Synthesis and metal coordination chemistry of (phenyl)(pyridin-2-ylmethyl)phosphinodithioic acid, [2-C5H4N]CH2P(S)(SH)(Ph)

► New (pyridin-2-ylmethyl)phosphinodithioic acid synthesis and structural characterization. ► Zwitterion formation. ► Ligand protonation constants determination. ► Ligand coordination chemistry toward Cd(II) and Pt(II). ► Metal complexation constant analysis for Cd(II), Zn(II) and La(III).