The Effect of Hydrogen Peroxide Colloidal-Ag Used in Dental Unit Waterline on Shear Bond Strength of Orthodontic Brackets

BACKGROUND

The quality of the water passing through the water lines is crucial to dental procedures. Studies on bracket adhesion of hydrogen peroxide colloidal-Ag, which is widely used to prevent biofilm formation, are limited in the literature.

AIM

To determine whether disinfecting the dental units' waterlines (DUW) with hydrogen peroxide colloidal-Ag has any effect on the shear bond strength (SBS) of orthodontic brackets bonded to enamel.

MATERIALS AND METHODS

Sixty premolar teeth were divided randomly into two groups. The study and control groups consists of 30 teeth that were etched for 30 seconds with 37% phosphoric acid. Study groups washed with hydrogen peroxide colloidal-Ag water and the control group washed with municipal water. Transbond XT adhesive system was used to bond stainless steel brackets on all the teeth. A 300-g force was applied using a tension gauge to ensure a uniform adhesive thickness and light cured with 6 seconds. The SBS was quantified by means of a universal testing machine. The residual adhesive on the enamel surface was evaluated after debonding using the adhesive remnant index (ARI).

RESULTS

The t-test results indicated that there were no significant differences in the SBS. The comparison of the results of ARI scores was found statistically insignificant.

CONCLUSION

It has been found that hydrogen peroxide colloidal-Ag, which is used to reduce the amount of biofilm in DUW, does not have a negative effect on the adhesion of the brackets.

Evaluation of the recipient and donor in organ transplantation in terms of orthorexia nervosa

OBJECTIVE

The aim of this study is to evaluate recipients and donors undergoing organ transplantation in terms of orthorexia nervosa.

SUBJECTS AND METHODS

The population of the study consisted of individuals over the age of 18 who were donors or recipients undergoing organ transplantation at the Organ Transplantation Centre of Research-Application Hospital of Gaziantep University in Turkey (n=74). A questionnaire consisting of 3 parts was used as a data collection tool. While the first part includes questions that ask socio-demographic characteristics of the participants and constitute the independent variables of the study (21 questions), the second and third parts include the Orthorexia Nervosa-15 (ORTO-15) and the Eating Attitude Test (EAT-40), respectively.

RESULTS

Based on the cut-off point of the ORTO-15 scale, it was determined that while 78.4% (n=58) of the participants were normal in terms of orthorexia nervosa, 21.6% (n=16) were orthorexic. In terms of the cut-off point of EAT-40, 37.8% (n=28) of the participants did not have an eating disorder and 62.2% (n=46) suffered from an eating disorder. The ORTO-15 mean ranks were high in those who were females (p=0.035), were suffering from chronic diseases (p=0.002), did not consume fast food (p=0.004), were making arrangements before eating their daily meals (p=0.018), and were doing regular physical activity (p=0.042).

CONCLUSIONS

Consequently, it was determined that those who were females, were suffering from chronic diseases, were making arrangements before eating their daily meals and were doing regular physical activity showed a more orthorexic tendency. It is recommended for healthcare professionals to determine the orthorexic tendency level of patients, who are female, suffer from chronic diseases, adhere to a regular diet and do a regular physical activity, and evaluate the whole patient group in terms of eating disorders while healthcare professionals conduct early diagnosis screenings of the patients (recipient/donor) in the organ transplantation process or referring them.

Hydrotalcite framework stabilized ruthenium nanoparticles (Ru/HTaL): efficient heterogeneous catalyst for the methanolysis of ammonia-borane

Ruthenium nanoparticles stabilized by a hydrotalcite framework (Ru/HTaL) were prepared by following a 2-step procedure comprising a wet-impregnation of ruthenium(III) chloride precatalyst on the surface of HTaL followed by an ammonia-borane (NH₃BH₃) reduction of precatalyst on the HTaL surface all at room temperature. The characterization of Ru/HTaL was done by using various spectroscopic and visualization methods including ICP-OES, P-XRD, FTIR, ¹¹B NMR, XPS, BFTEM, and HRTEM. The sum of the results gained from these analyses has revealed the formation of well-dispersed and highly crystalline ruthenium nanoparticles with a mean diameter of 1.27 ±0.8 nm on HTaL surface. The catalytic performance of Ru/HTaL in terms of activity, selectivity, and stability was investigated in the methanolysis of ammonia-borane (NH₃BH₃ , AB), which has been considered as one of the most promising chemical hydrogen storage materials. It was found that Ru/HTaL can catalyse methanolysis of AB effectively with an initial turnover frequency (TOF) value of 392.77 min^-1 at conversion (>95%) even at room temperature. Moreover, the catalytic stability tests of Ru/HTaL in AB methanolysis showed that Ru/HTaL acts as a highly stable and reusable heterogeneous catalyst in this reaction by preserving more than 95% of its initial activity even at the 5th recycle.

