Within the effective field theory （EFT）, staggered quadrupolar phase and bicritical point of spin-1 bond and anisotropy dilution Blume-Emery-Griffiths model is studied on simple cubic lattice in the restricted range...Within the effective field theory （EFT）, staggered quadrupolar phase and bicritical point of spin-1 bond and anisotropy dilution Blume-Emery-Griffiths model is studied on simple cubic lattice in the restricted range of biquadratic interaction and bilinear interaction ratio α≤-1. The phase diagrams present a line of staggered quadrupolarparamagnetic （SQ-P） phase and a line of ferromagnetic-paramagnetic （F-P） phase, separated by a bicritical point （BCP）. A large negative ratio and two different dilution factors magnify the range of the SQ phase and reduce range of ferro- magnetic phase in T-α or T-D plane. These parameters can assist the reentrant behavior of the SQ-P line and suppress that of the F-P line. The influence of bond dilution on the BCP is dissimilar to that of anisotropy dilution. There is a degenerate pattern at ground state in T-D plane. Some results obtained by the pure BEG model is in qualitative agreement with the results of Monte Carlo simulations.展开更多
A recent paper published in Journal of the American Chemical Society by W.Zhang and co-workers reported a ground-breaking advance by establishing 209 Bi and 127 I ultra-wideline solid-state NMR(UW SSNMR)as powerful to...A recent paper published in Journal of the American Chemical Society by W.Zhang and co-workers reported a ground-breaking advance by establishing 209 Bi and 127 I ultra-wideline solid-state NMR(UW SSNMR)as powerful tools for probing bismuth and iodine ions in metal-organic frameworks(MOFs),despite the severe challenges associated with their exceptionally large quadrupolar interactions,and enabled the elucidation of key structural features that are otherwise difficult to access[1].展开更多
Dynamic isotope effects on relaxation rate of quadrupolar nuclei are preliminarily reported. The relaxation rates of 17O and 14N in 12 simple organic molecules and their 18 corresponding deuterated species have been s...Dynamic isotope effects on relaxation rate of quadrupolar nuclei are preliminarily reported. The relaxation rates of 17O and 14N in 12 simple organic molecules and their 18 corresponding deuterated species have been systematically measured. The principal components of the molecular inertia tensors have been calculated. The results show that there is an intrinsic correlation between the dynamic isotope effects of the relaxation rate and the static isotope effects of the molecular inertia. The concepts of molecular collision frequency and translation-rotation coupling have been introduced into the NMR relaxation theory. Therefore, a reasonable explanation of the experimental results has been given.展开更多
A dimesitylboryl-ended oligothiophene with tetrazine as core(BTz)was synthesized and its reactivity and spectral changes toward trans-cyclooctene((4E)-TCO-OH),cis-cyclooctene and bicyclo[6.1.0]non-4-yn-9-ylmethanol we...A dimesitylboryl-ended oligothiophene with tetrazine as core(BTz)was synthesized and its reactivity and spectral changes toward trans-cyclooctene((4E)-TCO-OH),cis-cyclooctene and bicyclo[6.1.0]non-4-yn-9-ylmethanol were comprehensively studied.The fluorescence intensity of BTz was enhanced up to more than 100 times upon bioorthogonal reaction with(4E)-TCO-OH.In addition,the first crystal structure of isolated product of tetrazine derivative with cyclooctene was determined,which clearly confirmed a dehydrogenation occurred after Diels-Alder reaction under ambient conditions.展开更多
^(23)Na is a nuclear magnetic resonance(NMR)-active isotope with a nuclear spin quantum number of 3/2.^(23)Na relaxation phenomenon is at the core of ^(23)Na NMR measurement and analysis.Due to the dominance of quadru...^(23)Na is a nuclear magnetic resonance(NMR)-active isotope with a nuclear spin quantum number of 3/2.^(23)Na relaxation phenomenon is at the core of ^(23)Na NMR measurement and analysis.Due to the dominance of quadrupolar interaction,the relaxation behavior of ^(23)Na is physically and mathematically more complex than that of a typical spin-1/2 isotope.In this review,we overview the semi-classical Redfield theory for deriving the formulations of ^(23)Na relaxation.We show that the relaxation behaviors of ^(23)Na can be quantitatively described by constructing the spectral density functions based on the second-order perturbation theory.In addition,we summarize the applications of ^(23)Na relaxometry in different research fields,including biomedicine,sodium ion batteries,and quantum information processing.Because sodium is an essential element in our body,food and industrial materials,the research on sodium by ^(23)Na NMR emerges as important future directions.The theoretical and practical understandings on ^(23)Na relaxation are the step stones for mastering advanced ^(23)Na NMR techniques.展开更多
基金the Key Natural Science Foundation of Education Bureau of Jiangsu Province under Grant No.03KJA140117Jiangsu Thin Film Materials Key Laboratory Open Foundation under Grant No.K2022
文摘Within the effective field theory （EFT）, staggered quadrupolar phase and bicritical point of spin-1 bond and anisotropy dilution Blume-Emery-Griffiths model is studied on simple cubic lattice in the restricted range of biquadratic interaction and bilinear interaction ratio α≤-1. The phase diagrams present a line of staggered quadrupolarparamagnetic （SQ-P） phase and a line of ferromagnetic-paramagnetic （F-P） phase, separated by a bicritical point （BCP）. A large negative ratio and two different dilution factors magnify the range of the SQ phase and reduce range of ferro- magnetic phase in T-α or T-D plane. These parameters can assist the reentrant behavior of the SQ-P line and suppress that of the F-P line. The influence of bond dilution on the BCP is dissimilar to that of anisotropy dilution. There is a degenerate pattern at ground state in T-D plane. Some results obtained by the pure BEG model is in qualitative agreement with the results of Monte Carlo simulations.
