om0604425_si_005.cif (30.18 kB)
Charge-Assisted Hydrogen Bonding and Other Noncovalent Interactions in the Self-Assembly of the Organometallic Building Block [(η6-hydroquinone)Rh(P(OPh)3)2]+ with a Range of Counteranions
dataset
posted on 2006-10-23, 00:00 authored by Seung Uk Son, Jeffrey A. Reingold, Gene B. Carpenter, Paul T. Czech, Dwight A. SweigartThe synthesis and X-ray structures are reported for [(η6-hydroquinone)Rh(P(OPh)3)2]+X- (X = BF4,
ClO4, SbF6, OTf, OTs, OPf), [(η6-resorcinol)Rh(P(OPh)3)2]+BF4-, and [(η6-4,4‘-biphenol)Rh(P(OPh)3)2]+BF4-.
In these complexes, the −OH groups are activated by the electrophilic rhodium moiety to participate in
charge-assisted hydrogen bonding to the anionic counterion. The crystal structures feature three kinds of
noncovalent interactionshydrogen bonding, Coulombic attraction, and π−π stacking, which result in
an intriguing array of architectures: dimeric, 1-D chain, C2 helical, and C3 helical. The nature of the
charge-assisted hydrogen bonding and the resulting 3-D structure in these systems are remarkably dependent
on the identity of the anion. Robust porous networks are formed rapidly (minutes or less) with [(η6-hydroquinone)Rh(P(OPh)3)2]+X- (X = BF4, ClO4) and [(η6-resorcinol)Rh(P(OPh)3)2]+BF4-. The
hydrophobic pores in [(η6-hydroquinone)Rh(P(OPh)3)2]+ClO4- bind toluene reversibly. This work
demonstrates that self-assembly of well-designed organometallic building blocks via charge-assisted
hydrogen bonding is an effective strategy for the construction of robust porous networks. With counterions
containing both oxygen and fluorine, it was found that the former is invariably the hydrogen bond acceptor,
a result in agreement with atomic charge calculations. It is anticipated that self-assembly via charge-assisted hydrogen bonding is an approach applicable in many organometallic systems.