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The reactions of quinoline-2-carbaldehyde (pyridine-2-carbonyl)hydrazone (HL) and [RuCl2(PPh3)3] in various solvents at different temperatures gave the three geometrical isomers trans(Cl,Cl)-, cis(Cl,Cl),trans(P,N)-, and trans(P,P)-[RuCl2(PPh3)2{HL-κO(amide),κN(imine)}] (1, 2, and 3, respectively) as well as a linkage isomer trans(P,P)-[RuCl2(PPh3)2{HL-κN(imine),κN(quin)}] (4). The molecular and crystal structures of 1–4, together with both E and Z configurational isomers (with respect to the C=N double bond) of the free ligand HL, were determined by X-ray analysis. The ligand HL adopted a Z form and acted as a κO(amide),κN(imine) bidentate ligand in 1–3, whereas it was an E isomer with a κN(imine),κN(quin) coordination mode in 4. The gradual thermal conversions of 1 to 2 and of 2 to 3 were observed in dichloromethane and ethanol, respectively, but an interconversion between 3 and 4 was not detected. In dichloromethane, all complexes have a reversible RuIII/II redox couple in the range 110–412 mV (vs. Ag/Ag+), and the redox potential was largely dependent on the coordination mode of HL and on the mutual configuration of the two PPh3 ligands. Such a potential shift can be interpreted as a combination of Cl–/amide O π-donor and PPh3/quinoline N π-acceptor orbital contributions to the RuII dπ orbitals [highest occupied molecular orbitals (HOMOs)]. Complexes 3 and 4 in acetonitrile showed a gradual spectral change, probably because of the substitution of the Cl– ligand by the acetonitrile solvent. In addition, 2–4 showed solvatochromic behavior even in noncoordinating solvents that resulted from a blueshift of the metal-to-ligand charge-transfer (MLCT) transition band in polar solvents. These electrochemical and spectroscopic properties are also supported by DFT and time-dependent DFT (TD-DFT) calculations.

A spin-crossover iron(II) complex, fac-[FeII(HLn-Hx)3]Cl·PF6 (1), that exhibits stepwise spin transition and thermal hysteresis was synthesized by using the ligand 2-methylimidazol-4-ylmethylidene-n-hexylamine (HLn-Hx). Four complex cations (fac-[FeII(HLn-Hx)3]2+) and four Cl– anions associate through twelve imidazole···Cl– H bonds to give a tetrameric cubane-like assembly, and one PF6– anion is encapsulated within the cavity of the cubane. Magnetic susceptibility measurements showed a three-step spin transition, and the spin-crossover profile became less pronounced as the sweep rate increased. At a sweep rate of 0.5 K min–1, the midpoint temperatures of the three steps are Tc() = 131.2, 144.2, and 154.2 K in the heating mode and Tc() = 116.8, 137.8, and 151.8 K in the cooling mode. The respective thermal hystereses were evaluated to be 14.4, 6.3, and 2.4 K wide.

Objectives To determine whether the number of teeth lost can predict the risk of subsequent hip fracture. Methods We followed up 9992 male Japanese dentists aged 50 years or more (mean age ± standard deviation [SD], 61.1 ± 9.6 years) for incidence of hip fracture. From 2001 through 2006, they completed a baseline questionnaire on lifestyle and health factors including the number of teeth lost (excluding third molars). Incidence rate ratios (IRRs) were estimated by fitting proportional hazard models. Results During the mean follow-up period of 6.0 years, 20 new cases of hip fracture occurred. Participants who had lost 15 or more teeth at baseline were at a significantly increased risk of hip fracture: the multivariate-adjusted IRRs were 4.1 (95% confidence interval [CI], 1.2–14.2) for loss of 15–27 teeth and 4.5 (1.1–18.0) for edentulousness relative to loss of 0–14 teeth (trend P, 0.028). Overall, the risk of hip fracture was weakly associated with the number of teeth lost: the IRR per tooth was 1.06 (95% CI, 1.01–1.12). Conclusions Tooth loss was slightly associated with a higher risk of subsequent hip fracture. The number of teeth lost might be informative in predicting this risk.

