Article
Chemistry, Inorganic & Nuclear
Michael A. Land, Goran Bacic, Katherine N. Robertson, Sean T. Barry
Summary: This study prepared a series of adducts of molybdenum compounds and investigated their volatility, thermal stability, and decomposition pathways. The properties were determined using thermogravimetric analysis and differential scanning calorimetry, and the structures were characterized using single-crystal X-ray diffraction.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Patrick Commins, A. Bernard Dippenaar, Liang Li, Hideyuki Hara, Delia A. Haynes, Pance Naumov
Summary: This study reports and characterizes the first plastically bendable single crystal of a permanent organic radical, which exhibits exceedingly soft characteristics due to weak interactions between radicals and S-N interactions. EPR imaging of the bent single crystal reveals the impact of deformation on the crystal's three-dimensional spin density. The unusual mechanical compliance of this material opens prospects for the development of flexible light-weight organic magnetoresistance devices based on weak, non-hydrogen-bonded interactions in molecular crystals.
Article
Chemistry, Inorganic & Nuclear
Feng Li, Jianghao He, Tingting Song, Wei Gao, Xiaoyue Mu, Ying Mu
Summary: A series of new zirconium complexes with bulkier ligands were synthesized and their catalytic performance in ethylene polymerization and copolymerization reactions was studied. The results showed that these complexes exhibited high catalytic activity and good comonomer incorporations, and displayed excellent catalytic performance under different activation conditions.
INORGANIC CHEMISTRY
(2022)
Article
Polymer Science
Wiktor Bukowski, Agnieszka Bukowska, Aleksandra Sobota, Maciej Pytel, Karol Bester
Summary: The study investigated the effect of ligand structure on the catalytic activity of amine-bis(phenolate) chromium(III) complexes in the ring-opening copolymerization. Binary catalytic systems were found to be more active than complexes used individually, with DMAP proving to be the best co-catalyst choice.
Article
Chemistry, Physical
Othman Alajrawy, Ayad A. Almhmdi
Summary: In this study, two dioxomolybdenum(VI) complexes and two oxomolybdenum(IV) complexes were synthesized and characterized. The structures and properties of these complexes were determined using spectroscopic techniques and theoretical calculations. The results showed that the dioxomolybdenum(VI) complexes were diamagnetic while the oxomolybdenum(IV) complexes were paramagnetic, and both of them had distorted structures.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Chemistry, Inorganic & Nuclear
Maxime Boudjelel, Feng Zhai, Richard R. Schrock, Amir H. Hoveyda, Charlene Tsay
Summary: The molybdenum and tungsten oxo 2-adamantylidene complexes were prepared by adding 2-methylene- or 2-ethylideneadamantane to neophylidene or neopentylidene complexes. The tungsten complex 2(w) is a thermally stable dimer with unsymmetrically bridging oxo ligands, while the molybdenum complex 2(Mo) is a stable monomer. These complexes are reactive olefin metathesis initiators with dimers 5(Mo) and 5(w) being relatively poor initiators.
Article
Chemistry, Inorganic & Nuclear
Yue Zhang, Xiang Wang, Yue Wang, Lei Li, Na Xu, XiuLi Wang
Summary: A new 'V'-like bis-pyridine-bis-amide ligand was introduced to prepare four metal-organic complexes (MOCs) with remarkable adsorption capacities for organic dyes and electrochemical sensing behaviors toward Cr(VI) ions and Fe(III) ions, suggesting their potential application as multifunctional materials.
INORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Polymer Science
Feng Li, Yuhongxu Bai, Jianghao He, Tingting Song, Wei Gao, Xiaoyue Mu, Ying Mu
Summary: A series of novel Ti(IV) complexes with nonsymmetric amine-bis(phenolate) tetradentate ligands have been synthesized and characterized. These complexes exhibit moderate to high catalytic activities for ethylene polymerization and produce high molecular weight polyethylenes. They also show high catalytic activities for copolymerization reactions of propylene, 1-hexane, ethylene/1-hexene, and ethylene/1-octene, producing polyolefin thermoplastic elastomer or linear low-density polyethylene with high molecular weights and moderate to high comonomer incorporations.
