Photochemical reactions in solutions of the platinum(II) complex with 8-quinolinol

The rate of photochemical reaction in solutions of luminescent platinum(II) complex with 8-quinolinol was studied in relation to the type of solvent, irradiation time, photon energy and intensity of a luminous flux, concentration of the complex, and presence of oxygen. The structure of the photochemical reaction product was studied by X-ray photoelectron, IR, and electronic absorption spectroscopy. The quantitative kinetic parameters and quantum yield of the photochemical reaction performed under various irradiation conditions are reported.     

Eu chelate with phenanthroline derivative gives selective emission responses to Cu(II) ions

Two novel ternary europium(III) complexes (Eu-1 and 2) based on modified phenanthroline ring have been successfully synthesized and give characteristic purple-red emissions. The complex with 4-substituted carboxyl group has been proved to act as a selective luminescence quencher for copper(II) ions, as shown by the “on/off” switch phenomenon and the smart responsive changes in the UV-vis region (detection limit up to 0.5 μM). The preliminary data imply that Eu-1 could be applicable as a potential fluorescent sensor for detection of copper(II) ions.     

Photochemical reaction of anthracene with dioxygen catalyzed by platinum(II) porphyrin

Visible light irradiation of anthracene in the presence of platinum(II) porphyrin (PtPor) and dioxygen affords anthraquinone as the main product. This reaction involves two steps: the [4+2]cycloaddition of anthracene with singlet oxygen to afford anthracene-9,10-endoperoxide and the degradation of endoperoxide. PtPor catalyzes both reactions.     

Preparation of cationic chelate ylide complexes of palladium(II) and platinum(II)

Cationic palladium(II) and platinum(II) complexes with chelate ylides and neutral ligands of the type, [MCl (Y) (L)]⁺BPh₄^? (M  Pd or Pt; Y  bdep or bdmp*; L = 4-methylpyridine, 3,5-dimethylpyrazole, PPh₃, PCy₃, PMePh₂, P(OMe)₃, AsPh₃ or SbPh₃) and [M(bdep) (4-methylpyridine)₂] (BPh₄)₂ (M = Pd or Pt) were prepared and characterized by means of infrared and ¹H NMR spectra.     

Deep-red luminescence and efficient singlet oxygen generation by cyclometalated platinum(II) complexes with 8-hydroxyquinolines and quinoline-8-thiol

The synthesis and photophysical study of (C/\N)Pt(II)Q complexes, where C/\N is a bidentate cyclometalating ligand and Q is 8-hydroxyquinoline or quinoline-8-thiol, are presented. The compounds were obtained as a single isomer with N atoms of the C/\N and Q ligands trans-coordinated to the Pt(II) center as shown by X-ray crystallography. These chromophores absorb intensely in the visible region and emit in the deep-red spectral region from a quinolate-centered triplet intraligand charge-transfer excited state. The emission maxima are in the range 675-740 nm, with the quantum yields and lifetimes of up to 0.82% and 5.3 mus, respectively, in deoxygenated organic solvents at room temperature. These complexes are efficient photosensitizers of singlet oxygen in air-saturated solutions, with yields up to 90%.     

Novel chelate ring-opening induced by silver(I) of five-coordinate palladium(II) and platinum(II) complexes containing tripodal polyphosphines

The ionic complexes [Pd(NP 3)X]X [NP 3 = tris[2-(diphenylphosphino)ethyl]amine, X = Cl (1), Br(2)] and [M(PP 3)X]X [PP 3 = tris[2-(diphenylphosphino)ethyl]phosphine, M = Pd, X = Cl (3), Br(4); M = Pt, X = Cl (5), Br (6)] contain square pyramidal (1, 2) and trigonal bipyramidal (3- 6) cations with three fused chelate rings to M and one M-X bond. By addition of AgX salts (X = Cl, Br, NO 3) an unexpected ring-opening reaction occurs with formation of the heteronuclear species PdAg(NP 3)X 3 [X = Cl (7), Br (8)], MAg(PP 3)X 3 [M = Pd, X = Cl (9), Br (10), NO 3 (13);M = Pt, X = Cl (11), Br (12), NO 3 (14)]. The complexes have been characterized in the solid state and solution. The X-ray crystal structures of 9 and 13 reveal a distorted square-planar arrangement to Pd(II) that is coordinated to three P of PP 3 (the central and two terminal atoms) and to one chloride (9) or one oxygen atom of NO 3 (13). The resultant dangling phosphorus of the ring opening is bound to Ag(I) that completes the three- [PAgCl 2 ( 9)] and four-coordination [PAg(ONO 2)(O 2NO) (13)] through the donor atoms of the anions with the nitrates in 13 unusually acting as both mono- and bidentate ligands. Complexes 7, 8, 10, and 11 undergo oligomerization in solution. Complex 10 oligomerizes giving rise to the ionic compound [Pd 4Ag 2(PP 3) 2 Br 9]Br ( 10a) whose X-ray crystal structure indicates the presence of cations with a Pd(mu-Br) 3Pd unit that connects via bromide bridges two BrPdP 2PPAg Br 2 fragments containing distorted square-planar and trigonal-planar Pd(II) and Ag(I) centers, respectively. The palladium(II) metal centers in the central unit afford the five-coordination (PdBr 5) with a distorted trigonal bipyramidal geometry. The ionic system [Pt 2Ag 2(PP 3) 2 Cl 5]Cl (11a) consists of chloride anions and heteronuclear monocations. The X-ray crystal structure reveals that the cations contain two distorted square-planar ClPtP 3 units bridged by one PAgCl(mu-Cl) 2AgP fragment that is bearing tetrahedral (PAgCl 3) and trigonal planar PAgCl 2 silver(I) centers. Further additions of the corresponding AgX salts to complexes 7- 14 did not give rise to any new ring-opening reaction.     