Wakai K, Naito M, Naito T, Kojima M, Nakagaki H, Umemura O, Yokota M, Hanada N, Kawamura T. Tooth loss and intakes of nutrients and foods: a nationwide survey of Japanese dentists. Community Dent Oral Epidemiol 2010; 38: 43–49. © 2009 John Wiley & Sons A/S Abstract – Objectives: To clarify the association of tooth loss with dietary intakes among dentists, for whom sufficient dental care is available. Methods: We analyzed the data from 20 366 Japanese dentists (mean age ± SD, 52.2 ± 12.1 years; women 8.0%) who participated in a nationwide cohort study from 2001 to 2006. The baseline questionnaire included a validated food-frequency questionnaire to estimate intakes of foods and nutrients. We computed the geometric means of daily intakes by the number of teeth, adjusting for age, sex, smoking, physical activity, and history of diabetes. Results: The mean intakes of some key nutrients and food groups, such as carotene, vitamins A and C, milk and dairy products, and vegetables including green-yellow vegetables, decreased with the increasing number of teeth lost (P for trend

Nickel(II) complexes containing P―N-type bidentate hybrid ligands of 2-aminoethylphosphanes (RR'Pea; RR' = Ph 2 or MePh) or 8-quinolylphosphanes (RR'Pqn), namely [Ni(P―N) 2 ]-(BF 4 ) 2 [P―N = Ph 2 Pea (1), MePhPea (2), Ph 2 Pqn (3), or MePhPqn (4)] have been prepared, and their structural, spectroscopic, and electrochemical properties determined. The crystal structure analysis indicates that the 2-aminoethyl-phosphane complexes (1 and 2) have a square-planar coordination geometry around the Ni II center with a cis(P,P) configuration, whereas the 8-quinolylphosphane complexes (3 and 4) exhibit a severe tetrahedral distortion because of the steric repulsion between the ortho-H atoms in the mutually cis-positioned quinolyl rings. Complexes 1 and 2 maintain their diamagnetic square-planar four-coordinate structure on acetonitrile solution, whereas complexes 3 and 4 show paramagnetic behavior. Spectroscopic and electrochemical measurements suggest that the ligand-field strengths of these four P-N-type ligands increase in the order Ph 2 Pqn (3) < MePhPqn (4) < Ph 2 Pea (1) < MePhPea (2). The Ph 2 Pqn complex 3 is readily reduced by Zn powder to afford the corresponding nickel(I) complex [Ni(Ph 2 Pqn) 2 ]BF 4 (5). The crystal structure of complex 5 reveals that the Ni I ion adopts a distorted tetrahedral coordination geometry with slightly longer (= 0.05 A) Ni-P and Ni―N bond lengths than those in the corresponding Ni II complex 3.

The complex [Co(H3L)](ClO4)3·H2O (1), where H3L {tris[2-(4-imidazoylmethylideneamino)ethyl]amine} is a tripodal ligand obtained by condensation of tris(2-aminoethyl)amine and 4-formylimidazole in a 1:3 molar ratio, was synthesized and optically resolved by fractional crystallization of the diastereomeric salt with [Sb2{(R,R)-tart}2]2– [(R,R)-tart = (2R,3R)-tartrate(4–) ion]. From the less soluble part, Λ-[Co(H2L)][Sb2{(R,R)-tart}2]·4H2O (2) was isolated. Starting from 2, two optically active complexes, Λ-[Co(H3L)](ClO4)3·1.5H2O (Λ-1) and Λ-[Co(L)] (Λ-3), were obtained. The crystal structures of these complexes are compared with those of the racemic structures. Λ-1 shows an unusually strong circular dichroism (λ = 488 nm, Δϵ = –7.74 M–1 cm–1) in the first d–d absorption band region. The effects of deprotonation–reprotonation of the uncoordinated imidazole NH groups of Λ-[Co(H3L)]3+ on the UV/Vis and CD spectra and on the cyclic voltammograms were studied in methanol. Although the deprotonation–reprotonation reactions are reversible, the redox couple for the completely deprotonated species [CoIII/II(L)]0/– is not observed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The orange [RuII(H3L)](ClO4)2·3H2O (1) complex was synthesized from cis-[RuCl2(dmso)4] and H3L, where H3L (tris{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine) is a tripodal ligand obtained by condensation of tris(2-aminoethyl)amine and 4-formylimidazole in a 1:3 mol ratio. The X-ray crystal structure analysis revealed that the complex has an octahedral structure coordinated by three imidazole nitrogen atoms and three Schiff base (imine) nitrogen atoms. The uncoordinated NH groups of the imidazole moieties of 1 are easily deprotonated by the action of a base. The effect of deprotonation on the RuIII/RuII redox potential was studied by cyclic voltammetry in methanol containing 0.1 M LiClO4. Complete deprotonation shifts the RuIII/RuII potential to a much more negative value from –0.18 to –0.72 V vs. Ag/Ag+, making it easier to oxidize. The bluish-purple RuIII complex, [RuIII(H3L)]3+, was formed by controlled-potential electrolysis of 1, and the electronic spectrum is reported. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

