Synthesis and structure of ferrocenylphosphinic acids

The series of ferrocenylphosphinic acids Fc(P(R)(O)(OH)) (1a-d) and ferrocene-1,1'-diyl-phosphinic acids Fc(P(R)(O)(OH))(2)(2a-d) (R H (a), Me (b), Et (c), Ph (d)) have been obtained and studied using X-ray single crystal diffraction, IR-spectroscopy and quantum chemistry. The intermolecular hydrogen bonding in 1a-d proceeds highly stereoselectively and results in formation of racemic conglomerate of 1d. The formation of inter-and intra-molecular hydrogen bonds for disubstituted acids 2c-d depends on substituent at phosphorus atoms. (C) 2014 Elsevier B. V. All rights reserved.