Hydroaminoalkylation for Amine Functionalization of Vinyl-Terminated Polyethylene Enables Direct Access to Responsive Functional Materials.

While functionalized polyethylenes (PEs) exhibit valuable characteristics, the constraints of existing synthetic approaches limit the variety of readily incorporated functionality. New methods to generate functionalized PEs are required to afford new applications of this common material. We report 100 % atom economic tantalum-catalyzed hydroaminoalkylation of vinyl-terminated polyethylene (VTPE) as a method to produce amine-terminated PE.

Tetracopper(I) thiolate- and amido-(SNS) complexes and copper-catalyzed azide-alkyne cycloaddition in water.

Two tetranuclear Cu(I) complexes bearing thiolate- and amido-SNS ligands were characterized by X-ray diffraction and mass spectrometry. Although the amido ligand undergoes irreversible N-protonation by the copper-bound alkyne, the thiolate complex demonstrates good activity in the copper-catalyzed azide-alkyne cycloaddition reaction with a variety of substrates. The base-free reactions are performed in water and afford excellent yields over 2 h at 70 °C.

Coinage metal amido and thiolate SNS complexes: consequences of catalyst speciation in Cu(I)-catalysed carbonyl hydroboration.

Three new IPr-Ag- and -Au-SNS amido and thiolate complexes were synthesized and compared to their previously reported Cu analogues as carbonyl hydroboration catalysts (IPr = bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Although these complexes showed no catalytic activity, treatment of the IPr-Ag-SNS amido complex with pinacolborane released the -borylated ligand, SNS, (L1-Bpin). This finding led us to reinvestigate the IPr-Cu-SNS amido precatalyst, revealing that immediate loss of L1-Bpin converts our catalyst system to [CuH(IPr)].

Comparing B-H Bond Activation in NiX(NNN)-Catalyzed Nitrile Dihydroboration (X = Anionic N-, C-, O-, S-, or P-donor).

One of the key steps in many metal complex-catalyzed hydroboration reactions is B-H bond activation, which results in metal hydride formation. Anionic ligands that include multiple lone pairs of electrons, in cooperation with a metal center, have notable potential in redox-neutral B-H bond activation through metal-ligand cooperation. Herein, using an easily prepared NNN ligand (L), a series of divalent NiX(NNN) complexes were synthesized, with X = bromide (), phenoxide (), thiophenoxide (), 2,5-dimethylpyrrolide (), diphenylphosphide (), and phenyl ().

Solvent-free Zn (NSNO) complex-catalysed dihydroboration of nitriles.

N-donors are the most commonly employed Lewis bases in ligand-assisted catalysis. A dimeric zinc complex (Zn-1) employing a tetradentate pyridine-thioether-anilido-aryloxide NSNO ligand (L) effects the quantitative conversion of nitriles to the corresponding double hydroborated products at 1 mol% catalyst loading. Variable Time Normalization Analysis kinetic studies showed a first-order dependence with respect to the nitrile, pinacolborane and zinc and clear evidence for catalyst deactivation.

SNS ligand-assisted catalyst activation in Zn-catalysed carbonyl hydroboration.

Ligands that include Lewis acid/base functionality have extensive applications in bifunctional catalysis using first row metals. In this work, zinc bis(amido), bis(thiolate) and amido-thiolate SNS complexes were prepared and compared as precatalysts for carbonyl hydroboration using pinacolborane. Mechanistic studies revealed two different ligand-assisted precatalyst activation pathways, both leading to an active and robust zinc alkoxide catalyst.