A family of spin-crossover (SC) complexes, [Fe(II)H(3)L(Me)]Cl.X (X(-) = PF(6) (-), AsF(6) (-), SbF(6) (-), CF(3)SO(3) (-)), 1-4, has been synthesized, in which H(3)L(Me) denotes the hexadentate N(6) tripod-like ligand tris[2-{[(2-methylimidazol-4-yl)methylidene]amino}ethyl]amine, containing three imidazole groups, with a view to establishing the effect of the counter anion on the SC behavior. These complexes have been found to crystallize in the same monoclinic crystal system with similar cell dimensions. The general crystal structure consists of a two-dimensional (2D) extended network constructed by NH...Cl- hydrogen bonds between Cl- and the imidazole NH groups of three neighboring [Fe(II)H(3)L(Me)]2+ ions, while the anion X exists as an isolated counter anion and occupies the space between the 2D sheets. Magnetic susceptibilities and Mössbauer spectra have revealed a variety of SC behaviors depending on the counter anion, including a one-step HS==(HS + LS)/2 (1, X = PF(6) (-)), a two-step HS==(HS + LS)/2==LS with a slow thermal relaxation (2, X = AsF(6) (-)), a gradual one-step HS==LS (3, X = SbF(6) (-)), and a steep one-step HS==LS with hysteresis (4, X = CF(3)SO(3) (-)). The complexes assume the space group P2(1)/n in the HS state, P2(1) in the HS + LS state, and P2(1)/n in the LS state. The Fe-N bond lengths and the N-Fe-N bond angles are indicative of the HS, HS + LS, and LS states. The molecular volumes, V, of the counter anions have been evaluated by quantum-chemical calculations as follows: 53.4 A(3) (BF(4) (-)), 54.4 A(3) (ClO(4) (-)), 73.0 A(3) (PF(6) (-)), 78.5 A(3) (AsF(6) (-)), 88.7 A(3) (SbF(6) (-)), and 86.9 A(3) (CF(3)SO(3) (-)). The size and shape of the counter anion affects the flexible 2D network structure constructed by the hydrogen bonds, leading to modifications of the SC behavior. These estimated relative sizes of the counter anions correlate well with the observed SC behaviors.

Natural rubber (NR) vulcanizates filled with various contents of carbon black were devulcanized in supercritical CO2 in the presence of diphenyl disulfide as a devulcanizing reagent. The devulcanized rubbers were separated to sol and gel components using chloroform. Regardless of the carbon black content in the NR vulcanizates, sol fractions of 20–40% were obtained and the swelling ratios of the gel components were higher than the original vulcanizates. Dynamic mechanical properties of the devulcanized rubbers were also investigated. Devulcanized rubbers showed a slightly lower G′ values and slightly higher tan δ values than the initial compounds and much lower G′ values and much higher tan δ values than the vulcanizates. These results indicate that the presence of carbon black in NR vulcanizates does not disturb the devulcanization. A NR-based truck tire vulcanizate was also devulcanized. The physical properties of recycled rubber made from virgin rubber and various contents of the devulcanized tire rubber were measured. The decrease in tensile strength was only around 10% at up to 40 phr of the devulcanized tire rubber content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 137–143, 2005

In a previously reported ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) for antibody IgG to HIV-1, polystyrene beads in test tubes were handled with tweezers, and bound beta-D-galactosidase activity was measured with a fluorometer. The use of tweezers was causative of false-positivity by carryover, and testing many samples was difficult. Recently, these drawbacks have been minimized using microplates, a fluororeader, and modified polystyrene beads with sticks for easy handling. The modified polystyrene beads were transferred from wells to wells more quickly and easily without tweezers, eliminating false-positivity due to carryover. The fluorescence intensity for bound beta-D-galactosidase activity was quickly measured with a fluororeader. As a result, it became easy to test many samples with high reliability. However, modified polystyrene beads used were handmade, and the sensitivity was lower than the previous assay with test tubes. In the present study, the condition of the immune complex transfer enzyme immunoassay for antibody IgG to reverse transcriptase of HIV-1 was optimized using microplates, a fluororeader, and polystyrene solid phase with stick, which is commercially available. Testing many samples became easy with higher sensitivity.

