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organic compounds
The title compound, C17H10F5N5O2, 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 FF, OF, Fπ and Oπ interactions.
F—C interaction, generating double-chain strips running along [100]. These substructures are interlinked by a variety of weak FF, OF, Fπ and Oπ interactions.metal-organic compounds
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 CoII 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 CoII cation arranged in a regular centrosymmetric octahedral array, coordinated by two aqua ligands, two dap ligands and two O atoms from the β-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 β-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-κ5O:O,O′:O′,O′′,O′′′:O′′′′ mode of coordination of the cit tetraanion.
metal-organic compounds
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 OsIII centres present a highly distorted hexacoordinated Os(Os2C4) core and are in turn bridged by a hydride ligand. The remaining OsIII 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).
organic compounds
In the title compound, there are two independent molecules forming hydrogen- and π-bonded dimeric entities with a noticeable noncrystallographic C2 symmetry. Dimers are linked by medium-strength type-I C—FF—C interactions, forming elongated tetramers.
F—C interactions, forming elongated tetramers.metal-organic compounds
In a mononuclear NdIII complex, three chelating 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate ligands and three aqua ligands build up a distorted monocapped square antiprism around the cation. A complex hydrogen-bonding network results in a densely packed structure (packing index = 77.7%)
