title: Cyclic tetramer of a metalloporphyrin based on a quadruple hydrogen bond.
abstract: [reaction: see text] This paper describes the selective formation of a cyclic tetramer from a readily synthesized metalloporphyrin with two self-complementary quadruple hydrogen-bonding units. The extremely strong quadruple hydrogen-bonding unit, 2-ureido-4[1H]-pyrimidinone, enabled the formation of a stable cyclic tetramer based on a tetraphenylporphyrin derivative over a wide concentration range. This hydrogen-bonded tetramer is a new functional unit for use in a higher-ordered architecture of a supramolecular porphyrin assembly.
authors.affiliation: Consolidated Research Institute for Advanced Science and Medical Care, Waseda University (ASMeW), Shinjuku, Tokyo, Japan.
authors.forename: Haruki
authors.initials: H
authors.lastname: Ohkawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Takayama
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakajima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nishide