Synthesis, characterization, and electrochemical and electrical properties of novel mono and ball-type metallophthalocyanines with four 9,9-bis(4-hydroxyphenyl)fluorene

The new mono-nuclear 4-5 and ball-type homo-dinuclear 6 phthalocyanines have been synthesized from the corresponding phthalodinitrile derivative 3. The synthesized compounds have been characterized by elemental analysis, UV-vis, IR,(1)H-NMR and MALDI-TOF-mass spectroscopies. The redox behaviours of the complexes were identified by cyclic voltammetry and square wave voltammetry. The temperature dependence of the electronic properties of compounds and adsorption of SO(2) on thin film of 6 were investigated by conductivity measurements using an interdigital transducer structure on glass substrate. Dc conductivity, measured between 300-475 K, is thermally activated with the activation energy ranging between 0.67 and 0.90 eV. The ac conductivity is found to vary with frequency, ω, as ω(s) in which the frequency exponent s decreases with temperature suggesting a hopping conduction mechanism for all compounds. The SO(2) sensing result showed that the spin coated film of 6 exhibits very good SO(2) sensing properties, fast response and recovery rate, high sensitivity and good repeatability.     

Synthesis, characterization and some properties of novel bis(pentafluorophenyl)methoxyl substituted metal free and metallophthalocyanines

The preparation of some new tetrakis[bis(pentafluorophenyl)methoxyl] substituted metal free and metallophthalocyanine (MPcs) complexes were achieved by the tetramerization of 4-[bis(pentafluorophenyl)methoxy]phthalonitrile with Li metal in pentan-1-ol or metal [Co(II) or Zn(II)] acetates in DMAE, respectively. The structures of the target compounds were confirmed by elemental analysis, IR, UV–vis, ¹H NMR, ¹⁹F NMR and mass spectroscopic methods. MPcs are soluble only in strong and medium polar solvents while the metal free one is soluble in weakly, medium and strong polar solvents. The temperature and frequency dependence of the electrical conductivities were studied on spin coated films of the compounds using dc and impedance spectroscopy techniques in the frequency range from 40 to 10⁵ Hz and within the temperature range from 290 to 440 K. The temperature dependence of the exponent s and conductivity, σ_ac, were completely in agreement with the prediction of the hopping model. The redox properties of the complexes were determined by cyclic voltammetry. The nature of the redox processes was also confirmed using spectroelectrochemical measurements.     

Ruthenium(ii) bis(terpyridine) electron transfer complexes with alkynyl-ferrocenyl bridges: synthesis, structures, and electrochemical and spectroscopic studies

Two novel alkynyl-bridged symmetric bis-tridentate ligands 1,2-bis(1'-[4'-(2,2':6',2'-terpyridinyl)]ferrocenyl)ethyne (; tpy-Fc-C[triple bond, length as m-dash]C-Fc-tpy; Fc = ferrocenyl; tpy = terpyridyl) and 1,4-bis(1'-[4'-(2,2':6',2'-terpyridinyl)]ferrocenyl)-1,3-butadiyne (; tpy-Fc-C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C-Fc-tpy) and their Ru(2+) complexes and have been synthesized and characterized by cyclic voltammetry, UV-vis and luminescence spectroscopy, and in the case of by single-crystal X-ray diffraction. Cyclic voltammograms of both compounds, and , display two severely overlapping ferrocene-based oxidative peaks with only one reductive peak. The redox behavior of and is dominated by the Ru(2+)/Ru(3+) redox couple (E(1/2) from 1.33 to 1.34 V), the Fe(2+)/Fe(3+) redox couples (E(1/2) from 0.46 to 0.80 V), and the tpy/tpy(-)/tpy(2-) redox couples (E(1/2) from -1.19 to -1.48 V). The UV-vis spectra of and show absorption bands assigned to the (1)[(d(π)(Fe))(6)] → (1)[(d(π)(Fe))(5)(π*(tpy)(Ru))(1)] MMLCT transition at ～555 nm. Complexes and are luminescent in H(2)O-CH(3)CN (4?:?1, v/v) solution at room temperature, and exhibits the strongest luminescence intensity (λ(max)(em): 710 nm, Φ(em): 2.28 × 10(-4), τ: 358 ns) relative to analogous ferrocene-based bis(terpyridine) Ru(ii) complexes reported so far.     

