Structural and electronic properties of luminescent copper(I) halide complexes of bis[2-(diphenylphosphano)phenyl] ether (DPEphos). Crystal structure of [CuCl(DPEphos)(dmpymtH

Heteroleptic copper(I) halide complexes containing the bis[2-(diphenylphosphano)phenyl]ether (DPEphos) ligand and the heterocyclic thioamides pyridine-2(1H)-thione (py2SH), pyrimidine-2(1H)-thione (pymtH) or 4,6-dimethylpyrimidine-2(1H)-thione (dmpymtH) have been synthesized and characterized by (1)H-NMR, IR spectroscopy, elemental analyses and melting point determinations. The complexes can be readily obtained by the addition of the thione ligand to a CuX-diphosphane adduct in dichloromethane-ethanol solution. The molecular structure of [CuCl(DPEphos)(dmpymtH)] complex has been established by single-crystal X-ray diffraction. The structure features a tetrahedral copper(I) center with two phosphorus atoms from the chelating diphos ligand, one halogen atom and the exocyclic sulfur atom of the heterocyclic thioamide unit. The complexes are strongly emissive in the solid state at ambient temperature. DFT and TD-DFT calculations were employed to study the structural, electronic and photophysical properties of the novel complexes. Electronic absorption spectra show two broad bands in the regions 275-290 and 380-398 nm of mixed MLCT/IL character. Intense blue-green emission is observed in the region 500-558 nm for complexes having py2SH or dmpymtH thione ligands. The emitting first triplet excited state, T(1) is mainly localized on the thione ligand.     

Copper(I) halide complexes with 2,2′-bis(diphenylphosphano)-1,1′-binaphthyl (rac-binap) and heterocyclic thiones. Racemic compounds in chiral and achiral crystal space groups

Reactions of copper(I) halides with racemic 2,2′-bis(diphenylphosphano)-1,1′-binaphthyl (rac-binap) in 1:1 molar ratio afforded mononuclear complexes of the type [CuX(rac-binap)] (X = Cl, Br, I) which, on further treatment with 1 equiv. of pyridine-2-thione (py2SH), pyrimidine-2-thione (pymtH) or 4,6-dimethyl-pyrimidine-2-thione (dmpymtH) gave rise to the formation of mixed-ligand complexes of the formula [CuX(rac-binap)(thione)]. The molecular structures of [CuBr(rac-binap)(py2SH)] · 2CH₂Cl₂, [CuBr(rac-binap)(py2SH)] · CH₂Cl₂ and [CuBr(rac-binap)(dmpymtH)] · CH₂Cl₂ have been established by single-crystal X-ray diffraction. Each of the complexes features a distorted tetrahedral copper(I) center with the phosphane acting in a chelating fashion. The complexes are strongly luminescent in the solid state at ambient temperature. Unusually, the [CuBr(rac-binap)(py2SH)] · 2CH₂Cl₂ molecules crystallise in a chiral space group with independent S- and R-enantiomers in the asymmetric unit.     

Synthesis and characterization of the [Cu(Cin2bda)2]ClO4 and [Cu(Ncin2bda)2]ClO4 complexes: Crystal structure of [Cu(Ncin2bda)2]ClO4

Two copper(I) complexes [Cu(Cin₂bda)₂]ClO₄ (I) and [Cu(Ncin₂bda)₂]ClO₄ (II) have been prepared by the reaction of the ligands N²,N²′-bis(3-phenylallylidene)biphenyl-2,2′-diamine (L¹) and N²,N²′-bis[3-(2-nitrophenyl)allylidene]biphenyl-2,2′-diamine (L²) and copper(I) salt. These compounds were characterized by CHN analyses, ¹H NMR, IR, and UV-Vis spectroscopy. The C=N stretching frequency in the copper(I) complexes shows a shift to a lower frequency relative to the free ligand due to the coordination of the nitrogen atoms. The crystal and molecular structure of II was determined by X-ray single-crystal crystallography. The coordination polyhedron about the copper(I) center in the complex is best described as a distorted tetrahedron. A quasireversible redox behavior was observed for complexes I and II. The article is published in the original.     

