Effect of non-peripheral fluorosubstitution on the structure of metal phthalocyanines and their films

Abstract

In this work, we study crystal structures and thin films of tetrasubstituted metal phthalocyanines with fluorine substituents in non-peripheral positions, MPcF4-np (M = Cu(II), Co(II), Pd(II), Fe(II), Pb(II), VO). The effect of fluorosubstitution in non-peripheral positions of the phthalocyanine macrocycle on the structure of single crystals and thin films, and intermolecular interactions is elucidated and compared with that of other fluorinated phthalocyanine derivatives. MPcF4-np (M = Cu(II), Pd(II), Fe(II)) are isostructural and crystallize in the monoclinic P21/c space group, while CoPcF4-np forms two polymorphs (P21 and P21/c). Monoclinic PbPcF4-np (P21/n) is packed in chains along the c axis, in which one PbPcF4-np molecule is oriented “up” and two neighboring molecules face “down”. Two triclinic (P-1) phases were obtained for VOPcF4-np. For the better visualization and comparison of intermolecular contacts in different MPcF4-np, the analysis of Hirshfeld surfaces (HS) was carried out. All investigated MPcF4-np derivatives form thin films with a strong preferred orientation. The effect of the positions of F-substituents on the electronic absorption spectra of MPcF4 solutions and thin films is also discussed.