Complete Dehydrogenation of Hydrazine Borane on Manganese Oxide Nanorod-Supported Ni@Ir Core-Shell Nanoparticles

Hydrazine borane (HB; N₂H₄BH₃) has been considered to be one of the most promising solid chemical hydrogen storage materials owing to its high hydrogen capacity and stability under ambient conditions. Despite that, the high purity of hydrogen production from the complete dehydrogenation of HB stands as a major problem that needs to be solved for the convenient use of HB in on-demand hydrogen production systems. In this study, we describe the development of a new catalytic material comprised of bimetallic Ni@Ir core-shell nanoparticles (NPs) supported on OMS-2-type manganese oxide octahedral molecular sieve nanorods (Ni@Ir/OMS-2), which can reproducibly be prepared by following a synthesis protocol including (i) the oleylamine-mediated preparation of colloidal Ni@Ir NPs and (ii) wet impregnation of these ex situ synthesized Ni@Ir NPs onto the OMS-2 surface. The characterization of Ni@Ir/OMS-2 has been done by using various spectroscopic and visualization techniques, and their results have revealed the formation of well-dispersed Ni@Ir core-shell NPs on the surface of OMS-2. The catalytic employment of Ni@Ir/OMS-2 in the dehydrogenation of HB showed that Ni_0.22@Ir_0.78/OMS-2 exhibited high dehydrogenation selectivity (>99%) at complete conversion with a turnover frequency (TOF) value of 2590 h^-1 at 323 K, which is the highest activity value among all reported catalysts for the complete dehydrogenation of HB. Furthermore, the Ni_0.22@Ir_0.78/OMS-2 catalyst enables facile recovery and high stability against agglomeration and leaching, which make it a reusable catalyst in the complete dehydrogenation of HB. The studies reported herein also include the collection of wealthy kinetic data to determine the activation parameters for Ni_0.22@Ir_0.78/OMS-2-catalyzed dehydrogenation of HB.

A new technique of completely diverted tube ileostomy for the protection of colorectal anastomosis: a pilot study

AIM

This study was designed to evaluate a new technique for a completely diverting tube ileostomy achieved through temporary occlusion of the distal ileum using a flexible rubber strip.

METHODS

This prospective interventional study was conducted in one centre. Patients who underwent colorectal resections with a primary anastomosis and who were deemed as requiring a defunctioning stoma were included in the study. After completion of resection and anastomosis, the tube ileostomy was fashioned by inserting a reinforced (spiral) endotracheal tube with an inner diameter of 7.5 mm into the ileum. To provide complete faecal diversion, temporary occlusion of the distal ileum was performed using a flexible rubber strip. The primary outcome of this study was the incidence of complete diversion achieved using this method.

RESULTS

Fifty consecutive patients underwent a diverted tube ileostomy using the technique described above. Defaecation before removal of the strip did not occur in any of the patients inferring that complete diversion was observed in all patients (100%). The tube was removed at postoperative week 3. After tube removal, the resulting enterocutaneous fistulas closed spontaneously in a median of 6 (2-30) days.

CONCLUSION

The diverting tube ileostomy technique using an easily removable rubber strip to defunction the colorectal anastomosis is a safe and effective method that precludes the need to fashion a stoma.

Chromium based metal–organic framework MIL-101 decorated palladium nanoparticles for the methanolysis of ammonia-borane

Pd@MIL-101 synthesized by a novel and facile approach acts as a highly active nanocatalyst (TOF = 1080 min⁻¹) in the methanolysis of ammonia-borane (NH₃BH₃) under air at room temperature.