Synthesis and coordination chemistry of new tetradentate N2S2 donor Schiff-base ligand ca2-dapte: Mononuclear and dinuclear copper(I) complexes [Cu(ca2dapte)]ClO4 and [{Cu(PPh3)(X)}2(ca2dapte)] (X = I and Br)

A mononuclear copper(I) complex, [Cu(ca₂dapte)]ClO₄ (1), and two dinuclear copper(I) complexes, [{Cu(PPh₃)(X)}₂(ca₂dapte)] (X = I (2) and Br (3)), of a new tetradentate N₂S₂ donor Schiff-base ligand ca₂dapte have been prepared (ca₂dapte = N,N′-bis(trans-cinnamaldehyde)-1,2-di(o-iminophenylthio)ethane). These compounds have been characterized by elemental analyses (CHN), FT-IR, UV–Vis and ¹H NMR spectroscopy. The crystal structures of these copper(I) complexes have been determined by single-crystal X-ray diffraction. The coordination geometry around Cu(I) centers in these complexes is a distorted tetrahedron. The ca₂dapte is coordinated to Cu(I) as a tetradentate ligand in 1, while it acts as a bis-bidentate bridging ligand in 2 and 3.     

Synthesis,Characterization, and Luminescent Properties of Silver(I) Complexes based on Diphosphine Ligands and 2,9‐Dimethyl‐1,10‐phenanthroline

Five mono‐nuclear silver(I) complexes with the ligand 2,9‐dimethyl‐1,10‐phenanthroline, namely [Ag(DPEphos)(dmp)]BF₄ ( 1 ), [Ag(DPEphos)(dmp)]CF₃SO₃ ( 2 ), [Ag(DPEphos)(dmp)]ClO₄ ( 3 ), [Ag(DPEphos)(dmp)]NO₃ ( 4 ), and [Ag(dppb)(dmp)]NO₃ · CH₃OH ( 5 ) {DPEphos = bis[2‐(diphenylphosphanyl)phenyl]ether, dppb = 1,2‐bis(diphenylphosphanyl)benzene, dmp = 2,9‐dimethyl‐1,10‐phenanthroline} were characterized by X‐ray diffraction, IR, ¹H NMR, ³¹P NMR and fluorescence spectroscopy. Their terahertz (THz) time‐domain spectra were also studied. In these complexes the silver(I), which is coordinated by two kinds of chelating ligands, adopts four‐coordinate modes to generate mono‐nuclear structures. In complexes 1 , 3 – 5 , offset π ··· π weak interactions exist between the neighboring benzene rings. In the ³¹P NMR spectra, there exist splitting signals (dd), which can be attributed to the coupling of the ^107,109Ag–³¹P. All the emission peaks of these complexes are attributed to ligand‐centered excited states.     

Effect of ligands on the thermolysis of the double complexes [Co(NH3)6]2C2O4[Cu(C2O4)2]2 and [Co(NH3)6]Cl[Cu(C7H4O3)2]

The thermolysis of the complexes [Co(NH₃)₆]₂C₂O₄[Cu(C₂O₄)₂]₂ (I) and [Co(NH₃)₆]Cl[Cu(C₇H₄O₃)₂] (II) in air and hydrogen at 200, 350, and 500°C and the composition and properties of the thermolysis products are considered. The oxidative thermolysis of the complexes yields mixtures of cobalt and copper oxides, including mixed ones. The reductive thermolysis of the complexes yields a Co + Cu bimetallic powder in the case of compound I and a Co + Cu + C powder in the case of compound II. The thermal behavior of the complexes is governed by the nature of the ligand coordinated to the copper atom. The observed data are explicable in terms of the properties of this ligand. The chemistry of the oxidative and reductive thermolysis is discussed. Original Russian Text ? D.P. Domonov, S.I. Pechenyuk, N.L. Mikhailova, A.T. Belyaevskii, 2007, published in Zhurnal Neorganicheskoi Khimii, 2007, Vol. 52, No. 7, pp. 1104–1110.     

Synthesis,characterization and antimicrobial studies of mixed ligand silver(I) complexes of thioureas and triphenylphosphine; crystal structure of {[Ag(PPh3)(thiourea)(NO3)]2·[Ag(PPh3)(thiourea)]2(NO3)2}

