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
Poly(ethylene glycol)-poly(lactic acid)block copolymer(PEG-PLA)is one of the most widely used biomedical polymers in clinical drug delivery owing to its biocompatibility and biodegradability.However,endowing PEG-PLA m...Poly(ethylene glycol)-poly(lactic acid)block copolymer(PEG-PLA)is one of the most widely used biomedical polymers in clinical drug delivery owing to its biocompatibility and biodegradability.However,endowing PEG-PLA micelles with high drug loading,self-assembly stability and fast intracellular drug release is still challenging.Redox-responsive diblock copolymers(MPEG-SS-PMLA)of poly(ethylene glycol)and phenyl-functionalized poly(lactic acid)with disulfide bond as the linker are synthesized to prepare PLA-based micelles that demonstrate excellent colloidal stability and high Ru loading.Notably,MPEGSS-PMLA achieved a remarkably high Ru loading efficiency of 84.3%due to the existence of strongπ-πstacking between phenyl and Ru complex.MPEG-SS-PMLA exhibited good colloidal stability in physiological condition but quickly destabilized by reductive tumor microenvironment.Interestingly,about 74%of Ru complex was released under 10 mmol/L GSH concentration.Ru-loaded MEPG-SS-PMLA showed efficient delivery and release of Ru complex into MCF-7 cancer cells,achieving enhanced in vitro and in vivo antitumor activity of photodynamic therapy.This feasible functionalization method of MPEG-PLA has appeared to be a clinically viable platform for controlled delivery therapeutic agents and enhanced phototherapy.展开更多
The ground and the lowest-lying triplet excited state geometries, electronic structures, and spectroscopic properties of three mixed-ligand Ru（II） complexes [Ru（terpy）（phen）X]＋ （terpy=2,2＇,6＇,2″-terpyridine...The ground and the lowest-lying triplet excited state geometries, electronic structures, and spectroscopic properties of three mixed-ligand Ru（II） complexes [Ru（terpy）（phen）X]＋ （terpy=2,2＇,6＇,2″-terpyridine, phen=l,10-phenanthroline, and X=-C-=CH （1）, X=Cl （2）, X-CN （3）） were investigated theoretically using the density functional theory method. The ground and excited state geometries have been fully optimized at the B3LYP/LanL2DZ and UB3LYP/LanL2DZ levels, respectively. The absorption and emission spectra of the com- plexes in CHaCN solutions were calculated by time-dependent density functional theory with the PCM solvent model. The calculated bond lengths of Ru-C, Ru-N, and Ru-Cl in the ground state agree well with the corresponding experimental results. The highest occupied molecular orbital were dominantly localized on the Ru atom and monodentate X ligand for 1 and 2, Ru atom and terpy ligand for a, while the lowest unoccupied molecular orbital were π＊（terpy） type orbital. Therefore, the lowest-energy absorptions of 1 and 2 at 688 and 631 nln are attributed to a dyz （Ru）＋Tr/p（X）--π＊ （terpy） transition with MLCT/XLCT （metal-to-ligand charge transfer/X ligand to terpy ligand charge transfer） character, whereas that of 3 at 529 nm is related to a dyz （Ru）＋π（terpy）-π＊ （terpy） transition with MLCT and ILCT transition character. The calculated phosphorescence of three complexes at 1011 nm （1）, 913 nm （2）, and 838 nm （3） have similar transition properties to that of the lowest-lying absorption. It is shown that the lowest lying absorptions and emissions transition character of these Ru（II） complexes can be tuned by changing the electron-withdrawing ability of the monodentate ligand.展开更多
Cyclic voltammetry (CV) and single-step chronocoulometry were used to study the interaction of [Ru(phen)2dppz]2+ (phen=1,10-phenanthroline; dppz=dipyrido[3,2-a:2′,3′-c]phen- azine) with herring sperm DNA. The additi...Cyclic voltammetry (CV) and single-step chronocoulometry were used to study the interaction of [Ru(phen)2dppz]2+ (phen=1,10-phenanthroline; dppz=dipyrido[3,2-a:2′,3′-c]phen- azine) with herring sperm DNA. The addition of DNA caused a diminution in the peak current and a positive shift in the peak potential of the complex of [Ru(phen)2dppz]2+. The 12 mV positive shift in the peak potential of [Ru(phen)2dppz]2+ indicates that [Ru(phen)2dppz]2+ binds 2.6 times more strongly to DNA than its reductive form. In addition, by using fluorimetric and UV-spectrophotometric methods and studies of denatured DNA and the effect of NaCl solution, it was also found that the binding mode was intercalation. The decrease of peak current is proportional to the concentration of DNA, which can be applied to estimate DNA concentration.展开更多