Synthesis and electrical properties of novel supramolecular octa-phthalocyaninato-dicobalt(II)-hexazinc(II) and dicobalt(II)-dimeric-phthalocyanine with six ferrocenylimin pendant groups

In this study supramolecular octakis phthalocyaninato-diCo(II)hexakis-Zn(II) has been synthesized in two steps. Starting with tetracyanodibenzo(1,4,7,10-tetrathia-(12-crown)) (1) and 4-nitro-1,2-dicyanobenzene (2), nitro-substituted dimeric phthalocyanine (3) was synthesized. Compound 3 reacted with unsymmetric Zn(II) phthalocyanine (4) to furnish a supramolecular assemble of a Co(II) dimer with six Zn(II) phthalocyanines through azo bridges (5). Co(II) dimeric phthalocyanine with six ferrocenyl groups (7) was obtained by the condensation of 6 with ferrocenylaldehyde. Compounds 3, 5, 6 and 7 were characterized by elemental analysis, ICP-MS, IR, UV–Vis and ¹H NMR spectroscopy. The electronic properties of a thin film of the compounds were investigated by impedance spectroscopy and d.c. conductivity measurements as a function of temperature. The a.c. conductivity is found to vary with frequency, ω, as ω^s with index s  1, suggesting a hopping conduction mechanism for 3 and 6. Whereas a frequency independent conductivity was observed for 5. It was found that reducing the nitro group to amines and azo coupling by the asymmetric nitro groups increases the electrical conductivity. The higher conductivity of 5 can be attributed to the increase in the mobility of charge carriers due to overlap of the π electron systems along the stacking direction of the molecules.     

Synthesis and characterization of novel 4-nitro-2-(octyloxy)phenoxy substituted symmetrical and unsymmetrical Zn(II), Co(II) and Lu(III) phthalocyanines

Compounds 3 and 4 have been prepared by the reaction of 4-nitrocatechol 1 and 4-nitrophthalonitrile 2 by a common method, aromatic nucleophilic subtitution of the nitro group in 4-nitrophthalonitrile. Starting from 4 and 1-bromooctane, their alkylation reaction gave compound 5. Zn(II) 8, Co(II) 9 and Lu(III) 10 complexes were synthesized from the corresponding metal salts by the tetramerization of compound 5. Compound 7 was prepared by the statistical condensation of 5 and 4,5-bis(hexylthio)phthalonitrile 6 with CoCl₂ · 6H₂O in dry dimethylformamide. The new compounds were characterized by FT-IR, UV/Vis, NMR and mass spectra. The electrochemical properties of the complexes were also investigated by cyclic voltammetry in non-aqueous medium. The effect of temperature on the dc conductivity and the impedance spectra of spin coated film of the compounds was investigated at temperatures between 295 and 433 K and in the frequency range 40–10⁵ Hz. Thermally activated conductivity dependence on temperature was observed for all compounds.     

