Synthesis and some spectroscopic properties of tetra-2,3-pyridoporphyrazinatosilicon involving bulky axial ligands

Citation
T. Nonomura et al., Synthesis and some spectroscopic properties of tetra-2,3-pyridoporphyrazinatosilicon involving bulky axial ligands, J PORPHYR P, 4(5), 2000, pp. 538-543
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry
Journal title
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
ISSN journal
1088-4246 → ACNP
Volume
4
Issue
5
Year of publication
2000
Pages
538 - 543
Database
ISI
SICI code
1088-4246(200008)4:5<538:SASSPO>2.0.ZU;2-L
Abstract
Tetra-2,3-pyridoporphyrazinatosilicon (SiPyD) containing bis(tri-n-hexylsil oxy) (1) or bis(n-heptylcarbonyloxy) (2) axial ligands have been prepared a nd characterized by NMR, IR and electronic absorption spectroscopies and by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). These SiPyDs are soluble in common organic solvents, and face-to-face-type stacking is prevented in solution and films. Accordingly, their NMR spectra could be reasonably assigned. Their electronic absorption spectra in solut ion appear to the blue and red compared with those of the corresponding Si phthalocyanines (SiPcs) and Si tetrapyrazinoporphyrazines (SiPyZs) respecti vely. These characteristics are reproduced by molecular orbital calculation s in the framework of the Pariser-Parr-Pople approximation. On formation of films, the Q bands shift to the red of those in solution by ca 20 nm, sugg esting that other similar tetravalent metallophthalocyanines with two long axial ligands can be used for shifting the Q band to the red. TGA and DTA e xperiments show that the thermal stability of the macrocycles is markedly i nfluenced by the type of axial ligands. Copyright (C) 2000 John Wiley & Son s, Ltd.