Abstract
Four bisphosphinic acids RR´C[P(CH3)(O)OH]2 are characterized by 1H, 13C{1H}, and 31P{1H} NMR data. H3C-P-C-P-CH3 skeletons give rise to [A3X]2 spin systems. Some algebraic equations are derived for manual analysis of [A3X]2 spectra. HR NMR data for heteroaromatic substituents R in RC(H)[P(CH3)(O)OH]2 are reported. Dissociation constants and ion-specific chemical shifts δP of CH3C(OH)[P(CH3)(O)OH]2 are determined by 31P{1H} NMR controlled titrations of 2a.
Graphical Abstract
Acknowledgement
Thanks are due to Miss Beate Rau for help with literature, sample preparation and in particular for running patiently good NMR spectra. In addition we wish to thank Prof. Dr. Jürgen Voss, Hamburg, for helpful suggestions and literature concerning the structural interpretation of NMR data of thiazole and benzothiazol derivatives. Special thanks are due to Prof. Dr. F. H. Ebetino for publications on bisphosphonates and related structures.
Disclosure statement
No potential conflict of interest was reported by the authors.