Article
Chemistry, Multidisciplinary
Guojun Hu, Yanwei Wang, Yaorong Wang, Xuehua Zhu, Dan Yuan, Yingming Yao
Summary: Two amino-bridged bis(phenolate) neodymium complexes were synthesized and used as efficient initiators for the copolymerization of TMC and L-LA under mild conditions, resulting in the formation of random copolymers. NMR monitoring experiments confirmed the generation of a TMC/LA random copolymer through random copolymerization.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Mathis J. Benedikter, Janis V. Musso, Wolfgang Frey, Roman Schowner, Michael R. Buchmeiser
Summary: Despite their excellent selectivities and activities, Mo- and W-based catalysts for olefin metathesis have not been widely used due to their air sensitivity. The synthesized cationic-at-metal molybdenum and tungsten imido alkylidene NHC nitrile complexes are stable in air and can catalyze olefin metathesis reactions without prior activation. The presence of a nitrile ligand is crucial for their stability, while variations in imido and anionic ligands affect reactivities and stability.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Polymer Science
Yu-Lai Duan, Qian Guo, Gui-Yang Liu, Zhong-Zhou Yi, Shao-Ping Feng, Yong Huang
Summary: A series of new monomeric rare-earth alkoxides were successfully synthesized and characterized. These complexes served as efficient initiators for the stereoselective ring-opening polymerization of rac-LA, resulting in polymers with high heterotacticity. The substituents of the ligands had a significant impact on the reactivity of the alkoxides, while the stereoselectivity was minimally affected. The reactivity and heterotacticity were influenced by the ionic radii of the rare-earth metals and the polymerization media.
Article
Biochemistry & Molecular Biology
Esko Salojarvi, Anssi Peuronen, Narhari Sapkota, Ari Lehtonen
Summary: Molecular molybdenum complexes with sulfur donor ligands are studied as model compounds for molybdenum enzymes, showing a stable Mo(IV) complex after reaction with thionation reagent. The complexes retain the original geometry, despite formally being Mo(IV) systems.
Article
Polymer Science
Cyler W. Vos, James Beament, Christopher M. Kozak
Summary: The diamino-bis(phenolate) chromium(iii) complex exhibited good activity and control for the ring-opening polymerization (ROP) of rac-lactide (rac-LA) and epsilon-caprolactone (epsilon-CL), ring-opening copolymerization (ROCOP) of cyclohexene oxide (CHO) and phthalic anhydride (PA), ROCOP of epoxides and CO2, and synthesis of terpolymers containing polylactide or polycaprolactone, polycarbonate, and polyester segments.
Article
Chemistry, Inorganic & Nuclear
Narottam Mukhopadhyay, Arunava Sengupta, Aswin Kottapurath Vijay, Francesc Lloret, Rabindranath Mukherjee
Summary: Three square planar nickel (II) complexes of a new asymmetric tetradentate redox-active ligand H3L2 in its deprotonated form have been synthesized, and their electronic states and properties have been characterized. The experimental results are rationalized by density functional theory (DFT) calculations. The UV-VIS-NIR spectra and magnetic measurements provide insights into the electronic transitions and magnetic behaviors of the complexes.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Multidisciplinary
Youngsuk Kim, Jung Eun Byeon, Gu Yoon Jeong, Seoung Su Kim, Hayoung Song, Eunsung Lee
Summary: This study presents the design and synthesis of a novel organic radical based on a 1,2-dicarbonyl scaffold supported by N-heterocyclic carbenes (NHCs), which exhibits remarkable stability due to the steric and electronic stabilization provided by the two NHC moieties. The radical cations can tolerate various harsh conditions and surpass the stability of triphenylmethyl and TEMPO radicals.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Physics, Applied
Moe Moe Aye, Elmeri Rivasto, Hannes Rijckaert, Heikki Palonen, Hannu Huhtinen, Isabel Van Driessche, Petriina Paturi
Summary: Experimental study on the effect of BaZrO3 (BZO) nanorod density within the YBa2Cu3O6+x (YBCO) lattice reveals that the maximum flux pinning can be achieved by controlling the BZO content. The best pinning performance is observed at a BZO concentration of 10%, where the distance between nanorod edges is approximately equal to the nanorod diameter.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Applied
P. Paturi, H. Huhtinen
Summary: We present a method to achieve the maximum critical current density, J(c), for YBa2Cu3O6+x (YBCO) thin films. By optimizing both the mean free path and the flux pinning structure, the maximum values can be reached.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Anssi Peuronen, Esko Salojarvi, Pasi Salonen, Ari Lehtonen
Summary: An amine bisphenol ligand with an ammonium iodide group was reacted with V, Mo, and U oxometal precursors to form oxovanadium(V), dioxomolybdenum(VI), and dioxouranium(VI) species, respectively. The resulting complexes showed different coordination modes and counterbalancing units depending on the metal cations involved. The oxovanadium(V) complex exhibited catalytic activity in CO2 coupling reactions.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Physics, Applied
