Koji Kubono

The title compound, [Zn₂(C₂₂H₁₈ClN₄O)Cl₃], is a dinuclear zinc(II) complex with three chlorido ligands and one pentadentate ligand containing quinolin-8-olato and bis(pyridin-2-ylmethyl)amine groups. One of the two Zn^II atom adopts a tetrahedral geometry and coordinates two chlorido ligands with chelate coordination of the N and O atoms of the quinolin-8-olato group in the ligand. The other Zn^II atom adopts a distorted trigonal–bipyramidal geometry, and coordinates one chlorido-O atom of the quinolin-8-olato group and three N atoms of the bis(pyridin-2-ylmethyl)amine unit. In the crystal, two molecules are associated through a pair of intermolecular C—H...Cl hydrogen bonds, forming a dimer with an R ₂ ²(12) ring motif. Another intermolecular C—H...Cl hydrogen bond forms a spiral C(8) chain running parallel to the [010] direction. The dimers are linked by these two intermolecular C—H...Cl hydrogen bonds, generating a ribbon sheet structure in ac plane. Two other intermolecular C—H...Cl hydrogen bonds form a C(7) chain along the c-axis direction and another C(7) chain generated by a d-glide plane. The molecules are cross-linked through the four intermolecular C—H...Cl hydrogen bonds to form a three-dimensional network.

The asymmetric unit of the title compound is composed of two independent ion pairs of 4-(dimethylamino)pyridin-1-ium 8-hydroxyquinoline-5-sulfonate (HDMAP⁺·HqSA⁻, C₇H₁₁N₂ ⁺·C₉H₆NO₄S⁻) and neutral N,N-dimethylpyridin-4-amine molecules (DMAP, C₇H₁₀N₂), co-crystallized as a 1:1:1 HDMAP⁺:HqSA⁻:DMAP adduct in the monoclinic system, space group Pc. The compound has a layered structure, including cation layers of HDMAP⁺ with DMAP and anion layers of HqSA⁻ in the crystal. In the cation layer, there are intermolecular N—H...N hydrogen bonds between the protonated HDMAP⁺ molecule and the neutral DMAP molecule. In the anion layer, each HqSA⁻ is surrounded by other six HqSA⁻, where the planar network structure is formed by intermolecular O—H...O and C—H...O hydrogen bonds. The cation and anion layers are linked by intermolecular C—H...O hydrogen bonds and C—H...π interactions.

In the title compound, [Na(C₂₂H₁₉N₄O₄S)(CH₃CN)]_n, the Na^I atom adopts a distorted square-pyramidal coordination geometry, formed by one N and one O atom of the qunolinol moiety in the ligand, two O atoms of sulfonate moieties of two adjacent ligands and the N atom of the coordinated acetonitrile solvent. The Na^I atom is located well above the mean basal plane of the square-based pyramid. The apical position is occupied by a sulfonate O atom of a neighboring ligand. Three N atoms of the bis(pyridin-2-ylmethyl)amine moiety in the ligand are not coordinated by the sodium atom. The molecule forms an intramolecular bifurcated O—H...[N(tertiary amine),N(pyridine)] hydrogen bond, generating S(6) and S(5) rings. In the crystal, four molecules are linked by four Na—O(sulfonato) bridged coordination bonds, forming a supramolecular centrosymmetric tetramer unit comprising an eight-membered ring, and generating a two-dimensional network sheet. The molecules of different sheets form intermolecular C—H...O hydrogen bonds, and thereby a three-dimensional network structure.

The title compound, C₃₃H₃₃N₃, is a carbazolophane, which is a cyclophane composed of two carbazole fragments. It has a planar chirality but crystallizes as a racemate in the space group P-1. The molecule adopts an anti-configuration, in which two carbazole fragments are partially overlapped. Both carbazole ring systems are slightly bent, with the C atoms at 3-positions showing the largest deviations from the mean planes. The dihedral angle between two carbazole fragments is 5.19 (3)°, allowing an intramolecular slipped π–π interaction [Cg...Cg = 3.2514 (8) Å]. In the crystal, the molecules are linked via intermolecular C—H...N hydrogen bonds and C—H...π interactions into a network sheet parallel to the ab plane. The molecules of different sheets form other C—H...π interactions, thus forming a three-dimensional network.

