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
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.