Barbon Stephanie M, Staroverov Viktor N, Gilroy Joe B
Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario, 1151 Richmond Street North, London, Ontario, Canada N6A 5B7.
J Org Chem. 2015 May 15;80(10):5226-35. doi: 10.1021/acs.joc.5b00620. Epub 2015 May 6.
The effect of extended π conjugation on the spectroscopic and electrochemical properties of boron difluoride (BF2) formazanate complexes was studied by the systematic comparison of phenyl- and naphthyl-substituted derivatives. Each of the BF2 complexes described was characterized by (1)H, (13)C, (11)B, and (19)F NMR spectroscopy, cyclic voltammetry, infrared spectroscopy, UV-vis absorption and emission spectroscopy, and mass spectrometry. X-ray crystallography and electronic structure calculations were used to rationalize the trends observed, including direct comparison of 3-cyano-, 3-nitro-, and 3-phenyl-substituted BF2 formazanate complexes. In all cases, the wavelengths of maximum absorption and emission were red-shifted as π conjugation was systematically extended (by replacing phenyl with naphthyl), fluorescence quantum yields increased (up to 10-fold), and electrochemical conversion of the formazanate complexes to their radical anion and dianion forms occurred at less negative potentials (easier to reduce).
通过对苯基和萘基取代衍生物的系统比较，研究了扩展π共轭对二氟化硼（BF₂）甲脒配合物光谱和电化学性质的影响。所描述的每种BF₂配合物都通过¹H、¹³C、¹¹B和¹⁹F核磁共振光谱、循环伏安法、红外光谱、紫外可见吸收和发射光谱以及质谱进行了表征。利用X射线晶体学和电子结构计算来解释观察到的趋势，包括对3-氰基、3-硝基和3-苯基取代的BF₂甲脒配合物进行直接比较。在所有情况下，随着π共轭的系统扩展（用萘基取代苯基），最大吸收和发射波长发生红移，荧光量子产率增加（高达10倍），并且甲脒配合物电化学转化为其自由基阴离子和二阴离子形式发生在更正的电位下（更易还原）。