Luminescent bis-tridentate ruthenium(II) and osmium(II) complexes based on terpyridyl-imidazole ligand: synthesis, structural characterization, photophysical, electrochemical, and solvent dependence studies

Homo- and heteroleptic bis-tridentate ruthenium(II) and osmium(II) complexes of compositions [(tpy-PhCH(3))Ru(tpy-HImzPh(3))](ClO(4))(2) (1), [(H(2)pbbzim)Ru(tpy-HImzPh(3))] (ClO(4))(2) (2) and [M(tpy-HImzPh(3))(2)](ClO(4))(2) [M = Ru(II) (3) and Os(II) (4)], where tpy-PhCH(3) = p-methylphenyl terpyridine, H(2)pbbzim = 2,6-bis(benzimidazole-2-yl)pyridine and tpy-HImzPh(3) = 4'-[4-(4,5-diphenyl-1H-imidazol-2-yl)-phenyl]-[2,2':6',2']terpyridine, have been synthesized and characterized by using standard analytical and spectroscopic techniques. These compounds were designed to increase the room temperature excited-state lifetimes of bisterpyridine-type ruthenium(II) and osmium(II) complexes. The X-ray crystal structures of two homoleptic complexes 3 and 4 have been determined and show that both the compounds crystallized in orthorhombic form with space group Fddd. The photophysical and redox properties of the complexes have been thoroughly investigated. All the complexes display moderately strong luminescence at room temperature with lifetimes in the range of 6-35 ns. The complexes are found to undergo one reversible oxidation in the positive potential window (0 to +1.6 V) and one irreversible and two successive quasi-reversible reductions in the negative potential window (0 to -2.0 V). The influence of solvents on the photophysical properties of the complexes has also been investigated in detail.     

A series of complexes of the phosphorus-based TTF ligand o-P2 with the metal ions Fe(II), Co(II), Ni(II), Pd(II), Pt(II), and Ag(I)

Reactions of 3,4-dimethyl-3',4'-bis(diphenylphosphino)tetrathiafulvalene, o-P2, with [BF(4)](-) salts of Fe(ii), Co(ii), Ni(II), Pd(II), and Pt(II) yield complexes of general formula [M(o-P2)(2)][BF(4)](2). Similar reactions between o-P2 and AgSbF(6) or AgPF(6) produced the salts [Ag(o-P2)(2)][X] where X = [SbF(6)](-) or [PF(6)](-). The resulting compounds were fully characterized by (1)H and (31)P{(1)H} NMR, infrared and electronic absorption spectroscopies, cyclic voltammetry, FAB-MS and single-crystal X-ray diffraction. The paramagnetic Co(II) compound exhibits an S = 3/2 state with large spin-orbit coupling contribution at higher temperatures and an effective S' = 1/2 state below 20 K. Electrochemical studies of the compounds indicate that the two functionalized TTF ligands are not in electronic communication and that they essentially behave as isolated redox centers.     

Synthesis and characterization of a new trans-2,2′-azoquinoxaline bridged bisphthalocyanine

A new trans-2,2′-azoquinoxaline bridged bisphthalocyanine was synthesized from the corresponding quinoxaline-2(1H)-one oxime, which can be obtained by the reaction of s-trans-chloroethanedial with 2-(3,4-diaminophenoxy)-9,16,23-tri(hexylthio)phthalocyanine zinc(II). 2-(3,4-Diaminophenoxy)-9,16,23-tri(hexylthio)phthalocyanine zinc(II) was synthesized by reduction of 2-(4-amino-3-nitrophenoxy)-9,16,23-tri(hexylthio)phthalocyanine zinc(II). Novel compounds were characterized by elemental analysis, UV/vis, IR and ¹H NMR spectroscopy. The conductivity and the humidity sensing properties of spin coated films of these compounds were investigated by measuring the complex impedance spectra at different humidities. Films of the final product show up to 10³ orders of magnitude higher conductivity than the starting and intermediate compounds. The results indicate that the presence of water vapour always leads to a drop in the real and imaginary part of the complex impedance. At room temperature, the capacitance of the films exhibits reversible increase with relative humidity, which makes these films attractive for humidity sensing applications.     

