Several new chiral organogallium and indium complexes with chiral Salen (1 and 2) as anxciliary ligands have been synthesized and characterized by elemental analysis, IR, 1H NMR and Mass spectroscopy. For the gallium...Several new chiral organogallium and indium complexes with chiral Salen (1 and 2) as anxciliary ligands have been synthesized and characterized by elemental analysis, IR, 1H NMR and Mass spectroscopy. For the gallium, mono and bimetallic complexes were obtained, whereas ring closure complexes of indium were obtained.展开更多
The efficient catalytic systems generated in situ from RuCl2(PPh3)3 and chiral ligands N,N-bis[2-(di-o-tolylphosphino)-benzyl]cyclohexane-1,2-diamine(2) were employed for asymmetric transfer hydrogenation of aro...The efficient catalytic systems generated in situ from RuCl2(PPh3)3 and chiral ligands N,N-bis[2-(di-o-tolylphosphino)-benzyl]cyclohexane-1,2-diamine(2) were employed for asymmetric transfer hydrogenation of aromatic ketones, giving the corresponding optically active alcohols with high activities(up to 99% conversion) and excellent enantioselectivities(up to 96% e.e.) under mild conditions. The chiral ruthenium(Ⅱ) complex (R,R)-3 has been prepared and characterized by NMR and X-ray crystallography.展开更多
The title nickel complex I and cobalt complex II were obtained separately from the direct reaction of D-(+)-leucinol with Ni(II) chloride and L-(-)-leucinol with Co(II) acetate tetra- hydrate in anhydrous met...The title nickel complex I and cobalt complex II were obtained separately from the direct reaction of D-(+)-leucinol with Ni(II) chloride and L-(-)-leucinol with Co(II) acetate tetra- hydrate in anhydrous methanol. The crystal structures of I and II were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I: [Ni(C18H45N3O3)]Cl2, orthorhombic, P212121, a = 11.2807(9), b = 14.7115(11), c = 16.3580(13) A, V = 2714.7(4) A3, Z = 4, Pcalcd = 1.177 Mg/m3, the final R = 0.0407, and 16539 reflections observed with I 〉 2σ(/); For II: [Co(C45HI08N6015)], trigonal, R3:H, a = 23.981(3), b =23.981(3), c = 10.8925(15) A, γ = 120°, V = 5425.1(14) A3, Z = 3, Pcalcd = 1.002 Mg/m3, the final R = 0.0625 for 16556 observed reflections with I 〉 2σ(I). The complexes were then used to catalyze the Henry reaction and obtained good catalytic results. The catalytic activity of the complexes was determined by IH NMR. And research is going towards the application to other organic reactions such as cyanosilylation reaction.展开更多
The reactions of chiral four-coordinated nickel(Ⅱ) complex [Ni(RR-L)](ClO4)2/[Ni(SS- L)](ClO4)2 with β-dl-phenylalanine in acetonitrile/water gave a six-coordinated enantiomer of [Ni(RR-L)(β-d-HPhe)]...The reactions of chiral four-coordinated nickel(Ⅱ) complex [Ni(RR-L)](ClO4)2/[Ni(SS- L)](ClO4)2 with β-dl-phenylalanine in acetonitrile/water gave a six-coordinated enantiomer of [Ni(RR-L)(β-d-HPhe)](ClO4)2(1) and [Ni(SS-L)(β-l-HPhe)](ClO4)2(2), respectively(L = 5,5,7, 12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, HPhe = phenylalanine). Single-crystal X-ray diffraction analyses revealed that the nickel(Ⅱ) atom displays a distorted octahedral coordination geometry by coordinating with four nitrogen atoms of L in a folded configuration, and two carboxylate oxygen atoms of β-d/l-HPhe in cis-position in both complexes. The monomers of [Ni(RR-L)(β-d-HPhe)]2+ and [Ni(SS-L)(β-l-HPhe)]2+ are connected through intermolecular hydrogen bonds to generate one-dimensional zigzag chains, respectively. The homochiral natures of 1 and 2 are confirmed by the results of CD spectroscopy.展开更多
Two homochiral mercury (1) and cadmium (2) complexes derived from chiral twisted biphenyl pyridine ligand (3,3'-bipyridine-5,5',6,6'-tetramethyl-2,2'-dimethoxy-1,1'-biphenyl) have been synthesized and chara...Two homochiral mercury (1) and cadmium (2) complexes derived from chiral twisted biphenyl pyridine ligand (3,3'-bipyridine-5,5',6,6'-tetramethyl-2,2'-dimethoxy-1,1'-biphenyl) have been synthesized and characterized by IR, microanalysis, TGA, UV-Vis, powder and single-crystal X-ray crystallography. Both 1 and 2 crystallize in orthorhombic space group P21212 with Z = 2. For 1, a = 14.2038(16), b = 14.3630(17), c = 7.0257(8), V = 1433.3(3)3, Mr = 878.91, Dc = 2.037 g/cm3, μ = 7.549 mm-1, F(000) = 824, the final GOF = 1.017, R = 0.0296 and wR = 0.0645 for 2925 observed reflections with I 2σ(I). For 2, a = 14.212(3), b = 14.392(3), c = 7.0498(14), V = 1442.0(5)3, Mr = 790.72, Dc = 1.821 g/cm3, μ = 2.924 mm–1, F(000) = 760, the final GOF = 1.075, R = 0.0340 and wR = 0.0834 for 3144 observed reflections with I 2σ(I). The crystal structures of 1 and 2 are isostructural and each adopts a two-dimensional supramolecular network which contains the C–H···π interactions.展开更多
