Changes of vis. spectra of magnesium naphtalocyanine evaporated films with thermal transition.

Abstract

Magnesium naphthalocyanine (MgNc) was prepared through two different routes, i. e., from 2, 3-dicyanonaphthalene and Mg in alpha-chloronaphthalene (MgNc-a) and from diiminobenzo-isoindoline and magnesium acetate in tetralin (MgNc-b) and vacuum evaporated onto glass plates. The evaporated films were then examined spectroscopically.The results were • (1) Q band spectra differed with the source of MgNc ; specifically the spectra of MgNc-a varied slightly for each deposited film. (2) Absorption maxima of MgNc-a films were at 780nm and 720nm, the former for amorphous MgNc and the latter for crystalline.(3) MgNc-a tends to be amorphous because of the axial ligation of alpha-chloronaphthalene.(4) Alpha-chloronaphthalene splits off MgNc when the film is heated to the transition point and helps promote the rearrangement of MgNc molecules. MgNc-b does not make thermal transition because there are no solvent molecules effective for the relaxation.(5) For effective thermal transition, the vapor deposition of axially ligated Nc is recommended.