Determination of submicrogram amounts of Mercury(II) with 5-(2'-carbomethoxyphenyl)azo-8-quinolinol in presence of anionic surfactant by derivative spectrophotometry

A new sensitive, rapid and selective method is proposed for the determination of mercury in submicrogram level. Mercury(II) forms an insoluble complex with 5-(2'-carbomethoxyphenyl)azo-8-quinolinol in aqueous medium at pH 4-4.8 which can be made soluble by the action of anionic surfactant. The dissolution of the complex results in an orange red colour which is stable for at least 20 hr. The molar absorptivity and Sandell's sensitivity are at 512 nm 8.00 x 10(4) l. mol(-1) . cm(-1) and 0.0025 mug/cm(2), respectively. Derivative spectrophotometry is used to achieve selectivity.     

Highly efficient DNA compaction mediated by an in vivo antitumor-active tetrazolato-bridged dinuclear platinum(II) complex

We investigated the effects of antitumor-active tetrazolato-bridged dinuclear platinum(II) complexes [{cis-Pt(NH(3))(2)}(2)(μ-OH)(μ-tetrazolato-N(1),N(2))](2+) (1) and [{cis-Pt(NH(3))(2)}(2)(μ-OH)(μ-tetrazolato-N(2),N(3))](2+) (2) on the higher-order structure of a large DNA molecule (T4 phage DNA, 166 kbp) in aqueous solution through single-molecule observation by fluorescence microscopy. Complexes 1 and 2 cause irreversible compaction of DNA through an intermediate state in which coil and compact parts coexist in a single DNA molecule. The potency of compaction is in the order 2 > 1 ? cisplatin. Transmission electron microscopic observation showed that both complexes collapsed DNA into an irregularly packed structure. Circular dichroism measurements revealed that the dinuclear platinum(II) complexes change the secondary structure of DNA from the B to C form. These characteristics of platinum(II) complexes are markedly different from those of the usual condensing agents such as spermidine(3+) and [Co(III)(NH(3))(6)](3+). The ability to cause DNA compaction by the platinum(II) complexes is discussed in relation to their potent antitumor activity.     

Synthesis and efficient circularly polarized light emission of an optically active hyperbranched poly(fluorenevinylene) derivative

An optically active, hyperbranched poly(fluorenevinylene) derivative was synthesized by polymerization of (-)-2,4,7-tris(bromomethyl)-9-neomenthyl-9-pentylfluorene. A spin-coated film sample of the polymer exhibited efficient circularly polarized light (CPL) emission in the visible range of 400-700 nm on photo excitation even without annealing processes leading to chain ordering.     

Room-temperature phosphorescence and energy transfer in luminescent multinuclear platinum(II) complexes of branched alkynyls