In a previously reported ultrasensitive enzyme immunoassay (immune complex transfer enzyme immunoassay) for anti-HTLV-I IgG, polystyrene beads were handled with tweezers, and bound beta-D-galactosidase activity was measured with a fluorometer. The use of tweezers was causative of false-positivity by carryover, and testing many samples was difficult. Recently, these drawbacks have been minimized using microplates and a fluororeader. However, tweezers were still required in the initial and final steps. In the present study, the immune complex, comprising 2,4-dinitrophenyl-antigen, anti-HTLV-I IgG, and antigen-beta-D-galactosidase conjugate, was formed in and trapped onto microplate wells coated with (anti-2,4-dinitrophenyl group) IgG. Subsequently, the microplate wells were incubated with epsilon N-2,4-dinitrophenyl-L-lysine and polystyrene beads, modified by attaching to plates through cylindrical bars and coated with (antihuman IgG gamma-chain) IgG, to transfer the immune complex from the microplate wells to the modified polystyrene beads. Alternatively, modified polystyrene beads coated with (anti-2,4-dinitrophenyl group) IgG and microplate wells coated with (antihuman IgG gamma-chain) IgG were substituted for microplate wells coated with (anti-2,4-dinitrophenyl group) IgG and modified polystyrene beads coated with (antihuman IgG gamma-chain) IgG, respectively. The fluorescence intensity for bound beta-D-galactosidase activity was quickly measured with a fluororeader. Thus the modified polystyrene beads were transferred from wells to wells more quickly and easily without tweezers, eliminating false-positivity due to carryover, and it became easy to test many samples with high sensitivity and reliability, although the assay of bound beta-D-galactosidase activity became slightly more time-consuming.

1-D system: Copper(II) complex with pentadentate strand-type ligand involving two imidazole groups exhibits a self-complementary double-faced H-bonding recognition and enantioselective self-assembl...

The proton-decoupled carbon-13 NMR spectra were measured for the mer-Λ(ob), facial-Λ(ob), and facial-Δ(lel)[Co(l-pn)3]3+ ions using the Fourier transform technique. There was a clear difference between the Λ and Δ configurations. However, no appreciable difference was observed between the mer and facial isomers of Λ(ob)-[Co(l-Pn)3]3+.

The asymmetric oxidation of sulfides into the corresponding sulfoxides was achieved with organic hydroperoxides in the presence of a catalytic amount of optically active Schiff base-oxovanadium(IV) complexes; in most cases the optical yields (e.e.) ranged between 20 and 40%.

Synthese des complexes de Fe(II) et Co(II). Spectres RMN et RPE. Structure cristalline de [Ni{(CH 2 ) 8 (CH 2 pipz) 3 (3,6-dur) [16] cyclidene}](PF 6 ) 2 •CH 3 CN

Etude de la structure cristalline de l'hexafluorophosphate de (dibenzyl-3,11 dimethyl-14,20 diphenyl-2,12 hexaaza-3,11,15,19,22,26 tricyclo [11.7.7.1 5,9 ] octacosanonaene-1,5,7,9(28),12,14,29,21,16) nickel (II). Cristallisation dans le systeme monoclinique, groupe P2 1 /c et affinement jusqu'a R=8,3%. La structure illustre les contraintes steriques pesant sur le site lacunaire et la forme des substituants peripheriques. Proprietes electroniques et spectroscopiques d'une selection de complexes de nickel avec differents substituants

Four stereoisomers, mer-Δ, mer-Λ, fac-Δ, and fac-Λ, of the tris[(S)-1,3-butanediamine]cobalt(III) complex were obtained, and their absorption and circular dichroism spectra were recorded in water in the absence or presence of sulfate ions. The shift of absorption bands and the variation of circular dichroism spectra caused by the addition of sulfate ions seem to be correlated with the conformational instability of six-membered (S)-1,3-butanediamine chelate rings in the complexes.

A new complex containing a seven-membered chelate ring, [Co(amb)(en)2]2+ (amb=4-aminobutanoato ion) was prepared and resolved. The complex is decomposed in 1.0 M HClO4 at room temperature to give [Co(H2O)(Hamb)(en)2]3+ in which the Hamb acts as a unidentate ligand with a free carboxyl group.