Designing the self-assembly of neutral molecules or ions into preordained motifs by non-covalent interactions is an area of current interest, especially in the context of generating new molecular materials. In recent years, many compounds based on cations of guanidine and its derivatives are the object of chemical research owing to their biological role in living organisms, supramolecular structure, function as molecular switches, 1,2 and their interesting physico-chemical properties. Particularly, the guanidinium cation has been proven to be a powerful structure-determining template in the formation of both coordination polymer networks and hydrogen bonded networks.3 In order to explore the interactions between 2¢,4¢,5¢, 7¢-tetrabormofluorescein (eosin) and guanidinium cation, herein we report on the synthesis and crystal structure of the title compound, tetrakis(guanidinium)bis(eosinate) hexahydrate (I).Guanidine carbonate (0.045 g, 0.250 mmol) was dissolved in 2 mL of water and 2¢,4¢,5¢,7¢-tetrabormofluorescein (0.081 g, 0.125 mmol) was dissolved in 5 mL of 1:1 acetone by warming. Then, a clear solution of 2¢,4¢,5¢,7¢-tetrabormofluorescein was slowly added to the guanidine carbonate solution. The mixture was kept at room temperature for slow evaporation. After one week, needle-shaped pink-colored crystals of tetrakis(guanidini um)bis(eosinate) hexahydrate (I) were obtained. Single crystals with dimensions of (0.34 ¥ 0.20 ¥ 0.12) mm 3 were chosen for X-ray diffraction studies. Determinations of the unit-cell parameters and data collections were performed with Mo Ka radiation (l = 0.71073 Å) at 293 K on a Bruker Apex II CCD area-detector diffractometer. The structure was solved using direct methods.All non-hydrogen atoms were refined anisotropically by full matrix least-squares methods on F 2 . Primary non-hydrogen atoms were solved by direct method, and secondary non-hydrogen atoms were solved by a difference maps. The hydrogen atoms were added geometrically. The H- A co-crystal of tetrakis(guanidinium) bis(eosinate) hexahydrate (I) was synthesized, and the molecular and crystal structures of (I) were determined by a single-crystal X-ray diffraction technique. The crystal system is triclinic with a space group of P1 and Z = 4. The unit-cell dimensions are a = 14.4774 (8)
In the title complex, {[Cu(C8H8NO3S)2(H2O)] x 2 H2O}n, the Cu(II) cation has a distorted square-pyramidal coordination environment consisting of five O atoms, one from a water molecule, one from an N-O group and the other three from the carboxylate groups of two 3-(2-pyridylsulfanyl)propionate N-oxide anions. The aqua[3-(2-pyridylsulfanyl)propionato N-oxide]copper(II) moieties are bridged by 3-(2-pyridylsulfanyl)propionate N-oxide anions to form an infinite three-dimensional coordination polymer with a zigzag chain structure. The crystal structure is stabilized by hydrogen bonds.
Compounds containing N-oxides and sulfur possess important biological activity. N-Hydroxy pyridine-2-thione behaves as a source of the ˙OH radical upon irradiation. Further, compounds containing sulfur, such as 2-mercaptopyridine, 2mercaptopyridine N-oxide, 2,2′-dithiopyridine-1,1′-dioxide and related derivatives, as well as their metal complexes exhibit numerous biochemical applications. 1 Earlier we synthesized 1oxopyridinium-2-thiopropionic acid (OPTPH) and characterized its structure. 2 However, its coordination chemistry remains relatively unexplored. Thus, we wanted to investigate the coordination ability of this N-oxide that contains-COOH, NO , as well as C-S-C as donor entities, which could form stable chelates with various ions. Frequently, more complex macrostructures can be attained by the incorporation of organic components to yield composite inorganic-organic hybrid materials, providing a powerful synthetic approach. 3 Herein, we report on the synthesis and structural characterization of the title complex, Co(H2O)6(OPTP)2(I) [where OPTP = 1-oxopyridinium-2-thiopropionate]. A mixture of 1-oxo-pyridinium-2-thiopropionic acid (0.1 g, 0.5025 mmol), cobalt(II) chloride (0.0598 g, 0.251 mmol), sodium hydroxide (0.020 g, 0.5025 mmol) and methanol (20.0 mL) was mechanically stirred overnight. The solution was filtered and the filtrate kept aside for slow evaporation. After one week, shiny pink colored crystals of the titled complex(I) were formed. They were washed with cold water and dried (0.1103 g, 78%). High-quality single crystals were hand picked under a microscope for an X-ray investigation. X-ray data for (I) was collected by graphite-monochromatized Mo Kα radiation at 298 K. An analytical absorption-correction was applied. The structure was solved by direct methods and refined by full-matrix least-squares with anisotropic temperature factors for the non-hydrogen atoms. All H atoms other than those of water molecules were positioned geometrically (C-H = 0.93-0.97 Å) and refined as riding, with Uiso(H) = 1.2Ueq(C).
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