| Salicylaldeimine ligands contain heteroatoms such as N atom and O atom with lone electron pairs,so they have good coordination ability.Among the transition metals,nickel and copper are widely used,which have stable oxidation state and can form stable complexes with a variety of geometric forms of ligands.Based on the above,a series of tridentate salicyladimine ligands were synthesized in this paper,which were further reacted with Cu(OAc)2·H2O and Ni(OAc)2·4H2O to obtain metal complexes of Cu(II),Ni(II),respectively.The synthesized copper complexes were used to catalyze the oxidation of alcohols reactions,and the synthesized nickel complexes were used to catalyze the reaction of acceptorless dehydrogenative coupling(ADC)of alcohols and amines to form imines.The catalytic activities of the two kind of complexes in their respective catalytic reactions were investigated.The main research of this paper are listed as follow:1.Three ligands(C9H6N)N=CH(3,5-tBu2C6H2OH)(HL1)?(Et2N)C2H4N=CH(3,5-tBu2C6H2OH)(HL2)?(2-C5H4N)CH2N=CH(3,5-tBu2C6H2OH)(HL3)were reacted with Cu(OAc)2·H2O in ethanol,respectively,to obtain three complexes[(L1)Cu(OAc)]·H2O(1a)?(L2)Cu(OAc)(1b)?(L3)Cu(OAc)(1c);three ligands(HL1)?(HL2)and(2-C5H4N)C2H4N=CH(3,5-tBu2C6H2OH)(HL4)were reacted with Ni(OAc)2·4H2O in ethanol,respectively,to obtain three complexes[(L1)Ni(OAc)]·H2O(2a)?(L2)Ni(OAc)(2b)?(L4)2Ni(2c).The six complexes were characterized by elemental analysis,IR and high resolution mass spectrometry(HR-MS),and their crystal structures were further determined by X-ray single crystal diffraction.The complexes 1a,1b,1c,2a and 2b contain a molecular ligand,in which the O atom and metals atoms are connected by a covalent bond,and two N atoms are coordinated with the center metal atom,thus forming a stable six-membered ring and a stable five-membered ring.complex 2c contains two molecular ligands,and the central metal nickel has a hexagonal coordination structure.2.Using H2O2 as oxidant,the catalytic activity and application of copper complexes 1a-1c in alcohol oxidation reaction were investigated.The results show that these complexes can oxidize primary and secondary alcohols into corresponding aldehydes and ketones,respectively,and the catalytic yield was between 46%-94%.The catalytic effect of aromatic alcohols is better than that of aliphatic alcohols,especially aromatic alcohols with electron-donating groups on the benzene ring.However,the selectivity of this catalytic system in the catalytic primary alcohol is slightly low,there were a small amount of acid by-products.3.NaOH was used as the base to investigate the catalytic activity of nickel complexes 2a-2c in the reaction of alcohols and amines ADC to form imines,and the catalytic yield was between 73%-94%.The complexes 2a-2c showed good catalytic activity in this reaction,and 2a showed the best catalytic activity. |
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