The transient luminescence of three kinds of ruthenium complexes [Ru(bpy)2(7-CH3-dppz)]2+, [Ru(bpy)2(7-F-dppz)]2+ and [Ru(phen)2(7-F-dppz)]2+ bound to calf thy-mus DNA (ctDNA) has been studied by using the time-resolv...The transient luminescence of three kinds of ruthenium complexes [Ru(bpy)2(7-CH3-dppz)]2+, [Ru(bpy)2(7-F-dppz)]2+ and [Ru(phen)2(7-F-dppz)]2+ bound to calf thy-mus DNA (ctDNA) has been studied by using the time-resolved spectroscopy. The results show that the luminescence is due to the radiative decay from the charge-transfer states to the ground state. By the interaction with DNA, the radia-tiveless rate of the photoexcited Ru complex molecules decreases, which results in the increase of luminescence lifetime and efficiency. The structure of the Ru com-plex has an important impact on the interaction with DNA. The [Ru(bpy)2(7-CH3-dppz)]2+ shows the longest luminescence lifetime (about 382 ns), while the [Ru(bpy)2(7-F-dppz)]2+ shows the shortest lifetime (about 65 ns). The possible origin of the luminescence dynamics is discussed.展开更多
Structure Activity-Relationships (SARs) of the five possible isomers of RuCl<sub>2</sub>(Azpy)<sub>2</sub> were predicted thanks to DFT method. Azpy stands for 2-phenylazopyridine and the struc...Structure Activity-Relationships (SARs) of the five possible isomers of RuCl<sub>2</sub>(Azpy)<sub>2</sub> were predicted thanks to DFT method. Azpy stands for 2-phenylazopyridine and the structure of the isomers α-RuCl<sub>2</sub>(Azpy)<sub>2</sub>, β-RuCl<sub>2</sub>(Azpy)<sub>2</sub>, γ-RuCl2(Azpy)2, δ-RuCl<sub>2</sub>(Azpy)<sub>2</sub> and ε-RuCl<sub>2</sub>(Azpy)<sub>2</sub> call respectively α-Cl, β-Cl, γ-Cl, δ-Cl and ε-Cl are defined according to chlorine atoms orientations. Hence, they are divided into two groups. In the first group comprising α-Cl, β-Cl and ε-Cl, both chlorine atoms are in cis position and Azpy ligands are intervertical. Whereas the two others isomers (γ-Cl and δ-Cl), they form the second group. Here, both chlorine are in trans position and Azpy are planar. The five synthesized isomers were investigated as potential antitumor agents. Then, regarding the DNA, its bases are stacked by pair. Therefore, complexes are assumed to insert and to stack on them through intercalative mode. So the electronic and geometric structures become more important to describe their SARs. Consequently, group 2 regarding γ-Cl and δ-Cl presents the best structure to allow intercalation between DNA base-pairs. Besides, the energy order of the lower unoccupied molecular orbital (LUMO) of the isomers is ELUMO(β-Cl) > ELUMO(α-Cl) > ELUMO(ε-Cl) > ELUMO(γ-Cl) > ELUMO(δ-Cl). The energy gap between LUMO and HOMO was also sorted as Δ(L-H)(β-Cl) > Δ(L-H)(α-Cl) > Δ(L-H)(ε-Cl) > Δ(L-H)(γ-Cl) > Δ(L-H)(δ-Cl). In addition, the total dipole moment was classified as μ(ε-Cl) > μ(β-Cl) > μ(α-Cl) > μ(γ-Cl) > μ(δ-Cl). Finally, net charge of the ligand Azpy was also classified as QL(δ-Cl) > QL(γ-Cl) > QL(ε-Cl) > QL(α-Cl) > QL(β-Cl). All those parameters show that δ-Cl isomer displays the highest activity as antitumor drug when intercalating between the DNA basepairs Cytosine-Guanine/Cytosine-Guanine (CG/CG).展开更多
Using DFT/TDDFT methods,the excited-state lifetimes of Ru（Ⅱ） polypyridyl complexes were computed accurately and the reason of Ru（Ⅱ） polypyridyl complexes with long excited-state lifetimes was explained by the el...Using DFT/TDDFT methods,the excited-state lifetimes of Ru（Ⅱ） polypyridyl complexes were computed accurately and the reason of Ru（Ⅱ） polypyridyl complexes with long excited-state lifetimes was explained by the electron-transfer distances and HOMO-LUMO gaps.Finally,the photovoltaic conversion efficiencies of complexes were predicted using DFT and docking methods.This work has provided methods of predicting the excited-state lifetimes and photovoltaic conversion efficiencies of Ru（Ⅱ） polypyridyl complexes.展开更多