A series of luminescent branched platinum(II) alkynyl complexes, [1,3,5-{RC[triple bond]C(PEt3)2PtC[triple bond]C-C6H4C[triple bond]C}3C6H3] (R=C6H5, C6H4OMe, C6H4Me, C6H4CF3, C5H4N, C6H4SAc, 1-napthyl (Np), 1-pyrenyl (Pyr), 1-anthryl-8-ethynyl (HC[triple bond]CAn)), [1,3-{PyrC[triple chemical bond]C(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}2-5-{(iPr)3SiC[triple bond]C}C6H3], and [1,3-{PyrC[triple bond]C(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}2-5-(HC[triple bond]C)C6H3], was successfully synthesized by using the precursors [1,3,5-{Cl(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}3C6H3] or [1,3-{Cl(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}2-5-{(iPr)3SiC[triple bond]C}C6H3]. The X-ray crystal structures of [1,3,5-{MeOC6H4C[triple bond]C(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}3C6H3] and [1,8-{Cl(PEt3)2PtC[triple bond]C}2An] have been determined. These complexes were found to show long-lived emission in both solution and solid-state phases at room temperature. The emission origin of the branched complexes [1,3,5-{RC[triple bond]C(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}3C6H3] with R=C6H5, C6H4OMe, C6H4Me, C6H4CF3, C5H4N, and C6H4SAc was tentatively assigned to be derived from triplet states of predominantly intraligand (IL) character with some mixing of metal-to-ligand charge-transfer (MLCT) (dpi(Pt)-->pi*(C[triple bond]CR)) character, while the emission origin of the branched complexes with polyaromatic alkynyl ligands, [1,3,5-{RC[triple bond]C(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}3C6H3] with R=Np, Pyr, or HC[triple bond]CAn, [1,3-{PyrC[triple bond]C(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}2-5-{(iPr)3SiC[triple bond]C}C6H3], [1,3-{PyrC[triple bond]C(PEt3)2PtC[triple bond]CC6H4C[triple bond]C}2-5-(HC[triple bond]C)C6H3], and [1,8-{Cl(PEt3)2PtC[triple bond]C}2An], was tentatively assigned to be derived from the predominantly 3IL states of the respective polyaromatic alkynyl ligands, mixed with some 3MLCT (d(pi)(Pt)-->pi*(C[triple bond]CR)) character. By incorporating different alkynyl ligands into the periphery of these branched complexes, one could readily tune the nature of the lowest energy emissive state and the direction of the excitation energy transfer.     

Thin-film conducting polymers based on Ni(II), Pd(II), and Pt(II) complexes with 8-quinolinol

New thin polymeric films were prepared electrochemically on the basis of Ni(II), Pd(II), and Pt(II) complexes with 8-quinolinol, and conditions of synthesis were optimized. Basic characteristics of the films such as the thickness, charge transfer rate in the polymeric matrix, and photovoltaic effect were determined.     

Substitution of ligands in dichloro-2-(arylazo)heterocyclepalladium(II) by 8-quinolinol: kinetics and mechanistic studies

Nucleophilic substitutions of Pd(N,N)Cl₂[(N,N = 1-methyl-2-(arylazo)imidazole (RaaiMe), p-RC₆H₄N=NC₃H₂NN-1-Me; 2-(arylazo)pyridine (Raap), p-RC₆H₄N=NC₅H₄N; 2-(arylazo)pyrimidine (Raapm), p-RC₆H₄N=NC₄H₃N₂ where R = H (a), Me (b), Cl (c)] with 8-quinolinol (HQ) have been examined by spectrophotometry at 298 K in MeCN solution. The product, Pd(Q)₂, has also been confirmed by independent synthesis from Na₂[PdCl₄] and HQ in EtOH. The kinetics of the reaction have been studied under pseudo-first-order conditions and the analyses support a nucleophilic association path. A single phase reaction has been observed and follows the rate law, rate = a + k [Pd(N,N)Cl₂] [HQ]². Thus, the reaction is first order in [Pd(N,N)Cl₂] and second order in [HQ]. External addition of Cl^–(LiCl) suppresses the rate. The rate increases as follows: Pd(RaaiMe)Cl₂ < Pd(Raap)Cl₂ < Pd(Raapm)Cl₂.     

Preconcentration of copper(II) on immobilized 8-quinolinol in a flow-injection system with an ion-selective electrode detector

A column containing 8-quinolinol, immobilized on porous glass, is used for preconcentration and medium exchange in a flow-injection system with a copper ion-selective electrode detector. The metal ions are bound to the chelating ion exchanger while the anions and inert sample components pass to waste without contacting the electrode. Acid is then injected to elute the ions into a neutralizing buffer passing the electrode. Matrix effects are thus reduced because all measurements are made in the same buffer. The detection limits are 10^?7 and 3 × 10^?8 M copper(II) for sample volumes of 5 and 25 ml, respectively. The maximum throughput is 12 and 5 samples h^?1 for the two stated injection volumes.     

Inhibition of Thermus thermophilus HB8 thioredoxin activity by platinum(II)

A 1:1 thioredoxin-Pt(bpy) complex was prepared by adding [Pt(bpy)(en)]Cl(2)(bpy = 2,2'-bipyridine, en = ethylenediamine) to Thermus thermophilus HB8 thioredoxin in pH 8 phosphate buffer. Matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS) and UV spectra of indicate the formation of Pt(bpy)(cys-Ala-Pro-cys-containing peptide fragment). These findings suggest that the Pt(bpy)(2+) unit binds to the active site of thioredoxin. The thioredoxin-platinum complex has no catalytic activity for the reduction of glutathione disulfide in the presence of NADPH and thioredoxin reductase, so that the platinum complex functions as an inhibitor.     