Mixed ligand silver(I) complexes of triphenylphosphine and thioureas (thiourea (Tu), N-methylthiourea (Metu), N,N′-dimethylthiourea (Dmtu) and N,N′-diethylthiourea (Detu)) with the general formulae, [(Ph₃P)₂Ag(thione)]NO₃ and [(Ph₃P)Ag(thione)₂]NO₃, have been prepared and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ³¹P) spectroscopic methods. The crystal structure of one of them has been determined by X-ray crystallography. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). The single crystal X-ray structure of complex 1, {[Ag(PPh₃)(thiourea)(NO₃)]₂·[Ag(PPh₃)(thiourea)]₂(NO₃)₂}, shows that the complex consists of two independent centrosymmetric binuclear units, each having the silver atoms coordinated to one PPh₃ and two bridging thiourea molecules. In one of the independent units the silver atom is additionally bound to a nitrate ion, leading to a tetrahedral geometry, while in the other unit the silver atom adopts a trigonal planar environment. Antimicrobial activities of the complexes were evaluated by their minimum inhibitory concentration and the results showed that the complexes show a wide range of activity against two gram-negative bacteria (Escherichiacoli, Pseudomonasaeruginosa) and molds (Aspergillusniger, Penicilliumcitrinum), while the activities were poor against yeasts (Candidaalbicans, Saccharomycescerevisiae). However, the title complex did not show activity against any tested microorganism.     

Silver(I) bromide complexes of the rigid diphosphanes 1,2-bis(diphenylphosphano)benzene (dppbz) and 4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene (xantphos): Crystal structures of [Ag(μ2-Br)(dppbz)]2, [AgBr(xantphos)] and [AgBr(xantphos)(py2SH)]

Reaction of silver(I) bromide with equimolar amounts of the rigid diphos ligands 1,2-bis(diphenylphosphano)benzene (dppbz) and 4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene (xantphos) in acetone and acetonitrile led to the corresponding chelates [Ag(μ₂-Br)(dppbz)]₂ (1) and [AgBr(xantphos)] (2). Treatment of 1 and 2 with pyridine-2-thione (py2SH) in ethanol gave the mixed-ligand complexes [AgBr(dppbz)(py2SH)] (3) and [AgBr(xantphos)(py2SH)] (4), respectively. Compounds 1, 2 and 4 have been characterized by X-ray diffraction, establishing distorted tetrahedral or trigonal planar coordination geometries of the silver atoms.     

Products of the reactions of sparteine-2-thione with CuBr2 in protic and aprotic solvents

Reactions of copper(II) bromide with racemic sparteine-2-thione (SSp) in a 1:1 M ratio yielded two new complexes, whose structures depend on the solvent used. In acetonitrile, the reaction product is a sulfur-bridged dinuclear [CuBr₂(μ-SSp)]₂ complex (1) in which sparteine-2-thione acts as a bridging S-ligand, while in methanol it is a CuBr₂ complex (2) with sparteine deprived of the A-ring. Compound 1 crystallizes as an acetonitrile solvate in a 1:2 ratio and constitutes one of a few Cu(II) doubly bridged heterocyclic thionato complexes. The disorder of the C/D bisquinolizidine fragment in the crystal of 1 reflects the ease of the conversion from the common trans boat-chair to the unprecedented cis chair-boat stereoisomer. Obtained in methanol, the sparteine surrogate (Sp(surr)), is equally effective as a chelating ligand as sparteine and its isomers, and thus can be used as an alternative diamine ligand in metal complexation. Metal coordination with Sp(surr) brings the diamine nitrogens much closer together than in any other sparteine metal complexes.     

The first non-acetato members of the bis(anion)octacarboxylatotetrakis{di-2-pyridyl-methanediolate(−2)}enneametal(II) family of complexes: Synthesis, X-ray structures and magnetism of [M9(N3)2(O2CCMe3)8{(py)2CO2}4] (M = Co, Ni)

The combined use of di-2-pyridyl ketone [(py)₂CO] and azides (N₃⁻) in nickel(II) and cobalt(II) pivalate chemistry has afforded complexes [Ni₉(N₃)₂(O₂CCMe₃)₈{(py)₂CO₂}₄] (1) and [Co₉(N₃)₂(O₂CCMe₃)₈{(py)₂CO₂}₄] (2), where (py)₂CO₂²⁻ is the gem-diolate(−2) form of (py)₂CO. The complexes are isostructural and crystallize in the monoclinic P2₁/c space group. Their molecular structures consist of nine metal(II) ions, eight of which are arranged as two parallel squares flanking the ninth. DC magnetic susceptometry on powdered samples of 1 (1-p) reveal an overall antiferromagnetic behavior, leading to an S = 0 ground state. AC susceptometry reveals out-of-phase signals between 10 and 27 K, and ZFC and FC experiments show a divergence of the two curves below ∼27 K. Magnetization-decay and field-sweep experiments verify the relaxation behavior of the sample. Samples of the complex arising from carefully washed single crystals (1-cr) reveal a similar DC behavior, without however the appearance of cusps in the χ_ΜΤ versus T curves, and no relaxation. The relaxation behavior has been assigned to NiO impurities. The results illustrate the extreme care that should be taken when examining the magnetic properties of apparently analytically pure materials obtained under heating. Complex 2 exhibits an overall antiferromagnetic behavior, without observation of any relaxation phenomena.     