The catalytic synthesis of cyclic carbonates via the cycloaddition of CO2 to epoxides is a standard methodology for CO2 fixation.For this purpose,chiral basket-handle porphyrin-Co complexes were devised,prepared,and f...The catalytic synthesis of cyclic carbonates via the cycloaddition of CO2 to epoxides is a standard methodology for CO2 fixation.For this purpose,chiral basket-handle porphyrin-Co complexes were devised,prepared,and fully characterized by nuclear magnetic resonance,mass spectrometry,Fourier transform infrared spectroscopy,ultraviolet-visible spectroscopy,and specific rotation.The proposed metalloporphyrin catalysts were synthesized with either 1,1'-bi-2-naphthol or L-phenylalanine,which have different chirality,and then applied to the coupling of propylene oxide and CO2 for generating chiral cyclic carbonates with good enantioselectivity under extremely mild conditions in the presence of tetrabutyl ammonium chloride as a co-catalyst.The good enantioselectivity in the cycloaddition reaction is attributed to a synergistic interplay between the chiral porphyrin catalysts and the substrate.The mechanism and enantioselectivity of the asymmetric cycloaddition reaction is discussed.展开更多
Synthesized and characterized new chiral palladium complexes, some of which contain asymmetric donor nitrogen atom. Nitrogen-containing derivatives (+) - and (-)-2α-hydroxypinan-3-one- (1R,2R,5R)-3-(benzylimino)-2,6,...Synthesized and characterized new chiral palladium complexes, some of which contain asymmetric donor nitrogen atom. Nitrogen-containing derivatives (+) - and (-)-2α-hydroxypinan-3-one- (1R,2R,5R)-3-(benzylimino)-2,6,6-trimethylbicy- clo[3.1.1]heptane-2-ol (HL1), (1S,2S,3S,5S)-3- (benzylamino)-2,6, 6-trimethylbicyclo[3.1.1]- heptane-2-ol (HL2), (1R,2R,5R)-3-((S)-α-methyl- benzylimino)-2,6,6-trimethylbicyclo[3.1.1]- heptane-2-ol (HL3), (1R,2R,3R,5R)-3-((S)-α-methyl- benzylamino)-2,6,6-trimethylbicyclo[3.1.1]- heptane-2-ol (HL4) -were studied as optically active ligands.展开更多
The authors have prepared suprameolecular systems of chiral Schiffbase ZnAZSB (Zn(II) complexes with azo-groups) or without ZnSB (azo-groups) and colloidal AuNP (gold nanoparticles) of 10, 40 and 80 nm diamete...The authors have prepared suprameolecular systems of chiral Schiffbase ZnAZSB (Zn(II) complexes with azo-groups) or without ZnSB (azo-groups) and colloidal AuNP (gold nanoparticles) of 10, 40 and 80 nm diameters. They exhibited gradual shifts of surface plasmon bands as well as fluorescence bands. The authors observed and discussed induced CD bands on gold nanoparticles from chiral ZnAZSB or ZnSB. Absence of cis-trans photoisomerization of ZnAZSB with AuNP also supported direct contact near the surface of AuNP. Quenching and splitting of fluorescence bands of ZnSB (λex = 550 nm and λem = 400 nm) depending on concentration of ZnSB and size of AuNP also suggested intermolecular (electric) interaction on the surface of AuNE Decrease of the intensity of the CD band around 380 nm resulted from reciprocal induced CD effect due to parallel arrangement of electric transition moments of ZnAZSB or ZnSB and surface of AuNP.展开更多
The synthesis and characterization of two chiral fullerene complexes (+)_(430)^(CD)-[Mo(η~2-C_(60))(CO)_3(L^(RR))] 1 and (-)_(430)^(CD)-[Mo(η~2-C_(60))(CO)_3(L^(SS))] 2 were described. The CD spectra of 1 and 2 inth...The synthesis and characterization of two chiral fullerene complexes (+)_(430)^(CD)-[Mo(η~2-C_(60))(CO)_3(L^(RR))] 1 and (-)_(430)^(CD)-[Mo(η~2-C_(60))(CO)_3(L^(SS))] 2 were described. The CD spectra of 1 and 2 inthe visible range show weak Cotton effects, which are approximately of mirror image, indicatingthat the appended pineno-groups with opposite chirality in bipyridines can perturb the fullerenechromophores through the molybdenum centers and lead to induced CD effects.展开更多
