (dap is 2,6-diaminopurine) in a general position, two benzene-1,2,4,5-tetracarboxylate (btc(4-)) anions straddling two different inversion centres and four solvent water molecules. The structure presents a remarkable degree of pseudosymmetry, with the Co(II) cation lying almost exactly on a noncrystallographic pseudo-inversion centre. The overall spatial arrangement can be described in terms of cationic and anionic chains running along the [111] direction and linked into a three-dimensional network by a very complex hydrogen-bonding scheme in which all the available N-H and O-H groups take part.
RESUMO
The structure of the ionic title compound, (C(5)H(7)N(6))(2)[Nd(2)(C(5)O(5))(4)(H(2)O)(8)], consists of anionic dimers built around an inversion centre and is made up of an Nd(III) cation, two croconate (croco) dianions and four water molecules (plus their inversion images), with two noncoordinated symmetry-related 2,6-diamino-1H-purin-3-ium (Hdap(+)) cations providing charge balance. Each Nd(III) atom is bound to nine O atoms from four water and three croco units. The coordination polyhedron has the form of a rather regular monocapped square antiprism. The croconate anions are regular and the Hdap(+) cation presents a unique, thus far unreported, protonation state. The abundance of hydrogen-bonding donors and acceptors gives rise to a complex packing scheme consisting of dimers interlinked along the three crystallographic directions and defining anionic `cages' where the unbound Hdap(+) cations lodge, linking to the mainframe via (N-H)(Hdap)···O(water/croco) and (O-H)(water)···N(Hdap) interactions.
Assuntos
Ânions/química , Neodímio/química , Compostos Organometálicos/química , Cristalografia por Raios X , Ligação de Hidrogênio , Estrutura Molecular , Água/químicaRESUMO
In the title polymeric compound, [Cu(C(9)H(6)O(4))(C(3)H(4)N(2))(2)](n), the copper(II) cation occupies an N(2)O(3) coordination sphere defined by two 1H-imidazole (imid) ligands in trans positions and three carboxylate O atoms from three different 2-(carboxylatomethyl)benzoate (hpt(2-)) dianions. The geometry is that of a square pyramid with one of the O atoms at the apex, bridging neighbouring metal centres into an [-ON(2)CuO(2)CuN(2)O-] dinuclear unit. These units are in turn connected by hpt anions into a reticular mesh topologically characterized by two types of loops, viz. a four-membered Cu(2)O(2) diamond motif and a 32-membered Cu(4)O(8)C(20) ring. The imid groups do not take part in the formation of the two-dimensional structure, but take part in the N-H···O interactions. These arise only within individual planes, interplanar interactions being only of the van der Waals type.
Assuntos
Ânions/química , Metais/química , Compostos Organometálicos/química , Cristalografia por Raios X , Ligação de Hidrogênio , Ligantes , Modelos MolecularesRESUMO
The title polymeric compound, {(C(13)H(16)N(2))[Co(C(10)H(3)O(8))(C(13)H(14)N(2))(H(2)O)(2)](2)·5H(2)O}(n), is an ionic structure comprising an anionic two-dimensional mesh characterized by a {[Co(Hbtc)(bpp)(H(2)O)(2)](-)}(2) motif [Hbtc is 5-carboxybenzene-1,2,4-tricarboxylate and bpp is 1,3-bis(4-pyridyl)propane], with interspersed 4,4'-(propane-1,3-diyl)dipyridinium cations, denoted (H(2)bpp)(2+), and water molecules providing the charge balance and structure stabilization. The reticular mesh consists of two independent types of [Co(H(2)O)(2)](2+) cationic nodes (lying on inversion centres), interconnected in the [101] direction by two independent sets of neutral bridging bpp ligands, both types of ligands being split by non-equivalent twofold axes. One set is formed by genuinely symmetric moieties, while those in the second set are only symmetric by disorder in the central propane bridge. These chains contain only one type of Co(II) centre and one type of bpp ligand; the metal cations therein are laterally bridged by Hbtc anions, thus forming transverse chains of alternating types of Co(II) cations. The elemental motif of the resulting grid is a highly distorted parallelogram, with metal-metal distances of 13.5242 (14) Å in the bpp direction and 9.105 (2) Å in the Hbtc direction, and a large internal angle of 138.42 (18)°. These two-dimensional structures have a profusion of hydrogen-bonding interactions with each other, either directly (with the aqua molecules as donors and the Hbtc anions as acceptors) or mediated by the unbound (H(2)bpp)(2+) cations and water molecules of hydration. These interactions generate a very complex hydrogen-bonding scheme involving all of the available N-H and O-H groups and which links these two-dimensional grids into a three-dimensional network.