Preparation and structural characterization of [RuCl2(CO)2{Te(CH2SiMe3)2}2] and [RuCl2(CO){Te(CH2SiMe3)2}3]

The objective of the present work was to synthesize mononuclear ruthenium complex [RuCl₂(CO)₂{Te(CH₂SiMe₃)₂}₂] (1) by the reaction of Te(CH₂SiMe₃)₂ and [RuCl₂(CO)₃]₂. However, the stoichiometric reaction affords a mixture of 1 and [RuCl₂(CO){Te(CH₂SiMe₃)₂}₃] (2). The X-ray structures show the formation of the cis(Cl), cis(C), trans(Te) isomer of 1 and the cis(Cl), mer(Te) isomer of 2. The ¹²⁵Te NMR spectra of the complexes are reported. The complex distribution depends on the initial molar ratio of the reactants. With an excess of [RuCl₂(CO)₃]₂ only 1 is formed. In addition to the stoichiometric reaction, a mixture of 1 and 2 is observed even when using an excess of Te(CH₂SiMe₃)₂. Complex 1 is, however, always the main product. In these cases the ¹²⁵Te NMR spectra of the reaction solution also indicates the presence of unreacted ligand.     

Syntheses and X-ray structural studies of the novel complexes [Ni(en)2(3-pyt)2] and [Cu(en)2](3-pyt)2 based on 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione

Two novel mononuclear mixed-ligand complexes [Ni(en)₂(3-pyt)₂] (1) and [Cu(en)₂](3-pyt)₂ (2), derived from potassium [N′-(pyridine-3-carbonyl)-hydrazinecarbodithioate [K⁺(H₂L)⁻] and containing en as a co-ligand, have been synthesized. The [K⁺(H₂L)⁻] undergoes cyclization in the presence of ethylenediamine (en) and is converted to 5-(3-pyridyl)-1,3,4-oxadiazole-2-thione (3-pyt)⁻. [Ni(en)₂(3-pyt)₂] and [Cu(en)₂](3-pyt)₂ have been characterized with the aid of elemental analyses, IR, UV–Vis, magnetic susceptibility and single crystal X-ray studies. The complexes 1 and 2 crystallize in the orthorhombic and monoclinic systems with space groups Pca2(1) and C2/c, respectively. The single crystal X-ray diffraction studies of both complexes indicate that (3-pyt)⁻ adopts a thione form in 1 but is present as a thiolato form in 2.     

Synthesis of mono- and binuclear dioxomolybdenum(VI) complexes derived from N(4)-substituted thiosemicarbazones: X-ray crystal structures of [(MoO2L)2], [MoO2Lpy] and [MoO2Lpy]

Four molybdenum(VI) thiosemicarbazonato complexes have been synthesized and characterized. The dinuclear complexes [(MoO₂L¹)₂] (1) and [(MoO₂L²)₂] (3) have been prepared by the reaction of [MoO₂(acac)₂] with 2-hydroxyacetophenone N(4)-cyclohexyl (H₂L¹) and N(4)-phenyl (H₂L²) thiosemicarbazones in alcoholic medium. Mononuclear dioxomolybdenum(VI) complexes of the type [MoO₂L¹py] (2) and [MoO₂L²py] (4) have been prepared by the reaction of 1 or 3 with pyridine (py) in alcoholic medium. In all the complexes, molybdenum is coordinated by two terminal oxo-oxygen atoms, (O_t), oxygen, nitrogen and sulfur atoms from the principal ligand and by an oxygen atom from the second unit in 1, and by a nitrogen atom from pyridine in complexes 2 and 4. All complexes have been spectroscopically characterized. The molecular structures of complexes 1, 2 and 4 have been determined by the single crystal X-ray diffraction method.     

