The invention relates to quaternary ammonium multi-dentate mono-, bis-, tris- and tetrakis-phosphonate compounds, processes for preparing quaternary ammonium multi-dentate mono-, bis-, tris- and tetrakis-phosphonate compounds, antimicrobial coating compositions comprising quaternary ammonium multi-dentate mono-, bis-, tris- and tetrakis-phosphonate compounds and method of treating a surface with said compositions to provide a durable, antimicrobial-treated surface.

Lipophosphonoxins of general formula I, diastereomers and mixtures of diastereomers of compounds of general formula I and their pharmaceutically acceptable salts and hydrates as antibacterial agents, forming an active ingredient in pharmaceutical compositions for the treatment of resistant bacterial infections, disinfectants and/or selective culture media is disclosed.