Structure and Dynamics of P,N-Containing Heterocycles and Their Metal Complexes in Solution

Abstract

Conformations and dynamics of 1,5-diaza-3,7-diphosphacyclooctane (1) with chiral l-menthyl substituents on the phosphorus atoms and several metal complexes thereof were investigated by a variety of DNMR methods. In solution 1 adopts a C(2) symmetrical "crown"-like conformation (CW) and the conformational preference and dynamics of the complexes depend on the type of metal: for the Cu complex the CW form is preferred, whereas the Pd, Pt, or Mo complexes exist in an equilibrium of two "chair-boat"-like conformations (CB/CB*). The barriers of interconversion between these two conformations for the Pd and Pt complexes are about 2 times higher than for the Mo complex. Quantum chemical calculations (B3LYP/6-31G(d)) are in agreement with experimental findings.

Synthesis, Structural, and Electrocatalytic Reduction Studies of [Pd(P2N2)2]2+ Complexes

“…A variety of mono-P 2 N 2 complexes of Co, , Fe, , and Ru , have been studied by the DuBois group and their collaborators for H + /H 2 conversion and O 2 reduction. Several chiral and water-soluble Pd and Pt­(P 2 N 2 )­Cl 2 complexes have been studied by the Sinyashin group for information on ligand conformation and dynamics and for ethylene/CO copolymerization, respectively. , However, few bis-P 2 N 2 complexes of any metal other than Ni, and none of the heavier group 10 metals, have yet been reported in the literature. The series of [Pd­(P 2 N 2 ) 2 ] 2+ complexes reported here further extends the rich chemistry of these proton-relay-containing ligands.…”

A stimuli-responsive Au(i) complex based on an aminomethylphosphine template: synthesis, crystalline phases and luminescence properties

“…The conformation of the aminomethylphosphine cycle in the complexes depends on the metal oxidation state, solvent and temperature. 14 For the copper subgroup metals, the 1,5-diaza-3,7-diphosphacyclooctanes preferably exist in "crown" conformation with nearly co-directed lone electron pairs at the phosphorus atoms. This conformation allows the disposition of the AuIJI) ions in close proximity to each other, which in principle makes the formation of an aurophilic bond possible that in turn makes 1,5-diaza-3,7diphosphacyclooctanes prospective ligands for the design of stimuli-responsive AuIJI) complexes.…”

A NiII–Bis(diphosphine)–Hydride Complex Containing Proton Relays – Structural Characterization and Electrocatalytic Studies

“…A major focus of our group has been the development of Ni II catalysts containing 1,5‐diaza‐3,7‐diphosphacyclooctane (P R 2 N R′ 2 ) ligands 5,9–12. These ligands are suitable for substitution at both the phosphorus (R) and nitrogen (R′) atoms to aid in tuning the electronic and steric properties of their metal complexes.…”