Synthesis and structural characterization of novel neutral hexacoordinate silicon(IV) complexes with SiO2N4 skeletons containing cyanato-N or thiocyanato-N ligands

A series of novel hexacoordinate silicon(IV) complexes with an SiO2N4 skeleton (compounds (OC-6-12)-3, (OC-6-12)-4, (OC-6-12)-5, (OC-6-12)-6, and (OC-6-2'2)-7) were synthesized, starting from Si(NCO)4 or Si(NCS)4. These compounds contain (i) two bidentate O,N-chelate ligands (or one tetradentate O,N,N,O-chelate ligand) derived from 4-aminopent-3-en-2-ones of the formula type Me-C(NRH)=CH-C(O)-Me (R = organyl) and (ii) two monodentate cyanato-N or thiocyanato-N ligands. Formally, the bidentate singly negatively charged O,N-chelate ligands (tetradentate 2-fold negatively charged O,N,N,O-chelate ligand) behave as ligands of the imino-enolato type. In addition, the adduct trans-8 was synthesized by reaction of Si(NCS)4 with 2 molar equiv of Me-C(Ni-PrH)=CH-C(O)-Me. This hexacoordinate silicon(IV) complex contains (i) four monodentate thiocyanato-N ligands and (ii) two neutral monodentate ligands of the iminio-enolato type. All compounds synthesized were structurally characterized by single-crystal X-ray diffraction and solid-state and solution NMR spectroscopy. To get more information about the stereochemistry of these compounds, the experimental investigations were complemented by computational studies.     

A series of metal complexes with the non-innocent N,N'-bis(pentafluorophenyl)-o-phenylenediamido ligand: twisted geometry for tuning the electronic structure

A series of homoleptic complexes with non-innocent ligands derived from N,N'-bis(pentafluorophenyl)-o-phenylenediamine (H(2)(F)pda) are reported. [Ni(II)((F)sbqdi)(2)] (1), [Pd(II)((F)sbqdi)(2)] (2), [Co(II)((F)sbqdi)(2)] (3), and [Cu(II)((F)sbqdi)(2)] (4) were synthesized, where ((F)sbqdi)(1-) represents a radical anion formed by one-electron oxidation of the doubly deprotonated H2(F)pda. The oxidation states of ligands and metals in complexes 1-4 were assigned by single crystal X-ray crystallography performed at low temperatures. Complex 4 is the first Cu(II) complex where both o-phenylenediamine derived ligands are monoanionic radicals. The bulky N-C6F5 substituents force the complexes 1, 3, and 4 to adopt a twisted geometry (intermediate between square-planar and tetrahedral). The electronic structures of the neutral compounds 1-4 and of some of their cationic and/or anionic neighboring redox states were probed using EPR and UV-VIS-NIR spectroelectrochemistry. The twisted geometry of the complexes results in considerable changes in their electronic structures compared to the well known square-planar complexes while the strongly electron withdrawing N-C6F5 groups have a great influence on redox properties.     

2-甲基喹 淋与Cu(ClO~4)~2和Cu(BF~4)~2生成配合物的结构研究

以2-甲基喹 啉为配体合成了五种含有阴离子ClO~4^-或BF~4^-的铜(II)配合物, 利用元素分析、红外光谱、电子光谱、电导、热重谱、ESR谱及变温磁化率的测定推测了配合物的结构, 提出双核铜配合物中含有直线型单氧桥Cu(II)-O-Cu(II)键的可能构型。     

Synthesis, interface (Au/M2Pc2/p-Si), electrochemical and electrocatalytic properties of novel ball-type phthalocyanines

