Diphosphinite Ag^I and Pd^II Dinuclear Complexes as Adaptable Anion Receptors: An Unprecedented Bridging Mode for the PF₆⁻ Ion

Abstract

The special guest: In the host–guest chemistry of dinuclear complexes that contain the 9H‐fluorene‐9,9′‐dimethanediphenylphosphinite ligand the synergy between the phenyl groups and the axial fluorene moiety leads to the formation of molecular cavities that have selective steric affinity for the anions BF4− or PF6− (see picture). An unprecedented M⋅⋅⋅F(PF5)⋅⋅⋅M bridging coordination mode of PF6− has now been established.

INDOLPhosphole and INDOLPhos Palladium−Allyl Complexes in Asymmetric Allylic Alkylations

“…The remaining independent PF 6 − counteranions and lattice solvent molecules (i.e., dichloromethane) are found to be intercalated between the 2-D planes including the tetrameric boxes. These counteranions are in short contact with the Pd complexes via C−H···F interactions, which are comparable with those found for other encapsulated anions …”

Cover Picture: 51V NMR Chemical Shifts Calculated from QM/MM Models of Vanadium Chloroperoxidase (Chem. Eur. J. 17/2007)

“…In other words, the guest anions direct the configuration of the supramolecular framework assembly. It is noteworthy that similar host–guest interactions between weakly coordinating anions (PF 6 − , BF 4 − ) and cationic Pd II ‐dimer cavities have recently been reported 19. In these complexes, modifying the size of the anion results in major conformational changes of dipalladium complexes.…”

Confined Nanospaces in Metallocages: Guest Molecules, Weakly Encapsulated Anions, and Catalyst Sequestration

“…Anion-template approaches continue to be an important subject in supramolecular coordination chemistry. ,− These studies made possible the emergence of metal-based anion receptors. , The presence of a metal center in a coordination assembly may play a crucial role in anion recognition due to its intrinsic property to bind anions and also to organize the formation of the final assembly. Such coordination assemblies have shown a wide range of applications in biochemistry, environment, recognition, ion exchange, and chemical sensors. − Several reviews have appeared recently describing coordination chemistry of anions or anion templation strategy to form a variety of assemblies with different size and topology. − Previous reviews cover a variety of metallomacrocycles that do not possess a well-defined cavity or confined space for anion encapsulation. Therefore, such examples will not be discussed in this review; however, our attention will be devoted to discrete three-dimensional metallo-assemblies that possess a confined space for hosting anions inside their cavity.…”