This paper reviews some of the most common surface modification approaches in biosensing based on self-assembled monolayers with a particular focus on Au film thiolation and SiO2 film silanization. Such approaches are routinely used to alter the materials’ surface properties towards a desired bioresponse. Furthermore, the most appropriate characterization methods towards ensuring successful surface modification are presented including XPS, HREELS, SPFS, Raman and FTIR spectroscopy as well as UPS with specific examples to demonstrate their importance. In addition, the mechanisms of fluorescent and non-fluorescent biotinylation of thiolated Au films and silanized SiO2 are discussed considering its importance in conjugating biomolecules such as enzymes, antibodies or chemokines onto surfaces, which carries high significance for biosensing applications. Finally, within this frame characterization routes towards ensuring effective attachment are discussed.
{"title":"Determination of Au Film Thiolation and Silane Bonding Onto SiO2 Films Within the Frame of Biosensor Surface Functionalization – an Analysis of Best Practices and Techniques","authors":"L. Bousiakou, Stefanos Karapetis","doi":"10.5562/cca3640","DOIUrl":"https://doi.org/10.5562/cca3640","url":null,"abstract":"This paper reviews some of the most common surface modification approaches in biosensing based on self-assembled monolayers with a particular focus on Au film thiolation and SiO2 film silanization. Such approaches are routinely used to alter the materials’ surface properties towards a desired bioresponse. Furthermore, the most appropriate characterization methods towards ensuring successful surface modification are presented including XPS, HREELS, SPFS, Raman and FTIR spectroscopy as well as UPS with specific examples to demonstrate their importance. In addition, the mechanisms of fluorescent and non-fluorescent biotinylation of thiolated Au films and silanized SiO2 are discussed considering its importance in conjugating biomolecules such as enzymes, antibodies or chemokines onto surfaces, which carries high significance for biosensing applications. Finally, within this frame characterization routes towards ensuring effective attachment are discussed.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3640","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49585349","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}
S. Špirtović-Halilović, A. Osmanović, D. Završnik, Aida Selmanagić, Selma Škrbo, Nihada Škrijelj, S. Trifunović, S. Roca, D. Softić, A. Sapcanin, M. Salihović, E. Veljović
Four 4-hydroxycoumarin derivatives were synthesized and the structure was confirmed by NMR spectroscopy and Mass spectrometry. Tested compounds have shown significant antimicrobial activity against Bacillus subtilis subsp. spizizenii, Bacillus cereus, Staphylococcus aureus, and Staphylococcus epidermidis, and the effect of more halogens on the benzene nucleus, as well as the combination of halogen and alkyl groups, on the antimicrobial activity, was investigated. According to the docking study, these compounds can operate simultaneously on two enzymes, amylase and gyrase (1BAG and 1KZN), which are known to play an important role in bacterial life. Obtained docking study parameters for tested compounds showed an association with the in vitro results of the antimicrobial activity of these compounds. In silico tests of molecular properties of the tested compounds showed that the compounds met Lipinski's rule of five. In this paper, the ADME parameters of tested compounds were also calculated: Caco2 (in vitro Caco2 cell permeability), HIA (human intestinal absorption), MDCK (in vitro Mandin Darby Canine Kidney (MDCK) cell permeability), TPSA (topological polar surface area), etc.