Interaction between chiral diols BDPDD, DMBDPD and BINOL with prochiral compounds was examined and some new supramolecular complexes were prepared. It was found that these chiral hosts could include prochiral guests,...Interaction between chiral diols BDPDD, DMBDPD and BINOL with prochiral compounds was examined and some new supramolecular complexes were prepared. It was found that these chiral hosts could include prochiral guests, a, b-unsaturated compounds or piper- azinedione derivatives to give inclusion crystals in different molar ratio. Formations of these supramolecular complexes were characterized by the data of IR and 1H NMR spectra.展开更多
A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new((Rax)-BuP)/(R,R)-DPEN-Ru(Ⅱ) complex catalyst system.The hydrogenation ...A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new((Rax)-BuP)/(R,R)-DPEN-Ru(Ⅱ) complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol (t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H2,20℃,48 h) afforded(S)-1-(2'-methylphenyl)ethanol in 92%ee and〉99% conversion.展开更多
This is a review article including our recent results and some previous photo functional hybrid system having potential applications for environmental ion sensing. We have prepared several new and known chiral Schiff ...This is a review article including our recent results and some previous photo functional hybrid system having potential applications for environmental ion sensing. We have prepared several new and known chiral Schiff base Zn(II) complexes and measured (and also calculated) absorption and fluorescence spectra for sole complexes. After assembling hybrid systems with 1,3,3-trime- thylindolino-6’-nitrobenzopyrylospiran (SP) in methanol solutions, we measured spectral changes before and after alternate irradiation of UV and visible light. Intensity of fluorescence spectra for pale yellow Zn(II) complexes (λem = 450 nm, λex = 270 and 360 nm) was quenched by colorless SP (λem = 533 nm, λex = 612 nm). After UV light irradiation to form purple merocyanine (MC), photoisomerization resulted in changes of the intensity of absorption spectra as well as fluorescence spectra. Thus the hybrid systems could successfully act as molecular logic circuit by input (excitation by light) and output (intensity of fluorescence peaks). Moreover, we investigated concentration dependence of doped Zn(II) and Cu(II) ions to confirm quenching of intensity of fluorescence peaks by Zn(II) and Cu(II) MC complexes for metal ion sensing in solutions.展开更多
From evolutionary miniaturization activation of ancestral larger genes stocks, an electromagnetic field derivate from cancer microscopic collision events participates in the elaboration of geometric complexes and chir...From evolutionary miniaturization activation of ancestral larger genes stocks, an electromagnetic field derivate from cancer microscopic collision events participates in the elaboration of geometric complexes and chiral biomolecules that serve to build bodies with embryoid print as it develops during gestation. This miniaturization platform literally allows us to see what would otherwise remain completely invisible. In concordance with our observations collision extreme chaos generates in space time interval geometric scalable invariant extreme order. To determine whether our predictions are valid, we select Mars one of the planets with highest rate collision impact craters. The idea that impact events produce major geological effects that go far beyond the production of craters has recently been emphasized. We wonder if we could predict geometric chiral triangular hexagonal complexes in Martian landscape similar to those documented at microscopic, macroscopic, megascopic levels. We resolved to investigate the geomorphology patterns of more than 4000 collision impact craters in Mars landscape using images from Google Mars platforms, and HIRISE (High resolution imaging science experiment camera from the University of Arizona) based on a pattern recognition images algorithm we identified Mars mosaic order area (MOA). MOA is a circular cluster of overlap craters organized in apparent visible cycle sequential order oriented counterclockwise and consisting of nine craters that structure visible and measurable geometry in interface with biosignature morphologies in their interior not having been previously documented. Crater, therefore, is a step forward in understanding how collisions influence life, both on Earth and on other planets. We were pleased that the correctly pattern image algorithm predicted the identification of irreducible geometry matrix of GTCHC complexes in Martian impact craters. Cancer can inform astrobiology.展开更多