Assuntos
Ânions/química , Compostos Organometálicos/química , Cristalografia por Raios X , Ligantes , Estrutura MolecularRESUMO
The two isomorphous title compounds, [M(C(5)H(7)N(6))(2)(C(9)H(6)O(4))(2)(H(2)O)(2)]·4H(2)O or M(2+)(Hdap(+))(2)(hpt(2-))(2)(H(2)O)(2)·4H(2)O {where dap is 2,6-diaminopurine, H(2)hpt is homophthalic acid [2-(2-carboxyphenyl)acetic acid] and M is Ni(II) or Co(II)}, consist of neutral M(2+)(Hdap(+))(2)(hpt(2-))(2)(H(2)O)(2) monomers, where the M(II) cation lies on an inversion centre and its MN(2)O(4) octahedral environment is defined by one N atom (from Hdap(+)), two O atoms (from one hpt(2-) dianion and one water molecule) and their inversion images. The structures are unusual in that the Hdap(+) cation occurs in an uncommon protonated state (as 2,6-diamino-7H-purin-1-ium) and both ligands bind in an unprecedented monodentate fashion. The existence of a large number of donors and acceptors for hydrogen bonding, together with π-π interactions, leads to a rather complex three-dimensional structure.
Assuntos
2-Aminopurina/análogos & derivados , Cobalto/química , Complexos de Coordenação/química , Níquel/química , Compostos Organometálicos/química , Elementos de Transição/química , 2-Aminopurina/química , Cristalografia por Raios X , Ligação de Hidrogênio , Ligantes , Conformação Molecular , Estrutura MolecularRESUMO
The structures of three related keto diester and diester ylides, namely diethyl 3-oxo-2-(triphenylphosphoranylidene)glutarate, C(27)H(27)O(5)P, (I), diethyl 3-oxo-2-(triphenylphosphoranylidene)glutarate acetic acid monosolvate, C(27)H(27)O(5)P·C(2)H(4)O(2), (II), and diethyl 2-(triphenylphosphoranylidene)succinate, C(26)H(27)O(4)P, (III), are presented. The syn-keto anti-ester conformations in the crystalline keto diesters are governed by electronic delocalization between the P-C and ylidic bonds and an acyl group, and by intra- and intermolecular interactions. There are also intramolecular attractive and repulsive interactions of different types (C-H...O and C-H...π) controlling the molecular conformations. The mono-ylidic diester (III) has an anti-ester conformation, while those for (I) and (II) are related to pyrolytic formation of acetylene derivatives. The terminal nonylidic ester group in (I) was disordered over two sets of almost equally populated positions.
RESUMO
The title Nd complex [Nd(2)(C(4)H(5)O(2))(6)(H(2)O)(4)]·2C(5)H(6)N(6) is isotypic with two previously reported Dy and Ho isologues. It is composed of [Nd(crot)(3)(H(2)O)(2)](2) dimers [crot(onate) = but-2-enoate = C(4)H(5)O(2)], built up around symmetry centres and completed by 2,6-diamine-purine mol-ecules acting as solvates. The neodymium cations are coordinated by three chelating crotonato units and two water mol-ecules. One of the chelating carboxyl-ates acts also in a bridging mode, sharing one oxygen with both cations, and the final result is a pair of NdO(9) tricapped prismatic polyhedra linked to each other through a central (Nd-O)(2) loop. A most attractive aspect of the structures resides in the existence of a complex inter-molecular hydrogen-bonding interaction scheme involving two sets of tightly inter-linked, non-inter-secting one-dimensional structures, one of them formed by the [Nd(crot)(3)(H(2)O)(2)](2) dimers running along [100] and the second by the solvate mol-ecules evolving along [010].