Crystal packing in the structures of diethanolamine derivatives.

TL;DR: Four distinct hydrogen-bonding topologies were observed in the structures of six diethanolamine ligands, which contains two distinct non-equivalent systems of intermolecular O-H...O hydrogen bonds formed by disordered hydroxy H atoms.

Abstract: Four distinct hydrogen-bonding topologies were observed in the structures of six diethanol­amine ligands. These compounds are (1R*,2R*)-2-[(2-hydroxy­ethyl)(methyl)amino]-1,2-diphenyl­ethanol, C17H21NO2, (I), 1-[(2S)-2-(hydr­oxy­diphenyl­methyl)­pyrrolidin-1-yl]-2-methyl­propan-2-ol, C21H27NO2, (II), 2-[(2-hydroxy­ethyl)(methyl)amino]-1,1-diphenyl­ethanol, C17H21NO2, (III), 1-{(2-hydr­oxy-2-methyl­propyl)[(1S)-1-phenyl­ethyl]­amino}-2-methyl­propan-2-ol, C16H27NO2, (IV), 1-{[(2R)-2-hydroxy-2-phenyl­ethyl][(1S)-1-phenyl­ethyl]amino}-2-methyl­propan-2-ol, C20H27NO2, (V), and (1R*,2S*)-2-[(2-hydroxy­ethyl)­(methyl)­amino]-1,2-diphenyl­ethanol, C17H21NO2, (VI). In each compound, all `active' hydroxy H atoms are engaged in hydrogen bonding, but the N atoms are not involved in inter­molecular hydrogen bonding. In the structures of (I), (II) and (IV)–(VI), mol­ecules are linked into chains by inter­molecular O—H⋯O inter­actions. These chains are organized in such a way as to hide the hydro­philic groups inside, and so the outer surfaces of the chains are hydro­phobic. The structure of (VI) contains two distinct non-equivalent systems of inter­molecular O—H⋯O hydrogen bonds formed by disordered hydroxy H atoms.