Benzaldehyde has been trimethylsilylcyanated with a catalyst prepared in situ from titanium tetraisopropoxide and chiral Schiff bases. Cyanohydrin is obtalned in moderate e.e.values
We have prepared new chiral Schiff base complexes, and copper(Ⅱ) (2) to investigate steric effect of ligands for 1 and bis(N-R-l-phenylethyl-5- methoxysalicydenaminato) nickel(Ⅱ) (1) 2 and known bis(N-R-l...We have prepared new chiral Schiff base complexes, and copper(Ⅱ) (2) to investigate steric effect of ligands for 1 and bis(N-R-l-phenylethyl-5- methoxysalicydenaminato) nickel(Ⅱ) (1) 2 and known bis(N-R-l-phenylethyl-3,5-dichlorosalicydenaminato) nickel(Ⅱ) (3) and copper(Ⅱ) (4). By using two kinds of photochromic dyes, disperse red 1 (DRI) and azobenzene (AZ), we investigated the efficiency of increasing optical anisotropy of organic/inorganic hybrid materials of 1 through 4+AZ or DRI+PMMA in polymethylmethacrylate (PMMA) cast films by Weigert effect (and compared with cis-trans isomerization by alternate UV and visible light for 3 and 4 to previous study). Gradual increase of optical anisotropy was observed for all the hybrid materials regardless of flexibility of Schiff base complexes, and the degree of dichroism and weak intermolecular interactions were discussed based on polarized absorption electronic spectra.展开更多
The asymmetric alkylations of chiral transition metal complexes derived from (+)-camphor and 2-aminomethyl-6-methylpyridine were examined under mild conditions.The formation of the complexes 2 is conductive to the enh...The asymmetric alkylations of chiral transition metal complexes derived from (+)-camphor and 2-aminomethyl-6-methylpyridine were examined under mild conditions.The formation of the complexes 2 is conductive to the enhancement of di- astereoselectivity in the alkylations at room temperature.展开更多
The authors have designed and synthesized new chiral salen-type metal (M = Fe, Co, Ni, Cu, Zn) complexes (1-5) for new conceptual dyes (co-sensitizer or colorful multi-dyes) of DSSCs (dye-sensitized solar cells...The authors have designed and synthesized new chiral salen-type metal (M = Fe, Co, Ni, Cu, Zn) complexes (1-5) for new conceptual dyes (co-sensitizer or colorful multi-dyes) of DSSCs (dye-sensitized solar cells). The authors measured substituent effects on their absorption spectra and redox properties, and compared them with TD-DFT (time-dependent density functional theory) calculations. Electron withdrawing groups resulted in red-shift of ultraviolet-visible (UV-Vis) spectra. For the first time, the authors also proposed and confirmed the importance of substituent effects on their electric transition dipole moments, calculated by TD-DFT for designing dyes. Chemisorption for TiO2 of the complex by carboxyl groups was confirmed by XPS measurement. In view of electronic properties, all compounds have the possibility to be dyes of DSSCs.展开更多
A mononuclear chiral copper(ll) complex, [Cu(RRchxn)2(C(CN)3)2]'H20 (RRchxn = (1R, 2R)-diaminocyclohexane) (RRchxnH), and its deuterated compound, [Cu(RRchxn)2(C(CN)3)z].D20 (RRchxnD), and their...A mononuclear chiral copper(ll) complex, [Cu(RRchxn)2(C(CN)3)2]'H20 (RRchxn = (1R, 2R)-diaminocyclohexane) (RRchxnH), and its deuterated compound, [Cu(RRchxn)2(C(CN)3)z].D20 (RRchxnD), and their isomers, [Cu(trchxn)2(C(CN)3)2]'H20 (trchxn = trans-l,2-diaminocyclohexane) (trchxnH) and [Cu(trchxn)2(C(CN)3)2]'D20 (trchxnD) have been prepared and characterized by means of 1R (infrared), electronic, and CD (circular dichroism) spectra, magnetic susceptibility, and variable-temperature X-ray crystallography as single crystals or powder. Interestingly, depending on grain size of samples, RRchxnH exhibits the monoclinic form and the orthorhombic form, which are distinguished by systematic absence and powder XRD (X-ray diffraction) patterns clearly. Although single crystals did not exhibit phase transition, powder XRD patterns of RRchxnH and weakly hydrogen bonded RRchxnD emerged low-temperature phase of monoclinic in the orthorhombic patterns only around 200-220 K. However, as a control, powder XRD patterns of both trchxnH and trchxnD did not exhibit such phase transition clearly.展开更多
Several chiral mixed-ligand complexes have been synthesized and their efficiency as catalysts for the asymmetric synthesis of chrysanthemic acid tested.