Vapochromic and mechanochromic phosphorescence materials based on a platinum(II) complex with 4-trifluoromethylphenylacetylide

Planar platinum(II) complex Pt(Me(3)SiC≡CbpyC≡CSiMe(3))(C≡CC(6)H(4)CF(3)-4)(2) (6) with 5,5'-bis(trimethylsilylethynyl)-2,2'-bipyridine and 4-trifluoromethylphenylacetylide exhibits remarkable luminescence vapochromic and mechanochromic properties and a thermo-triggered luminescence change. Solid-state 6 is selectively sensitive to vapors of oxygen-containing volatile compounds such as tetrahydrofuran (THF), dioxane, and tetrahydropyrane (THP) with phosphorescence vapochromic response red shifts from 561 and 608 nm to 698 nm (THF), 689 nm (dioxane), and 715 nm (THP), respectively. Upon being mechanically ground, desolvated 6, 6·CH(2)Cl(2), and 6·(1)/(2)CH(2)ClCH(2)Cl exhibit significant mechanoluminescence red shifts from 561 and 608 nm to 730 nm, while vapochromic crystalline species 6·THF, 6·dioxane, or 6·THP affords a mechanoluminescence blue shift from 698 nm (THF), 689 nm (dioxane), or 715 nm (THP) to 645 nm, respectively. When the compounds are heated, a thermo-triggered luminescence change occurs, in which bright yellow luminescence at 561 and 608 nm turns to red luminescence at 667 nm with a drastic red shift. The multi-stimulus-responsive luminescence switches have been monitored by the changes in emission spectra and X-ray diffraction patterns. Both X-ray crystallographic and density functional theory studies suggest that the variation in the intermolecular Pt-Pt interaction is the key factor in inducing an intriguing luminescence switch.     

Structures of platinum(II) complexes of 2-aminomethylaziridine and S-2-aminomethylazetidine and correlation of anticancer activities of (2-aminomethylazacycloalkane)platinum(II) complexes with the geometry of the chelate rings formed with platinum(II)

The spectroscopic properties of platinum(II) complexes with 2-aminomethyl-derivatives of small-membered 1-aza-cycloalkane, i.e., =2-aminomethylaziridine=azida and S-2-aminomethylazetidine=S-azeda, and the crystal structures of their dichloro complexes demonstrate that the conformation of the fused three- (azida) or four- (S-azeda) and five-membered chelate ring formed by the coordination of S-azida and S-azeda to platinum(II) has an S(N) absolute configuration at the secondary amine site and that the two alkyl groups extend axially from the five-membered chelate ring. The chelate ring of the azida is more planar than the S-azeda or other 2-aminomethyl-1-azacycloalkanes. The anticancer activity reported for azeda and 2-aminomethylpyrrolidine appears to be related to their coordination structure, namely the presence of cis-fused successive rings.     

Complexes of palladium(II) and platinum(II) with 2-hydrazinopyridine and 8-hydrazinoquinoline

The square planar complexes cis-[MCl₂(hypy)], cis-[MCl₂(hyqu)], [Pt(hypy)₂] [PtCl₄], [Pd(hypy)₂][ClO₄]₂ and [Pd(hyqu)₂][ClO₄]₂ (M = Pd or Pt, hypy = 2-hydrazinopyridine, hyqu = 8-hydrazinoquinoline), in which hypy and hyqu act as bidentate chelating ligands, have been prepared and characterized. Complexes containing hyqu do not appear to have been isolated previously.     

聚(乙烯基二苯甲酮)及其共聚物的磷光光谱和磷光淬灭

本工作对聚(乙烯基二苯甲酮)及其共聚物在玻璃态(77K)时的磷光光谱进行测定.发现在相同发色团浓度条件下,聚(乙烯基二苯甲酮)有着最低的磷光强度,说明聚(乙烯基二苯甲酮)体系存在着严重的T-T湮灭过程.用降冰片二烯去淬灭聚(乙烯基二苯甲酮)及其共聚物磷光时,所得结果能较好地符合Stern-Volmer关系式,表明其间存在着能量迁移的作用。     

Solvent extraction of cobalt(II) with 8-quinolinol and its analogues in the presence of some heterocyclic nitrogen bases

Summary Pyridine and its 2-methyl, 2,4-dimethyl and 2,4,6-trimethyl derivatives enhance the extraction of cobalt(II) into chloroform in the presence of 8-quinolinol and its 2-methyl, 4-methyl, 5-chloro and 5-nitro analogues. Adduct formation constants were determined for the cobalt(II) chelates, which formed diadducts with the pyridine bases. The special role of steric factors is discussed. The results are consistent with Lewis acid-base concepts.