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Syntheses, Crystallization, and Spectroscopic Characterization of 3,5-Lutidine N-Oxide Dehydrate
Published on: April 24, 2018
Crystal structures of [(μ2-L1)di-bromidodicopper(II)] dibromide and
Tokouré Assoumatine1, Helen Stoeckli-Evans2
1Institute of Chemistry, University of Neuchâtel, Av. de Bellevax 51, CH-2000 Neuchâtel, Switzerland.
Abstract:
The reaction of the hexa-thia-pyrazino-phane ligand, 2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane (L1), with copper(II) dibromide led to the formation of a binuclear complex, [μ2-2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane]bis-[bromi-docopper(II)] dibromide, [Cu2Br2(C16H24N2S6)]Br2, (I). The complex possesses inversion symmetry with the pyrazine ring being situated about a center of symmetry. The ligand coordinates to the copper(II) atom in a bis-tetra-dentate manner and the copper atom has a fivefold NS3Br coordination environment with a distorted shape. The reaction of ligand L1 with copper(I) iodide also gave a binuclear complex, which is bridged by a Cu2I2 unit to form a two-dimensional coordination polymer, poly[[μ2-2,5,8,11,14,17-hexa-thia-[9.9](2,6,3,5)-pyrazino-phane]tetra-μ-iodido-tetra-copper(I)], [Cu4I4(C16H24N2S6)] , (II). The binuclear unit possesses inversion symmetry with the pyrazine ring being located about a center of symmetry. The Cu2I2 unit is also located about an inversion center. The two independent copper(I) atoms are both fourfold coordinate. That coordinating to the ligand L1 in a bis-tridentate manner has an NS2I coordination environment and an irregular shape, while the second copper(I) atom, where L1 coordinates in a bis-monodentate manner, has an SI3 coordination environment with an almost perfect tetra-hedral geometry. In the crystal of I, the cations and Br- anions are linked by a number of C-H⋯S and C-H⋯Br hydrogen bonds, forming a supra-molecular network. In the crystal of II, the two-dimensional coordination polymers lie parallel to the ab plane and there are no significant inter-layer contacts present.
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