The molecule of the title compound, C₁₆H₁₄N₂O, contains an essentially planar indole ring system and a phenyl ring. In the crystal, the molecules are linked by a weak intermolecular C—H...O hydrogen bond and C—H...π interactions, forming a one-dimensional column structure along the b-axis direction. These columns are linked by other C—H...π interactions, forming a two-dimensional network structure.

In the title compound, [ZnBr₂(C₂₂H₁₉ClN₄O)], the Zn^II atom adopts a distorted square-pyramidal coordination geometry, formed by two bromido ligands and three N atoms of the bis(pyridin-2-ylmethyl)amine moiety in the pentadentate ligand containing quinolinol. The Zn^II atom is located well above the mean basal plane of the square-based pyramid. The apical position is occupied by a Br atom. The O and N atoms of the quinolinol moiety in the ligand are not coordinated to the Zn^II atom. An intramolecular O—H...N hydrogen bond, generating an S(5) ring motif, stabilizes the molecular structure. In the crystal, the molecules are linked by intermolecular C—H...Br hydrogen bonds, generating ribbon structures containing alternating R ₂ ²(22) and R ₂ ²(14) rings. These ribbons are linked through an intermolecular C—H...Br hydrogen bond, forming a two-dimensional network sheet.

In the title compound, C24H15Cl2N3O2, one quinoline ring system is essentially planar and the other is slightly bent. An intramolecular O-H center dot center dot center dot N hydrogen bond involving the hydroxy group and a pyridine N atom forms an S(5) ring motif. In the crystal, two molecules are associated into an inversion dimer with two R-2(2)(7) ring motifs through intermolecular O-H center dot center dot center dot N and O-H center dot center dot center dot O hydrogen bonds. The dimers are further linked by an intermolecular C-H center dot center dot center dot O hydrogen bond and four C-H center dot center dot center dot pi interactions, forming a two-dimensional network parallel to (001).

Partially overlapped dicarbazolophanes exhibit a planar chirality. In this study, C-2-symmetrical [3.3](3,9)dicarbazolophane derivatives (CZ1-CZ3) have been optically resolved by preparative chiral high-performance liquid chromatography for the first time. In their circular dichroism (CD) spectra, moderate Cotton effects (CEs) were observed for their L-1(b) and L-1(a) transitions (vertical bar Delta epsilon vertical bar = 10-12 and 51-57 M-1 cm(-1), respectively), while intense CEs were notified in their B-1 transitions (vertical bar Delta epsilon vertical bar = 156-216 M-1 cm(-1)), absorption dissymmetry (g(abs)) factors being in orders of 10(-2). Circularly polarized luminescence spectrum was also obtained for cyanamide derivative CZ1, with a comparative luminescence dissymmetry (g(lum)) factor of 0.013. A computational investigation was applied to address the factors for such remarkable chiroptical responses in these dicarbazolophanes of planar chirality. Absolute configurations were unambiguously determined by the comparison of experimental and theoretical CD spectra, which was affirmed by the X-ray crystal structural analysis of enantiomerically pure sulfonamide derivative CZ2.

In the title compound, C₂₇H₂₉BrN₂, the carbazole ring system is essentially planar, with an r.m.s. deviation of 0.0781 (16) Å. An intramolecular N—H...N hydrogen bond forms an S(6) ring motif. One of the tert-butyl substituents shows rotational disorder over two sites with occupancies of 0.592 (3) and 0.408 (3). In the crystal, two molecules are associated into an inversion dimer through a pair of C—H...π interactions. The dimers are further linked by another pair of C—H...π interactions, forming a ribbon along the c-axis direction. A C—H...π interaction involving the minor disordered component and the carbazole ring system links the ribbons, generating a network sheet parallel to (100).

A series of novel mono- and bis[(9-alkylcarbazol-3-yl) methyl]acrylamides were synthesized and their radical polymerization was investigated. Emissions of bis(carbazolyl) acrylamide polymers were extended to longer wavelengths compared with those of the corresponding mono(carbazolyl) polymers, indicating the existence of interchromophoric interaction between carbazole moieties. Ionization potentials of the polymers by photoelectron yield spectroscopy showed that donor ability of the biscarbazolyl polymer was higher than that of the monocarbazolyl polymer.

