RESUMO
The crystal structures of five new transition-metal complexes synthesized using thiazole-2-carboxylic acid (2-Htza), imidazole-2-carboxylic acid (2-H2ima) or 1,3-oxazole-4-carboxylic acid (4-Hoxa), namely diaquabis(thiazole-2-carboxylato-κ2N,O)cobalt(II), [Co(C4H2NO2S)2(H2O)2], 1, diaquabis(thiazole-2-carboxylato-κ2N,O)nickel(II), [Ni(C4H2NO2S)2(H2O)2], 2, diaquabis(thiazole-2-carboxylato-κ2N,O)cadmium(II), [Cd(C4H2NO2S)2(H2O)2], 3, diaquabis(1H-imidazole-2-carboxylato-κ2N3,O)cobalt(II), [Co(C4H2N2O2)2(H2O)2], 4, and diaquabis(1,3-oxazole-4-carboxylato-κ2N,O4)cobalt(II), [Co(C4H2NO3)2(H2O)2], 5, are reported. The influence of the nature of the heteroatom and the position of the carboxyl group in relation to the heteroatom on the self-assembly process are discussed based upon Hirshfeld surface analysis and used to explain the observed differences in the single-crystal structures and the supramolecular frameworks and topologies of complexes 1-5.
RESUMO
The crystal structures of N'-amino-pyridine-2-carboximidamide (C6H8N4), 1, and N'-{[1-(pyridin-2-yl)ethyl-idene]amino}-pyridine-2-carboximidamide (C13H13N5), 2, are described. The non-H atoms in compound 1 are nearly planar (r.m.s. deviation from planarity = 0.0108â Å), while 2 is twisted about the central N-N bond by 17.8â (2)°. Both mol-ecules are linked by inter-molecular N-Hâ¯N hydrogen-bonding inter-actions; 1 forms a two-dimensional hydrogen-bonding network and for 2 the network is a one-dimensional chain. The bond lengths of these mol-ecules are similar to those in other literature reports of azine and di-imine systems.
RESUMO
In the title compound, C17H16O7, which was isolated from the leaves of Micromelum integerrimum, the furan ring adopts an envelope conformation with the O atom as the flap. An intra-molecular C-Hâ¯O hydrogen bond occurs. The carbonyl O atom is disordered in a 0.57â (8):0.43â (8) ratio. In the crystal, mol-ecules are linked by weak C-Hâ¯O hydrogen bonds into a C(10) chain along [010].