Synthesis and spectral properties of new soluble naphthalocyaninatometal derivatives

Several naphthalocyanines, including soluble asymmetrical derivatives, were prepared by conventional condensation methods or by ring-expansion of the corresponding subnaphthalocyanine. the latter method offers two major advan tages, over the mixed condensation method, viz., convenient purification an d relatively high yield, electronic absorption spectral data indicate that the majority of the new colorants have Q-bands above 750 nm. the substituen t effect at peripheral sites was small with respect to the position of the Q-bands, but the nature of the central metal atoms significantly affected t he Q-bands. In addition, asymmetrical tri-t-butyl naphthalocyaninatozinc sh ows interesting spectral properties in solvents without heteroatoms, due to the formation of plane-to-plane and head-to-tail aggregated dimers simulta neously, which can be prevented in solvents such as ether, alcohol and amin es. (C) 2001 Elsevier Science Ltd. All rights reserved.