In the title compound, C15H18N2O3, the coumarin ring is essentially planar, with an r.m.s. deviation of 0.012Å. An intramolecular O - H⋯N hydrogen bond forms an S(6) ring motif. The piperazine ring adopts a chair conformation. In the crystal, a C - H⋯O hydrogen bond generates a C(4) chain motif running along the c axis. The chain structure is stabilized by a C - H⋯π interaction. The chains are linked by π-π interactions [centroid-centroid distance of 3.5745(11)Å], forming a sheet structure parallel to the bc plane.

In the title compound, C22H19ClN4O, the quinolinol moiety is almost planar [r.m.s. deviation = 0.012Å]. There is an intramolecular O - H⋯N hydrogen bond involving the hydroxy group and a pyridine N atom forming an S(9) ring motif. The dihedral angles between the planes of the quinolinol moiety and the pyridine rings are 44.15(9) and 36.85(9)°. In the crystal, molecules are linked via C - H⋯O hydrogen bonds forming inversion dimers with an R 4 4(10) ring motif. The dimers are linked by C - H⋯N hydrogen bonds, forming ribbons along [01-1]. The ribbons are linked by C - H⋯π and π-π interactions [inter-centroid distance = 3.7109(11)Å], forming layers parallel to (01-1).

Photoinduced color change of naphthalene diimides (NDIs) bearing alkylamine moieties has been observed in the solid state. The color change is attributed to the generation of a NDI radical-anion species, which may be formed through a photoinduced electron-transfer process from the alkylamine moiety to the NDI. The photosensitivity of NDIs is highly dependent on the structures of the alkylamine moieties. Crystallographic analysis, kinetic analysis, UV/Vis/NIR spectroscopic measurements, and analysis of the photoproduct suggested that a radical anion was formed through an irreversible process initiated by proton abstraction between an amine radical cation and the neutral amine moiety. The radical anions formed stacks including mixed-valence stacks and radical-anion stacks, as shown by the broad absorption bands in near-IR spectra. These photosensitive NDIs also showed crystal bending upon photoirradiation, which may be associated with a change in the intermolecular distance of the NDI stacks by the formation of monomeric radical anions, mixed-valence stacks, and radical-anion stacks.

In the title linear homo-trinuclear complex, [Cd3(C 19H18Cl2N2O2)2(C 2H3O2)2], the central CdII atom is located on a centre of inversion and has a distorted octahedral coordination geometry formed by four O atoms from two bidentate/tetradentate Schiff base ligands and two O atoms from two bridging acetate ligands. The coordination geometry of the terminal CdII atom is square-pyramidal with the tetradentate part of the ligand in the basal plane and one O atom from an acetate ligand occupying the apical site. The six-membered CdN2C 3 ring adopts a chair conformation. The acetate-bridged Cd⋯Cd distance is 3.3071 (2) Å. The crystal structure is stabilized by C-H⋯O hydrogen bonds, which form C(7) chain motifs and give rise to a two-dimensional supramolecular network structure lying parallel to the ab plane.

Formation dynamics of intramolecular excimer in dioxa[3.3](3,6)carbazolophane (CzOCz) was studied by time-resolved spectroscopic methods and computational calculations. In the ground state, the most stable conformer in CzOCz is the anti-conformation where two carbazole rings are in antiparallel alignment. No other isomers were observed even after the solution was heated up to 150 degrees C, although three characteristic isomers were found by the molecular mechanics calculation: the first is the anti-conformer, the second is the syn-conformer where two carbazole rings are stacked in the same direction, and the third is the int-conformer where two carbazole rings are aligned in an edge-to-face geometry. Because of the anti-conformation, the interchromophoric interaction in CzOCz is negligible in the ground state. Nonetheless, the intramolecular excimer in CzOCz was dynamically formed in an acetonitrile (MeCN) solution, indicating strong interchromophoric interaction and the isomerization from the anti- to syn-conformation in the excited state. The excimer formation in CzOCz is more efficient in polar solvents than in less polar solvents, suggesting the contribution of the charge transfer (CT) state to the excimer formation. The stabilization in the excited state is discussed in terms of molecular orbital interaction between two carbazole rings. The solvent-polarity-induced excimer formation is discussed in terms of the CT character in the int-conformation.

