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组氨酸铜络合物是构成铜蛋白的重要组份之一。研究组氨酸铜络合物中C_x~(2+) 离子的电子顺磁共振(EPR)波谱对了解铜蛋白所参与的许多重要的生理生化过程是很重要的。本文采用电子顺磁共振技术在4.2K研究了嵌入离子C_x~(2+)的盐酸组氨酸晶体。C_u~(2+)离子的电子顺磁共振波谱表明,C_x~(2+)离子嵌入到L—盐酸组氨酸晶体中的位置与天然的L—组氨酸铜络合物中C_x~(2+)离子处于完全不同的化学环境中。嵌入到L—盐酸组氨酸晶体的C_x~(2+)离子的基态是一个Kramer双重态。应用实验测定的g张量主值计算了双重态的分子轨道系数,并由此计算得到铜原子的超精细偶合常数Acu。实验结果分析指出、半充满的d轨道是3d_x~2型轨道,并在Z轴方向有轴向的轻微压缩。单电子d轨道的次序:3d_x~2>3d_(x~2-y~2)>3d_(yz)>3d_(xz)>3d_(xy)。C_u~(2+)离子嵌入到L—盐酸组氨酸晶体中的位置具有一个畸变的六配位体环境,近似有D_2点群对称性。
Histidine copper complex is one of the important components of copper protein. It is important to study the electron paramagnetic resonance (EPR) spectra of C_x ~ (2+) ions in the histidine copper complex to understand the many important physiological and biochemical processes involved in copper. In this paper, the electron paramagnetic resonance technique was used to study the C_x ~ (2+) hydrochloride histidine hydrochloride crystal at 4.2K. Electron paramagnetic resonance spectra of C_u ~ (2+) ions show that the position of C_x ~ (2+) ions intercalating into L-histidine hydrochloride crystal is almost the same as that of C_x ~ (- 2+) ions are in completely different chemical environments. The ground state of C_x ~ (2+) ions embedded in L-histidine hydrochloride crystal is a Kramer doublet. The molecular orbital coefficients of the doublet state were calculated by experimentally determining the principal value of the g-tensor, and the hyperfine coupling constant Acu of the copper atom was calculated. The experimental results show that the semi-filled d orbit is of 3d_x ~ 2 orbitals and slightly compressed in the axial direction of Z axis. Single electron d orbital sequence: 3d_x ~ 2> 3d_ (x ~ 2-y ~ 2)> 3d_ (yz)> 3d_ (xz)> 3d_ (xy). C_u ~ (2+) ions have a distorted hexacoordinate environment embedded in the L-histidine hydrochloride crystal, with an approximately D 2 point symmetry.