The phthalodinitrile derivative (3) was prepared by the reaction of 4,4'-(octahydro-4,7-methano-5H-inden-5-ylidene)bisphenol (1) and 4-nitrophthalonitrile (2) with dry DMF as the solvent in the presence of the base K(2)CO(3) by the method of nucleophilic substitution of an activated nitro group in an aromatic ring. The template reaction of 3 with the corresponding metal salts gave the novel bi-nuclear ball-type metallophthalocyanines, MPcs {M = Co (4), Cu (5), Zn (6)}. Newly synthesized compounds were characterized by elemental analysis, UV-vis, FT-IR (ATR), MALDI-TOF mass and (1)H-NMR spectroscopy techniques. The electronic spectra exhibit an intense π→π* transition of characteristic Q and B bands of the Pc core. The dielectric properties and interface between the spin coated films of 4-6 and a p-type silicon substrate have been studied by fabricating metal-insulator-semiconductor capacitors. The results indicated that the frequency dependence of the dielectric permittivity, ε'(ω), exhibits non-Debye type relaxation for all the temperatures investigated. The ac conductivity results indicated that the conduction mechanism can be explained by a hopping model at low temperatures (<430 K) and a free band conduction mechanism at high temperatures (≥430 K). The density of interface state calculations on these novel compounds showed that the combination of Au/4/p-Si is a promising structure with a high dielectric constant and a low interface trap density suitable for metal-oxide-semiconductor devices. The electrochemical properties of the Pc complexes were examined by cyclic voltammetry, differential voltammetry and controlled potential coulometry on platinum in non-aqueous media. The complexes showed ring-based and/or metal-based mixed-valence behaviours as a result of the remarkable interaction between the two Pc rings and/or metal centres. The mixed-valence splitting values for the complexes suggested that the mixed valence species are considerably stable. The Vulcan XC-72(VC)/Nafion(Nf)/4 modified glassy carbon electrode showed much a higher catalytic performance towards oxygen reduction than those of VC/Nf/5 and VC/Nf/6 modified ones.     

Deactivation pathways of ethylene polymerization catalysts derived from titanium and zirconium 1,3-bis(furyl)-1,1,3,3-tetramethyldisilazide complexes

The stoichiometric reaction between the previously described lithium amide salts, LiN(SiMe2R)2 [Li{i}, R = furyl, Li{ii}, R = 2-methylfuryl] and titanium(iv)chloride at low temperature afforded the mono-amide compounds Ti{i}Cl3 (1a) and Ti{ii}Cl3 (1b). The analogous zirconium derivatives Zr{i}Cl3 (3a) and Zr{ii}Cl3 (3b) were accessed via the reaction of excess trimethylsilylchloride with the mixed tetra-amide species, Zr{i}(NMe2)3 (2a) and Zr{ii}(NMe2)3 (2b). The bis-amide complexes Ti{ii}2Cl2 (4b), Zr{i}2Cl2 (5a) and Zr{ii}2Cl2 (5b) were synthesized in a straightforward salt metathesis reaction employing two equivalents of Li{i} or Li{ii} with the metal salts, MCl4(THF)2. The reactivity of the halide compounds 1 and 3-5 with a variety of alkylating agents was studied, with ligand transfer from the transition-element to the main group metal-alkyl reagent being the predominant reaction pathway. The reaction of 4b with MeLi was, however, partially successful affording the titanium(III) complex, Ti{ii}2X (X = Cl/Me, 6b'); this compound was subsequently made as the pure chloride from the reaction of two equivalents of Li{iii} with TiCl3(THF)3. The targeted dialkyl species, Ti{ii}Me2 (7b), was successfully isolated from the reaction between the dichloride 4b and dimethylmagnesium. The molecular structures of 1a, 1b, [3a]2 [3b]2, 4b, 5b and 6b have been solved using single-crystal X-ray diffraction techniques, indicating varying nuclearity of the complexes and hapticities for the amide ligands in the solid-state. The catalytic activity of selected complexes in the polymerization of ethylene is reported.     

Synthesis and liquid-crystalline properties of substituted β-aminovinyl ketones and their complexes with copper(ii)

Mesogenic complexes were synthesized by the reaction of -aminovinyl ketones with copper(ii) acetate. On going from the ligands to complexes, the temperature of phase transitions increases and the nematic phase disappears. The initial members of the homological 1-(4-nonyloxyphenyl)-3-(4-methoxyphenylamino)-1-propen-1-one series demonstrate the alternation of clearing temperatures, which is absent for the corresponding copper(ii) complexes.     

