Metal-Salens As Catalysts In Electroreductive Cyclization and Electrohydrocyclization: Computational and Experimental Studies

Abstract

The use of chiral Ni(II)-salen derivatives was examined in mediated electrohydrocyclization (EHC) reactions. Cyclic voltammetry established the existence of a catalytic current. Bulk electrolysis revealed a slight change in the diastereoselectivity of the cyclizations. Density functional theory (DFT) computational studies showed that Ni(II)-salen and Zn(II)-salen were the best metal-salens for electron transfer, while Co(II)-salen and Cu(II)-salen would likely be ineffective for this purpose. Electron transfer was both considerably more thermodynamically and kinetically (whether through an inner or outer sphere pathway) favorable with Ni(II)salen and Zn(II)-salen. Computational data also suggests Ni(II)-salen to be preferred for promoting inner sphere electron transfer, due in part to the ligand-centered reduction of Ni(II)-salen, and thus for affecting stereoselectivity in mediated EHC reactions.

Synthesis, characterization, and investigation of some properties of the new symmetrical bisimine Ni(II), Zn(II), and Fe(III) complexes derived from the monoimine ligand

“…[ 16 ] Ni(II)–salen complexes exhibit antimicrobial and DNA‐binding activities and also play a key role as catalysts in the electroreductive cyclization and hydrogenation reactions. [ 17–20 ] Zn(II)‐centered complexes are used to develop new materials with various photophysical, catalytic, and sensor properties. [ 21,22 ] Poly(imine)s (PLs) have nonlinear optical properties, semiconductivity, and fiber‐forming ability, and some PLs also show liquid crystal properties.…”

Reducing properties of 1,2-dipyridyl-1,2-disodioethanes: chemical validation of theoretical and electrochemical predictions

“…The tunability of redox reactions is a topic of primary importance in chemistry, nding application in a variety of areas such as extension of the synthetic usefulness of reagents such as SmX 2 , 1,2 Ni(II)-salen 3,4 or neutral organic electron donors, 5 control of the particle size during the formation of metal nanoparticles, 6 or electrochemical performance of fuel cells. 7 1,2-Diaryl-1,2-disodioethanes 8 constitute an easily accessible class of organometallic compounds endowed with interesting reducing properties.…”

Kinetics of Redox Processes in the Polymer Films of Ni(II)SalenType Complexes

“…[14][15][16][17][18][19][20][21][22] That is why salen type complexes and their electroactive polymer films are still investigated. [23][24][25][26][27][28][29] One of the important aspects of these studies is the kinetics of charge transport by polymer films. It gives the opportunity to assess the type and mobility of ions that control the rate of redox processes.…”