The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are ...The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are 4.7×10 2 binding sites of cisplatin(CDDP) in a spectrin tetramer(SPT). Among them, about 70 sites with apparent binding constant K 1】3.47×10 6 were of highest affinity, 1.8×10 2 sites with K 2 = 3.47×10 6 were of high affinity, and other 2.2×10 2 sites with K 3 = 8.77×10 5 were of low affinity. The conformation change of spectrin, depending on the concentration of Pt(II) complex and molar ratio(R) of Pt(II) complex to spectrin, was induced by the binding of Pt(II) complexes. It indicated that the interaction of both CDDP and cis diaquodiamine platinum(DADP) with SP followed a two step first order kinetic process in the first stage (1 h), and the kinetic constants were determined. In the second stage, the induced conformation change, polymerization and depolymerization of SP were probably involved. It was noticed that in the reaction of SP and Pt(II) complexes with 1,2 cyclohexanediammine isomers as chiral carrier ligand, stereo matching played a more important role than the affinity of Pt(II) to thiol groups of SP.展开更多
基金the National Natural Science Foundation of China (20102002) Science Foundation of Jiangsu Province (BK2001030) and the 863 High Technology Program for their financial support. The research funds for Y. Pan from Qin-Lan Program of Jiangsu Province and
文摘Several new chiral organogallium and indium complexes with chiral Salen (1 and 2) as anxciliary ligands have been synthesized and characterized by elemental analysis, IR, 1H NMR and Mass spectroscopy. For the gallium, mono and bimetallic complexes were obtained, whereas ring closure complexes of indium were obtained.
基金Supported by the National Natural Science Foundation of China(Nos.2042300220703034)+1 种基金the Natural Science Foundation of Fujian Province of China(No.2008J0235)the Natural Science Foundation of Guangxi Province of China(No. 0991016)
文摘The efficient catalytic systems generated in situ from RuCl2(PPh3)3 and chiral ligands N,N-bis[2-(di-o-tolylphosphino)-benzyl]cyclohexane-1,2-diamine(2) were employed for asymmetric transfer hydrogenation of aromatic ketones, giving the corresponding optically active alcohols with high activities(up to 99% conversion) and excellent enantioselectivities(up to 96% e.e.) under mild conditions. The chiral ruthenium(Ⅱ) complex (R,R)-3 has been prepared and characterized by NMR and X-ray crystallography.
文摘The title nickel complex I and cobalt complex II were obtained separately from the direct reaction of D-(+)-leucinol with Ni(II) chloride and L-(-)-leucinol with Co(II) acetate tetra- hydrate in anhydrous methanol. The crystal structures of I and II were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I: [Ni(C18H45N3O3)]Cl2, orthorhombic, P212121, a = 11.2807(9), b = 14.7115(11), c = 16.3580(13) A, V = 2714.7(4) A3, Z = 4, Pcalcd = 1.177 Mg/m3, the final R = 0.0407, and 16539 reflections observed with I 〉 2σ(/); For II: [Co(C45HI08N6015)], trigonal, R3:H, a = 23.981(3), b =23.981(3), c = 10.8925(15) A, γ = 120°, V = 5425.1(14) A3, Z = 3, Pcalcd = 1.002 Mg/m3, the final R = 0.0625 for 16556 observed reflections with I 〉 2σ(I). The complexes were then used to catalyze the Henry reaction and obtained good catalytic results. The catalytic activity of the complexes was determined by IH NMR. And research is going towards the application to other organic reactions such as cyanosilylation reaction.