H. Rijckaert, M. Malmivirta, S. Banerjee, S. J. L. Billinge, H. Huhtinen, P. Paturi, K. De Buysser, I Van Driessche
Summary: Two different types of HfO2 nanocrystals were studied to investigate their effect on the structural defects in the YBCO matrix. The results showed that the crystallinity, lattice parameters, nanocrystal structures, and core diameter of the nanocrystals played a significant role in the formation of structural defects around the particles in the YBCO matrix, leading to different pinning performances.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Condensed Matter
E. Rivasto, T. Hynninen, H. Huhtinen, P. Paturi
Summary: We propose that the current carrying properties of high-temperature superconducting thin films can be enhanced by introducing multilayer structures that balance zero field critical current and vortex pinning performance. In this study, we investigate a simple bilayer structure composed of pure YBCO and BZO doped YBCO under a mid-field range magnetic field. Our computational model reveals that the optimized bilayer structure can have up to 50% higher current carrying capability compared to single layer films. The results provide a foundation for future experimental realization of the proposed bilayer structures and further study of vortex interactions.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Biochemistry & Molecular Biology
Esko Salojarvi, Anssi Peuronen, Narhari Sapkota, Ari Lehtonen
Summary: Molecular molybdenum complexes with sulfur donor ligands are studied as model compounds for molybdenum enzymes, showing a stable Mo(IV) complex after reaction with thionation reagent. The complexes retain the original geometry, despite formally being Mo(IV) systems.
Article
Chemistry, Multidisciplinary
Anssi Peuronen, Anni I. I. Taponen, Elina Kalenius, Ari Lehtonen, Manu Lahtinen
Summary: In this study, a coordination cage assembled from Cu3I4- clusters and tripodal cationic N-donor ligands was synthesized and its structure was determined. The cage selectively binds iodide anions in specific regions through ionic interactions, which enables the selective binding of bromomethanes as secondary guest species. This selective binding was confirmed by single-crystal X-ray diffraction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Materials Science, Multidisciplinary
Naman A. Naushahi, I. Angervo, M. Saloaro, A. Schulman, H. Huhtinen, P. Paturi
Summary: The effect of deposition distance on SFMO thin films was investigated, and it was found that optimal properties can be achieved at longer deposition distances than previously expected. The films deposited at longer distances showed increased metallicity and magnetoresistive response, with an onset Curie temperature of about 400 K and a middle transition value of 372 K.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Education & Educational Research
Teemu Hynninen, Henna Pesonen, Olli Lintu, Petriina Paturi
Summary: We examine the changes in attitudes towards physics among Finnish first-year physics majors as a result of mandatory remote learning during the coronavirus pandemic. Our findings suggest that the extended period of remote learning had a negative impact on students' expertlike thinking, and those who experienced remote learning in high school also displayed a lower level of expertlike thinking upon entering university. However, moderate positive gains were observed as contact teaching resumed, although it did not fully bridge the gap in student attitudes caused by the pandemic.
PHYSICAL REVIEW PHYSICS EDUCATION RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Etienne A. LaPierre, Lara K. Watanabe, Brian O. Patrick, Jeremy M. Rawson, Heikki M. Tuononen, Ian Manners
Summary: In this study, the synthesis and properties of an acyclic carbene-stabilized diphospha(aminyl) PNP radical compound were reported. The radical compound exhibited a conjugated framework and showed facile one-electron oxidation and reduction to form nonclassical nitrenium and amide species. Additionally, the conformational flexibility of a cationic compound and the coordination chemistry of a formal amide were also explored.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Pasi Salonen, Joerg A. Schachner, Anssi Peuronen, Manu Lahtinen, Ferdinand Belaj, Nadia C. Moesch-Zanetti, Ari Lehtonen
Summary: The use of dioxidomolybdenum(VI) and -tungsten(VI) complexes supported by different aminobisphenolato ligands as pre-catalysts in alkene epoxidation has been established, but these complexes have shown modest activity at standard 1 mol-% catalyst loadings. The introduction of amide functionalities in the ligand design has been found to enhance the catalytic activity. Furthermore, a dilution effect was discovered, allowing for significantly reduced pre-catalyst loadings without a significant decrease in activity, and the [pre-catalyst]:[oxidant] molar ratio was found to be critical for optimal catalytic performance.