Synthesis, characterization, in vitro cytotoxicity and anti-inflammatory activity of palladium(II) complexes with tertiary phosphines and heterocyclic thiolates: Crystal structure of [PdC28H19N8PS2]

The new four-coordinated mononuclear palladium(II) complexes 1-9 with chelating heterocyclic thiolates and tertiary phosphines with general formula [Pd(L)_nCl(R′R₂P)] (L = Pym2SH (pyrimidine-2-thiolate), Pur6SH (purine-6-thiolate), Py2SH (pyridine-2-thiolate), R₃P = PPh₃, P(o-tolyl)₃, PPh₂Cl), n = 1, 2) have been synthesized by the direct reaction of [PdCl₂(R′R₂P)₂] with polyfunctional heterocyclic thiolates which display a wide variety of coordinations. These compounds were characterized by elemental analysis, FT-IR and multinuclear (¹H, ¹³C and ³¹P) NMR. The X-ray diffraction study of non-ionic compound 5 showed that the thiolate acts as unidentate and that the chelating (-N,S) ligand adopts a slightly distorted square planar geometry around the palladium atom. In vitro the anti-inflammatory inhibition of compounds 1-9 was 10-15% greater than that of the standard drug Declofenac. Compounds 1 and 4 showed mostly a moderate to low cytotoxicity against seven human tumor cell lines whereas compound 3 was somewhat more active.     

Co(III) complexes of Me-salpn and Me-salbn and the ring size effect on the coordination modes and electrochemical properties: The crystal structures of trans-[Co(Me-salpn)(py)2]PF6 and cis-α-[Co(Me-salbn)(4-Mepy)2]BPh4 · 4-Mepy

The synthesis and characterization of a series of cobalt(III) complexes of the general type [Co(N₂O₂)(L₂)]⁺ are described. The N₂O₂ Schiff base ligands used are Me-salpn (H₂Me-salpn = N,N′-bis(methylsalicylidene)-1,3-propylenediamine) (1–3) and Me-salbn (H₂Me-salbn = N,N′-bis(methylsalicylidene)-1,4-butylenediamine) (4–5). The two ancillary ligands L include: pyridine (py) 1, 3-metheylpyridine (3-Mepy) 2, 1-methylimidazole (1-MeIm) 3, 4-methylpyridine (4-Mepy) 4 and pyridine (py) 5. These complexes have been characterized by elemental analyses, IR, UV–Vis, and ¹H NMR spectroscopy. The crystal structures of trans-[Co^III(Me-salpn)(py)₂]PF₆, 1, and cis-α-[Co^III(Me-salbn)(4-Mepy)₂]BPh₄ · 4-Mepy, 4, have been determined by X-ray diffraction. Examination of the solution and crystalline structures revealed that the outer coordination sphere of the complexes exerts a noticeable influence on the inner coordination sphere of the Co(III) ion. The electrochemical reduction of these complexes at a glassy carbon electrode in acetonitrile solution indicates that the first reduction process corresponding to Co^III–Co^II is electrochemically irreversible, which is accompanied by the dissociation of the axial (R-py)–cobalt bonds. It has also been observed that the Co(III) state is stabilized with increasing the flexibility of the ligand environment.     

Syntheses and X-ray crystallographic studies of {[Ni(en)2(pot)2]0.5CHCl3} and [Ni(en)2](3-pytol)2

Two novel Ni(II) complexes {[Ni(en)₂(pot)₂]0.5CHCl₃} (3) {pot = 5-phenyl-1,3,4-oxadiazole-2-thione} (1) and [Ni(en)₂](3-pytol)₂ (4) {3-pytol = 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiol} (2) have been synthesized using en as coligand. The metal complexes have been characterized by physical and analytical techniques and also by single crystal X-ray studies. The complexes 3 and 4 crystallize in monoclinic system with space group P21/a and P121/c, respectively. The complex 3 has a slightly distorted octahedral geometry with trans (pot)⁻ ligands while 4 has a square planar geometry around the centrosymmetric Ni(II) center with ionically linked trans (3-pytol)⁻ ligands. The π?π (face to face) interaction plays an important role along with hydrogen bondings to form supramolecular architecture in both complexes.     

Transition metal complexes of the tripodal ligand 4-(2′-pyridylmethyl)-4-azaheptane-1,7-diamine. Crystal structures of [CuLCl]ClO4 and [NiL(MeCN)2](ClO4)2

The tripodal ligand 4-(2′-pyridylmthyl)-4-azaheptane-1,7-diamine has been prepared by reaction of 2-aminemethyl pyridine with acrylonitrile, followed by the reduction of the nitrile groups. Copper(II), nickel(II), zinc(II), cobalt(III) and chromium(III) complexes of the ligand have been prepared and characterized and the crystal structures of the complexes [CuLCl]ClO₄ and [NiL(MeCN)₂](ClO₄)₂ determined. The copper complex is five coordinate with approximate square pyramidal stereochemistry with the apical position occupied by a primary amine donor. The nickel complex is octahedral with the pyridine nitrogen donor lying trans to an acetonitrile ligand.     

