Serendipitous Self-Assembly of Cyclometalated Complexes through Hydrogen Bonds: Dimers or Chains within Compact or Porous Networks

X-ray diffraction analysis of cyclometalated, chiral-at-metal rhodium and iridium complexes with the general formula [Cp*MCl{κ2(N,C)-(2-phenyl-2-imidazoline}] reveals that they undergo noncovalent self-assembly through intermolecular NH···Cl hydrogen bonding and, in some cases, CH/π interactions. Compound (±)-6b coordinated with an unsubstituted, achiral phenylimidazoline ligand forms dimers, whereas (SM)-7a,b and (RM)-8a,b (a, M = Ir; b, M = Rh) generated from chiral, (RC,RC)-phenylimidazoline ligands crystallize as infinite 1D chains. The pitch of the chains is ca. 35–50% higher for 8a,b than for 7a,b. 8a,b display a C2-helical motif. However, 8b differs from 8a by (1) the existence of intermolecular CH/π interactions within the helix and (2) a head-to-head self-assembly of the helices, yielding hydrophobic, worm-screw channels.