The title compound, [Cu3(C19H18Cl 2N2O2)2(CH3CO2)2], is a linear homo-trinuclear CuII complex. The central CuII atom is located on a centre of inversion and has a distorted octahedral coordination environment formed by six O atoms from two tetradentate Schiff base ligands and two bridging acetate ligands. The coordination geometry of the terminal Cu II atom is square-pyramidal with a tetradentate ligand in the basal plane. The apical site is occupied by one O atom from an acetate ligand. The acetate-bridged Cu⋯Cu distance is 3.0910(5)Å. An intramolecular C-H⋯O hydrogen bond forms an S(6) ring motif. The crystal of the trinuclear complex is stabilized by C-H⋯O hydrogen bonds.

Diarylethene derivatives, 1c and 1d, having carrier mobilization sites have been synthesized. Their photochromic properties are examined both in solution and in thin film. Current voltage characteristics at photostationary state of 1c and 1d showed drastic current increase compared with the corresponding open-ring isomers 1c and 1d, respectively.

The title compound, C43H32F6N2S2, is a new symmetrical photochromic diarylethene derivative with 9-ethylcarbazol-3-yl substituents. The molecule adopts a photoactive antiparallel conformation [Irie (2000). Chem. Rev. 100, 1685-1716; Kobatake et al. (2002). Chem. Commun. pp. 2804-2805], with a dihedral angle between the mean planes of the two thiophene rings of 56.23 (6)degrees. The distance between the two reactive C atoms is 3.497 (3) angstrom. In the crystal, two molecules are associated through a pair of C-H center dot center dot center dot F intermolecular hydrogen bonds, forming a centrosymmetric dimer. Dimers are linked by weak pi-pi interactions [centroid-centroid distance = 3.8872 (13) angstrom], forming chains along the c axis.

A pretreatment method for the speciation of dissolved phosphorus compounds in water samples is proposed. For a sample solution containing orthophosphate, organophosphorus compound, and polyphosphoric acid, a three-step procedure has been developed for the determination of each phosphorus compound. At first, orthophosphate was determined with a conventional molybdenum-blue method. Second, an organophosphorus compound was decomposed selectively to orthophosphate by five minutes of UV irradiation with using a 400 W low-pressure mercury lamp. Finaly, in the presence of sulfuric acid and photocatalytic TiO(2), the organophosphorus compound and polyphosphoric acid were decomposed to orthophosphate by thirty-five minutes of UV irradiation. The orthophosphate concentration obtained for each step was successfully used to estimate the concentration of the orthophosphate, organophosphorus compound, and the polyphosphoric acid originally present. In addition, an investigation of the wavelength dependence of the decomposition efficiency with a colored glass filter, showed that the irradiation of 184.9 nm is important for photodecomposing an organophosphorus compound; that of 365 nm in the presence of photocatalytic TiO(2) is important to photodecompose polyphosphoric acid. This new method should be effective as a pretreatment method for the speciation of dissolved phosphorus compounds.

In the centrosymmetric dinuclear Cu(II) title complex, [Cu(2)(C(18)H(16)Cl(4)N(2)O(2))(2)], the Cu(II) atom adopts a square-pyramidal geometry with a tetradentate ligand in the basal plane. The apical site is occupied by a phenolate O atom from an adjacent ligand, forming a dimer. The molecular structure is stabilized by intramolecular C-H center dot center dot center dot O and C-H center dot center dot center dot Cl hydrogen bonds.

Tris-bridged [3.3.n](3,6,9)carbazolophanes 1n (n = 3-6), which are appropriate model Compounds for fully overlapped excimer in carbazole chromophore, have been synthesized and characterized by NMR, X-ray, absorption and fluorescence spectra; lit showed excimeric fluorescence, whose emission maxima strongly depended on the angles and distances between carbazole rings.

The titile compound, C(18)H(20)Cl(2)N(2)O(2), crystallizes as a monoclinic form in the space group P2(1)/n, with Z ' = 1/2. It is polymorphic with the previously reported orthorhombic form [Kubono, Tsuno, Tani & Yokoi (2008). Acta Cryst. E64, o2309]. In the present polymorph, the molecule lies on a crystallographic inversion centre at the piperazine ring centroid. An intramolecular O-H center dot center dot center dot N hydrogen bond forms an S(6) ring motif. Intermolecular C-H center dot center dot center dot O hydrogen bonding generates a C(5) chain motif propagating along the b axis, forming sheets parallel to (202) with a first-level graph set S(6)C(5)R(6)(6)(34).