{"title":"Synthesis, Microbiological Activity and In Silico Investigation for Some Synthesized Coumarin Derivatives","authors":"S. Špirtović-Halilović, A. Osmanović, D. Završnik, Aida Selmanagić, Selma Škrbo, Nihada Škrijelj, S. Trifunović, S. Roca, D. Softić, A. Sapcanin, M. Salihović, E. Veljović","doi":"10.5562/cca3637","DOIUrl":"https://doi.org/10.5562/cca3637","url":null,"abstract":"Four 4-hydroxycoumarin derivatives were synthesized and the structure was confirmed by NMR spectroscopy and Mass spectrometry. Tested compounds have shown significant antimicrobial activity against Bacillus subtilis subsp. spizizenii, Bacillus cereus, Staphylococcus aureus, and Staphylococcus epidermidis, and the effect of more halogens on the benzene nucleus, as well as the combination of halogen and alkyl groups, on the antimicrobial activity, was investigated. According to the docking study, these compounds can operate simultaneously on two enzymes, amylase and gyrase (1BAG and 1KZN), which are known to play an important role in bacterial life. Obtained docking study parameters for tested compounds showed an association with the in vitro results of the antimicrobial activity of these compounds. In silico tests of molecular properties of the tested compounds showed that the compounds met Lipinski's rule of five. In this paper, the ADME parameters of tested compounds were also calculated: Caco2 (in vitro Caco2 cell permeability), HIA (human intestinal absorption), MDCK (in vitro Mandin Darby Canine Kidney (MDCK) cell permeability), TPSA (topological polar surface area), etc.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3637","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46598119","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}
Editor: Danijel Namjesnik Published by: Croatian Chemical Society, Zagreb, 2020 ISBN 978-953-8334-00-9 (Hardcover) ISBN 978-953-8334-01-6 (pdf) 310 pages Open access: https://prelog.hkd.hr/
Structural characterization of the β-polymorph of glycolaldehyde dimer by powder X-ray diffraction, Raman and infrared spectroscopies is described. The previously described α-polymorph and the β-polymorph both crystallize in the monoclinic crystal system, space group P21/c, but with different cell parameters. There are no significant differences in the glycolaldehyde dimer molecular structure, the molecules in both polymorphs are trans-isomers with the hydroxyl groups in axial positions. The two polymorphs have a different arrangement of the glycolaldehyde dimer molecules. In the previously reported α-polymorph the molecules are arranged in hydrogen bonded layers parallel to (100) while in the β-polymorph the hydrogen bonded molecules are arranged in a three-dimensional network. Theoretically calculated Gibbs free energy as well as differential scanning calorimetry indicate β-polymorph to be the stable crystal phase of glycolaldehyde.
{"title":"Structural Characterization of β-Glycolaldehyde Dimer","authors":"V. Mohaček-Grošev, B. Prugovečki, S. Prugovečki","doi":"10.5562/cca3606","DOIUrl":"https://doi.org/10.5562/cca3606","url":null,"abstract":"Structural characterization of the β-polymorph of glycolaldehyde dimer by powder X-ray diffraction, Raman and infrared spectroscopies is described. The previously described α-polymorph and the β-polymorph both crystallize in the monoclinic crystal system, space group P21/c, but with different cell parameters. There are no significant differences in the glycolaldehyde dimer molecular structure, the molecules in both polymorphs are trans-isomers with the hydroxyl groups in axial positions. The two polymorphs have a different arrangement of the glycolaldehyde dimer molecules. In the previously reported α-polymorph the molecules are arranged in hydrogen bonded layers parallel to (100) while in the β-polymorph the hydrogen bonded molecules are arranged in a three-dimensional network. Theoretically calculated Gibbs free energy as well as differential scanning calorimetry indicate β-polymorph to be the stable crystal phase of glycolaldehyde.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43077712","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}
Numerous biological and pharmacological properties of coumarins have designated them as significant synthetic target in many fields. Biscoumarins are considered as an important class of coumarin derivatives that show remarkable pharmacological properties. Therefore, development of the efficient new methods for their synthesis, based on green methodology, would be of a great importance in medicinal and pharmaceutical chemistry. In this work, the ultrasound and microwave assisted synthesis of biscoumarins, starting from corresponding aldehydes and 4-hydroxycoumarin is reported. Molecular iodine was used as an efficient and inexpensive catalyst for a simple synthesis, to obtain excellent yields using ethanol as a solvent. It was found that 10 % (n / n) of molecular iodine catalyzes biscoumarin synthesis in high yields (80–94 %) and in short reaction times, using both ultrasound, as well as microwave promoted conditions. Furthermore, when those two methods are compared, ultrasound promoted reactions were proven to be more suitable for this kind of reaction.
