Iron homo- and heterobimetallic complexes supported by a symmetrical dinucleating ligand.

The selective synthesis of biomimetic Fe/Mn complexes able to mimic the geometry and catalytic activity of enzymes possessing this cofactor is still a challenge. Herein, we discuss the stepwise synthesis, characterization, and magnetic properties of a Fe(II)/Mn(II) species and related Fe(II)/Fe(II) complexes.

Diborane Reductions of CO and CS Mediated by Dicopper μ-Boryl Complexes of a Robust Bis(phosphino)-1,8-naphthyridine Ligand.

A dinucleating 1,8-naphthyridine ligand featuring fluorene-9,9-diyl-linked phosphino side arms (PNNP) was synthesized and used to obtain the cationic dicopper complexes , [(PNNP)Cu(μ-Ph)][NTf]; [NTf] = bis(trifluoromethane)sulfonimide, , [(PNNP)Cu(μ-CCPh)][NTf], and , [(PNNP)Cu(μ-OBu)][NTf]. Complex reacted with diboranes to afford dicopper μ-boryl species (, with μ-Bcat; cat = catecholate and , with μ-Bpin; pin = pinacolate) that are more reactive in C(sp)-H bond activations and toward activations of CO and CS, compared to dicopper μ-boryl complexes supported by a 1,8-naphthyridine-based ligand with di(pyridyl) side arms. The solid-state structures and DFT analysis indicate that the higher reactivities of and relate to changes in the coordination sphere of copper, rather than to perturbations on the Cu-B bonding interactions.

Tetracopper σ-Bound μ-Acetylide and -Diyne Units Stabilized by a Naphthyridine-based Dinucleating Ligand.

Reactions of a dicopper(I) tert-butoxide complex with alkynes possessing boryl or silyl capping groups resulted in formation of unprecedented tetracopper(I) μ-acetylide/diyne complexes that were characterized by NMR and UV/Vis spectroscopy, mass spectrometry and single-crystal X-ray diffraction. These compounds possess an unusual μ -η :η :η :η coordination mode for the bridging organic fragment, enforced by the rigid and dinucleating nature of the ligand utilized. Thus, the central π system remains unperturbed and accessible for subsequent reactivity and modification.

Robust dicopper(i) μ-boryl complexes supported by a dinucleating naphthyridine-based ligand.

Copper boryl species have been widely invoked as reactive intermediates in Cu-catalysed C-H borylation reactions, but their isolation and study have been challenging. Use of the robust dinucleating ligand DPFN (2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine) allowed for the isolation of two very thermally stable dicopper(i) boryl complexes, [(DPFN)Cu(μ-Bpin)][NTf] (2) and [(DPFN)Cu(μ-Bcat)][NTf] (4) (pin = 2,3-dimethylbutane-2,3-diol; cat = benzene-1,2-diol). These complexes were prepared by cleavage of the corresponding diborane reaction with the alkoxide [(DPFN)Cu(μ-O Bu)][NTf] (3).