A binucleating ligand(2)combining a monoanionic PCP pincer cleft with a monoanionic N-N cleft has been prepared on the basis of bis(imidazolyl)methane(1).Installation of divalent Pd or Pt into the PCP cleft proceeded ...A binucleating ligand(2)combining a monoanionic PCP pincer cleft with a monoanionic N-N cleft has been prepared on the basis of bis(imidazolyl)methane(1).Installation of divalent Pd or Pt into the PCP cleft proceeded smoothly,with the formation of square planar(PCP)MCl complexes(M=Pd or Pt).The“C”in the PCP is the central carbon of theβ-diketiminate-like N-N cleft.The N-N cleft in these com-plexes was obtained in three levels of protonation.In 4-Pd and 4-Pt,the N-N cleft carries one proton and is neutral;in 3-Pd or 3-Pt,it is additionally protonated by HCl,and in 6-Pd or 6-Pt,the proton has been removed by the(Me_(3)Si)_(2)NLi base and replaced by Li.The chloride in 4-Pd/Pt was replaced with an iodide to make 6-Pd/Pt in a metathesis with Me_(3)SiI.Compounds 4-Pd/Pt and 6-Pd/Pt exhibited tauto-merism reminiscent of acetylacetone andβ-diketimines,possessing either an NH or a CH bond.Compounds 6-Pd/Pt possess a lithiated N-N cleft and serve as convenient transmetallation agents.Their reactions with BF(3)(OE_(t)2),1/2ZnCl_(2),or TaCl_(5)produced new compounds 7-Pd/Pt,8-Pd/Pt,and 9-Pd/Pt that carry a BF_(2),1/2Zn,or TaCl_(4)units in the N-N cleft.Compounds 8-Pd/Pt are trimetallic with a central Zn co-ordinated by two N-N clefts each of which carries a(PCP)MCl on the opposite side.Structures of 3-Pd,7-Pt,8-Pd,and 9-Pd in the solid state were established by X-ray diffractometry.They demonstrate the remarkable planarity of the extended conjugated organicπ-system into which the N-N and the PCP binding sites are incorporated.Electrochemical studies on 7-9 established that each of these extendedπ-systems can be oxidized twice quasi-reversibly.Compounds 9-Pd/Pt could be additionally reduced quasi-reversibly by a single electron,which was ascribed to the reduction of the Ta^(Ⅴ)center to Ta^(Ⅳ).They also differed from 7 and 8 in possessing apparent lower-energy LMCT bands responsible for the blue or purple colors.展开更多
A series of binuclear ruthenium(Ⅱ)arene benzil bis(benzoylhydrazone)complexes(1-6)of the common composition[(η^(6)-arene)_(2)Ru_(2)(L)Cl_(2)](arene=benzene or p-cymene;L=benzil bis(benzoylhydrazone derivatives))have...A series of binuclear ruthenium(Ⅱ)arene benzil bis(benzoylhydrazone)complexes(1-6)of the common composition[(η^(6)-arene)_(2)Ru_(2)(L)Cl_(2)](arene=benzene or p-cymene;L=benzil bis(benzoylhydrazone derivatives))have been synthesized.The synthesised complexes have been thoroughly characterised by elemental analysis,IR,NMR,UV-vis and ESI-MS spectral methods.The coordination of the binucleating ligand to each ruthenium centre through azomethine nitrogen and imidolate oxygen was confirmed by single crystal XRD,which indicates the presence of the pseudo octahedral geometry.All the complexes were carefully screened for their cytotoxicity against HeLa,MDA-MB-231 and Hep G2 cells under in vitro conditions.Interestingly,the complexes 4 and 6 exhibit higher cytotoxicity than cisplatin,with low IC50 values against all screened cancer cell lines.Furthermore,the mode of cell death in MDA-MB-231 cells was assessed by AO-EB,Hoechst 33258 staining and a flow cytometry technique along with the comet assay.The result of western blot analysis suggests that complexes 4 and 6 were shown to induce apoptosis via the mitochondrial pathway by up-regulating p53 and Bax,and down-regulating Bcl-2.展开更多
