Schaniel Dominik, Woike Theo, Delley Bernard, Biner Daniel, Krämer Karl W, Güdel Hans-Ueli
I. Physikalisches Institut, Universität zu Köln, Zülpicherstrasse 77, 50937, Köln, Germany.
Phys Chem Chem Phys. 2007 Oct 7;9(37):5149-57. doi: 10.1039/b707912e. Epub 2007 Jul 25.
One metastable linkage nitrosyl isomer can be generated in [Pt(NH(3))(4)Cl(NO)]Cl(2) by irradiation with light in the red spectral range. The potential energy barrier for the thermal relaxation of the metastable state to the ground state has an amount of E(A) = (0.27 +/- 0.03) eV. The decay follows the Arrhenius law and E(A) is independent of temperature. At room temperature the metastable state has a lifetime of tau = 3.8 x 10(-5) s after generation by pulsed laser illumination. Below T = 100 K about 30% linkage NO isomers can be generated in a powder sample by irradiation with lambda = 658 nm. DFT calculations demonstrate the rotation of the NO ligand from Pt-N-O to Pt-O-N as a unique linkage isomer. Consequently, only one new nu(NO) stretching vibration is detected with a shift from 1673 cm(-1) to 1793 cm(-1) by 120 cm(-1), to higher frequencies in good agreement with the DFT calculations. In the metastable state new electronic absorption bands are observed in the blue-green and near infrared spectral range. The metastable state can be optically accessed via a (5d + pi(NO)) -->pi*(NO) transition. [Pt(NH(3))(4)Cl(NO)]Cl(2) is diamagnetic with a Pt(5d(8)) configuration and thus represents the first {MNO}(8) complex with experimental evidence for a light-induced nitrosyl linkage isomer.
通过在红色光谱范围内照射[Pt(NH₃)₄Cl(NO)]Cl₂，可生成一种亚稳态的键连亚硝酰异构体。亚稳态向基态热弛豫的势能垒大小为E(A) = (0.27 ± 0.03) eV。衰变遵循阿仑尼乌斯定律，且E(A)与温度无关。在室温下，通过脉冲激光照射产生的亚稳态的寿命为τ = 3.8×10⁻⁵ s。在T = 100 K以下，用λ = 658 nm的光照射粉末样品，可生成约30%的键连NO异构体。密度泛函理论计算表明，NO配体从Pt-N-O旋转到Pt-O-N是唯一的键连异构体。因此，仅检测到一个新的ν(NO)伸缩振动，其从1673 cm⁻¹位移120 cm⁻¹至1793 cm⁻¹，向更高频率移动，与密度泛函理论计算结果吻合良好。在亚稳态下，在蓝绿色和近红外光谱范围内观察到新的电子吸收带。亚稳态可通过(5d + π(NO))→π*(NO)跃迁进行光学探测。[Pt(NH₃)₄Cl(NO)]Cl₂具有Pt(5d⁸)构型，呈抗磁性，因此是首个有光致亚硝酰键连异构体实验证据的{MNO}₈配合物。
