title: Potassium Phthalocyanine, KPc: one-dimensional molecular stacks bridged by K+ ions.
abstract: We report the synthesis of potassium phthalocyanine (KPc) and its structural characterization by synchrotron X-ray powder diffraction. We find that while KPc adopts the beta-polymorphic structural type (monoclinic space group P21/a) common for many MPc solids, its structure is characterized by unique features. The K+ ions, which are statistically disordered over two symmetry-equivalent positions, reside in the intrastack spacing of the rodlike molecular assemblies and strongly bond equidistantly to selected N atoms of the two neighboring Pc rings along the chain direction with an unusual 5-fold coordination. The K+-stuffed slipped stacks of Pc units display much greater intrastack and slippage distances than those of other beta-MPc polymorphs. They may be thought as comprising disordered dimeric (Pc)22- units; this leads to electron pairing and is consistent with the observed nonmagnetic response of the system.
authors.affiliation: School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, U.K. serena.margadonna@ed.ac.uk
authors.forename: Serena
authors.initials: S
authors.lastname: Margadonna
authors.forename: Kosmas
authors.initials: K
authors.lastname: Prassides
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Iwasa
authors.forename: Yasujiro
authors.initials: Y
authors.lastname: Taguchi
authors.forename: Monica F
authors.initials: MF
authors.lastname: Craciun
authors.forename: Sven
authors.initials: S
authors.lastname: Rogge
authors.forename: Alberto F
authors.initials: AF
authors.lastname: Morpurgo