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Omar S, Irran E, Wiedemann D, Baabe D, Grohmann A. Sterically crowded di-indazolyl-pyridines: Iron(II) complexation studies. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2023. [DOI: 10.1515/znb-2023-0311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Abstract
Abstract
4-(2,6-Di(2H-indazol-2-yl)pyridin-4-yl)benzoic acid (1) and 10-(2,6-di(1H-pyrazol-1-yl)pyridin-4-yl)anthracene-9-carboxylic acid (2) were required for adsorption studies on Ag(111), with a view to subsequent iron(II) complexation and formation of well-ordered spin-responsive self-assembled monolayers. While the generation of these compounds has remained elusive, several intermediates and by-products were obtained, potentially useful as dipyrazolylpyridine-related derivatives and for metal ion coordination. 3,5-Dichloro-2,6-diindazolylpyridine-4-amine, which forms as a mixture of regioisomers, was synthesised, the mixture separated, and the components characterised (3,5-dichloro-2,6-di(2H-indazol-2-yl)pyridin-4-amine; 3,5-dichloro-2-(1H-indazol-1-yl)-6-(2H-indazol-2-yl)pyridin-4-amine; 3,5-dichloro-2,6-di(1H-indazol-1-yl)pyridin-4-amine). Their iron(II) complexes have been prepared and fully characterised, including single crystal X-ray structure determination. The complexes are instructive examples of the influence of ligand design (“steric jamming”) on the spin-crossover (SCO) activity of FeII centres. Bulky substitution, which entails twisted ligand conformation, increases intramolecular crowding. This prevents contraction of the metal coordination sphere, which would be a prerequisite for thermally inducible SCO. Mössbauer spectroscopy has revealed that the complexes remain predominantly high-spin (HS) between 20 and 200 K, and that a mixture of conformational HS isomers is present in the microcrystalline solid.
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Affiliation(s)
- Suhad Omar
- Institut für Chemie, Technische Universität Berlin , Straße des 17. Juni 135, 10623 Berlin , Germany
| | - Elisabeth Irran
- Institut für Chemie, Technische Universität Berlin , Straße des 17. Juni 135, 10623 Berlin , Germany
| | - Dennis Wiedemann
- Institut für Chemie, Technische Universität Berlin , Straße des 17. Juni 135, 10623 Berlin , Germany
- GfBU-Consult Gesellschaft für Umwelt- und Managementberatung mbH , Mahlsdorfer Straße 61b, 15366 Hoppegarten , Germany
| | - Dirk Baabe
- Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig , Hagenring 30, 38106 Braunschweig , Germany
| | - Andreas Grohmann
- Institut für Chemie, Technische Universität Berlin , Straße des 17. Juni 135, 10623 Berlin , Germany
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Jia S, Zhou Y, Li J, Gong B, Ma S, Ou J. Highly selective enrichment and direct determination of imazethapyr residues from milk using magnetic solid-phase extraction based on restricted-access molecularly imprinted polymers. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:426-435. [PMID: 33427265 DOI: 10.1039/d0ay02116d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Restricted access media magnetic molecularly imprinted polymers (RAM-MMIPs) were prepared as magnetic solid phase extraction (M-SPE) material by reversible addition fragmentation chain transfer (RAFT) technique. The resulting RAM-MMIPs had a uniform, imprinted, hydrophilic layer (63 nm), good binding capacity (34.85 mg g-1) and satisfactory selectivity. In addition, these RAM-MMIPs had a robust ability to eliminate the interference of protein macromolecules. These RAM-MMIPs were then coupled with HPLC/UV to identify imazethapyr (IM) residues in untreated milk samples. Several major factors would affect M-SPE extraction efficiency, such as the amount of RAM-MMIPs, pH, extraction time of the sample solution, and the volume ratio of the elution solvent. Under the optimal conditions, the developed method had good linearity (R2 > 0.9993), low detection limit (2.13 μg L-1), and low quantitative limit (7.15 μg L-1). These results indicated this proposed approach is an efficient method for direct enrichment and detection of IM herbicides in milk and other biological samples.
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Affiliation(s)
- Shicong Jia
- School of Chemistry and Chemical Engineering, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan, P. R. China.
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Peloquin AJ, Houck MB, McMillen CD, Iacono ST, Pennington WT. Perfluoropyridine as an Efficient, Tunable Scaffold for Bis(pyrazol‐1‐yl)pyridine Copper Complexes. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Andrew J. Peloquin
- Department of Chemistry Clemson University 219 Hunter Laboratories 29634 Clemson SC USA
| | - Matthew B. Houck
- Department of Chemistry & Chemistry Research Center Laboratories for Advanced Materials United States Air Force Academy 2355 Fairchild Dr., Suite 2N‐225 80840 Colorado Springs CO USA
| | - Colin D. McMillen
- Department of Chemistry Clemson University 219 Hunter Laboratories 29634 Clemson SC USA
| | - Scott T. Iacono
- Department of Chemistry & Chemistry Research Center Laboratories for Advanced Materials United States Air Force Academy 2355 Fairchild Dr., Suite 2N‐225 80840 Colorado Springs CO USA
| | - William T. Pennington
- Department of Chemistry Clemson University 219 Hunter Laboratories 29634 Clemson SC USA
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Ortiz de la Morena R, Asyuda A, Lu H, Aitchison H, Turner K, Francis SM, Zharnikov M, Buck M. Shape controlled assembly of carboxylic acids: formation of a binary monolayer by intercalation into molecular nanotunnels. Phys Chem Chem Phys 2020; 22:4205-4215. [PMID: 32043099 DOI: 10.1039/c9cp06724h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Binary self-assembled monolayers (SAMs) combining a Y-shaped aromatic carboxylic acid (1,3,5-benzenetribenzoic acid, H3BTB) and a cage-type alicyclic carboxylic acid (adamantane carboxylic acid, AdCA) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The SAMs, prepared by molecular adsorption from solution on Au substrates modified by underpotential deposition of Ag, exhibit a pronounced dependence of their structure on the assembly protocol. Exposing an H3BTB SAM to AdCA, the highly regular row structure of the native H3BTB layer persists and STM imaging does not show signs of AdCA adsorption. This is in striking contrast to the disordered arrangements of H3BTB and the presence of AdCA employing the inverted adsorption sequence or coadsorption of the two molecules. However, spectroscopic analysis of the H3BTB SAM exposed to AdCA reveals the presence also of the latter, suggesting that the AdCA molecules are hidden in the nanotunnels of the H3BTB monolayer. Direct evidence for the intercalation of AdCA is obtained by STM manipulation experiments which lay bare areas of AdCA molecules upon local removal of H3BTB. Surprisingly, these are densely packed and arranged into a highly ordered monolayer. Formation of such a compact AdCA layer is explained by expulsion of AdCA from the H3BTB nanotunnels of the surrounding intact mixed SAM, driven by release of stress in the nanotunnels built up when AdCA is intercalated.
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Affiliation(s)
| | - Andika Asyuda
- Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Hao Lu
- Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Hannah Aitchison
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
| | - Kelly Turner
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
| | - Stephen M Francis
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
| | - Michael Zharnikov
- Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Manfred Buck
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK.
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