Crystal structure of diaqua-dinitrato-κ1O-bis(2-(pyridin-4-ylthio)- pyrazine-κ1N)cadmium(II), C18H18CdN8O8S2

Abstract

Source of materialAll organic reagents and solvents purchased from commercial sources were used without further purification. Sodium pyridine-4-thiolate (0.66 g, 5 mmol) dissolved in methanol was added to 10 ml acetonictrile containing 2-chloro-pyrazine (0.58 g, 5 mmol) with stirring at room temperature. After 5 hours, the solvent were removed under vacuum. The products were then separated and purified by column chromatography on silica gel (eluent: dichloromethane/methanol = 95:5, v/v), and the di-[2-(pyridine-4-ylthio)pyrazine] was obtained in 33.1% yield. Di-[2-(pyridine-4-ylthio)pyrazine] (38 mg, 0.2 mmol) and Cd(NO 3 ) 2 ×6H 2 O (345 mg, 0.1 mmol) were dissolved and mixed in acetonitrile, the filtrate of which was then left to stand in air to let the solvent evaporate slowly. The colourless block-shaped crystals of the title compound were deposited, yield 20.1 mg (31% based on di-[2-(pyridine-4-ylthio)pyrazine]). Experimental detailsAll hydrogen atoms were added using riding models. The U iso values of the hydrogen atoms were set to 1.2U eq (C,N). DiscussionPyridyl-based ligands have been widely used to construct different transition complexes with fascinating structures and attractive properties [3][4][5]. Dipyridyl ligands with the bent C-S-C fragment exhibit diverse coordination geometries in construction various transition metal complexes [6][7][8], and the coordination chemistry of these N-positional isomers has been extensively studied. In the present context, we report a new complex derived from 2-(pyridine-4-ylthio)pyrazine and cadmium(II)nitrate. In the asymmetric unit of the title complex, there is one 2-(pyridine-4-ylthio)pyrazine, one water molecule, one nitrate anion and half of a Cd(II) ion. The Cd(II) lies in an inversion center and adopts an N 2 O 2 (H 2 O) 2 octahedral geometry with two 4-pyridyl N locating at the axial positions (Fig.). The Cd1-N1 bond length is 2.249(3) Å, and the Cd1-O1w equals 2.402(3) Å. The C3-S1-C6 angle is 106.85(18)°, comparable to that 104.27(7)°of C-S-C in di-pyrazinyl sulfide [8].