posted on 2012-08-06, 00:00authored byGoutam Mukherjee, Puspendra Singh, Chandrasekhar Ganguri, Sagar Sharma, Harkesh B. Singh, Nidhi Goel, Udai P. Singh, Ray J. Butcher
The synthesis and characterization of the complexes of
Cu(I), Ag(I),
Cu(II), and Co(II) ions with 1,2,5-selenadiazolopyridine (psd) is
reported. The following complexes have been prepared: [Cu2(psd)3(CH3CN)2]2+2(PF6–); [(CuCl)2(psd)3]; [Cu2(psd)6]2+2(ClO4)−; [Ag2(psd)2]2+2(NO3)−; [Ag2(psd)2]2+2(CF3COO)−; [Cu(psd)2(H2O)3]2+2(ClO4)−·(psd)2; [Cu(psd)4(H2O)]2+2(ClO4)−·(CHCl3); [Cu(psd)2(H2O)3]2+2(NO3)−·(H2O)·(psd)2, and [Co(psd)2(H2O)4]2+2(ClO4)−·(psd)2. The electronic structure of ligand psd,
in particular the bond order of Se–N bonds, has been probed
by X-ray diffraction, 77Se NMR, and computational studies.
A detailed analysis of the crystal structures of the ligand and the
complexes revealed interesting supramolecular assembly. The assembly
was further facilitated by the presence of neutral ligands for some
complexes (Cu(II) and Co(II)). The molecular structure of the ligand
showed that it was present as a dimer in the solid state where the
monomers were linked by strong secondary bonding Se···N
interactions. The crystal structures of Cu(I) and Ag(I) complexes
revealed the dinuclear nature with characteristic metallophilic interactions
[M···M] (M = Cu, Ag), while the Cu(II) and Co(II) complexes
were mononuclear. The presence of M···M interactions
has been further probed by Atoms in Molecules (AIM) calculations.
The paramagnetic Cu(II) and Co(II) complexes have been characterized
by UV–vis, ESI spectroscopy, and room temperature magnetic
measurements.