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The catecholase activity of two dinuclear Cu(II) complexes with distant metal centers is discussed together with solid state and solution studies. The crystal structure for one of them, [Cu(2)(diep)(H(2)O)(4)](ClO(4))(4)·2H(2)O, is described, showing the two copper ions are 7.457 Å apart and in a square pyramidal coordination. Both complexes display a weak antiferromagnetic coupling in the solid state that is manifest in the dimer EPR spectra obtained in frozen solution. The pH-potentiometric speciation performed in 1:1 MeOH-H(2)O allowed the assignment of hydrolyzed copper species as those catalytically active in the oxidation of 3,5-di-tert-butylcatechol (DTBC). The kinetic measurements led us to propose behavior consistent with Michaelis-Menten plus a linear dependence of the initial rate on [DTBC]. This can be associated with the presence of more than one catalytically active species, which is consistent with the evidence of several differently hydrolyzed species shown in the predominance diagrams. Product characterization studies led to establishing the formation of hydrogen peroxide during the catalytic cycle, while semiquinone and superoxide radicals were detected by EPR spectroscopy, supporting one-electron transference at each of the copper centers.

A series of 18 3-tetrazolyl-tetrazolo[1,5-a]quinolines were synthesized in 21-90% yields via a novel one-pot Ugi-azide/SAr/ring-chain azido-tautomerization process. We report also the synthesis of 10 3-imidazo[1,2-a]pyridin-tetrazolo[1,5-a]quinolines in 28-94% yields via a novel one-pot Groebke-Blackburn-Bienaymé/SAr/ring-chain azido-tautomerization process. Both synthetic strategies involve the use of microwaves or ultrasound, and catalyst-free conditions. Finally, we show the synthesis of the tetrazolo[1,5-a]quinoline-3-carbaldehyde and tetrazolo[1,5-a]quinoline-3-dimethyl acetal at room temperature in methanol as solvent.

We report herein the first example of a homogeneous manganese catalyzed transfer hydrogenation of nitriles using 2‐BuOH as the hydrogen source. Compound fac‐[(CO)3Mn{iPr2P(CH2)2PiPr2}Br] (Mn‐1, 3 mol %) exhibited catalytic activity in the presence of KOtBu (10 mol %) for the transfer hydrogenation of benzonitrile to yield a mixture of benzylamine (BA) and N‐sec‐butylidenebenzylamine (SBA). Subsequent acidic hydrolysis yielded isolated benzylamine hydrochloride in 96 %. The title system featured reversible formation of N‐benzylidenebenzylamine (BBA) prior to formation of SBA. A series of amine hydrochlorides was prepared following this methodology (39–92 % isolated yields, 4 examples). Best substrates for this transformation are electron‐rich aromatic nitriles, nonetheless electron‐deficient aromatic as well as aliphatic nitriles were also hydrogenated. Mechanistic studies suggested coordinatively unsaturated Mn‐hydride species performing catalytic turnover.

The potentially tridentate ligand bis[(1-methyl-2-benzimidazolyl)ethyl]amine ( 2BB ) was employed to prepare copper complexes [( 2BB )Cu I ]OTf and [( 2BB )Cu II (H 2 O) 2 ](OTf) 2 as bioinspired models of lytic polysaccharide copper-dependent monooxygenase (LPMO) enzymes. Solid-state characterization of [( 2BB )Cu I ]OTf revealed a Cu(I) center with a T-shaped coordination environment and metric parameters in the range of those observed in reduced LPMOs. Solution characterization of [( 2BB )Cu II (H 2 O) 2 ](OTf) 2 indicates that [( 2BB )Cu II (H 2 O) 2 ] 2+ is the main species from pH 4 to 7.5; above pH 7.5, the hydroxo-bridged species [{( 2BB )Cu II (H 2 O) x } 2 (μ-OH) 2 ] 2+ is also present, on the basis of cyclic voltammetry and mass spectrometry. These observations imply that deprotonation of the central amine of Cu(II)-coordinated 2BB is precluded, and by extension, amine deprotonation in the histidine brace of LPMOs appears unlikely at neutral pH. The complexes [( 2BB )Cu I ]OTf and [( 2BB )Cu II (H 2 O) 2 ](OTf) 2 act as precursors for the oxidative degradation of cellobiose as a cellulose model substrate. Spectroscopic and reactivity studies indicate that a dicopper(II) side-on peroxide complex generated from [( 2BB )Cu I ]OTf/O 2 or [( 2BB )Cu II (H 2 O) 2 ](OTf) 2 /H 2 O 2 /NEt 3 oxidizes cellobiose both in acetonitrile and aqueous phosphate buffer solutions, as evidenced from product analysis by high-performance liquid chromatography-mass spectrometry. The mixture of [( 2BB )Cu II (H 2 O) 2 ](OTf) 2 /H 2 O 2 /NEt 3 results in more extensive cellobiose degradation. Likewise, the use of both [( 2BB )Cu I ]OTf and [( 2BB )Cu II (H 2 O) 2 ...