Croatica Chemica Acta最新文献_第8页

Monitoring of the Forced Hydrolysis of FeCl3 Solutions in the Presence of Sodium Dodecyl Sulphate 十二烷基硫酸钠存在下FeCl3溶液强制水解的监测

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-12-29 DOI: 10.5562/CCA3412

M. Ristić, Jasenka Štajdohar, Ivana Mitar, S. Musić

{"title":"Monitoring of the Forced Hydrolysis of FeCl3 Solutions in the Presence of Sodium Dodecyl Sulphate","authors":"M. Ristić, Jasenka Štajdohar, Ivana Mitar, S. Musić","doi":"10.5562/CCA3412","DOIUrl":"https://doi.org/10.5562/CCA3412","url":null,"abstract":"Precipitations by the forced hydrolysis of 0.2 M FeCl3 aqueous solutions between 2 and 72 hours in the presence of 1% sodium n-dodecyl sulphate (SDS) were investigated. In the absence of SDS a direct phase transformation b- FeOOH → a-Fe2O3 via dissolution/ recrystallization occurred in the precipitation system. In the presence of SDS small amounts (traces) of a-FeOOH as an intermediate phase precipitated, and with a prolonged time of forced hydrolysis a-FeOOH also transformed to a-Fe2O3 via the dissolution/recrystallization mechanism. On the basis of Mossbauer spectra it was concluded that in the presence of SDS the a-Fe2O3 phase exhibited a lower degree of crystallinity. During the precipitation process in the presence of SDS the competition between the stability of Fe(III)-dodecyl sulphate on one side and the formation of iron oxide phases on the other also played an important role. Thermal field emission scanning electron microscopy (FE SEM) revealed that the big a- Fe2O3 particles possessed a substructure. The elongation of primary a-Fe2O3 particles produced in the presence of SDS was noticed. This effect can be assigned to the preferential adsorption of sulphate groups on nuclei and crystallites of FeOOH and a-Fe2O3 phases during the forced hydrolysis of FeCl3 solutions.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"403-410"},"PeriodicalIF":0.3,"publicationDate":"2018-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44148323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Molecular Design of Sugar-Based Polyurethanes 糖基聚氨酯的分子设计

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-12-29 DOI: 10.5562/CCA3328

Min Lu, Attila Surányi, B. Viskolcz, Béla Fiser

引用次数: 10

Time-Independent Methodology to Access Michaelis-Menten Constant by Exploring Electrochemical-Catalytic Mechanism in Protein-Film Cyclic Staircase Voltammetry 通过探索蛋白质膜循环阶梯伏安法的电化学催化机理获得米氏常数的时间无关方法

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-12-29 DOI: 10.5562/CCA3383

R. Gulaboski, Pavlinka Kokoskarova, Sofija Petkovska

{"title":"Time-Independent Methodology to Access Michaelis-Menten Constant by Exploring Electrochemical-Catalytic Mechanism in Protein-Film Cyclic Staircase Voltammetry","authors":"R. Gulaboski, Pavlinka Kokoskarova, Sofija Petkovska","doi":"10.5562/CCA3383","DOIUrl":"https://doi.org/10.5562/CCA3383","url":null,"abstract":": Protein-film voltammetry is recognized as a very efficient tool in mechanistic enzymology, but it is also seen as a relevant approach to gain thermodynamic and kinetic information related to the redox chemistry of many enzymes. This technique requires a small amount of redox enzyme, whose molecules form monomolecular film on the working electrode surface. In this paper we present a simple and time - independent cyclo-voltammetric method for the determination of kinetics of the chemical step of an electrochemical-catalytic (EC’) mechanism in protein- film scenario. Theoretical results of a surface EC’ mechanism show that the limiting cyclo -voltammetric catalytic current, measured at large overpotentials, depends solely on the rate of the chemical regenerative re action. At large overpotentials, the limiting current of the steady-state cyclic voltammograms is independent on all kinetics and thermodynamic parameters related to the electrode reaction of adsorbed enzyme. The approach proposed relies on the dependence of the magnitude of limiting current of the experimental cyclic steady-state voltammograms as a function of the substrate concentration.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"377-382"},"PeriodicalIF":0.3,"publicationDate":"2018-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3383","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45334963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Order-Disorder in Diaquobis(salicylato)copper(II) Revisited 水杨酸铜的有序-无序(II)再访

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-06-28 DOI: 10.5562/cca3362

M. Lutz, Dai, Louiseinfoeu-repo Kroon Batenburg

引用次数: 1

Content of Bioactive Constituents and Antioxidant Potential of Galium L. Species Galium L.属植物的生物活性成分含量及抗氧化能力

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-06-05 DOI: 10.5562/CCA3379

Maja Friščić, Maja Štibrić Baglama, M. Milović, K. H. Pilepić, Ž. Maleš

引用次数: 6

Chalcone and Flavonol Copper(II) Complexes Containing Schiff Base Co-Ligand: Synthesis, Crystal Structures and Catecholase-like Activity 含席夫碱共配体的查尔酮和黄酮醇铜（II）配合物的合成、晶体结构和类儿茶酚酸酯活性