The title compound, C18H18Cl4N2O2, crystallizes as monoclinic and ortho-rhom-bic polymorphs from CHCl3-CH3OH solution. In both polymorphic forms, the mol-ecule lies on a crystallographic centre of inversion (at the piperazine ring centroid) and exhibits an intra-molecular O - H⋯N hydrogen bond. In the monoclinic polymorph (space group P21/c), the mol-ecules are linked by inter-molecular C - H⋯Cl hydrogen bonds into a ribbon sheet built from R 8 8(34) rings. In the ortho-rhom-bic polymorph (space group Pbcn), the mol-ecules are linked by inter-molecular C - H⋯O hydrogen bonds into a ribbon sheet of R 6 6(34) rings. The sheets in the ortho-rhom-bic polymorph are crosslinked into a three-dimensional framework by π-π stacking inter-actions. © International Union of Crystallography 2007.

Cyanamide- andoxa-bridged [3.n](3,9)carbazolophanes 1n and 2n (n = 4 and 5) were synthesized. X-ray analysis Of 14 and 25 revealed that carbazole rings are taken to be partially overlapped geometry. Electronic spectra of 1n and 2n (n = 4 and 5) showed the existence of transannular pi-pi electronic interaction between two carbazole rings, whereas fluorescence of these carbazolophanes indicated monomer-like emission.

In the title compound, [Cu(C12H14Cl2NO)(2)], the Cu-II atom is four-coordinated in a distorted square-planar geometry by two N atoms and two O atoms from two 2,4-dichloro-6-(piperidin-1-ylmethyl) phenolate ligands. The dihedral angle between the N/Cu/O coordination planes is 16.53 (9)degrees.

In the title compound, C12H15Cl2NO, the piperidine ring adopts a chair conformation. An intramolecular O-H center dot center dot center dot N hydrogen bond is observed. The packing of the molecules in the crystal structure is stabilized by pi-pi interactions and Cl center dot center dot center dot Cl contacts.

The title compound, C16H14C12N2O2, crystallizes in a centrosymmetric space group with one-half molecule in the asymmetric unit. The salicylideneimine moiety is almost planar. An intramolecular O-H...N hydrogen bond is observed [O-H...N = 2.611 (3) Angstrom]. The packing of the molecules in the crystal structure is stabilized by pi-pi stacking interactions between salicylideneimine moieties.

The X-ray crystal structure of the title complex, Co(Cl(2)bprpi) is described. In this complex the Co(II) center displays a distorted octahedral coordination geometry. The piperazine ring exhibits boat conformation, forming chelate rings and capping the Co atom. The N2-Col-N3 angle is 69.41(15)degrees, extremely smaller than 90degrees. Because the small angle causes a large steric hindrance, the piperazine ring can be effective as an ion size-recognition site. The molecular structure is stabilized by intramolecular N-(HO)-O-... hydrogen bonds and (ClH)-H-... contacts.

Di-Schiff base ligand, N,N'-bis(2-pyridylmethylidene)-trans-1,2-diiminocyclohexane (trans-BPIC), having sufficient hydrophobicity acts as neutral bidentate ligand in ion-pair extraction of divalent metal cations into nitrobenzene with picrate anion. In present study, the effect of steric restriction by chemical structure around imine-N donor atoms in trans-BPIC analogs on their complexation with divalent metal cations in ion-pair extraction was investigated by using N,N'-bis(2-pyridylmethylidene)-cis-1,2-diiminocyclohexane (cis-BPIC) and N,N'-bis(2-pyridylmethylidene)-o-diiminobenezene (BPIB). The former was used to observe the effect by geometrical restriction and the latter was by conjugate restriction. In BPIB-NaPic system, the higher extractability was obtained than those in cis- and trans-BPIC systems, and this result seems to be led by the increase of steric distortion originated from conformational restriction. Namely, it is considered that the extractability can be controlled by steric restriction on the complexation. (C) 2003 Elsevier Science B.V. All rights reserved.

High-spin Co(II) complexes (S = 3/2) with hydrogen bonding network were synthesized as models for magnetic quantum wires or 2D magnetic network systems. Their magnetic properties were characterized in terms of the SQIUD measurement. An analysis for the magnetic susceptibilities assuming an effective angular momentum L'=1 reproduced the experimental temperature dependences of the susceptibilities. In order to evaluate intermolecular magnetic interactions, it turned out that models beyond Heisenberg-Dirac exchange Hamiltonian are required for the analysis.