Which one predicts mortality better? Hemogram and ST elevation myocardial infarction

Objective

The aim of this study was to determine the effectiveness of hematological parameters measured at the moment of admission to the emergency room in predicting in-hospital mortality and to determine cut-off values of strongly predictive values.

Subjects and Methods

The study began with approval of the ethics committee. In total, 1,929 patients over 18 years of age, whose date could be obtained, were included in the study. From the hemogram parameters, white blood cells (WBC), red cell distribution width, mean platelet volume, and ratio of neutrophils to lymphocytes (NLR) values were determined and recorded. CK-MB and high-sensitive Troponin T values were recorded as cardiac markers. For statistical analysis, "SPSS for Windows Version 21" package program was used.

Findings

About 71.7% (n = 1384) of the patients were male and 28.3% (n = 545) of the patients were female. About 92.5% of the patients (n = 1785) were discharged from the hospital, whereas the remaining 144 patients (7.5%) were exitus in the hospital. When the efficacy of hematological parameters and cardiac markers in predicting mortality was examined by receiver operating charecteristics analysis, NLR was found to be the strongest predictor (area under the curve [AUC], 0.772, standard deviation [SD] = 0.022, 95% confidence interval [CI]). It was found that the WBC value came in second place after NLR as a strong predictor of mortality (AUC, 0.749, SD = 0.024, % 95 CI).

Conclusion

The use of predictors for the prediction of mortality for ST elevation myocardial infarction patients is of great importance for faster implementation of treatment modalities. We found that WBC and especially NLR values obtained with a simple method can be used as powerful predictors.

Atomic Layer Deposition of Ruthenium Nanoparticles on Electrospun Carbon Nanofibers: A Highly Efficient Nanocatalyst for the Hydrolytic Dehydrogenation of Methylamine Borane

We report the fabrication of a novel and highly active nanocatalyst system comprising electrospun carbon nanofiber (CNF)-supported ruthenium nanoparticles (NPs) (Ru@CNF), which can reproducibly be prepared by the ozone-assisted atomic layer deposition (ALD) of Ru NPs on electrospun CNFs. Polyacrylonitrile (PAN) was electropsun into bead-free one-dimensional (1D) nanofibers by electrospinning. The electrospun PAN nanofibers were converted into well-defined 1D CNFs by a two-step carbonization process. We took advantage of an ozone-assisted ALD technique to uniformly decorate the CNF support by highly monodisperse Ru NPs of 3.4 ± 0.4 nm size. The Ru@CNF nanocatalyst system catalyzes the hydrolytic dehydrogenation of methylamine borane (CH₃NH₂BH₃), which has been considered as one of the attractive materials for the efficient chemical hydrogen storage, with a record turnover frequency of 563 mol H₂/mol Ru × min and an excellent conversion (>99%) under air at room temperature with the activation energy ( E_a) of 30.1 kJ/mol. Moreover, Ru@CNF demonstrated remarkable reusability performance and conserved 72% of its inherent catalytic activity even at the fifth recycle.

Amine-functionalized graphene nanosheet-supported PdAuNi alloy nanoparticles: efficient nanocatalyst for formic acid dehydrogenation

PdAuNi/f-GNS provides CO-free hydrogen generation from additive-free dehydrogenation of formic acid even at room temperature.

Crystal structure of 2-ethyl-4-methyl-1-(2-oxido-3,4-dioxocyclobut-1-en-1-yl)-1H-imidazol-3-ium

In the crystal of the inner salt of the title compound, N—H⋯O and C—H⋯O hydrogen bonds form an (9) ring motif.

In the title inner salt molecule, C₁₀H₁₀N₂O₃, the four-membered cyclobutene ring is twisted by 7.1 (2)° with respect to the five-membered imidazole ring. The crystal packing exhibits an R₂²(9) hydrogen-bonding ring motif through N—H⋯O and C—H⋯O inter­actions. The potential non-linear optical properties were studied by a computational ab initio calculations performed at the DFT/B3LYP/6–31++G(d,p) level of theory.