{"title":"Green Chemistry Approach to the Synthesis of Biscoumarins from 4-Hydroxycoumarin","authors":"Mirjana Lončar, Marija Kovač, M. Molnar","doi":"10.5562/cca3643","DOIUrl":"https://doi.org/10.5562/cca3643","url":null,"abstract":"Numerous biological and pharmacological properties of coumarins have designated them as significant synthetic target in many fields. Biscoumarins are considered as an important class of coumarin derivatives that show remarkable pharmacological properties. Therefore, development of the efficient new methods for their synthesis, based on green methodology, would be of a great importance in medicinal and pharmaceutical chemistry. In this work, the ultrasound and microwave assisted synthesis of biscoumarins, starting from corresponding aldehydes and 4-hydroxycoumarin is reported. Molecular iodine was used as an efficient and inexpensive catalyst for a simple synthesis, to obtain excellent yields using ethanol as a solvent. It was found that 10 % (n / n) of molecular iodine catalyzes biscoumarin synthesis in high yields (80–94 %) and in short reaction times, using both ultrasound, as well as microwave promoted conditions. Furthermore, when those two methods are compared, ultrasound promoted reactions were proven to be more suitable for this kind of reaction.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3643","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44010953","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}
Though challenging, conversion of carbon dioxide (CO2) to valuable products is an emerging area of research. Electrochemical reduction (ECR) has emerged as an efficient and rapid technique to achieve this goal. Herein, 5,10,15,20-tetraphenyl-21H, 23H-porphine manganese(III) chloride [(Mn(TPP)Cl)] catalyzed CO2 reduction at vitreous carbon electrode in acetonitrile electrolyte is reported. The effect of catalyst concentration, addition of Brönsted acid (CF3CH2OH) to CO2-saturated solution have been studied and reported. Based on the results, possible mechanistic pathways have also been suggested and discussed.
{"title":"Mn(III) Catalyzed Electrochemical Reduction of CO2 on Carbon Electrodes","authors":"Khalaf M. Alenezi","doi":"10.5562/cca3614","DOIUrl":"https://doi.org/10.5562/cca3614","url":null,"abstract":"Though challenging, conversion of carbon dioxide (CO2) to valuable products is an emerging area of research. Electrochemical reduction (ECR) has emerged as an efficient and rapid technique to achieve this goal. Herein, 5,10,15,20-tetraphenyl-21H, 23H-porphine manganese(III) chloride [(Mn(TPP)Cl)] catalyzed CO2 reduction at vitreous carbon electrode in acetonitrile electrolyte is reported. The effect of catalyst concentration, addition of Brönsted acid (CF3CH2OH) to CO2-saturated solution have been studied and reported. Based on the results, possible mechanistic pathways have also been suggested and discussed.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3614","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47484850","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}
N. Bašić, P. Fowler, Sara Sabrina Zemljič, P. Stadler, Nancy Retzlaff, T. Pisanski, Thomas Gatter, Jörg Fallmann, Sarah J. Berkemer
In 2012, a family of benzenoids was introduced by Cruz, Gutman, and Rada, which they called convex benzenoids. In this paper we introduce the convexity deficit, a new topological index intended for benzenoids and, more generally, fusenes. This index measures by how much a given fusene departs from convexity. It is defined in terms of the boundary-edges code. In particular, convex benzenoids are exactly the benzenoids having convexity deficit equal to 0. Quasi-convex benzenoids form the family of non-convex benzenoids that are closest to convex, i.e., they have convexity deficit equal to 1. Finally, we investigate convexity deficit of several important families of benzenoids.
{"title":"Convexity Deficit of Benzenoids","authors":"N. Bašić, P. Fowler, Sara Sabrina Zemljič, P. Stadler, Nancy Retzlaff, T. Pisanski, Thomas Gatter, Jörg Fallmann, Sarah J. Berkemer","doi":"10.5562/CCA3602","DOIUrl":"https://doi.org/10.5562/CCA3602","url":null,"abstract":"In 2012, a family of benzenoids was introduced by Cruz, Gutman, and Rada, which they called convex benzenoids. In this paper we introduce the convexity deficit, a new topological index intended for benzenoids and, more generally, fusenes. This index measures by how much a given fusene departs from convexity. It is defined in terms of the boundary-edges code. In particular, convex benzenoids are exactly the benzenoids having convexity deficit equal to 0. Quasi-convex benzenoids form the family of non-convex benzenoids that are closest to convex, i.e., they have convexity deficit equal to 1. Finally, we investigate convexity deficit of several important families of benzenoids.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2020-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3602","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47844649","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}
Karlo Sović, T. Ostojić, I. Primožič, T. Hrenar, Mirjana Skočibušić, R. Odžak, A. Ramić, Sara Cepić
Full conformational space of cinchonine and cinchonidine has been investigated by means of statistical analysis of quantum chemical molecular dynamics simulations. Recently developed procedure comprising principal component analysis of molecular dynamics trajectories was applied on cinchonine and cinchonidine as well as on their protonated and methylated quaternary derivatives. The method for full conformational analysis includes Cartesian coordinates sampling through quantum chemical molecular dynamics simulations, reduction of dimensionality by principal component analysis, determination of probability distributions in a reduced space of Cartesian coordinates and search for all the strict extrema points in probability distribution functions. In order to gain crucial insight in the understanding of chirality induction of these alkaloids, comparison of the determined conformational spaces of pseudo-enantiomers has been made. It was shown that protonation of the quinuclidine nitrogen atom stabilizes the conformers with the intramolecular 1N–H∙∙∙9O hydrogen bond whereas methylation on the same position results in the reduction of the domain of internal coordinates responsible for the conformational space.
