Crystal structure of [2-({4-[2,6-bis(pyri-din-2-yl)pyri-din-4-yl]phenyl}(methyl)amino)-ethanol-κ(3) N,N',N'']bis-(thio-cyan-ato-κN)zinc N,N-di-methyl-formamide monosolvate.

In the title compound, [Zn(NCS)2(C24H22N4O)]·C3H7NO, the Zn(II) cation is N,N',N''-chelated by one 2-({4-[2,6-bis-(pyridin-2-yl)pyridin-4-yl]phen-yl}(meth-yl)amino)-ethanol ligand and coordinated by two thio-cyanate anions in a distorted N5 trigonal-bipyramidal geometry. In the mol-ecule, the three pyridine rings are approximately coplanar [maximum deviation = 0.026 (5) Å], and the mean plane of the three pyridine rings is twisted to the benzene ring with a small dihedral angle of 5.9 (2)°. In the crystal, complex mol-ecules are linked by weak C-H⋯O hydrogen bonds into supra-molecular chains propagated along [110]; π-π stacking is observed between adjacent chains [centroid-centroid distance = 3.678 (4) Å]. The di-methyl-formamide solvent mol-ecules are linked with the complex chains via weak C-H⋯O hydrogen bonds.

[Optimization of melamine structure using density functional theory and vibrational spectra studies].

Melamine was used in foodstuff and feed industry as a feed additive occasionally. In the present work, melamine geometry structure was optimized by density functional theory (DFT) method. Raman and infrared spectra were calculated based on MP2/6-31G sets and DFT/DGTIVP sets, and then two theoretical Raman spectra were carefully compared with other experimental spectra. Good agreements were obtained between the theoretical and experimental results. Melamine structure parameters were given also in the paper including bond lengths and bond angles. Vibrational modes were assigned to all bands in the 550-4 000 cm(-1) range. This work will benefit the measurement research of the content of melamine in foods.