Synthesis and characterization of copper(II), cobalt(II), nickel(II), and iron(III) complexes with two diamine Schiff bases and catalytic reactivity of a chiral diamine cobalt(II) complex

Abstract

New transition metal complexes of Co(II), Cu(II), Ni(II), and Fe(III) of the ligands 6,6 0 -(1E,1 0 E)-(4, 5-dimethyl-1,2-phenylene)bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(7-hydroxy-5-methoxy-2-methyl-4H-chromen-4-one) H 2 L 1 and 6,6'-(1E,1 0 E)-cyclohexane-1, 2-diylbis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis-(7-hydroxy-5-methoxy-2-methyl-4H-chromen-4-one) H 2 L 2 have been prepared and characterized using physio-chemical and spectroscopic methods. The results obtained for the complexes indicated that the geometries of the metal centres are either square planar or octahedral. Cyclopropanation reactions of unactivated olefins by ethyldiazoacetate (EDA) in the presence of [L 1 Cu]ÁH 2 O, [L 2 Cu]Á2H 2 O and [L 2 *Co]Á 2H 2 O as catalysts were examined. The results showed that only [L 2 *Co]Á2H 2 O can act as a catalyst for the cyclopropanation reaction of unactivated olefins with very high selectivity (up to 99% based on EDA).

Synthesis and Characterization of a New Difunctional Ligand and Its Metal Complexes: An Experimental, Theoretical, Cyclic Voltammetric, and Antimicrobial Study

“…All the carbon atoms due to heteroatomic and aromatic groups were found in their expected region [40] . In the spectra of diamagnetic complexes, these signals shifted downfield due to the increased conjugation and [41] .…”

2-[(E)-(3-Carboxy-4-hydroxyphenyl)iminiomethyl]-4-chlorophenolate

“…For applications of Schiff bases, see: Youssef et al (2009); Salih & Hamdi (2008); Belaid et al (2006); Karthikeyan et al (2006). For hydrogen-bond motifs, see: Bernstein et al (1995).…”

“…Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 Schiff bases have received much attention, mainly because of their extensive application in the field of synthesis and catalysis (Youssef et al, 2009;Salih & Hamdi, 2008). Schiff bases derived from ortho-phenylenediamine are of particular interests because of the proximity of the nitrogen atoms, which permits their simultaneous coordination to the same metal cation, leading to more stable compounds (Belaid et al, 2006).…”

Asymmetric hydrogen-transfer hydrogenation on rhodium(I) complexes with new optically active salen ligands derived from (4S,5S)-4,5-bis(aminomethyl)-2,2-dimethyl-1,3-dioxolane

“…Transition metal complexes with Schiff bases (socalled salen complexes) in which the donor centers are oxygen and nitrogen atoms are extensively studied due to the possibility for controlling their steric and electronic properties via appropriate selection of primary mono-and diamine precursors and substituted aldehydes [1][2][3][4][5][6]. Chiral salen metal complexes effectively catalyze various processes.…”

“…Chiral salen metal complexes effectively catalyze various processes. Catalytic asymmetric epoxidation and cyclopropanation reactions in the presence of Mn(III), Co(III), and Cr(III) salen complexes [2][3][4][5][6], including complexes intercalated into zeolite pores and macromolecules [7], were studied in most detail. Chiral C 2 -symmetric salen ligands (and the corresponding metal complexes) obtained from optically active 1,2-diarylethane-1,2-diamines or cyclohexane-1,2-diamine were used most frequently [3,[8][9][10].…”