{"title":"Conformational Analysis of Cinhonine and Cinhonidine by Tensor Decomposition of Molecular Dynamics Trajectories","authors":"Karlo Sović, T. Ostojić, I. Primožič, T. Hrenar, Mirjana Skočibušić, R. Odžak, A. Ramić, Sara Cepić","doi":"10.5562/CCA3557","DOIUrl":"https://doi.org/10.5562/CCA3557","url":null,"abstract":"Full conformational space of cinchonine and cinchonidine has been investigated by means of statistical analysis of quantum chemical molecular dynamics simulations. Recently developed procedure comprising principal component analysis of molecular dynamics trajectories was applied on cinchonine and cinchonidine as well as on their protonated and methylated quaternary derivatives. The method for full conformational analysis includes Cartesian coordinates sampling through quantum chemical molecular dynamics simulations, reduction of dimensionality by principal component analysis, determination of probability distributions in a reduced space of Cartesian coordinates and search for all the strict extrema points in probability distribution functions. In order to gain crucial insight in the understanding of chirality induction of these alkaloids, comparison of the determined conformational spaces of pseudo-enantiomers has been made. It was shown that protonation of the quinuclidine nitrogen atom stabilizes the conformers with the intramolecular 1N–H∙∙∙9O hydrogen bond whereas methylation on the same position results in the reduction of the domain of internal coordinates responsible for the conformational space.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3557","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46919179","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}
Jihen Ajmi, Ichraf Nagazi, T. B. Issa, Ali Harchani, A. Haddad
The current investigation undertakes the synthesis, crystal structure, spectroscopic, thermal analyses and theoretical calculations of a new 3 D Strandberg-type polyoxometalate-based inorganic (NH4)4[Se2Mo5O21]·3H2O (denoted as ASH). Structural data obtained by single crystal X-ray diffraction revealed that the titled compound crystallizes in orthorhombic system with Pbcn space group, having parameters a = 15.0927(2) Å, b = 13.3633(1) Å, c = 23.8204(3) Å and Z = 8. Molecular structure and spectroscopic analysis were performed using experimental techniques like X-ray diffraction, infrared spectrum, UV–visible spectroscopy and thermogravimetric analysis. Hirshfeld surface analysis was performed to study the intermolecular interactions. The structural arrangement is mainly made by a system of H-bonds. All Strandberg clusters anions [Se2Mo5O21]4– are connected to each other through water molecules and the ammonium groups NH4+ to build a 3D (3 dimensional) supramolecular framework. Theoretical calculations were performed using PM3 semi-empirical model and several properties were studied.