The effect of topical anti-muscarinic agents on subfoveal choroidal thickness in healthy adults

PurposeTo investigate the effects of tropicamide and cyclopentolate, which are two anti-muscarinic agents commonly used in the ophthalmologic practice, on subfoveal choroidal choroidal thickness (ChT) in healthy adults.MethodsA total of 74 healthy adult subjects were enrolled in the study. Subjects were randomly divided into two groups: (1) cyclopentolate group (n=37) in which the right eye (study eye) of each subject received topical cyclopentolate 1%, and the fellow eye (control eye) received artificial tears and (2) tropicamide group (n=37) in which the right eye (study eye) of each subject received topical tropicamide 1% and the fellow eye (control eye) received artificial tears. Each topical medication was applied three times with 10-min intervals. ChT measurements were performed at baseline and 40 min after the last drops of the topical medications by enhanced depth imaging (EDI) optical coherence tomography (OCT).ResultsIn the cyclopentolate group, subfoveal ChT significantly increased in the study eyes (P=0.013), whereas it did not significantly change in the control eyes (P=0.417). On the other hand, in the tropicamide group, no significant subfoveal ChT changes were observed in either the study eyes (P=0.715) or the control eyes (P=0.344).ConclusionsThe current study demonstrated that cyclopentolate caused significant choroidal thickening, whereas tropicamide had no significant effect on ChT in healthy adults. As a result, mydriasis by cyclopentolate may complicate ChT measurements by EDI OCT. Use of tropicamide may provide more reliable results for evaluation of ChT in ocular pathologies.

Sulfamethizole–2-amino-4,6-dimethoxypyrimidine (1/1)

In the title 1:1 co-crystal, C9H10N4O2S2·C6H9N3O2[systematic name: 4-amino-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide–2-amino-4,6-dimethoxypyrimidine (1/1)], the sulfamethazole molecule is found in the form of the imidine tautomer. In the crystal, the components are linked by a pair of N—H...N hydrogen bonds, which generate anR22(8) loop. Further N—H...N and N—H...O hydrogen bonds link the dimers into [100] chains.

3-Phenylpyridinium hydrogen squarate: experimental and computational study of a nonlinear optical material

The detailed investigation of an organic nonlinear optical (NLO) squarate salt of 3-phenylpyridinium hydrogen squarate (1), C11H10N+·C4HO4(-), was reported in this study. The XRD data indicates that the crystal structure of the title compound is in the triclinic P-1 space group. In the asymmetric unit, the 3-phenylpyridine molecule is protonated by one hydrogen atom donation of squaric acid molecule, forming the salt (1). The X-ray analysis shows that the crystal packing has hydrogen bonding ring pattern of D2(2)(10) (α-dimer) through NH···O interactions. The structural and vibrational properties of the compound were also studied by computational methods of ab initio at DFT/B3LYP/6-31++G(d,p) (2) and HF/6-31++G(d,p) (3) levels of theory. The calculation results on the basis of two models for both the optimized molecular structure and vibrational properties for the 1 are presented and compared with the experimental results. Non-linear optical properties (NLO) of the title compound together with the molecular electrostatic potential (MEP), electronic absorption spectrum, frontier molecular orbitals (FMOs) and conformational flexibility were also studied at the 2 level and the results were reported. In order to evaluate the suitability for NLO applications thermal analysis (TG, DTA and DTG) data of 1 were also obtained.

Structural, spectroscopic, magnetic and electrochemical studies of monomer N-substituted-sulfanilamide copper (II) complex with 2,2'-bipyridine

A novel copper (II) complex of sulfamethazine (4-amino-N-[4,6-dimethyl-2-pyrimidinyl] benzene sulfonamide, Hsmz) ([Cu(smz)2bipy]⋅0.8H2O; bipy: 2,2'-bipyridine) has been synthesized and characterized by single crystal X-ray diffraction, EPR, IR, UV-vis and electrochemical methods. The single crystal X-ray analysis indicated that the compound crystallizes in the monoclinic space group P21/c with Z=4. The central copper (II) ion is coordinated by two bidentate sulfamethazine anions through the nitrogen atoms together with one bidentate 2,2'-bipyridine ligand forming the octahedral geometry. The characteristic vibration bands support the X-ray analysis results. The EPR spectral analysis has led to that the ground state wave function of the unpaired electron of copper ion is [Formula: see text] ((2)B1g state) and also indicated that the metal ions are located in distorted octahedral sites (D4h) elongated along the z-axis. The electrochemical studies of the complex were also carried out to determine the active sites of the ligands. The cyclic and square wave voltammetric techniques have been used to determine the complex.