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-06-04 DOI: 10.5562/CCA3334

E. Kahrović, A. Zahirović, A. Višnjevac, Irnesa Osmanković, E. Turkušić, H. Kurtagić

{"title":"Chalcone and Flavonol Copper(II) Complexes Containing Schiff Base Co-Ligand: Synthesis, Crystal Structures and Catecholase-like Activity","authors":"E. Kahrović, A. Zahirović, A. Višnjevac, Irnesa Osmanković, E. Turkušić, H. Kurtagić","doi":"10.5562/CCA3334","DOIUrl":"https://doi.org/10.5562/CCA3334","url":null,"abstract":"Four new heteroleptic copper(II) complexes having chalcone or flavonol ligands and Schiff base (N-phenyl-5-chlorosalicylideneimine) as co-ligand were prepared, chemically and structurally characterized and investigated as functional biomimetic catecholase models. The complexes were prepared by the solution synthesis and crystal and molecular structures were determined by X-ray diffraction. Complexes were chemically characterized by elemental analysis, infrared and electronic absorption spectroscopy as well as by electrochemical measurements. Copper(II) chalcone complexes, with square-pyramidal CuO4N core, are binuclear, featuring phenolate oxygen from the Schiff base as a bridging atom, while copper(II) flavonol complexes are mononuclear, and reveal a square planar CuO3N coordination core. Catalytic activity of the complexes in 3, 5-di-tert-butylcatechol oxidation was confirmed by spectrophotometric and electrochemical measurements. Kinetic measurements revealed that the binuclear (chalcone-containing) complexes have enhanced catalytic activity as compared to the mononuclear Cu(II) flavonol complexes. Relatively high kcat values (300 – 750 h–1) confirmed their respectable biomimetic catecholase-like activity.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"195-207"},"PeriodicalIF":0.3,"publicationDate":"2018-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49485699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Crystal structure of S-adenosyl-L-homocysteine hydrolase from Cytophaga hutchinsonii in complex with adenosine 哈氏细胞噬菌s -腺苷- l-同型半胱氨酸水解酶与腺苷复合物的晶体结构

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-06-04 DOI: 10.2210/PDB6GBN/PDB

J. Czyrko, M. Jaskólski, K. Brzezinski

引用次数: 0

The Mechanism of Peptide Hydrolysis Catalysed by Dipeptidyl Peptidase III from Bacteroides thetaiotaomicron 拟杆菌二肽基肽酶III催化肽水解的机理

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-06-04 DOI: 10.5562/CCA3343

M. Tomin, A. Tomić, B. Kovačević, S. Tomić

引用次数: 1

Non-canonical Structures in Promoter Modulate Gene Expression in Escherichia coli 启动子调控基因在大肠杆菌中表达的非规范结构

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-06-04 DOI: 10.5562/cca3349

Sabina Božič Abram, M. Marušič, M. Živkovič, J. Brčić, J. Plavec

引用次数: 1

Aggregation in Three Benzamide or Pyridylcarboxamide Hydrates: Formation of 1D Chains Comprising Water Molecules in a Chloro(pyridyl)benzamide Dihydrate 三种苯甲酰胺或吡啶甲酰胺水合物中的聚集：氯（吡啶基）苯甲酰胺二水合物中包含水分子的1D链的形成

IF 0.3 4区化学

Croatica Chemica Acta Pub Date : 2018-06-04 DOI: 10.5562/CCA3347

P. Mocilac, J. Gallagher, C. Jelsch

{"title":"Aggregation in Three Benzamide or Pyridylcarboxamide Hydrates: Formation of 1D Chains Comprising Water Molecules in a Chloro(pyridyl)benzamide Dihydrate","authors":"P. Mocilac, J. Gallagher, C. Jelsch","doi":"10.5562/CCA3347","DOIUrl":"https://doi.org/10.5562/CCA3347","url":null,"abstract":"Three benzamide hydrated derivatives as para-methyl-N-(3-pyridyl)benzamide monohydrate (I) or Mpm ∙ H2O; N-(3-fluorophenyl)-4pyridylcarboxamide monohydrate (II) or NpmF ∙ H2O and para-chloro-N-(3-pyridyl)benzamide dihydrate (III) or Clpm ∙ 2H2O are obtained from a series of crystallization experiments using a range of solvents to obtain polymorphs and solvates (hydrates). Most of the crystallization experiment attempts did not provide hydrates and yielded the starting parent crystalline materials. However, from the experiments, two benzamides, Mpm as a monohydrate and Clpm as a dihydrate were isolated and together with a carboxamide monohydrate as NpmF ∙ H2O are reported herein. The water molecules play a key role in crystal structure formation using classical hydrogen bonding via amide N–H∙∙∙OH2, O– H∙∙∙Npyridine and O–H∙∙∙O=C interactions. They compensate for the excess of strong hydrogen bonding acceptors over donors in the benzamide/pyridinecarboxamide molecules, by participating as O-H hydrogen bond donors twice and usually as an O acceptor once. In the Clpm dihydrate, both water molecules form hydrogen bonded chains along the a-axis direction. The lack of hydrate formation in the majority of related benzamides is presumably related to the relative hydrophobicity of these compounds.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":"91 1","pages":"281-288"},"PeriodicalIF":0.3,"publicationDate":"2018-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3347","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45613352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2