A new binucleating macrocyclic ligand 2,6-bis (1,4,7,10-te-traazacyclododecan-10-ylmethyl)methoxy-benzene (L) and its binuclear copper (II) complex, [ Cu2LBr2 ] (ClO4 )2 · 3H2O (1), was prepared and the structure...A new binucleating macrocyclic ligand 2,6-bis (1,4,7,10-te-traazacyclododecan-10-ylmethyl)methoxy-benzene (L) and its binuclear copper (II) complex, [ Cu2LBr2 ] (ClO4 )2 · 3H2O (1), was prepared and the structure was determined by X-ray crystallography. Complex 1 crystallizes in monoclinic crystal system, P21/n space group with a = 0.8206(3), b = 2.0892(8), c = 2.3053(7) nm, β=95.83(2)°, V = 3.932 nm3, Mr = 1017.57, Z = 4, Dc= 1.692 g/cm3, and R = 0. 0489, Rw= 0.0552 for 6571 observed reflections with I≥2σ (I). Both of the copper(II) centers are coordinated by four amine nitrogen donors of cyclen subunits and a bromide an-ion, and each copper (II) ion is in a square-pyramidal coordination environment. Variable temperature magnetic susceptibility studies indicate that there exists weak intramolecular an-tiferro-magnetic coupling ( - 2J = 2.06 cm-1) between the two copper(n) centers.展开更多
A localized INDO method was used to calculate the ion [Fe_2 (CH_3) (CO) (Ph_2PCH_2PPh_2)- Cp_2]^+. Based on the analysis of the localized molecular orbitals (LMO), bond orders and contour maps, it was pointed out that...A localized INDO method was used to calculate the ion [Fe_2 (CH_3) (CO) (Ph_2PCH_2PPh_2)- Cp_2]^+. Based on the analysis of the localized molecular orbitals (LMO), bond orders and contour maps, it was pointed out that the LMO no. 20 corresponds to the coordination of C(1)-H(I) σbond to Fe(2) atom. Non occurrence of metal-metal bond between Fe(1) and Fe(2) atoms was found and the covalence of irons was numerated, which coincides with the value in ref 17.展开更多
基金support of this work by the Welch Foundation(grant A-1717 to O.V.O.).
文摘A binucleating ligand(2)combining a monoanionic PCP pincer cleft with a monoanionic N-N cleft has been prepared on the basis of bis(imidazolyl)methane(1).Installation of divalent Pd or Pt into the PCP cleft proceeded smoothly,with the formation of square planar(PCP)MCl complexes(M=Pd or Pt).The“C”in the PCP is the central carbon of theβ-diketiminate-like N-N cleft.The N-N cleft in these com-plexes was obtained in three levels of protonation.In 4-Pd and 4-Pt,the N-N cleft carries one proton and is neutral;in 3-Pd or 3-Pt,it is additionally protonated by HCl,and in 6-Pd or 6-Pt,the proton has been removed by the(Me_(3)Si)_(2)NLi base and replaced by Li.The chloride in 4-Pd/Pt was replaced with an iodide to make 6-Pd/Pt in a metathesis with Me_(3)SiI.Compounds 4-Pd/Pt and 6-Pd/Pt exhibited tauto-merism reminiscent of acetylacetone andβ-diketimines,possessing either an NH or a CH bond.Compounds 6-Pd/Pt possess a lithiated N-N cleft and serve as convenient transmetallation agents.Their reactions with BF(3)(OE_(t)2),1/2ZnCl_(2),or TaCl_(5)produced new compounds 7-Pd/Pt,8-Pd/Pt,and 9-Pd/Pt that carry a BF_(2),1/2Zn,or TaCl_(4)units in the N-N cleft.Compounds 8-Pd/Pt are trimetallic with a central Zn co-ordinated by two N-N clefts each of which carries a(PCP)MCl on the opposite side.Structures of 3-Pd,7-Pt,8-Pd,and 9-Pd in the solid state were established by X-ray diffractometry.They demonstrate the remarkable planarity of the extended conjugated organicπ-system into which the N-N and the PCP binding sites are incorporated.Electrochemical studies on 7-9 established that each of these extendedπ-systems can be oxidized twice quasi-reversibly.Compounds 9-Pd/Pt could be additionally reduced quasi-reversibly by a single electron,which was ascribed to the reduction of the Ta^(Ⅴ)center to Ta^(Ⅳ).They also differed from 7 and 8 in possessing apparent lower-energy LMCT bands responsible for the blue or purple colors.