Synthesis, structural and electrochemical properties of nickel(II) sulfamethazine complex with diethylenetriamine ligand

In this study, [Ni(dien)2]⋅smz2⋅(Hsmz: sulfamethazine and dien: diethylenetriamine) complex has been synthesized and its crystal structure has been determined by X-ray diffraction technique. The title complex crystallizes in orthorhombic system with space group Pbnb [a=8.556(5), b=16.228(5), c=28.209(5)Å, V=3917(3)Å(3) and Z=4]. The nickel(II) ion has distorted octahedral coordination geometry. The metal atom, which rides on a crystallographic center of symmetry, is coordinated by six nitrogen atoms of two dien ligands to form a discrete [Ni(dien)2](2+) unit, which captures two sulfamethazine ions, each through intermolecular hydrogen bonds. The powder EPR spectrum of Cu(2+) doped Ni(II) complex was recorded at room temperature. The vibrational investigation has been carried out by considering the characteristic bands related to the functional groups of the complex. The electrochemical behavior of Ni(II) ions in the presence and in the absence of smz and dien were studied by square wave and cyclic voltammetry. A well-defined irreversible peak at -1.112V different from those of the Ni(II)-smz (-0.876V) and the Ni(II)-dien complex (-1.064V) was observed in the solution containing Ni(II) ions, which was attributed to the formation of the new mixed ligand complex of Ni(II) with smz and dien.

2-Pyridinium propanol hydrogen squarate: experimental and computational study of a nonlinear optical material

The experimental and theoretical investigation of a novel organic nonlinear optical (NLO) squarate salt of 2-pyridinium propanol hydrogen squarate (1), C8H12ON(+)·C4HO4(-), were reported in this study. The crystal structure of the title compound was found to crystallize in the triclinic P-1 space group. In the asymmetric unit each squaric acid molecules have donated one H atom to the pyridines N1 and N2 atoms of a 2-pyridine propanol molecule, forming the salt (1). The X-ray analysis clearly indicated that the crystal packing has shown the hydrogen bonding ring pattern of D2(2)(10) (α-dimer) through N-H⋯O interactions. The structural and vibrational properties of the compound were also studied by computational methods of ab initio performed on the compound at DFT/B3LYP/6-31++G(d,p) (2) and HF/6-31++G(d,p) (3) level of theory. The calculation results on the basis of two models for both the optimized molecular structure and vibrational properties for the 1 are presented and compared with the X-ray analysis result. The molecular electrostatic potential (MEP), electronic absorption spectra, frontier molecular orbitals (FMOs), conformational flexibility and non-linear optical properties (NLO) of the title compound were also studied at the 2 level and the results are reported. In order to evaluate the suitability for NLO applications thermal analysis (TG, DTA and DTG) data of 1 were also obtained.

Effect of verapamil and lidocaine on TRPM and NaV1.9 gene expressions in renal ischemia-reperfusion

BACKGROUND

To determine effects on calcium and sodium channels of Ca(2+) and Na(+) channel blockers in the present study, expression levels of TRPM1, TRPM2, TRPM3, TRPM4, TRPM5, TRPM6, TRPM7, TRPM8, and NaV1.9 genes were evaluated in kidney tissues after induced ischemia-reperfusion.

MATERIAL AND METHODS

Forty albino Wistar male rats were equally divided into 4 groups as follows: group I: control group (n = 10), group II: ischemia group (60 minutes of ischemia + 48 hours of reperfusion; n = 10), group III: ischemia (60 minutes of ischemia + 48 hours of reperfusion) + calcium channel blocker (n = 8), group IV: ischemia (60 minutes of ischemia + 48 hours of reperfusion) + sodium channel blocker (n = 8).

RESULTS

When compared to ischemia group expression levels of TRPM2, TRPM4, TRPM6, and NaV1.9 in Ca(2+) and Na(+) channel blocker groups were increased, whereas that of TRPM7 was decreased. However, expression levels of TRPM1, TRPM3, TRPM5, and TRPM8 were not determined in kidney tissue. Histologically, the Ca(2+) channel blocker verapamil and the Na(+) channel blocker lidocaine inhibited the cell death in kidney tissue compared to control.

CONCLUSION

Our study suggested that verapamil and lidocaine significantly reduce the degree of ischemia-reperfusion injury due to effects to TRPM and Nav1.9 genes.

