Solid State Study on Rhenium Dimethylphosphinoethane Complexes: X‐ray Crystal Structures of trans‐[ReO₂(dmpe)₂]PF₆·2H₂O, trans‐[ReO(OH)(dmpe)₂](CF₃SO₃)₂, trans‐[ReN(Cl)(dmpe)₂]CF₃SO₃ and trans‐[ReCl₂(dmpe)₂]ReO₄

cis-Dioxorhenium(V/VI) Complexes Supported by Neutral Tetradentate N4 Ligands. Synthesis, Characterization, and Spectroscopy

“…There have been extensive works on trans -dioxo d 2 metal complexes, ,,,,− whereas their cis -dioxo counterparts have been comparatively less explored, with the octahedral species having a few well-characterized examples. − Interesting types of cis -dioxo d 2 metal complexes to be developed are the octahedral species bearing chiral tetradentate ligands currently employed in asymmetric oxidation reactions, such as the neutral C 2 -symmetric N 4 ligands pyxn, pdp, and bqcn and their derivatives, which have been increasingly used in iron and manganese catalysis. − We have endeavored to try to explore a synthetic route to chiral d 2 cis -[M­(O) 2 (N 4 )] n + (M = Fe, Mn) species; such attempts, however, have not been successful. In the literature, there have been a lack of isolated examples for cis -Fe VI O 2 and cis -Mn V O 2 complexes, owing to their high reactivity/instability.…”

“…Complexes trans -2 and cis -2 bearing the same ligand contribute a unique pair of structurally characterized trans and cis isomers of d 2 Re V (O) 2 complexes. In previously reported cis -Re V (O) 2 complexes, − ,− the ligands employed are different from those in the trans -Re V (O) 2 complexes. ,,,,,,− For example, trans -[Re V (py) 4 (O) 2 ] + 3 bears monodentate pyridine ligands, whereas a bidentate bpy ligand was used for isolation of the corresponding cis analogue ( cis -[Re V (O) 2 (bpy)­(py) 2 ] + ) …”

“…Relative to trans -dioxo d 2 complexes, ,,,,− there have been limited reports on the electronic spectroscopy of cis -dioxo d 2 complexes. Theoretically, there are two singlet transitions within the Re­(5dπ) orbitals for cis -dioxo d 2 metal complexes having C 2 v symmetry, which are 1 [d xz (Re) → d yz (Re)] and 1 [d xz (Re) → d xy (Re)], respectively.…”

“…The cis configuration is generally favored in d 0 and d 1 dioxo systems to maximize π-bonding interactions between dπ­(metal) and pπ­(O) orbitals. A large number of trans -dioxo d 2 metal complexes ,,,,− have been studied; a notable example with Re­(V) ion is trans -[Re V (O) 2 (py) 4 ] + (py = pyridine), which has been demonstrated to show interesting spectroscopic and photophysical properties by Gray and co-workers , and Ru­(VI) complexes , as well as limited examples of Re­(V) complexes: cis -[Re V (O) 2 (bpy)­(py) 2 ] + , cis -[Re V (O) 2 (Me 3 tacn)­(OH 2 )] + , and cis -[Re V (O) 2 (Hdab)­(py) 2 ] (bpy = 2,2′-bipyridine; Me 3 tacn = N,N ′ ,N ″-trimethyl-1,4,7-triazacyclononane; H 2 dab = 1,2-diaminobenzene).…”

Kinetic and High-Pressure Mechanistic Investigation of the Aqua Substitution in the Trans-Aquaoxotetracyano Complexes of Re(V) and Tc(V): Some Implications for Nuclear Medicine

“…Nonradioactive rhenium is widely utilized to imitate technetium chemistry on a macroscale and has been extensively pursued for the past two decades or more, describing changes in coordination modes. We reported structural effects induced by different Re-cores while maintaining an equatorial ligand set, utilizing two dmpe ligands, while varying the axial core, to investigate the impact this change induces on the solid-state structure of the coordinated polyhedron and on the bidentate tertiary phosphine ligand, dmpe [26]. Similarly, the effect of different conformers/isomers and energies associated therewith has been described [27].…”