The interactions of mixed porphyrin-polypyridyl Ru（Ⅱ） complexes [m（Py-3＇）TPP-Ru（phen）2Cl]^＋（1） and its derivatives [Nim（Py-3＇）TPP-Ru（phen）2Cl]＋（2） and [Cum（Py-3＇）TPP-Ru（phen）2Cl]^＋（3）（phen=...The interactions of mixed porphyrin-polypyridyl Ru（Ⅱ） complexes [m（Py-3＇）TPP-Ru（phen）2Cl]^＋（1） and its derivatives [Nim（Py-3＇）TPP-Ru（phen）2Cl]＋（2） and [Cum（Py-3＇）TPP-Ru（phen）2Cl]^＋（3）（phen=1,10-phenanthroline; m（Py-3＇）TPP=5-（3＇-pyridyl）-10,15,20-triphenylporphyrin） with bovine serum albumin（BSA） were investigated by fluorescence, UV-Vis and circular dichroism（CD） spectroscopies. The UV-Vis and CD spectral experiments indicated that the secondary structures of the protein were perturbed in the presence of the porphyrin Ru（Ⅱ） complex and the perturbation was enhanced under the irradiation with ultra-violet light. The fluorescence quenching mechanism of BSA by the three complexes was determined to be a static process, and the apparent binding constant K values for complexes 1, 2 and 3 measured by fluorescence quenching method were （3.86±0.03）×10^3 L/mol（n=0.94±0.04）, （5.69±0.04）× 103 L/mol（n=1.03±0.06）, and （6.54±0.02）× 10^3 L/mol（n=1.03±0.05）, respectively.展开更多
The spectroscopic properties for a recently synthesized hetero-metallo- binuclear complex Ru(bpy)_2 (bpy-cyclam-Ni)^(4+)(3)and its related complexes 1 and 2 were investigated by UV-vis and emission spectral methods.A ...The spectroscopic properties for a recently synthesized hetero-metallo- binuclear complex Ru(bpy)_2 (bpy-cyclam-Ni)^(4+)(3)and its related complexes 1 and 2 were investigated by UV-vis and emission spectral methods.A drastic quenching of fluorescence from the Ru(bpy)_3^(2+) subunit by the covalently attached quencher sub- unit Ni(cyclam)^(2+) was observed for complex 3,and the mechanism was discussed.展开更多
Photoinduced electron transfer reaction between the excited state ruthenium (II) polypyridyl complexes and quinones has been investigated in cetyltrimethylammonium bromide using luminescent quenching techniques. The c...Photoinduced electron transfer reaction between the excited state ruthenium (II) polypyridyl complexes and quinones has been investigated in cetyltrimethylammonium bromide using luminescent quenching techniques. The complexes have the absorption and emission maximum in the range 452 - 468 nm and 594 - 617 nm respectively. The static nature of quenching is confirmed from the ground state absorption studies. The association constants for the complexes with quinones are calculated from the Benesi-Hildebrand plots using absorption spectral data. The value of quenching rate constant (kq) is highly sensitive to the nature of the ligand and the quencher, the medium, structure and size of the quenchers. Compared to the aqueous medium, the electron transfer rate is altered in CTAB medium. The oxidative nature of the quenching is confirmed by the formation of Ru3+ ion and quinone anion radical.展开更多
Spectrophotometric method was used to evaluate the kinetic of the complex formation from the reaction between H[Ru(III)Cl2(H2EDTA)] and the modifier agent [3-(2-aminoethyl)aminopropyl] trimethoxysilane (AEATS) (μ = 0...Spectrophotometric method was used to evaluate the kinetic of the complex formation from the reaction between H[Ru(III)Cl2(H2EDTA)] and the modifier agent [3-(2-aminoethyl)aminopropyl] trimethoxysilane (AEATS) (μ = 0.50 mol.dm-3 with NaCF3COO, 298.15 K), in pseudo-first order conditions. These studies showed that the reactions are successives producing several species influenced by the concentrations ratio. The electronics spectrum of all solutions showed a band in 457 nm with variable molar absorptivity (ε).展开更多
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.
