Organic-inorganic hybrid materials assembled through weak intermolecular interactions. Synthesis, structures and non-linear optical properties of [4,4 '-bipyH(2)][M(NCS)(4)] (M = Mn2+, Co2+ or Zn2+; 4,4 '-bipy=4,4 '-bipyridine)

Three compounds [4,4'-bipyH(2)][M(NCS)(4)] (M=Mn2+, Co2+ or Zn2+; 4,4'-bipy =4,4'-bipyridine) were obtained from the reactions of 4,4'-bipy with M(SCN) (2) in acidic solution and their crystal structures determined by single-cr ystal X-ray diffraction. All crystallise isomorphously in the chiral orthor hombic space group P2(1)2(1)2. The tetrahedral [M(NCS)(4)](2-) anions are i nter-connected by S ... S contacts (ca. 3.63 Angstrom) and are hydrogen bon ded with the diprotonated [4,4'-bipyH(2)](2+) cations [N ... S 3.241 Angstr om in 1; 3.235 Angstrom in 2; 3.239 Angstrom in 3] to form two-dimensional, highly wavy networks with hourglass-shaped cavities (ca. 12.3 Angstrom lon g; 9.4 Angstrom wide at the ends, 6.8 Angstrom at the waist). These two-dim ensional networks are stacked with each other to furnish a channel accommod ating the diprotonated [4,4'-bipyH(2)](2+) cations. The three organic-inorg anic hybrid compounds are thermally stable with melting points above 230 de grees C. The powder second harmonic generation efficiencies were measured a s moderate.