本研究进行了一种新的三维strandberg型多金属氧酸盐基无机物(NH4)4[Se2Mo5O21]·3H2O(表示为ASH)的合成、晶体结构、光谱、热分析和理论计算。通过x射线单晶衍射得到的结构数据表明，该化合物为具有Pbcn空间群的正交晶系，其参数为a = 15.0927(2) Å， b = 13.3633(1) Å， c = 23.8204(3) Å， Z = 8。使用x射线衍射、红外光谱、紫外可见光谱和热重分析等实验技术进行分子结构和光谱分析。Hirshfeld表面分析研究了分子间相互作用。结构排列主要是由氢键系统构成的。所有Strandberg簇阴离子[Se2Mo5O21]4 -通过水分子和铵基NH4+相互连接，构建了一个3D(三维)超分子框架。采用PM3半经验模型进行理论计算，研究了PM3的几种性能。
{"title":"Theoretical, Spectroscopic and Crystal Structure Investigation of a Novel Selenomolybdate (NH4)4[Se2Mo5O21]·3H2O","authors":"Jihen Ajmi, Ichraf Nagazi, T. B. Issa, Ali Harchani, A. Haddad","doi":"10.5562/cca3605","DOIUrl":"https://doi.org/10.5562/cca3605","url":null,"abstract":"The current investigation undertakes the synthesis, crystal structure, spectroscopic, thermal analyses and theoretical calculations of a new 3 D Strandberg-type polyoxometalate-based inorganic (NH4)4[Se2Mo5O21]·3H2O (denoted as ASH). Structural data obtained by single crystal X-ray diffraction revealed that the titled compound crystallizes in orthorhombic system with Pbcn space group, having parameters a = 15.0927(2) Å, b = 13.3633(1) Å, c = 23.8204(3) Å and Z = 8. Molecular structure and spectroscopic analysis were performed using experimental techniques like X-ray diffraction, infrared spectrum, UV–visible spectroscopy and thermogravimetric analysis. Hirshfeld surface analysis was performed to study the intermolecular interactions. The structural arrangement is mainly made by a system of H-bonds. All Strandberg clusters anions [Se2Mo5O21]4– are connected to each other through water molecules and the ammonium groups NH4+ to build a 3D (3 dimensional) supramolecular framework. Theoretical calculations were performed using PM3 semi-empirical model and several properties were studied.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/cca3605","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46392198","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}
Reactive aluminum alkoxide (ASB, aluminium sec-butoxide) was chelated using β-diketone (EAA, ethyl acetoacetate) in order to gain control over rapid hydrolysis in the course of the sol-gel process. Derived chelates were analysed using several NMR spectroscopic techniques: one-dimensional 1H, 13C, 27Al NMR and two-dimensional COSY, HSQC and DOSY. The NMR analysis enabled identification of the formed chelate species, as well as determination of their quantitative relationships. Several complexation products were observed: tris-chelated monomer, Al(EAA)3, bis-chelated dimmer, Al2(OnBu)4(EAA) 2, tris-chelated dimmer, Al2(OnBu)3(EAA)3, tetra-chelated dimmer, Al2(OnBu)2(EAA)4, and monochelated trimer, Al3(OnBu)8(EAA). Of the formed oligomer compounds, this is the first evidence of Al2(OR)3L3 in any alkoxide and β-ketoester or β-diketone combination. Aluminium sec-butoxide and ethyl acetoacetate complexes Al2(OnBu)4(EAA) 2 and Al2(OnBu)2(EAA)4 were also observed for the first time. With the increase of the EAA/ASB ratio the coordination of aluminium shifts towards six, whereas above the EAA/ASB ratio of 2.5 solely six-coordinated aluminium exists.
{"title":"Multinuclear Magnetic Resonance Study on Aluminium Sec-butoxide Chelated with Ethyl Acetoacetate in Various Amounts","authors":"S. Kurajica, G. Mali, V. Mandić, I. Minga","doi":"10.5562/CCA3426","DOIUrl":"https://doi.org/10.5562/CCA3426","url":null,"abstract":"Reactive aluminum alkoxide (ASB, aluminium sec-butoxide) was chelated using β-diketone (EAA, ethyl acetoacetate) in order to gain control over rapid hydrolysis in the course of the sol-gel process. Derived chelates were analysed using several NMR spectroscopic techniques: one-dimensional 1H, 13C, 27Al NMR and two-dimensional COSY, HSQC and DOSY. The NMR analysis enabled identification of the formed chelate species, as well as determination of their quantitative relationships. Several complexation products were observed: tris-chelated monomer, Al(EAA)3, bis-chelated dimmer, Al2(OnBu)4(EAA) 2, tris-chelated dimmer, Al2(OnBu)3(EAA)3, tetra-chelated dimmer, Al2(OnBu)2(EAA)4, and monochelated trimer, Al3(OnBu)8(EAA). Of the formed oligomer compounds, this is the first evidence of Al2(OR)3L3 in any alkoxide and β-ketoester or β-diketone combination. Aluminium sec-butoxide and ethyl acetoacetate complexes Al2(OnBu)4(EAA) 2 and Al2(OnBu)2(EAA)4 were also observed for the first time. With the increase of the EAA/ASB ratio the coordination of aluminium shifts towards six, whereas above the EAA/ASB ratio of 2.5 solely six-coordinated aluminium exists.","PeriodicalId":10822,"journal":{"name":"Croatica Chemica Acta","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5562/CCA3426","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44734206","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}
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