基金Supported by the Scientific Research Fund of Hunan Provincial Education Department(13B029,13A030,13CY029)the Program for Excellent Talents in Hunan University of Science and Engineering(2013)+2 种基金the Construct Program of the Key Discipline in Hunan Province(2011-76)the Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province(2012-318)NSF of Hunan(11JJ2009)
文摘The reactions of chiral four-coordinated nickel(Ⅱ) complex [Ni(RR-L)](ClO4)2/[Ni(SS- L)](ClO4)2 with β-dl-phenylalanine in acetonitrile/water gave a six-coordinated enantiomer of [Ni(RR-L)(β-d-HPhe)](ClO4)2(1) and [Ni(SS-L)(β-l-HPhe)](ClO4)2(2), respectively(L = 5,5,7, 12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, HPhe = phenylalanine). Single-crystal X-ray diffraction analyses revealed that the nickel(Ⅱ) atom displays a distorted octahedral coordination geometry by coordinating with four nitrogen atoms of L in a folded configuration, and two carboxylate oxygen atoms of β-d/l-HPhe in cis-position in both complexes. The monomers of [Ni(RR-L)(β-d-HPhe)]2+ and [Ni(SS-L)(β-l-HPhe)]2+ are connected through intermolecular hydrogen bonds to generate one-dimensional zigzag chains, respectively. The homochiral natures of 1 and 2 are confirmed by the results of CD spectroscopy.
基金supported by NNSFC (20971085)"973" Programs (2007CB209701 and 2009CB930403)the Key Project and Scientific Research Foundation for the Returned Overseas Chinese Scholars of State Education Ministry
文摘Two homochiral mercury (1) and cadmium (2) complexes derived from chiral twisted biphenyl pyridine ligand (3,3'-bipyridine-5,5',6,6'-tetramethyl-2,2'-dimethoxy-1,1'-biphenyl) have been synthesized and characterized by IR, microanalysis, TGA, UV-Vis, powder and single-crystal X-ray crystallography. Both 1 and 2 crystallize in orthorhombic space group P21212 with Z = 2. For 1, a = 14.2038(16), b = 14.3630(17), c = 7.0257(8), V = 1433.3(3)3, Mr = 878.91, Dc = 2.037 g/cm3, μ = 7.549 mm-1, F(000) = 824, the final GOF = 1.017, R = 0.0296 and wR = 0.0645 for 2925 observed reflections with I 2σ(I). For 2, a = 14.212(3), b = 14.392(3), c = 7.0498(14), V = 1442.0(5)3, Mr = 790.72, Dc = 1.821 g/cm3, μ = 2.924 mm–1, F(000) = 760, the final GOF = 1.075, R = 0.0340 and wR = 0.0834 for 3144 observed reflections with I 2σ(I). The crystal structures of 1 and 2 are isostructural and each adopts a two-dimensional supramolecular network which contains the C–H···π interactions.
文摘The catalytic synthesis of cyclic carbonates via the cycloaddition of CO2 to epoxides is a standard methodology for CO2 fixation.For this purpose,chiral basket-handle porphyrin-Co complexes were devised,prepared,and fully characterized by nuclear magnetic resonance,mass spectrometry,Fourier transform infrared spectroscopy,ultraviolet-visible spectroscopy,and specific rotation.The proposed metalloporphyrin catalysts were synthesized with either 1,1'-bi-2-naphthol or L-phenylalanine,which have different chirality,and then applied to the coupling of propylene oxide and CO2 for generating chiral cyclic carbonates with good enantioselectivity under extremely mild conditions in the presence of tetrabutyl ammonium chloride as a co-catalyst.The good enantioselectivity in the cycloaddition reaction is attributed to a synergistic interplay between the chiral porphyrin catalysts and the substrate.The mechanism and enantioselectivity of the asymmetric cycloaddition reaction is discussed.
文摘The authors have prepared suprameolecular systems of chiral Schiffbase ZnAZSB (Zn(II) complexes with azo-groups) or without ZnSB (azo-groups) and colloidal AuNP (gold nanoparticles) of 10, 40 and 80 nm diameters. They exhibited gradual shifts of surface plasmon bands as well as fluorescence bands. The authors observed and discussed induced CD bands on gold nanoparticles from chiral ZnAZSB or ZnSB. Absence of cis-trans photoisomerization of ZnAZSB with AuNP also supported direct contact near the surface of AuNP. Quenching and splitting of fluorescence bands of ZnSB (λex = 550 nm and λem = 400 nm) depending on concentration of ZnSB and size of AuNP also suggested intermolecular (electric) interaction on the surface of AuNE Decrease of the intensity of the CD band around 380 nm resulted from reciprocal induced CD effect due to parallel arrangement of electric transition moments of ZnAZSB or ZnSB and surface of AuNP.