Conducting polymers containing in-chain metal centers: electropolymerization of oligothienyl-substituted {M(tpy)2} complexes and in situ conductivity studies, M = Os(II), Ru(II)

The electropolymerization of a series of Ru and Os bis-terpyridine complexes that form rodlike polymers with bithienyl, quaterthienyl, or hexathienyl bridges has been studied. Absorption spectroscopy, scanning electron microscopy, and cyclic voltammetry have been used to characterize the monomers and resulting polymer films. The absolute dc conductivity of the quaterthienyl-bridged {Ru(tpy)2} and {Os(tpy)2} polymers is unusually large and independent of the identity of the metal center at 1.6 x 10(-3) S cm(-1). The maximum conductivity occurs at the formal potential of each redox process, which typically is observed for systems where redox conduction is the dominant charge transport mechanism. Significantly, the dc conductivity of the metal-based redox couple observed in these polymers is 2 orders of magnitude higher thanthat of a comparable nonconjugated system.     

Synthesis and low dimensional conductive behaviour of columnar bis(beta-diketonato)copper(II) complexes with oligo(ethylene oxide) groups

Several kinds of beta-diketone with oligo(ethylene oxide) groups and their Cu-complexes were synthesized and characterized by ¹H NMR, IR, MS, and elemental analysis. The columnar mesomorphism of the bis [1-(p-ethoxy-di(ethyleneoxy)phenyl)-3-(p-n-hexyloxylphenyl)propane-1,3-dionato]copper(II) complex (abbreviated as C₆EDK-Cu) was studied by differential scanning calorimetry, polarizing optical microscopy and temperature variable X-ray diffraction. In comparison with the conductivity value of c. 10^-8 S cm^-1 of the pure columnar liquid crystal (C₆EDK-Cu), that of C₆EDK-Cu doped with LiClO₄ or iodine is increased by about three orders of magnitude and reaches 10^-5 S cm^-1 when heated to the columnar mesophase. It is noteworthy that the conductivity of C₆EDK-Cu doped with iodine is maintained when the sample is cooled from the mesophase to room temperature, while that of C₆EDK-Cu doped with LiClO4 is decreased. The two kinds of conductive mechanism of C₆EDK-Cu doped with LiClO4 or iodine are discussed.     

New porphyrin-polyoxometalate hybrid materials: synthesis, characterization and investigation of catalytic activity in acetylation reactions

New hybrid complexes based on covalent interaction between 5,10,15,20-tetrakis(4-aminophenyl)porphyrinatozinc(ii) and 5,10,15,20-tetrakis(4-aminophenyl)porphyrinatotin(iv) chloride, and a Lindqvist-type polyoxometalate, Mo(6)O(19)(2-), were prepared. These new porphyrin-polyoxometalate hybrid materials were characterized by (1)H NMR, FT IR and UV-Vis spectroscopic methods and cyclic voltammetry. These spectro- and electrochemical studies provided several spectral data for synthesis of these compounds. Cyclic voltammetry showed the influence of the polyoxometalate on the redox process of the porphyrin ring. The catalytic activity of tin(iv)porphyrin-hexamolybdate hybrid material was investigated in the acetylation of alcohols and phenols with acetic anhydride. The reusability of this catalyst was also investigated.     