Synthesis, an experimental and quantum chemical computational study: proton sharing in 4-Morpholinium bis(hydrogen squarate)

The experimental and theoretical investigation results of a novel organic squarate salt of 4-Morpholinium bis(hydrogen squarate) (1), C₆H₁₄ON(+)·C₈H₃O₈(-), were reported in this study. The crystal structure of the title compound was found to crystallize in the triclinic P-1 space group. In the crystals of 1 the morpholine ring adopts the chair conformation with the ethyl group in the equatorial and hydrogen atoms in axial positions. The hydrogen squarate anions are linked into a homoconjugated anion, [(HSQ)₂H], by a short symmetric, nonlinear O₈⋯H₂⋯O₂ hydrogen bond of 2.444 (2)Å. The structural and vibrational properties of the compound were also studied by computational methods of ab-initio performed on the compound at DFT/B3LYP/6-31++G(d,p) (2) and HF/6-31++G(d,p) (3) level of theory. The obtained calculation results on the basis of two models for both the optimized molecular structure and vibrational properties for the 1 obtained are presented and compared with the X-ray analysis result. On the other hand the molecular electrostatic potential (MEP), electronic absorption spectra, frontier molecular orbitals (FMOs), conformational flexibility and non-linear optical properties (NLO) of the title compound were also studied at the 2 level and the results are reported. In order to evaluate the suitability for NLO applications thermal analysis (TG, DTA and DTG) data of 1 were also obtained.

Macrocyclic Cu(ii)-organophosphonate building block with room temperature magnetic ordering

A novel macrocyclic Cu(ii)-organophosphonate building block displaying high temperature magnetic ordering, and the structure of [{Cu(2,2′-bpy)}₂(HO₃P(CH₂)₈PO₃H₂)₄] (1).

Amine grafted silica supported CrAuPd alloy nanoparticles: superb heterogeneous catalysts for the room temperature dehydrogenation of formic acid

The CrAuPd/N-SiO₂ catalyst generates H₂ from formic acid solution with unprecedented activity even at room temperature and in the absence of additives.

Synthesis, an experimental and quantum chemical computational study of a new nonlinear optical material: 2-picolinium hydrogensquarate

The experimental and theoretical investigation results of a novel organic non-linear optical (NLO) organic squarate salt of 2-Picolinium hydrogensquarate (1), C6H8N+·C4HO4-, were reported in this study. The space group of the title compound was found in the monoclinic C2/c space group. It was found that the asymmetric unit consists of one monohydrogen squarate anion together with mono protonated 2-Picolinium, forming the (1) salt. The X-ray analysis clearly indicated that the crystal packing has shown the hydrogen bonding ring pattern of D2(2)(10) (α-dimer) through NH⋯O interactions. The hydrogensquarate anions form α-dimer, while 2-Picolinium molecule interacts through NH⋯O and CH⋯O with the hydrogensquarate anion. The structural and vibrational properties of the compound were also studied by computational methods of ab initio performed on the compound at DFT/B3LYP/6-31++G(d,p) (2) and HF/6-31++G(d,p) (3) level of theory. The calculation results on the basis of two models for both the optimized molecular structure and vibrational properties for the 1 obtained are presented and compared with the X-ray analysis result. On the other the molecular electrostatic potential (MEP), electronic absorption spectra, frontier molecular orbitals (FMOs), conformational flexibility and non-linear optical properties (NLO) of the title compound were also studied at the 2 level and the results are reported. In order to evaluate the suitability for NLO applications thermal analysis (TG, DTA and DTG) data of 1 were also obtained.

EPR Studies of VO2+ in Ba(ClO4) 2 ・3H2O Single Crystals

The results of an electron paramagnetic resonance (EPR) study of vanadyl ion VO2+ doped in single crystals of Ba(ClO4)2 - 3 H2O are reported. The spectra indicated the presence of two substitutional and interstitial sites depending on the orientation. The spin-Hamiltonian parameters were determined from single crystal and powder EPR data. These parameters were found to be axial symmetric for the powder sample, whereas they showed deviations from axial symmetry for the single crystal

EPR Studies of Cu2+ in dl-Aspartic Acid Single Crystals

EPR studies of Cu2+ doped dl-Aspartic Acid [NH2CH(CH2COOH)COO] powder and single crystal have been carried out at 113 and 300 K. The principal hyperfine and g values, covalancy parameter, mixing coefficients and Fermi-contact term of the complex were obtained, and the ground-state wavefuntion of the Cu2+ ion in the lattice has been constructed.