基金financially supported by the National Science Foundation of China(Nos.22022803,22078046,21808028)Science and Technology Foundation of Liaoning Province(Nos.2019BS-047,2021-YGJC-17)Fundamental Research Funds for the Central Universities(No.DUT20YG131)。
文摘Poly(ethylene glycol)-poly(lactic acid)block copolymer(PEG-PLA)is one of the most widely used biomedical polymers in clinical drug delivery owing to its biocompatibility and biodegradability.However,endowing PEG-PLA micelles with high drug loading,self-assembly stability and fast intracellular drug release is still challenging.Redox-responsive diblock copolymers(MPEG-SS-PMLA)of poly(ethylene glycol)and phenyl-functionalized poly(lactic acid)with disulfide bond as the linker are synthesized to prepare PLA-based micelles that demonstrate excellent colloidal stability and high Ru loading.Notably,MPEGSS-PMLA achieved a remarkably high Ru loading efficiency of 84.3%due to the existence of strongπ-πstacking between phenyl and Ru complex.MPEG-SS-PMLA exhibited good colloidal stability in physiological condition but quickly destabilized by reductive tumor microenvironment.Interestingly,about 74%of Ru complex was released under 10 mmol/L GSH concentration.Ru-loaded MEPG-SS-PMLA showed efficient delivery and release of Ru complex into MCF-7 cancer cells,achieving enhanced in vitro and in vivo antitumor activity of photodynamic therapy.This feasible functionalization method of MPEG-PLA has appeared to be a clinically viable platform for controlled delivery therapeutic agents and enhanced phototherapy.
文摘The ground and the lowest-lying triplet excited state geometries, electronic structures, and spectroscopic properties of three mixed-ligand Ru（II） complexes [Ru（terpy）（phen）X]＋ （terpy=2,2＇,6＇,2″-terpyridine, phen=l,10-phenanthroline, and X=-C-=CH （1）, X=Cl （2）, X-CN （3）） were investigated theoretically using the density functional theory method. The ground and excited state geometries have been fully optimized at the B3LYP/LanL2DZ and UB3LYP/LanL2DZ levels, respectively. The absorption and emission spectra of the com- plexes in CHaCN solutions were calculated by time-dependent density functional theory with the PCM solvent model. The calculated bond lengths of Ru-C, Ru-N, and Ru-Cl in the ground state agree well with the corresponding experimental results. The highest occupied molecular orbital were dominantly localized on the Ru atom and monodentate X ligand for 1 and 2, Ru atom and terpy ligand for a, while the lowest unoccupied molecular orbital were π＊（terpy） type orbital. Therefore, the lowest-energy absorptions of 1 and 2 at 688 and 631 nln are attributed to a dyz （Ru）＋Tr/p（X）--π＊ （terpy） transition with MLCT/XLCT （metal-to-ligand charge transfer/X ligand to terpy ligand charge transfer） character, whereas that of 3 at 529 nm is related to a dyz （Ru）＋π（terpy）-π＊ （terpy） transition with MLCT and ILCT transition character. The calculated phosphorescence of three complexes at 1011 nm （1）, 913 nm （2）, and 838 nm （3） have similar transition properties to that of the lowest-lying absorption. It is shown that the lowest lying absorptions and emissions transition character of these Ru（II） complexes can be tuned by changing the electron-withdrawing ability of the monodentate ligand.
文摘Cyclic voltammetry (CV) and single-step chronocoulometry were used to study the interaction of [Ru(phen)2dppz]2+ (phen=1,10-phenanthroline; dppz=dipyrido[3,2-a:2′,3′-c]phen- azine) with herring sperm DNA. The addition of DNA caused a diminution in the peak current and a positive shift in the peak potential of the complex of [Ru(phen)2dppz]2+. The 12 mV positive shift in the peak potential of [Ru(phen)2dppz]2+ indicates that [Ru(phen)2dppz]2+ binds 2.6 times more strongly to DNA than its reductive form. In addition, by using fluorimetric and UV-spectrophotometric methods and studies of denatured DNA and the effect of NaCl solution, it was also found that the binding mode was intercalation. The decrease of peak current is proportional to the concentration of DNA, which can be applied to estimate DNA concentration.
