Raman spectra of pyridazines

IR spectra of pyridazines and polypyridazines were studied with respect to interactions with the side chain. The IR spectral shift due to hydrogenbonding between methanol and pyridazine (and other azines) was determined the Av was compared with the pK . In connection with the structure of maleic hydrazide and its methyl derivatives, the Raman spectrum of the 1,2-dimethyl derivative was recorded and helped to explain the anomalously low reported IR carbonyl frequency. The laser Raman polarization spectrum of the lattice vibrational region of pyridazine was reported. ... 

The wideline NMR, IR, and Raman spectra of maleic hydrazide were determined and discussed in connection with its tautomeric forms. NMR techniques have been used to predict the structure of cyclization products from 3-carboxyacryloylhydrazines. The NMR spectra of JV-methyl-pyridazinium iodides and pyridazine iV-oxide were investigated, and the... 

The molecular symmetry of octahydropyridazino[ 1,2-a ]pyridazine (24) has been analyzed using band numbers, frequency coincidences and Raman depolarization factors in the IR and Raman spectra. A centrosymmetric trans conformation was confirmed for this compound (76SA(A)157). IR spectral data also indicate that the carbonyl absorption for pyridazino[l,2-a]pyridazine-l,4-diones (26) occurs at ca. 1625 cm-1 (72TL1885). 

Salts of [OsL(NH3)5]3+ (L = pyrazine, pyrimidine, pyridazine) can be made by displacement of nitrogen from [Os(N2)(NH3)5]2+9° or from the triflato complex [0s(0S02CF3)(NH3)J]2+ and the ligands.62 Cyclic voltammetry showed reduction to the osmium(II) species, 90 and the surface-enhanced Raman spectra (SERS) of [Os(pyz)(HNH3)5]3+, [Os(pyz)(NH3)5]2+ and of their ammine-d5 derivatives were measured, as were the IR spectra.91... 

Assignments for pyridazine and pyrazine were suggested by Ito et al. [40], who noted that the latter differed from other heteroaromatics in having no infrarred absorptions above 1480 cm". However, this is a consequence of its symmetry and the usual four bands in the 1600—1400 cm" range are shown in the Raman spectrum. Several bands also appear in the infra-red when the symmetry is lost by substitution. Alkyl pyrazines show three or four bands in this range. Pyridazines have been studied as 3 6-substituted compounds and show two bands between 1600—1540 cm" and 1430— 1395 cm" [63]. Both series show medium to weak bands between 1300 and 1000 cm" from in plane CH bends and ring modes. These are better seen in the Raman spectra [44]. Below 1000 cm" the out of plane CH bends appear. Pyridazine has its as a band at 760 cm" which would correspond to four adjacent hydrogens, and pyrazine at 804 cm". ... 

---