Synthesis, Crystal Structure, Spectral and Thermal Characterization of cis-Diaquabis(1,10-phenanthroline)zinc(II) Diorotate Hydrate, cis-[Zn(H2O)2(phen)2](H2Or)2 · (H2O)2.125

Preparation, X-ray crystal structure, thermal behavior, and IR spectroscopic studies of cis-diaquabis(1,10-phenanthroline)zinc(II) diorotate hydrate are described. In the compound [Zn(H2O)2(C12H8N2)2](C5H3N2O4)2·(H2O)2.125 (1), the zinc ion, located on a twofold axis, is coordinated by two aqua ligands together with a pair of bidentate 1,10-phenanthroline (phen) molecules, and exhibits a distorted octahedral coordination. The orotate anions have a single negative charge each. The metal−coordinated water molecules link the orotate ions to the metal complex via O-H· · ·O hydrogen bonds. Also the uncoordinated water molecules are bonded to orotate ions through O-H· · ·O hydrogen bonds. Thus, an extensive network of hydrogen bonds together with π-π, and π-ring interactions stabilize the crystal structure and form an infinitive three dimensional structure. The thermal decomposition pathway of 1 has been investigated by the help of thermal analysis data (TG, DTG and DTA).

Crystal Structure, Spectroscopic and Redox Properties of Copper(II) Bis{2-[(2,6-dimethylphenyl)iminomethyl-3-methoxyphenolate]}

The coordination chemistry of N-(2,6-di-methylphenyl)-2-hydroxy-3-methoxybenzaldimine (1) with Cu(II) has been investigated by X-ray crystallography, electronic and EPR spectroscopies, as well as by electro- and magnetochemistry. The title complex 2 crystallizes in the orthorhombic space group P212121 (a = 8.1538, b = 17.7466, c =19.8507 Å). The mononuclear square-planar molecules 2 featuring trans-N2O2 coordination are connected via weak intermolecular C-H· · ·π interactions into infinite chains parallel to the a axis. Although the intermolecular Cu· · ·Cu separations within individual chains and between chains are very long (8.154 and 9.726 Å ), the exchange interaction parameter G = 2.03 < 4, estimated from solid state EPR spectra, suggests the existence of long-distance superexchange pathways between adjacent Cu(II) centers. The electronic and electrochemical features of the compound are also discussed.

Structural, spectroscopic and voltammetric studies of bis(acetazolamido)bis(aquo)bis(nicotinamide)copper(II)

Polymeric copper(II) complex, [Cu(Hacm)(2)(na)(2)(H(2)O)(2)] [H(2)acm; acetazolamide, na; nicotinamide] was synthesized and characterized by spectroscopic (IR; infrared spectroscopy, EPR; electron paramagnetic resonance), structural (XRD) and voltammetric structural (CV) methods. The copper(II) compound crystallizes in the triclinic space group P1¯, Z=1, with the unit-cell dimensions: a=7.672 (5)Å, b=8.681 (5)Å, c=11.938 (5)Å, α=90.807 (7)°, β=98.616 (5)° and γ=110.647 (5)°. The Cu(II) ion has a distorted octahedral coordination geometry. The crystal packing of the complex is stabilized by intermolecular O-H…O and N-H…O hydrogen bonds. The powder EPR spectrum of copper(II) complex have indicate that the paramagnetic center is in a tetragonal symmetry with the Cu(2+) ion having a distorted octahedral geometry. The vibrational investigation has been carried out on the basis of some characteristic IR bands of acetazolamide and nicotinamide molecules.