基金the National Natural Science Foundation of China (Grant Nos. 60478013 and 20571089)The Key Program of Natural Science Foundation of Guangdong Province of China (Grant No. 05101819)+1 种基金the Doctoral Program Foundation of Institutions of Higher Education of China (Grant No. 20040558031)the Scientific Research Foundation of Maoming College (Grant No. 203346)
文摘The transient luminescence of three kinds of ruthenium complexes [Ru(bpy)2(7-CH3-dppz)]2+, [Ru(bpy)2(7-F-dppz)]2+ and [Ru(phen)2(7-F-dppz)]2+ bound to calf thy-mus DNA (ctDNA) has been studied by using the time-resolved spectroscopy. The results show that the luminescence is due to the radiative decay from the charge-transfer states to the ground state. By the interaction with DNA, the radia-tiveless rate of the photoexcited Ru complex molecules decreases, which results in the increase of luminescence lifetime and efficiency. The structure of the Ru com-plex has an important impact on the interaction with DNA. The [Ru(bpy)2(7-CH3-dppz)]2+ shows the longest luminescence lifetime (about 382 ns), while the [Ru(bpy)2(7-F-dppz)]2+ shows the shortest lifetime (about 65 ns). The possible origin of the luminescence dynamics is discussed.
基金Supported by the State Key Program of Fundamental Research( G19980 613 0 8) National Natural Science Foundationof China( Nos.2 99710 0 5 ,2 0 0 2 3 0 0 5 ,2 0 0 710 0 4) ,and Scientific Research Foundation for the Returned Overseas ChineseScholars( State
文摘Structure Activity-Relationships (SARs) of the five possible isomers of RuCl<sub>2</sub>(Azpy)<sub>2</sub> were predicted thanks to DFT method. Azpy stands for 2-phenylazopyridine and the structure of the isomers α-RuCl<sub>2</sub>(Azpy)<sub>2</sub>, β-RuCl<sub>2</sub>(Azpy)<sub>2</sub>, γ-RuCl2(Azpy)2, δ-RuCl<sub>2</sub>(Azpy)<sub>2</sub> and ε-RuCl<sub>2</sub>(Azpy)<sub>2</sub> call respectively α-Cl, β-Cl, γ-Cl, δ-Cl and ε-Cl are defined according to chlorine atoms orientations. Hence, they are divided into two groups. In the first group comprising α-Cl, β-Cl and ε-Cl, both chlorine atoms are in cis position and Azpy ligands are intervertical. Whereas the two others isomers (γ-Cl and δ-Cl), they form the second group. Here, both chlorine are in trans position and Azpy are planar. The five synthesized isomers were investigated as potential antitumor agents. Then, regarding the DNA, its bases are stacked by pair. Therefore, complexes are assumed to insert and to stack on them through intercalative mode. So the electronic and geometric structures become more important to describe their SARs. Consequently, group 2 regarding γ-Cl and δ-Cl presents the best structure to allow intercalation between DNA base-pairs. Besides, the energy order of the lower unoccupied molecular orbital (LUMO) of the isomers is ELUMO(β-Cl) > ELUMO(α-Cl) > ELUMO(ε-Cl) > ELUMO(γ-Cl) > ELUMO(δ-Cl). The energy gap between LUMO and HOMO was also sorted as Δ(L-H)(β-Cl) > Δ(L-H)(α-Cl) > Δ(L-H)(ε-Cl) > Δ(L-H)(γ-Cl) > Δ(L-H)(δ-Cl). In addition, the total dipole moment was classified as μ(ε-Cl) > μ(β-Cl) > μ(α-Cl) > μ(γ-Cl) > μ(δ-Cl). Finally, net charge of the ligand Azpy was also classified as QL(δ-Cl) > QL(γ-Cl) > QL(ε-Cl) > QL(α-Cl) > QL(β-Cl). All those parameters show that δ-Cl isomer displays the highest activity as antitumor drug when intercalating between the DNA basepairs Cytosine-Guanine/Cytosine-Guanine (CG/CG).
