Cofacial assembly of partially oxidized metallomacrocycles as an approach to controlling lattice architecture in low-dimensional molecular solids. Synthesis and properties of cofacially joined silicon and germanium hemiporphyrazine polymers

This contribution reports an integrated chemical, spectroscopic, X-ray diffractometric, and charge transport investigation of the cofacially linked metallomacrocyclic polymers [M(hp)O]_n where M = Si and Ge and hp = hemiporphyrazinato. The synthesis of the new = Si compound (from Si(hp)Cl₂ and Si(hp)(OH)₂) and modified syntheses of the M = Ge analogue are reported. Optical spectra are discussed as a function of M and X for the various M(hp)X₂ derivatives. Radiotracer studies of the degree of polymerization using M(hp)(O³H)₂ precursors yield Ò values for typical [M(hp)O]_n samples of 20 (M = Si) and 50 (M = Ge). On the basis of data for monomeric M(hp)X₂ derivatives, both vibrational and high-resolution solid-state ¹³C NMR spectra of the [M(hp)O]_n polymers can be assigned in terms of a cofacially linked polymer architecture. X-ray diffraction data suggest that the [M(hp)O]_n polymers are crystalline and structurally similar; however, the crystal structures are not similar to that of [Fe(hp)O]_n nor to those of the analogous [M(Pc)O]_n polymers, Pc = phthalocyaninato. Doping of the [M(hp)O]_n polymers with iodine using several procedures results in iodine uptake but no significant increase in electrical conductivity. It appears that iodination is accompanied by destruction of the polymer M-O-M framework.