Structural characterization and EPR spectral studies on mononuclear copper(II) complex of saccharin with ethylnicotinate

Mononuclear copper(II) saccharinate (sac) complex containing ethylnicotinate (enc), [Cu(enc)(2)(sac)(2)(H(2)O)].1.4H(2)O has been synthesized and characterized by spectroscopic (IR, UV-vis, EPR), X-ray diffraction technique and electrochemical methods. It crystallizes in the tetragonal crystal systems with space group I4(1)cd and Z=8. The copper(II) ion presents a CuN(4)O distorted square pyramidal coordination. Based on EPR and optical absorption studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values, calculated for title complex in polycrystalline state at 298 K and in frozen DMF (110K), indicate the presence of the unpaired electron in the d(x)(2)-(y)(2) orbital. The evaluated metal-ligand bonding parameters showed strong in-plane sigma and in-plane pi-bonding. Some comparisons with related structures are made and the most important features of its IR spectrum were also discussed. The cyclic voltammogram of the title complex investigated in DMF (dimethylformamide) solution exhibits only metal centred electroactivity in the potential range +/-1.25 V vs. Ag/AgCl reference electrode.

Crystal structure and EPR studies of mixed ligand complex of cobalt(II) with saccharin and ethylisonicotine

The tetraaquabis(ethylisonicotinate)cobalt(II) disaccharinate, [Co(ein)2(H2O)4].(sac)2, (CENS), (ein: ethylisonicotinate and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The title complex crystallizes in monoclinic system with space group P2(1)/c and Z=2. The Co(II) cations present a slightly distorted CoN2O4 octahedral environment, with equatorially coordinated water molecules and axially pyridine N-bound ethylisonicotinate ligands. The magnetic environments of Cu2+-doped Co(II) complex have been identified by electron paramagnetic resonance (EPR) technique. Cu2+-doped CENS single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu2+-doped CENS indicate that Cu2+ ion substitute with the Co2+ ion in the host lattice. The angular variations of the EPR spectra have shown that two different Cu2+ complexes are located in different chemical environments, and each environment contains two magnetically inequivalent Cu2+sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The cyclic voltammogram of the title complex investigated in dimethylformamide (DMF) solution exhibits only metal centered electroactivity in the potential range -1.0-1.25V versus Ag/AgCl reference electrode.

Synthesis, spectroscopy, X-ray structure and redox behaviors of 4-(N-R-salicylideneimine)-2,6-diphenylphenols

A series of sterically hindered 4-(N-R-salicylaldimine)-2,6-diphenylphenols (X), where R=H (1), 3-CH3 (2), 5-CH3 (3), 3-OCH3 (4), 4-OCH3 (5), 5-OCH3 (6), 3-tBu (7), 5-tBu (8), 3,5-tBu2(9) and 5,6-benzo(10), were synthesized and their structure as well as redox behavior studied by analytical, spectroscopic [1H, (13C) NMR, IR, UV-vis and mass spectrometry] and cyclic voltammetric (CV) techniques. Single crystal X-ray diffraction studies of 7 evidenced its existence as non-planar enol-imine tautomer structure, in which the phenol ring of the molecule is twisted around C-N single bond by 21.5(2) degrees. The packing structure of 7 is stabilized by C-H...pi(Ph) and O...O and C...O intermolecular short contact interactions. The CV of X display rate is dependent on irreversible and quasi-reversible redox waves in the anodic and cathodic regions due to oxidation and reduction of phenolic and iminic groups, respectively. As evidenced by ESR and UV-vis study, chemical oxidation of X by PbO2 and (NH4)2Ce(NO3)6 in MeCN and CHCl3 generates stable phenoxyl radicals [(g approximately 2.005 and lambda approximately 450 nm (1600-8200 M(-1) cm(-1))].

Synthesis, spectroscopic and structural studies of new Schiff bases prepared from 3,5-Bu2t-salicylaldehyde and heterocyclic amines: X-ray structure of N-(3,5-di-tert-butylsalicylidene)-1-ethylcarboxylato-4-aminopiperidine

Two new sterically hindered salicylaldimines, N-(2,2,6,6-tetramethyl-piperidine-4)-3,5-Bu2t-salicylaldimine (I) and N-(1-carboxyethyl piperidine-4)-3,5-Bu2t-salicylaldimine (II), have been prepared and characterized by IR, UV-vis, 1H NMR, 13C NMR techniques and the structure of II has been examined by X-ray crystallography. No intermolecular H-bonding, pi-pi stacking or C--H...pi interactions are observed in the structure. The crystal structure the was mainly governed by intermolecular steric repulsions, due to bulky tert-butyl groups and the tendency of salicylaldimine rings to pack in parallel mode forms one-dimensional columns.