Synthesis and spectral characterization of mercury(II) complexes with the bidentate Schiff base ligand N,N′-bis(2,3-dimethoxybenzylidene)-1,2-diaminoethane: The crystal structures of [Hg((23-MeO-ba)2en)I2] and [Hg((23-MeO-ba)2en)Br2]

Three mercury(II) complexes, [Hg((23-MeO-ba)₂en)X₂] (X = I (1), Br (2) and Cl(3)), and the ligand (23-MeO-ba)₂en ((23-MeO-ba)₂en = N,N′-bis(2,3-dimethoxybenzylidene)-1,2-diaminoethane) have been synthesized and characterized by elemental analyses, FT-IR and ¹H NMR spectroscopy. The crystal and molecular structures of 1 and 2 were determined by X-ray crystallography from single-crystal data. The metal-to-ligand ratio was found to be 1:1. The mercury(II) center in 1 and 2 has a distorted tetrahedral geometry with HgN₂I₂ and HgN₂Br₂ chromophores, respectively. The Schiff base ligand (23-MeO-ba)₂en acts as a chelating ligand, coordinating via the two nitrogen atoms to the mercury(II) center, and it adopts an E,E conformation. The coordination sphere of the mercury(II) center in 1 and 2 is completed by the two I and Br atoms, respectively. In complex 1 an inter-molecular non-classical hydrogen bond of the type C-H?O was found, while in complex 2 inter- and intra-molecular non-classical hydrogen bonds of the type C-H?X (X = O and Br) were found. The ¹H NMR spectra of the complexes exhibit downfield as well as upfield shifts of the free ligand resonances, reflecting changes in the ligand’s geometry during its coordination.     

Three- and four-coordinate copper(I) halide complexes of 2-(diphenylphosphano)benzaldehyde: Dimerization induced by thione-S ligation

Reactions of copper(I) halides with 2-(diphenylphosphano)benzaldehyde (PCHO) in 1:2 molar ratio afforded mononuclear complexes of the type [CuX(PCHO)₂], whereas treatment of these compounds with equimolar amounts of pyridine-2-thione or pyrimidine-2-thione gave rise to the formation of mixed-ligand dimers of the formula [CuX(PCHO)(thione)]₂. The molecular structures of [CuCl(PCHO)₂], [CuBr(PCHO)₂] and [CuCl(PCHO)(pymtH)]₂ have been established by single-crystal X-ray diffraction. The two homoleptic complexes feature a trigonal copper(I) centre with the phosphane acting as a monodentate ligand via the P atom. In the structure of the dimeric mixed-ligand complex each of the two metal centres exhibit a distorted tetrahedral environment with the thione-S atoms acting in a doubly bridging mode.     

Synthesis, DNA-binding and photocleavage studies of [Ru(phen)2(pbtp)] and [Ru(bpy)2(pbtp)] (phen = 1,10-phenanthroline; bpy = 2,2′-bipyridine; pbtp = 4,5,9,11,14-pentaaza-benzo[b]triphenylene)

Based on the ligand dppz (dppz = dipyrido-[3,2-a:2′,3′-c]phenazine), a new ligand pbtp (pbtp = 4,5,9,11,14-pentaaza-benzo[b]triphenylene) and its polypyridyl ruthenium(II) complexes [Ru(phen)₂(pbtp)]²⁺ (1) (phen = 1,10-phenanthroline and [Ru(bpy)₂(pbtp)]²⁺ (2) (bpy = 2,2′-bipyridine) have been synthesized and characterized by elemental analysis, ES-MS and ¹H NMR spectroscopy. The DNA-binding of these complexes were investigated by spectroscopic methods and viscosity measurements. The experimental results indicate that both complexes 1 and 2 bind to CT-DNA in classical intercalation mode, and can enantioselectively interact with CT-DNA. It is interesting to note that the pbtp ruthenium(II) complexes, in contrast to the analogous dppz complexes, do not show fluorescent behavior when intercalated into DNA. When irradiated at 365 nm, both complexes promote the photocleavage of pBR 322 DNA.