基金supported by the National Natural Science Foundation of China(Grants 22472075 and 22272075).
文摘A recent paper published in Journal of the American Chemical Society by W.Zhang and co-workers reported a ground-breaking advance by establishing 209 Bi and 127 I ultra-wideline solid-state NMR(UW SSNMR)as powerful tools for probing bismuth and iodine ions in metal-organic frameworks(MOFs),despite the severe challenges associated with their exceptionally large quadrupolar interactions,and enabled the elucidation of key structural features that are otherwise difficult to access[1].
基金Project supported by the Alexander von Humboldt-Foundation of Germany and the Chinese Academy of Sciences.
文摘Dynamic isotope effects on relaxation rate of quadrupolar nuclei are preliminarily reported. The relaxation rates of 17O and 14N in 12 simple organic molecules and their 18 corresponding deuterated species have been systematically measured. The principal components of the molecular inertia tensors have been calculated. The results show that there is an intrinsic correlation between the dynamic isotope effects of the relaxation rate and the static isotope effects of the molecular inertia. The concepts of molecular collision frequency and translation-rotation coupling have been introduced into the NMR relaxation theory. Therefore, a reasonable explanation of the experimental results has been given.
基金National Natural Science Foundation of China(Nos.52150222,21672130 and 52073163)the Shenzhen Science and Technology Research and Development Funds(No.JCYJ20190806155409104)the State Key Laboratory of Crystal Materials.We acknowledge Prof.Dr.Cuihua Zhao of Shandong University for her valuable suggestions.
文摘A dimesitylboryl-ended oligothiophene with tetrazine as core(BTz)was synthesized and its reactivity and spectral changes toward trans-cyclooctene((4E)-TCO-OH),cis-cyclooctene and bicyclo[6.1.0]non-4-yn-9-ylmethanol were comprehensively studied.The fluorescence intensity of BTz was enhanced up to more than 100 times upon bioorthogonal reaction with(4E)-TCO-OH.In addition,the first crystal structure of isolated product of tetrazine derivative with cyclooctene was determined,which clearly confirmed a dehydrogenation occurred after Diels-Alder reaction under ambient conditions.
基金National Natural Science Foundation of China 22275159 and 22072133.Leading Innovation and Entrepreneurship Team of Zhejiang Province 2020R01003.
文摘^(23)Na is a nuclear magnetic resonance(NMR)-active isotope with a nuclear spin quantum number of 3/2.^(23)Na relaxation phenomenon is at the core of ^(23)Na NMR measurement and analysis.Due to the dominance of quadrupolar interaction,the relaxation behavior of ^(23)Na is physically and mathematically more complex than that of a typical spin-1/2 isotope.In this review,we overview the semi-classical Redfield theory for deriving the formulations of ^(23)Na relaxation.We show that the relaxation behaviors of ^(23)Na can be quantitatively described by constructing the spectral density functions based on the second-order perturbation theory.In addition,we summarize the applications of ^(23)Na relaxometry in different research fields,including biomedicine,sodium ion batteries,and quantum information processing.Because sodium is an essential element in our body,food and industrial materials,the research on sodium by ^(23)Na NMR emerges as important future directions.The theoretical and practical understandings on ^(23)Na relaxation are the step stones for mastering advanced ^(23)Na NMR techniques.