Linear and star-shaped polynuclear Ru(II) complexes of 2-(2'-pyridyl)benzimidazolyl derivatives: syntheses, photophysical properties and red light-emitting devices

Two new star-shaped ligands with a 1,3,5-triphenylbenzene core, tmpb (1,3,5-tris[p-2-(2'-pyridyl)benzimidazolylphenyl]benzene), and a 2,4,6-tris(p-biphenyl)-1,3,5-triazine core, tmbt (2,4,6-tris[p-2-(2'-pyridyl)benzimidazolylbiphenyl]-1,3,5-triazine), have been synthesized. Their corresponding trinuclear Ru(II) complexes [Ru3(tmpb)(bpy)6](PF6)6 (3) and [Ru3(tmpt)(bpy)6](PF6)6 (4) have been obtained. Two dinuclear linear Ru(II) complexes with previously reported ligands bmb (1,4-bis[2-(2'-pyridyl)benzimidazolyl]benzene) and bmbp (4,4'-bis[2-(2'-pyridyl)benzimidazolyl]biphenyl) and formulae [Ru2(bmb)(bpy)4](PF6)4 (1) and [Ru2(bmbp)(bpy)4](PF6)4 (2) have also been synthesized. Photophysical and electrochemical properties of the new compounds have been investigated. All four compounds display a characteristic metal-to-ligand-charge transfer (MLCT) absorption band and emit a red light when excited at the maximum of the MLCT band with emission maximum at 624, 629, 623 and 625 nm, respectively in neat films at ambient temperature. The emission quantum efficiency of the four complexes in neat films was determined to be 0.15, 0.17, 0.04 and 0.05, respectively. Light emitting devices based on these four compounds were fabricated by spin-casting the compound as a neat film to an ITO substrate, followed by the deposition of an aluminium metal layer. All devices emit a deep red light and the device behavior resembles that of a light emitting electrochemical cell. The EL maximum of the devices 1, 2, 3, and 4 is at 637, 657, 678, and 655 nm, respectively. All four devices have a fast response time when a sufficiently high voltage is applied. The device based on 2 is the brightest with a maximum luminance of 133 cd m(-2) at 7 V. The performance of devices based on 1, 2, and 4 is in general much more efficient than the device based on [Ru(bpy)3](PF6)2, which was fabricated and evaluated under the same experimental conditions as for the devices based on 1-4.     

Ferrocenoyl pyridine arene ruthenium complexes with anticancer properties: synthesis, structure, electrochemistry, and cytotoxicity

Organometallic ruthenium(II) complexes of general formula [Ru(eta(6)-arene)Cl(2)(NC(5)H(4)OOC-C(5)H(4)FeC(5)H(5))], where arene = C(6)H(6) (1), C(6)H(5)Me (2), p-iPrC(6)H(4)Me (3), and C(6)Me(6) (4), and of general formula [Ru(eta(6)-arene)Cl(2)](2)(NC(5)H(4)OOC-C(5)H(4)FeC(5)H(4)-COOC(5)H(4)N), where arene = p-iPrC(6)H(4)Me (5) and C(6)Me(6) (6), have been synthesized and characterized, the molecular structures of these complexes being confirmed by single-crystal X-ray structure analysis of complex 4 as a representative example. The redox properties and in vitro anticancer activities of complexes 1-6 have been studied. All the compounds are moderately cytotoxic toward the A2780 and A2780cisR (cisplatin-resistant) human ovarian carcinoma cell lines. The diruthenium arene complexes 5 and 6 are about twice as active as their mononuclear analogues 3 and 4. Cyclic voltammetry revealed a good correlation of the RuII/RuIII redox potentials of 1-4 and the number of alkyl substituents in the arene ligand.     

Conductive liquid crystalline compounds having a piperazine structure

New conductive thermotropic liquid crystalline materials having a piperazine ring in the central core: 1-[4-(9-decenyloxy)phenyl]-4-alkylpiperazines ( 6 ) were synthesized. The mesomorphic behaviours of these compounds and their conductivity in the liquid crystal phase were measured. The principal features of these compounds are to exhibit a smectic B phase around room temperature (for example 6 : Cr 50 SmB 81 I, °C) and to exhibit a large dark current (6d: 430 μA cm^-2, applied voltage 20 V, at 70°C) in the smectic B phase.