Cu(ii) complexes with tridentate sulfur and selenium ligands: catecholase and hydrolysis activity

Abstract

Two new copper(II) mononuclear complexes (CSe and CS) were synthesized and characterized by the following techniques: X-ray crystallography, elemental analysis, IR, EPR and UV-Vis spectroscopies, conductimetric analysis and mass spectrometry....

Aerobic oxidation of vanillyl alcohol to vanillin catalyzed by air-stable and recyclable copper complex and TEMPO under base-free conditions

“…98 The bond distances around the metal centers in 2a and 2b are consistent with similar complexes. 94,99 Diverse hydrogen bonds (H⋯Cl) and π⋯π stacking interaction between the pyridine rings of two neighboring molecules gives the solid-state stability in 2a. On the other hand, hydrogen bonding between the amine proton of one molecule and chlorine atom of the neighboring molecule provides additional stability in the solid-state structure of 2b.…”

Experimental and theoretical insights into thetransinfluence of organo-sulfur and -selenium ligands in 5,6-membered palladium(ii) cationic pincer complexes based on iminophosphoranes

“…The N(1)–Pd(1)–E [E = S(2), Se(1)] bite angle in the 5-membered chelate ring is approximately the same for complexes 4a–d [(84.06(6)° to 85.83(8)°] and somewhat smaller than those found by Singh for related and more flexible 5-membered chelate rings in 5,6-membered SNS and SNSe-Pd( ii ) pincers based on Schiff bases (around 87°). 22 In contrast, the 6-membered chelate ring adopts a twist-boat conformation, and displays a larger N(1)–Pd(1)–S(1) bite angle when the R group linked to the chalcogen in trans is a methyl [93.64(7)° 4a and 93.77(8)° 4c ], instead of a phenyl substituent [87.92(6)° 4b and 87.46(15)° 4d ]. The Pd(1)–N(1), Pd(1)–S(1) and Pd(1)–E(1) (E = S, and Se) distances are within the expected values for this type of complex.…”

“…[18][19][20][21] In addition, coordination complexes with sulfur-based and selenium containing flexible tridentate ligands have been used to model the active sites of metalloproteins or Se containing biomolecules. 22,23 The group of Singh reported a series of flexible tridentate Schiff bases and amine derivatives including different combinations of group 16 donors (S, Se, and Te) and described their Pd(II) unsymmetrical complexes containing 5, 6-membered fused rings, which were found to be promising as catalysts for Suzuki-Miyaura coupling. 24,25 There have been a number of quantum mechanical studies at the DFT level concerning transition metal pincer ligands, to explore the structure, reactivity and spectroscopic properties of the compounds.…”

Selective aerobic oxidation of biomass model compound veratryl alcohol catalyzed by air-stable copper(ii) complexes in water

“…In all the complexes, the equatorial bond distances are in the range of 1.960(2)-2.7817 Å, while the axial bond length is in the range of 1.960(2)-2.7817 Å, similar to the reported Cu II square pyramidal complexes. 95,100 Moreover, the C-H⋯Br noncovalent interaction in complex 1 and 3 and the N-H⋯Br hydrogen bonding interaction in 2 gave the solid-state stability of the complexes.…”