Spontaneous resolution of a diastereomeric ruthenium(II) complex with an atropisomeric 4,4biquinazoline ligand

The ligand 4,4ʹ-biquinazoline, 1, forms the complex [Ru(bipy)2(1)]2+ which consists of atropisomeric ((delta)(lambda)/(lambda)(delta)) and (delta)(delta)/(lambda)(delta)) pairs of enantiomers but upon spontaneous crystallization, resolution of the major (delta)(lambda)/(lambda)(delta) pair occurs to give (delta)(lambda) and (lambda)(delta) crystals; although the free ligand is covalently hydrated in aqueous solution the ruthenium complex is not