XRD Study of Tetrachlorosubstituted Tin Phthalocyanines

In recent decades, there has been a marked rise of interest in the films of halogen-substituted metal phthalocyanines (MPcHal_x) as promising materials for field-effect transistors and chemical sensors. Even though fluoro-substituted phthalocyanines are poorly soluble, they can sublimate in a vacuum without decomposition, so their thin films can be prepared by physical vapor deposition. Chloro-substituted phthalocyanines are more soluble than their fluoro-substituted analogs, so their films can be prepared by solution methods. The present work reports a synthesis and a study of SnCl₂PcCl₄ tetrachloro-substituted tin(IV) phthalocyanine complexes with substituents at peripheral (SnCl₂PcCl₄-p) and non-peripheral (SnCl₂PcCl₄-np) positions. It was shown that SnCl₂PcCl₄-p crystallizes in the \(P\bar{1}\) space group (Z = 1). It contains layer of molecules packed in a brick masonry mode and is isostructural to its fluoro-substituted analog SnCl₂PcF₄-p. The SnCl₂PcCl₄-np compound crystallizes in the C2/c (Z = 4) space group; its molecules are packed into 2D layers whose structure differs from that of SnCl₂PcF₄-np. For both compounds, thin films on glass substrates are prepared by spin coating. It is shown that the phase composition of thin films coincides with that of the initial powder and that films have a distinct preferential orientation [0 0 1] for SnCl₂PcCl₄-p and [–1 –1 1] for SnCl₂PcCl₄-np, while their molecules are tilted relative to the substrate surface by 72.30(2) and 42.13(1)°, respectively.