title: The missing entry in the agostic-anagostic series: Rh(I)-η(1)-C interactions in P(CH)P pincer complexes.
abstract: The missing entry, namely, the "C-anagostic" or η(1)-C interaction, closing the agostic-anagostic series of metal-CH(aryl) interactions is found in a bis(amidiniophosphine) P(CH)P pincer rhodium complex. The three entries, namely, agostic η(2)-(C,H), anagostic (related to hydrogen bonding, thus recoined here as "H-anagostic"), and C-anagostic interactions, are unambiguously characterized by electron localization function (ELF) topological analysis. Other theoretical tools such as noncovalent interaction (NCI) analysis and multicenter electron delocalization indices (MCIs) support the ELF characterization. A η(2)-(C,H) agostic interaction is evidenced by a disynaptic V(C,H) or trisynaptic V(M,C,H) ELF basin with a significant quantum topological atoms in molecules (QTAIM) atomic contribution of the metal M and a large covariance (in absolute value) with the metal core basin C(M). The C-anagostic η(1)-C interaction is characterized by a disynaptic V(M,C) basin, a weak covariance (in absolute value) of V(C,H) and C(M) populations, and a negligible QTAIM atomic contribution of M to V(C,H). The relevance of these ELF signatures is evidenced in a selected series of related rhodium and osmium complexes.
authors.affiliation: Laboratoire de Chimie de Coordination, CNRS , 205 route de Narbonne, BP 44099, F-31077 Toulouse Cedex 4, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Lepetit
authors.forename: Jordi
authors.initials: J
authors.lastname: Poater
authors.forename: M Esmail
authors.initials: ME
authors.lastname: Alikhani
authors.forename: Bernard
authors.initials: B
authors.lastname: Silvi
authors.forename: Yves
authors.initials: Y
authors.lastname: Canac
authors.forename: Julia
authors.initials: J
authors.lastname: Contreras-García
authors.forename: Miquel
authors.initials: M
authors.lastname: Solà
authors.forename: Remi
authors.initials: R
authors.lastname: Chauvin