title: Low-temperature spectral observation of the first six-coordinate nitrosyl complexes of cobalt(II) meso-tetratolylporphyrin with trans nitrogen base ligands.
abstract: Low-temperature interaction of nitrogen base ligands with layered Co(TTP)(NO) (TTP = meso-tetratolylporphyrinato dianion) as well as its toluene solution leads to the formation of the first six-coordinate species of the general formula (B)Co(TTP)(NO) (where B = piperidine and pyridine). The nu(NO) stretching bands of these species appear at lower frequencies compared with the five-coordinate nitrosyl derivative and depend on the nature of the trans axial ligand. The equilibrium constants and enthalpies of formation of these new species are determined. Fairly stable at low-temperature conditions in the solid state, they slowly dissociate the nitrogen base ligands upon warming to restore the five-coordinate nitrosyl complex Co(TTP)(NO).
authors.affiliation: Molecule Structure Research Center NAS, 26 Azatutyan av, 375014 Yerevan, Armenia.
authors.forename: Tigran S
authors.initials: TS
authors.lastname: Kurtikyan
authors.forename: Emil R
authors.initials: ER
authors.lastname: Markaryan
authors.forename: Artur N
authors.initials: AN
authors.lastname: Mardyukov
authors.forename: John A
authors.initials: JA
authors.lastname: Goodwin
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D008024:Ligands; D009584:Nitrogen / Q000737:chemistry*; D009603:Nitroso Compounds / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature
chemical_list: D008024:Ligands; D009603:Nitroso Compounds; D009942:Organometallic Compounds; D011166:Porphyrins; D003035:Cobalt; D009584:Nitrogen