Insights into the ‑P,N-Coordination of 1,3,5-Triaza-7-2 phosphaadamantane and Derivatives: ‑P,N-Heterometallic Complexes and a 15N Nuclear Magnetic Resonance Survey

Abstract

Complexes {[(PTA)2CpRu-μ-CN-1κC:2κ2N-RuCp- (PTA)2-ZnCl3]}·2DMSO (13) {[ZnCl2(H2O)]-(PTA-1κP:2κ2N)- (PTA)CpRu-μ-CN-1κC:2κ2N-RuCp(PTA)(PTA-1κP:2κ2N)- [ZnCl2(H2O)]}Cl (14), [RuCp(HdmoPTA)(PPh3)(PTA)]- (CF3SO3)2 (20), [RuCp(HdmoPTA)(HPTA)(PPh3)](CF3SO3)3 (21), and [RuCp(dmoPTA)(PPh3)(PTA)](CF3SO3) (22) were obtained and characterized, and their crystal structure together with that of the previously published complex 18 is reported. The behavior of the 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane (PTA) and 3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (dmoPTA) ligands against protonation and κN-coordination is discussed, on the basis of 15N nuclear magnetic resonance data collected on 22 different compounds, including PTA (1), HdmoPTA (7H), and some common derivatives as free ligands (2−6 and 8), along with mono- and polymetallic complexes containing PTA and/or HdmoPTA (9−22). 15N detection via 1H−15N heteronuclear multiple bond correlation allowed the construction of a small library of 15N chemical shifts that shed light on important features regarding κN-coordination in PTA and its derivatives.