Thomas James A., Hutchings Michael G., Jones Christopher J., McCleverty Jon A.
School of Chemistry, The University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K., ZENECA Specialties Research Centre, Blackley, Manchester M9 8ZS, U.K., and School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K.
Inorg Chem. 1996 Jan 17;35(2):289-296. doi: 10.1021/ic950357h.
The heteroleptic molybdenum complexes [{Mo(NO)TpX}(n)()(L-L)] [Tp = HB(3,5-Me(2)C(3)HN(2))(3); X = Cl, I; L-L = 4-NC(5)H(4)(CH=CH)(4)C(5)H(4)N-4', n = 1, 2; X = Cl; L-L = {4,4'-NC(5)H(4)CH=CHC(Me)=CHCH=}(2), n = 2] have a low energy absorbance in their electronic spectra which exhibits solvatochromic shifts. These have been analyzed quantitatively by means of linear solvation energy relationships based on Kamlet-Taft solvatochromism parameters, as well as on Drago's "unified scale of solvent polarity". Each of these approaches leads to satisfactory linear models, in qualitative agreement with one another. The solvatochromism is due to a combination of increased solvent dipolarity/polarizability and solvent-to-solute hydrogen bonding, each preferentially stabilizing polar ground states compared with less polar excited states. The latter originate from metal-to-ligand charge transfer. Quantitatively, the Drago and Kamlet-Taft models differ somewhat. The former are statistically slightly better than those based on Kamlet-Taft parameters.
杂配钼配合物[{Mo(NO)TpX}(n)()(L-L)] [Tp = HB(3,5-Me(2)C(3)HN(2))(3); X = Cl, I; L-L = 4-NC(5)H(4)(CH=CH)(4)C(5)H(4)N-4', n = 1, 2; X = Cl; L-L = {4,4'-NC(5)H(4)CH=CHC(Me)=CHCH=}(2), n = 2]在其电子光谱中具有低能量吸收峰，并呈现溶剂化显色位移。已基于Kamlet-Taft溶剂化显色参数以及Drago的“溶剂极性统一标度”，通过线性溶剂化能关系对这些位移进行了定量分析。这些方法中的每一种都得出了令人满意的线性模型，彼此在定性上一致。溶剂化显色是由于溶剂偶极矩/极化率增加以及溶剂与溶质之间的氢键作用共同导致的，与极性较小的激发态相比，每一种作用都优先稳定极性基态。后者源自金属到配体的电荷转移。在定量方面，Drago模型和Kamlet-Taft模型略有不同。前者在统计学上比基于Kamlet-Taft参数的模型略好。
