Nine peptide-modified Salen-Co(Ⅱ)complexes based on three Salen ligand frameworks SA1~SA3 and four oligopeptides P1~P4 have been prepared.Their catalytic activities were examined through a model hydrohydrazination of...Nine peptide-modified Salen-Co(Ⅱ)complexes based on three Salen ligand frameworks SA1~SA3 and four oligopeptides P1~P4 have been prepared.Their catalytic activities were examined through a model hydrohydrazination of cinnamic alcohol with azodicarboxylate.While peptide-modified Salen-Co(Ⅱ)complexes derived from SA1 are ineffective,its parent 1SalenCo and those based on SA2 and SA3 are excellent catalyst for this reaction.These results demonstrate that peptide ligands significantly modulate the catalytic activity of SalenCo(Ⅱ)complexes,particularly at lower temperatures,likely due to hydrogen-bonding interactions.展开更多
Six novel chiral dinuclear Salen complexes[Cu 2 L 1 ·H 2 O(3a),Cu 2 L 2 (3b),Ni 2 L 1 ·2H 2 O(4a),Ni 2 L 2 (4b),Mn 2 Cl 2 L 1 ·H 2 O(5a),Mn 2 Cl 2 L 2 (5b)]have been synthesized(L 1 and L 2 are chiral d...Six novel chiral dinuclear Salen complexes[Cu 2 L 1 ·H 2 O(3a),Cu 2 L 2 (3b),Ni 2 L 1 ·2H 2 O(4a),Ni 2 L 2 (4b),Mn 2 Cl 2 L 1 ·H 2 O(5a),Mn 2 Cl 2 L 2 (5b)]have been synthesized(L 1 and L 2 are chiral dimeric Salen ligands with different chain length which were synthesized from(R,R) - diaminocyclohexane,salicylaldehyde,4,4 ’- (1,10 - decaneoxy)sali - cylaldehyde,4,4 ’- (1,6 - hexyloxy)salicylaldehyde).These compounds were charactered by elemental analysis,1 H NMR,FT - IR,UV - Vis and CD spectra.The FT - IR,UV - Vis and CD spectra were discussed and compared with those of monomeric ligand and complex in detail.It was found that the spectra properties of compounds of differ - ent chain length were almost alike,and the properties of dimeric and monomeric compound were similar too.Furthermore Cotton effect and Cotton split of CD spectra of these chiral compounds were explained by the exciton interaction theory.It seemed that the direction of Cotton split depend on the configuration of diaminohexane.(R,R) - diaminohexane determine the chirality of Salen compounds as negative,and the positive and negative compo - nent of Cotton split lie at higher and lower energy respectively.展开更多
SalenMX has drawn much attention recently,because it is nonsensitive to moisture and effective for copolymerization of CO2 and epoxides.However,usually expensive organic metal compounds were used.A low cost procedure ...SalenMX has drawn much attention recently,because it is nonsensitive to moisture and effective for copolymerization of CO2 and epoxides.However,usually expensive organic metal compounds were used.A low cost procedure of SalenMX preparation is described that SalenAl（OPr） can be obtained by using aluminium iso-propoxide reacted with SalenH2 in tetrahydrofuran at room temperature overnight.The catalyst precursor Schiff-base SalenH2 （N,N′-Bis（salicylidene）-1,2-phenylenediamine） was synthesized by refluxing 2 equiv salicylaldehyde and 1 equiv of 1,2-phenylendiamine in methnol for a period of time.SalenH2 and SalenAl（OPr） were characterized by FT-IR,mass Spectroscopy,UV-Vis and 1H-NMR.The copolymerization of carbon dioxide and cyclohexene oxide（CHO） was carried out at 80℃ for a certain period time using 50 mg SalenAl（OPr） as catalyst.SalenAl（OPr） had been shown to be an effective catalyst for the copolymerization of CO2 and CHO along with a small quantity of byproduct cyclic carbonate.The addition of various cocatalysts,including DMAP,N-MeIm,DBU and Bu4NCl or Bu4NBr salts can greatly enhance the rate of copolymerization.The copolymers were produced with >95% carbonate linkages and <5% cyclic carbonates.The highest catalytic efficiency is 190 g copolymer per g catalyst.展开更多
文摘Nine peptide-modified Salen-Co(Ⅱ)complexes based on three Salen ligand frameworks SA1~SA3 and four oligopeptides P1~P4 have been prepared.Their catalytic activities were examined through a model hydrohydrazination of cinnamic alcohol with azodicarboxylate.While peptide-modified Salen-Co(Ⅱ)complexes derived from SA1 are ineffective,its parent 1SalenCo and those based on SA2 and SA3 are excellent catalyst for this reaction.These results demonstrate that peptide ligands significantly modulate the catalytic activity of SalenCo(Ⅱ)complexes,particularly at lower temperatures,likely due to hydrogen-bonding interactions.
文摘Six novel chiral dinuclear Salen complexes[Cu 2 L 1 ·H 2 O(3a),Cu 2 L 2 (3b),Ni 2 L 1 ·2H 2 O(4a),Ni 2 L 2 (4b),Mn 2 Cl 2 L 1 ·H 2 O(5a),Mn 2 Cl 2 L 2 (5b)]have been synthesized(L 1 and L 2 are chiral dimeric Salen ligands with different chain length which were synthesized from(R,R) - diaminocyclohexane,salicylaldehyde,4,4 ’- (1,10 - decaneoxy)sali - cylaldehyde,4,4 ’- (1,6 - hexyloxy)salicylaldehyde).These compounds were charactered by elemental analysis,1 H NMR,FT - IR,UV - Vis and CD spectra.The FT - IR,UV - Vis and CD spectra were discussed and compared with those of monomeric ligand and complex in detail.It was found that the spectra properties of compounds of differ - ent chain length were almost alike,and the properties of dimeric and monomeric compound were similar too.Furthermore Cotton effect and Cotton split of CD spectra of these chiral compounds were explained by the exciton interaction theory.It seemed that the direction of Cotton split depend on the configuration of diaminohexane.(R,R) - diaminohexane determine the chirality of Salen compounds as negative,and the positive and negative compo - nent of Cotton split lie at higher and lower energy respectively.
文摘SalenMX has drawn much attention recently,because it is nonsensitive to moisture and effective for copolymerization of CO2 and epoxides.However,usually expensive organic metal compounds were used.A low cost procedure of SalenMX preparation is described that SalenAl（OPr） can be obtained by using aluminium iso-propoxide reacted with SalenH2 in tetrahydrofuran at room temperature overnight.The catalyst precursor Schiff-base SalenH2 （N,N′-Bis（salicylidene）-1,2-phenylenediamine） was synthesized by refluxing 2 equiv salicylaldehyde and 1 equiv of 1,2-phenylendiamine in methnol for a period of time.SalenH2 and SalenAl（OPr） were characterized by FT-IR,mass Spectroscopy,UV-Vis and 1H-NMR.The copolymerization of carbon dioxide and cyclohexene oxide（CHO） was carried out at 80℃ for a certain period time using 50 mg SalenAl（OPr） as catalyst.SalenAl（OPr） had been shown to be an effective catalyst for the copolymerization of CO2 and CHO along with a small quantity of byproduct cyclic carbonate.The addition of various cocatalysts,including DMAP,N-MeIm,DBU and Bu4NCl or Bu4NBr salts can greatly enhance the rate of copolymerization.The copolymers were produced with >95% carbonate linkages and <5% cyclic carbonates.The highest catalytic efficiency is 190 g copolymer per g catalyst.