基金supported by the Research Foundation of the National Natural Science Foundation of China(No.U1204209)the Major Program of the Natural Science of Anhui University(No.KJ2016SD52)+1 种基金the Key Program of the Natural Science of Anhui University for Young and Middle-aged Key Talent to Study in the Domestic(No.gxfx ZD2016097)Undergraduates Innovating Project(No.201510373083)
文摘Using DFT/TDDFT methods,the excited-state lifetimes of Ru（Ⅱ） polypyridyl complexes were computed accurately and the reason of Ru（Ⅱ） polypyridyl complexes with long excited-state lifetimes was explained by the electron-transfer distances and HOMO-LUMO gaps.Finally,the photovoltaic conversion efficiencies of complexes were predicted using DFT and docking methods.This work has provided methods of predicting the excited-state lifetimes and photovoltaic conversion efficiencies of Ru（Ⅱ） polypyridyl complexes.
基金Supported by the National Natural Science Foundation of China(Nos.20871056, 20771044 and 20901030)the Natural Science Foundation of Guangdong Province, China(Nos.8251063201000008 and 9451063201002077)+1 种基金the Planned Item of Science and Technology of Guangdong Province, China (No.2008A030201020)the "211" Project Grant of Jinan University,China
文摘The interactions of mixed porphyrin-polypyridyl Ru（Ⅱ） complexes [m（Py-3＇）TPP-Ru（phen）2Cl]^＋（1） and its derivatives [Nim（Py-3＇）TPP-Ru（phen）2Cl]＋（2） and [Cum（Py-3＇）TPP-Ru（phen）2Cl]^＋（3）（phen=1,10-phenanthroline; m（Py-3＇）TPP=5-（3＇-pyridyl）-10,15,20-triphenylporphyrin） with bovine serum albumin（BSA） were investigated by fluorescence, UV-Vis and circular dichroism（CD） spectroscopies. The UV-Vis and CD spectral experiments indicated that the secondary structures of the protein were perturbed in the presence of the porphyrin Ru（Ⅱ） complex and the perturbation was enhanced under the irradiation with ultra-violet light. The fluorescence quenching mechanism of BSA by the three complexes was determined to be a static process, and the apparent binding constant K values for complexes 1, 2 and 3 measured by fluorescence quenching method were （3.86±0.03）×10^3 L/mol（n=0.94±0.04）, （5.69±0.04）× 103 L/mol（n=1.03±0.06）, and （6.54±0.02）× 10^3 L/mol（n=1.03±0.05）, respectively.
文摘The spectroscopic properties for a recently synthesized hetero-metallo- binuclear complex Ru(bpy)_2 (bpy-cyclam-Ni)^(4+)(3)and its related complexes 1 and 2 were investigated by UV-vis and emission spectral methods.A drastic quenching of fluorescence from the Ru(bpy)_3^(2+) subunit by the covalently attached quencher sub- unit Ni(cyclam)^(2+) was observed for complex 3,and the mechanism was discussed.
文摘Photoinduced electron transfer reaction between the excited state ruthenium (II) polypyridyl complexes and quinones has been investigated in cetyltrimethylammonium bromide using luminescent quenching techniques. The complexes have the absorption and emission maximum in the range 452 - 468 nm and 594 - 617 nm respectively. The static nature of quenching is confirmed from the ground state absorption studies. The association constants for the complexes with quinones are calculated from the Benesi-Hildebrand plots using absorption spectral data. The value of quenching rate constant (kq) is highly sensitive to the nature of the ligand and the quencher, the medium, structure and size of the quenchers. Compared to the aqueous medium, the electron transfer rate is altered in CTAB medium. The oxidative nature of the quenching is confirmed by the formation of Ru3+ ion and quinone anion radical.
文摘Spectrophotometric method was used to evaluate the kinetic of the complex formation from the reaction between H[Ru(III)Cl2(H2EDTA)] and the modifier agent [3-(2-aminoethyl)aminopropyl] trimethoxysilane (AEATS) (μ = 0.50 mol.dm-3 with NaCF3COO, 298.15 K), in pseudo-first order conditions. These studies showed that the reactions are successives producing several species influenced by the concentrations ratio. The electronics spectrum of all solutions showed a band in 457 nm with variable molar absorptivity (ε).
