Hydrogen Bonds Dictate O Capture and Release within a Zinc Tripod.

Six directed hydrogen bonding (H-bonding) interactions allow for the reversible capture and reduction of dioxygen to a trans-1,2-peroxo within a tripodal zinc(II) framework. Spectroscopic studies of the dizinc peroxides, as well as on model zinc diazides, suggest H-bonding contributions serve a dominant role for the binding/activation of these small molecules.

Second sphere ligand modifications enable a recyclable catalyst for oxidant-free alcohol oxidation to carboxylates.

Modification of the classic terpyridine pincer ligand with pendent NHR (R = mesityl) groups provides enhanced activity and stability in Ru-catalyzed dehydrogenation catalysis. These second sphere modifications furnish highly active catalysts for the oxidant-free dehydrogenative oxidation of primary alcohols to carboxylates and facilitate catalyst recycling.

Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square-Planar Copper(I) Complex.

6,6''-Bis(2,4,6-trimethylanilido)terpyridine (H2Tpy(NMes)) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H2 Tpy(NMes))copper(I)-halide (Cl, Br and I) complexes is dictated by the strength of the NH-halide hydrogen bond. The Cu(I)Cl and Cu(II)Cl complexes are nearly isostructural, the former presenting a highly unusual square-planar geometry about Cu(I) .

Beyond H₂: exploiting 2-hydroxypyridine as a design element from [Fe]-hydrogenase for energy-relevant catalysis.

The unique primary and secondary coordination environments surrounding the active site of hydrogenase enzymes play a crucial role in H2 activation and transfer reactions. [Fe]-hydrogenase contains a 2-hydroxypyridine ligand motif, and many researchers have incorporated this design element into synthetic catalysts. Transition metal complexes supported by 2-hydroxypyridine scaffolds are catalysts for chemical conversion schemes relevant to alternative energy applications and, in addition to hydrogenase-type reactivity, find new uses in other chemical domains.

The functional model complex [Fe2(BPMP)(OPr)(NO)2](BPh4)2 provides insight into the mechanism of flavodiiron NO reductases.

Flavodiiron nitric oxide reductases (FNORs), found in many pathogenic bacteria, are able to detoxify NO by reducing it to N2O. In this way, FNORs equip these pathogens with immunity to NO, which is a central immune defense agent in humans. Hence, FNORs are thought to promote infection of the human body, leading to chronic diseases.