文摘The synthesis and characterization of two chiral fullerene complexes (+)_(430)^(CD)-[Mo(η~2-C_(60))(CO)_3(L^(RR))] 1 and (-)_(430)^(CD)-[Mo(η~2-C_(60))(CO)_3(L^(SS))] 2 were described. The CD spectra of 1 and 2 inthe visible range show weak Cotton effects, which are approximately of mirror image, indicatingthat the appended pineno-groups with opposite chirality in bipyridines can perturb the fullerenechromophores through the molybdenum centers and lead to induced CD effects.
基金This work was supported by the National Natural Science Foundation of China (Project 29972033) and the Key Science Research Foundation of Hubei Province of China (Project 98IP1305).
文摘Interaction between chiral diols BDPDD, DMBDPD and BINOL with prochiral compounds was examined and some new supramolecular complexes were prepared. It was found that these chiral hosts could include prochiral guests, a, b-unsaturated compounds or piper- azinedione derivatives to give inclusion crystals in different molar ratio. Formations of these supramolecular complexes were characterized by the data of IR and 1H NMR spectra.
基金the National Natural Science Foundation of China(Nos.20343005,20473107,20673130,and 20773147)the Hong Kong PolyU Joint Supervision Scheme(A-PH78) for financial support.
文摘A series of chiral secondary alcohols were easily prepared by means of asymmetric hydrogenation of prochiral aromatic ketones using a new((Rax)-BuP)/(R,R)-DPEN-Ru(Ⅱ) complex catalyst system.The hydrogenation of 2-methylacetophenone in n-butanol (t-BuOK/Ru =45.6/1,S/C = 500,20 atm.of H2,20℃,48 h) afforded(S)-1-(2'-methylphenyl)ethanol in 92%ee and〉99% conversion.
文摘This is a review article including our recent results and some previous photo functional hybrid system having potential applications for environmental ion sensing. We have prepared several new and known chiral Schiff base Zn(II) complexes and measured (and also calculated) absorption and fluorescence spectra for sole complexes. After assembling hybrid systems with 1,3,3-trime- thylindolino-6’-nitrobenzopyrylospiran (SP) in methanol solutions, we measured spectral changes before and after alternate irradiation of UV and visible light. Intensity of fluorescence spectra for pale yellow Zn(II) complexes (λem = 450 nm, λex = 270 and 360 nm) was quenched by colorless SP (λem = 533 nm, λex = 612 nm). After UV light irradiation to form purple merocyanine (MC), photoisomerization resulted in changes of the intensity of absorption spectra as well as fluorescence spectra. Thus the hybrid systems could successfully act as molecular logic circuit by input (excitation by light) and output (intensity of fluorescence peaks). Moreover, we investigated concentration dependence of doped Zn(II) and Cu(II) ions to confirm quenching of intensity of fluorescence peaks by Zn(II) and Cu(II) MC complexes for metal ion sensing in solutions.
文摘From evolutionary miniaturization activation of ancestral larger genes stocks, an electromagnetic field derivate from cancer microscopic collision events participates in the elaboration of geometric complexes and chiral biomolecules that serve to build bodies with embryoid print as it develops during gestation. This miniaturization platform literally allows us to see what would otherwise remain completely invisible. In concordance with our observations collision extreme chaos generates in space time interval geometric scalable invariant extreme order. To determine whether our predictions are valid, we select Mars one of the planets with highest rate collision impact craters. The idea that impact events produce major geological effects that go far beyond the production of craters has recently been emphasized. We wonder if we could predict geometric chiral triangular hexagonal complexes in Martian landscape similar to those documented at microscopic, macroscopic, megascopic levels. We resolved to investigate the geomorphology patterns of more than 4000 collision impact craters in Mars landscape using images from Google Mars platforms, and HIRISE (High resolution imaging science experiment camera from the University of Arizona) based on a pattern recognition images algorithm we identified Mars mosaic order area (MOA). MOA is a circular cluster of overlap craters organized in apparent visible cycle sequential order oriented counterclockwise and consisting of nine craters that structure visible and measurable geometry in interface with biosignature morphologies in their interior not having been previously documented. Crater, therefore, is a step forward in understanding how collisions influence life, both on Earth and on other planets. We were pleased that the correctly pattern image algorithm predicted the identification of irreducible geometry matrix of GTCHC complexes in Martian impact craters. Cancer can inform astrobiology.