Journal of Ion Exchange 14巻の別冊に掲載

Structural control of Schiff base ligands for selective extraction of copper(II) was investigated by changing pendant arms and the distance between two imine-N donor atoms in ligands. Di-Schiff base ligands, N,N-bis(2-quinolylmethylidene)-1,2-diiminoethane (BQIE), N,N-bis(2-pyridylmethylidene)-1,3-diimino-2,2-dimethylpropane (BPMP) and N,N'-bis(2-quinolylmethylidene)-1,3-diimino-2,2-dimethylpropane (BQMP), were used as complexation reagents for ion-pair extraction of divalent transition metal cations into nitrobenzene with picrate anion. The pendant arms affected the lipophilicity of ligand to nitrobenzene, due to their polarity. The distance between two imine-N atoms, on the contrary, was a factor of controlling the extraction selectivity. BQMP has both 2-quinolyl pendant arms and trimethylene backbone structure; use of BQMP as a complexation reagent led to the selective extraction of Cu2+ in the system.

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The use of neutral di-Schiff base ligands, N,N ' -bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) and its analogues, N,N ' -bis[1-(2-pyridyl)ethylidene]-1,2-diiminoethane (BPEE) and N,N ' -bis(2-pyridylmethylidene)-trans-1,2-diiminocyclohexane (BPIC), as complexation reagents for ion-pair extraction of divalent transition metal cations into nitrobenzene with picrate anion was investigated. The results of numerical analysis concerning the extraction behavior indicated that they act as imine-N bidentate ligands in the extraction system. Furthermore, the introduction of the alkyl substituents onto imine-C on BPIE led to the change in the extraction selectivity by steric distortion of the cationic complexes, whereas that onto ethylene-C only caused the enhancement of the extractability. (C) 2001 Elsevier Science B.V. All rights reserved.

Solvent extraction of trivalent group 13 metal cations such as aluminum, gallium and indium with tripod quadridentate phenolic ligand, tris(2-hydroxy-3,5-dimethylbenzyl)amine (H(3)tdmba), was investigated as fundamental study for their mutual separation. Gallium was extracted almost quantitatively as Ga(tdmba) (log K-ex = - 6.66 +/- 0.06 on using chloroform as extraction solvent), whereas aluminum and indium were hardly extracted due to steric hindrance on complexation of them with the ligand. The extracted Ga species was estimated as trigonal bipyramidal complex with one H2O molecule. Furthermore, extractability of Ga was increased by changing the ligand to more acidic tris(5-chloro-2-hydroxy-3-methylbenzyl)amine (H(3)tcmba) (log K-ex = -6.18 +/- 0.18 on using dichloroethane as extraction solvent). (C) 2001 Elsevier Science B.V. All rights reserved.

A novel mutual selectivity of lanthanoids in the N,N'-bis(5-nitrosalicylidene)ethylenediamine (H(2)Nsalen)-KCl and N,N'-bis(5-nitrosalicylidene)-o-phenylenediamine (H(2)Nsaloph)-KCl extraction systems was evaluated by the X-ray analysis of similar model complexes for extracted species. Cerium(IV) complexes with N,N'-bis(5-chlorosalicylidene)-ethylenediamine (H(2)Clsalen), N,N'-bis(salicylidene)-o-phenylenediamine (H(2)saloph) and N,N'-bis(3,5-dibromosalicylidene)-o-phenylenediamine (H(2)Br(2)saloph) were selected as the models. The result of the X-ray analysis suggested that [Ln(III)(Nsalen)(2)](-) and [Ln(III)(Nsaloph)(2)](-) are meridional type (two ligands are oriented perpendicular to each other) and sandwich type (two ligands are oriented parallel to each other), respectively. It was suggested that the selectivity of the meridional structure is superior to that of the sandwich structure in these extraction systems.

A high output low-pressure mercury lamp, 400 W L-Hg, was successfully used for the photolytic decomposition of dissolved oganic compounds as the pretreatment for the determination of trace metal ion in aqueous solution by stripping voltammetry. Various amino acids, showing interferences on voltammetric determination of metal ions, can be removed quite easily by intensive UV irradiation at room temperature. Effect of pH concentration of electrolyte and dissolved oxygen on the efficiency of photolysis are also described. This method uses no additional chemicals such as acids or oxidants and can be carried out in closed clean conditions.