cis-Diaquabis(di-2-pyrimidinyl sulfide-κ2N,N′) Cobalt(II) Ditetrafluoridoborate: Lone Pair-aromatic and Anion-π Interactions in the Self-assembly of Coordination Complex

The title complex, [Co(DprS)(2)(H2O)(2)](2)(BF4)(4) (DprS is di-2-pyrimidinyl sulfide), was obtained and characterized by elemental analysis, FT-IR and X-ray crystallography. The complex crystallizes in space group P2(1)/c with a = 11.742(1), b = 22.439(2), c = 20.538(2) angstrom, beta = 109.713(5)degrees, Z = 4, V = 5094.3(3) angstrom(3), D-c = 1.692 g.cm(-3), mu = 0.929 mm(-1), F(000) = 2600, R = 0.0756 and wR = 0.1929. The asymmetric unit of the title complex is comprised of two isomeric cobalt(II) centers (Co(1) and Co(2)) with a cis-[Co(DprS)(2)(H2O)(2)](2+) moiety. Each Co(II) center exhibits a similar distorted N4O2-octahedral coordination geometry surrounded by a pair of DprS in a N,N'-chelate mode and two aqua ligands in a cis-relationship. Unconventional S center dot center dot center dot pi(pyrimidinyl), N center dot center dot center dot pi(pyrimidinyl), and anion(BF4-)center dot center dot center dot pi(pyrimidinyl) are found to combine with the C-H center dot center dot center dot F and O-H center dot center dot center dot F interactions to stabilize a whole three-dimensional framework with the mononuclear units (Co(1) and Co(2)). The ligand conformation will be also discussed.