Supramolecular assembly of ferrocenes via hydrogen bonds: dimensional variation in ferrocenylpyrimidine complexes with carboxylic acids and aromatic alcohols

Abstract

Co-crystallization of 5-ferrocenylpyrimidine (FcPM) with various carboxylic acids and aromatic alcohols produces hydrogen-bonded supramolecular architectures. Thus, reaction of FcPM with compounds containing two hydrogen-bonding sites gives 2:1 co-crystals with discrete structures of the type [(FcPM)2·D] [where D = succinic acid (1), hydroquinone (2), resorcinol (3) and 2,2′-thiodiglycolic acid (4)]. A complex with a chiral chain structure, [FcPM·{(R)-(+)-1,1′-bi-2-naphthol}]n (5), is obtained by the combination of FcPM with (R)-(+)-1,1′-bi-2-naphthol. The binaphthol molecules form hydrogen-bonded helical chains, which carry ferrocene units as pendants. The combination of FcPM with trimesic acid and pyromellitic acid produces supramolecular complexes with tape structures, [FcPM·(trimesic acid)]n (6) and [FcPM2·(pyromellitic acid)]n (7), respectively. The tape structure of 6 consists of repeating units of large hexagonal rings while that of 7 consists of rhomboidal rings. Combination of FcPM with phloroglucinol produces a layered structure complex, [FcPM·(phloroglucinol)·2H2O]n (8), exhibiting three-dimensional hydrogen bonding. In this complex, FcPM molecules link hydrogen-bonded sheets composed of phloroglucinol and water molecules. The dimensionality of the assembled structures is influenced by the number of hydrogen-bonding substituents on the donor molecules.