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F.F.B.J. Janssen, R. de Gelder, A.E. Rowan,

The multiple phenyl embrace as a synthon in Cu(I)/PPh₃/N-Donor ligand coordination polymers,

Cryst. Growth Des. 11 (2011) 4326-4333

Abstract

The multiple phenyl embrace is a supramolecular motif comprised of phenyl phenyl interactions, which can, like hydrogen bonds, form extended networks between molecules in the solid state. The analysis of 23 crystal structures of coordination polymers based on the M/PPh(3)/N-donor ligand system (M = Cu(I) or Ag(I)) showed that 71% of the independent M-PPh(3) groups are involved in a 6-fold phenyl embrace (6PE). Strong 6PE interactions are obtained when the geometry of the PPh(3) group can be described as a rotor. The analysis of these groups showed that 83% of the PPh(3) groups have their phenyl groups in the rotor conformation. It is shown, however, that these good rotors are not necessarily involved in the 6PE and that the 6PE can also be formed by nonrotors. In the Cu(I)/PPh(3)/N-donor ligand system, the 6PE interactions form an independent connection (often) perpendicular to the backbone of the coordination polymer. In many cases, the 6PE increases the dimensionality of the network formed between Cu(I) and N-donor ligands. Therefore, the multiple phenyl embrace seems to be a useful synthon in crystal engineering of stable networks.