Impact of Chlorine Substitution on Electron Spin Relaxation of a Trityl Radical.
Impact of Chlorine Substitution on Electron Spin Relaxation of a Trityl Radical.
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DOI：
10.1007/s00723-021-01405-3
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发表时间：
2022-05
影响因子：
1
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在磷酸盐缓冲盐水溶液(pH=7.2)(PBS)中，研究了中心碳(13C)富含99%~(13)C的全氯三芳基甲基三元酸根(13C-PTMTC)。将样品固定在1：1PBS：甘油和9：1海藻糖：蔗糖中，研究了温度对固定样品的影响。在c1处的同位素浓缩产生了一种可用于精确测量微观粘度的三苯基。了解~(13)C超精细相互作用对电子自旋弛豫的影响，对于将~(13)C超精细相互作用应用于血氧测量和距离测量具有重要意义。各向异性~(13)C l超精细耦合(Ax=Ay=24±2 MHz，Az=200±1 MHz)大于相应的~(13)C l-过氚芬兰三叔丁基化合物(~(13)C_1-D_(FT))，g~(13)各向异性(g_x=2.0013，g_y=2.0016，G_z=2.0042)略大于~(13)C_1-D_(FT)。13Cl-PTMTC在PBS溶液中的翻滚相关时间(τR)为0.2 0±0.0 2 ns，在3：1 PBS：甘油溶液中为0.4 0±0.0 5 ns，均小于13C l-DFT在相同溶液中的翻滚相关时间。~(13)C l-PTMTC的T_1在PbS中为3.5±0.5μS，在3：1 PBS：甘油中为5.3±0.4μS，比13C l-DFT短，这是由于滚动速度更快，~(13)C l超精细的各向异性较大，局域模的贡献大约30%所致.在固定化样品中，13C l-PTMTC的T_1与13C_1-DFT和其他不含氯或13C_1取代基的三苯基的T_1相似，说明苯环上的13C_1和C_1取代基对T_1影响不大。用直接模、拉曼模和局域模过程的贡献对T1的温度依赖性进行了模拟。液体中约0.6G的连续波线宽和刚性晶格中约2G的连续波线宽可归因于未分辨的35，37Cl超精细耦合。
A perchlorotriarylmethyl tricarboxylic acid radical 99% enriched in 13C at the central carbon (13C1-PTMTC) was characterized in phosphate buffered saline solution (pH = 7.2) (PBS) at ambient temperature. Samples immobilized in 1:1 PBS:glycerol or in 9:1 trehalose:sucrose were studied as a function of temperature. Isotope enrichment at C1 creates a trityl that can be used to accurately measure microscopic viscosity. Understanding of the impact of the 13C hyperfine interaction on electron spin relaxation is important for application of this trityl in oximetry and distance measurements. The anisotropic 13C1 hyperfine couplings (Ax = Ay = 24 ± 2 MHz, Az = 200 ± 1 MHz) are larger than for the related 13C1-perdeuterated Finland trityl (13C1-dFT) and the g anisotropy (gx = 2.0013, gy = 2.0016, gz = 2.0042) is slightly larger than for 13C1-dFT. The tumbling correlation times (τR) for 13C1-PTMTC are 0.20 ± 0.02 ns in PBS and 0.40 ± 0.05 ns in 3:1 PBS:glycerol, which are shorter than for 13C1-dFT in the same solutions. T1 for 13C1-PTMTC is 3.5 ± 0.5 μs in PBS and 5.3 ± 0.4 μs in 3:1 PBS:glycerol, which are shorter than for 13C1-dFT due to faster tumbling, larger anisotropy of the 13C1 hyperfine, and about 30% larger contribution from the local mode. In immobilized samples T1 for 13C1-PTMTC is similar to that for 13C1-dFT and other trityls without chlorine or 13C1 substituents, indicating that the 13C1 and Cl substituents on the phenyl rings have little impact on T1. The temperature dependence of T1 was modeled with contributions from the direct, Raman, and local mode processes. Broadening of CW linewidths of about 0.6 G in fluid solution and about 2 G in rigid lattice is attributed to unresolved 35,37Cl hyperfine couplings.
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影响因子：
2.6
作者：
Boś-Liedke A;Walawender M;Woźniak A;Flak D;Gapiński J;Jurga S;Kucińska M;Plewiński A;Murias M;Elewa M;Lampp L;Imming P;Tadyszak K
通讯作者：
Tadyszak K
影响因子：
2.2
作者：
Epel, Boris;Halpern, Howard J.
通讯作者：
Halpern, Howard J.
影响因子：
3.3
作者：
Carlos Paniagua, Juan;Mugnaini, Veronica;Pons, Miquel
通讯作者：
Pons, Miquel
影响因子：
4.4
作者：
MCCLUNG, RED;KIVELSON, D
通讯作者：
KIVELSON, D
影响因子：
3.9
作者：
Ngendahimana, Thacien;Ayikpoe, Richard;Eaton, Sandra S.
通讯作者：
Eaton, Sandra S.