文摘Benzaldehyde has been trimethylsilylcyanated with a catalyst prepared in situ from titanium tetraisopropoxide and chiral Schiff bases. Cyanohydrin is obtalned in moderate e.e.values
文摘We have prepared new chiral Schiff base complexes, and copper(Ⅱ) (2) to investigate steric effect of ligands for 1 and bis(N-R-l-phenylethyl-5- methoxysalicydenaminato) nickel(Ⅱ) (1) 2 and known bis(N-R-l-phenylethyl-3,5-dichlorosalicydenaminato) nickel(Ⅱ) (3) and copper(Ⅱ) (4). By using two kinds of photochromic dyes, disperse red 1 (DRI) and azobenzene (AZ), we investigated the efficiency of increasing optical anisotropy of organic/inorganic hybrid materials of 1 through 4+AZ or DRI+PMMA in polymethylmethacrylate (PMMA) cast films by Weigert effect (and compared with cis-trans isomerization by alternate UV and visible light for 3 and 4 to previous study). Gradual increase of optical anisotropy was observed for all the hybrid materials regardless of flexibility of Schiff base complexes, and the degree of dichroism and weak intermolecular interactions were discussed based on polarized absorption electronic spectra.
基金This work was supported by the National Natural Science Foundation of China.
文摘The asymmetric alkylations of chiral transition metal complexes derived from (+)-camphor and 2-aminomethyl-6-methylpyridine were examined under mild conditions.The formation of the complexes 2 is conductive to the enhancement of di- astereoselectivity in the alkylations at room temperature.
文摘The authors have designed and synthesized new chiral salen-type metal (M = Fe, Co, Ni, Cu, Zn) complexes (1-5) for new conceptual dyes (co-sensitizer or colorful multi-dyes) of DSSCs (dye-sensitized solar cells). The authors measured substituent effects on their absorption spectra and redox properties, and compared them with TD-DFT (time-dependent density functional theory) calculations. Electron withdrawing groups resulted in red-shift of ultraviolet-visible (UV-Vis) spectra. For the first time, the authors also proposed and confirmed the importance of substituent effects on their electric transition dipole moments, calculated by TD-DFT for designing dyes. Chemisorption for TiO2 of the complex by carboxyl groups was confirmed by XPS measurement. In view of electronic properties, all compounds have the possibility to be dyes of DSSCs.
文摘A mononuclear chiral copper(ll) complex, [Cu(RRchxn)2(C(CN)3)2]'H20 (RRchxn = (1R, 2R)-diaminocyclohexane) (RRchxnH), and its deuterated compound, [Cu(RRchxn)2(C(CN)3)z].D20 (RRchxnD), and their isomers, [Cu(trchxn)2(C(CN)3)2]'H20 (trchxn = trans-l,2-diaminocyclohexane) (trchxnH) and [Cu(trchxn)2(C(CN)3)2]'D20 (trchxnD) have been prepared and characterized by means of 1R (infrared), electronic, and CD (circular dichroism) spectra, magnetic susceptibility, and variable-temperature X-ray crystallography as single crystals or powder. Interestingly, depending on grain size of samples, RRchxnH exhibits the monoclinic form and the orthorhombic form, which are distinguished by systematic absence and powder XRD (X-ray diffraction) patterns clearly. Although single crystals did not exhibit phase transition, powder XRD patterns of RRchxnH and weakly hydrogen bonded RRchxnD emerged low-temperature phase of monoclinic in the orthorhombic patterns only around 200-220 K. However, as a control, powder XRD patterns of both trchxnH and trchxnD did not exhibit such phase transition clearly.
文摘Several chiral mixed-ligand complexes have been synthesized and their efficiency as catalysts for the asymmetric synthesis of chrysanthemic acid tested.
文摘The interactions between human erythrocyte spectrin(SP) and Pt(II) complexes with different composition and configuration were studied by fluorescence and circular dichroism spectra. The results showed that there are 4.7×10 2 binding sites of cisplatin(CDDP) in a spectrin tetramer(SPT). Among them, about 70 sites with apparent binding constant K 1】3.47×10 6 were of highest affinity, 1.8×10 2 sites with K 2 = 3.47×10 6 were of high affinity, and other 2.2×10 2 sites with K 3 = 8.77×10 5 were of low affinity. The conformation change of spectrin, depending on the concentration of Pt(II) complex and molar ratio(R) of Pt(II) complex to spectrin, was induced by the binding of Pt(II) complexes. It indicated that the interaction of both CDDP and cis diaquodiamine platinum(DADP) with SP followed a two step first order kinetic process in the first stage (1 h), and the kinetic constants were determined. In the second stage, the induced conformation change, polymerization and depolymerization of SP were probably involved. It was noticed that in the reaction of SP and Pt(II) complexes with 1,2 cyclohexanediammine isomers as chiral carrier ligand, stereo matching played a more important role than the affinity of Pt(II) to thiol groups of SP.