基金the University Grants Commission(UGC),New Delhi,for financial assistance through the UGC-BSR fellowship(Ref.No.F.7-22/2007(BSR))DST,Govt.of India for a DST-INSPIRE Fellowship(IF150745).
文摘A series of binuclear ruthenium(Ⅱ)arene benzil bis(benzoylhydrazone)complexes(1-6)of the common composition[(η^(6)-arene)_(2)Ru_(2)(L)Cl_(2)](arene=benzene or p-cymene;L=benzil bis(benzoylhydrazone derivatives))have been synthesized.The synthesised complexes have been thoroughly characterised by elemental analysis,IR,NMR,UV-vis and ESI-MS spectral methods.The coordination of the binucleating ligand to each ruthenium centre through azomethine nitrogen and imidolate oxygen was confirmed by single crystal XRD,which indicates the presence of the pseudo octahedral geometry.All the complexes were carefully screened for their cytotoxicity against HeLa,MDA-MB-231 and Hep G2 cells under in vitro conditions.Interestingly,the complexes 4 and 6 exhibit higher cytotoxicity than cisplatin,with low IC50 values against all screened cancer cell lines.Furthermore,the mode of cell death in MDA-MB-231 cells was assessed by AO-EB,Hoechst 33258 staining and a flow cytometry technique along with the comet assay.The result of western blot analysis suggests that complexes 4 and 6 were shown to induce apoptosis via the mitochondrial pathway by up-regulating p53 and Bax,and down-regulating Bcl-2.
基金Project supported by the National Natural Science Foundation of China (No. 19771022 and 29971019), the Natural Science Foundation of Tianjin and the Trans-Century Talents Training Program Foundation from the State Education Ministry of China to Bu, X. H.
文摘A new binucleating macrocyclic ligand 2,6-bis (1,4,7,10-te-traazacyclododecan-10-ylmethyl)methoxy-benzene (L) and its binuclear copper (II) complex, [ Cu2LBr2 ] (ClO4 )2 · 3H2O (1), was prepared and the structure was determined by X-ray crystallography. Complex 1 crystallizes in monoclinic crystal system, P21/n space group with a = 0.8206(3), b = 2.0892(8), c = 2.3053(7) nm, β=95.83(2)°, V = 3.932 nm3, Mr = 1017.57, Z = 4, Dc= 1.692 g/cm3, and R = 0. 0489, Rw= 0.0552 for 6571 observed reflections with I≥2σ (I). Both of the copper(II) centers are coordinated by four amine nitrogen donors of cyclen subunits and a bromide an-ion, and each copper (II) ion is in a square-pyramidal coordination environment. Variable temperature magnetic susceptibility studies indicate that there exists weak intramolecular an-tiferro-magnetic coupling ( - 2J = 2.06 cm-1) between the two copper(n) centers.
文摘A localized INDO method was used to calculate the ion [Fe_2 (CH_3) (CO) (Ph_2PCH_2PPh_2)- Cp_2]^+. Based on the analysis of the localized molecular orbitals (LMO), bond orders and contour maps, it was pointed out that the LMO no. 20 corresponds to the coordination of C(1)-H(I) σbond to Fe(2) atom. Non occurrence of metal-metal bond between Fe(1) and Fe(2) atoms was found and the covalence of irons was numerated, which coincides with the value in ref 17.