MOLECULAR CATALYSIS
(2023)
Article
Chemistry, Inorganic & Nuclear
Anssi Peuronen, Henri Kivela, Pasi Salonen, Ville Eskonen, Marta Karman, Manu Lahtinen, Grzegorz Romanowski, Ari Lehtonen
Summary: Dioxidomolybdenum(VI) compound [MoO2Cl2(dmso)(2)] reacts with a chiral tetradentate O3N-type L-alanine bisphenol ligand precursor (Et3NH)H2Lala to form an oxidochloridomolybdenum(VI) complex [MoOCl(L-ala)] (1) as two separable geometric isomers with phenolate groups in cis or trans positions. The single crystal X-ray and NMR analyses of cis- and trans-1 reveal that the complexes are formed of monomeric molecules, in which the ligand has a tetradentate coordination through three oxygen donors and one nitrogen donor. The reaction of Na2MoO4 center dot 2H(2)O with the same ligand precursor in an acidic methanol solution leads to the formation of an anionic dioxido complex (Et3NH)[MoO2(L-ala)] (2) with a trans coordination of the tetradentate ligand. Trans-1 and 2 were studied as active catalysts for olefin epoxidation: i.e. styrene, cyclohexene, S(-)-limonene and (-)-alpha-pinene using H2O2 and tBuOOH as oxidants.
INORGANICA CHIMICA ACTA
(2023)
Article
Physics, Condensed Matter
A. Tuomola, E. Rivasto, M. M. Aye, Y. Zhao, H. Huhtinen, P. Paturi
Summary: The effect of multilayering YBCO thin films with sequentially deposited CeO2 layers on self-field critical current density J(c)(0) is investigated. The improvement in J(c)(0) depends on YBCO layer thickness and temperature, with a potential increase of 50% at high temperature compared to single layer films. A critical thickness for YBCO layer is determined based on experimental results and theoretical analysis of the growth mechanism, where the maximum self-field J(c)(0) is strongly influenced by the competing issues of strain relaxation and defect formation during film growth. These findings can be applied in future coated conductor technology to maximize overall in-field J(c)(B).
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Physics, Multidisciplinary
Elmeri Rivasto, Milica Todorovic, Hannu Huhtinen, Petriina Paturi
Summary: This study investigates the possibility of using artificial intelligence (AI) models to optimize high-temperature superconducting (HTS) multilayer structures for specific field and temperature ranges. A new vortex dynamics simulation method is proposed to improve the efficiency of training data sampling required for AI models. The performance of different AI models, including kernel ridge regression (KRR), gradient-boosted decision tree (GBDT), and neural network, is compared, and the GBDT model is found to be the best fitted for the problem. The use of GBDT in finding optimal multilayer structures at 10K temperature under 1T field is demonstrated, and the results align well with previous studies, further validating the use of AI in this problem. The AI models are considered highly efficient tools for optimizing HTS multilayer structures and are suggested as the primary method for pushing the limits of HTS films for specific applications.
NEW JOURNAL OF PHYSICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Hannu T. Vuori, J. Mikko Rautiainen, Erkki T. Kolehmainen, Heikki M. Tuononen
Summary: This paper reports high-level computational data for 116 compounds of boron and compares them with experimental and computational benchmark values. Important trends and outliers are identified, and recommendations are made to revise some key quantities. The uncertainties associated with experimental values are found to exceed those of high-level calculations, prompting the need for a reevaluation of computational contributions. The applicability of the established group contribution values is demonstrated by comparing the results with existing experimental and computational values for large organoboron compounds.
DALTON TRANSACTIONS
(2022)
