Kundu Gargi, Dash Soumya Ranjan, Kumar Ravi, Vanka Kumar, Ghosh Aryya, Sen Sakya S
Inorganic Chemistry and Catalysis Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road Pashan, Pune, 411008, India.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
Chempluschem. 2023 Aug;88(8):e202300273. doi: 10.1002/cplu.202300273.
In this work, 5-SIDipp [SIDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene] (1) derived Chichibabin's hydrocarbon with an octafluorobiphenylene spacer (3) has been reported. The addition of two equivalents of 5-SIDipp with decafluorobiphenyl in presence of BF gives the double C-F bond activated imidazolium salt with two tetrafluoroborate anions, 2. Further reduction of 2 gives the fluorine substituted 5-SIDipp based Chichibabin's hydrocarbon, 3. Quantum chemical calculations suggested a singlet state of 3 with a singlet-triplet energy gap (ΔE ) of 3.7 kcal mol , which is substantially lower with respect to the hydrogen substituted NHC-based Chichibabin's hydrocarbons (10.7 kcal mol , B3LYP). As a result, the diradical character (y) of 3 (y=0.62) is also noticeably higher than the hydrogen substituted CHs (y=0.41-0.43). The ▵E was found to be higher in CASSCF (22.24 kcal mol ) and CASPT2 (11.17 kcal mol ) for 3 and the diradical character (d) is 44.6 %.
在这项工作中，已报道了由5-SIDipp [SIDipp = 1,3-双（2,6-二异丙基苯基）-咪唑啉-2-亚基]（1）衍生的带有八氟亚苯基间隔基的齐齐巴宾烃（3）。在BF存在下，将两当量的5-SIDipp与十氟联苯加成得到带有两个四氟硼酸根阴离子的双C-F键活化咪唑鎓盐2。2的进一步还原得到氟取代的基于5-SIDipp的齐齐巴宾烃3。量子化学计算表明3的单重态的单重态-三重态能隙（ΔE）为3.7 kcal·mol，相对于氢取代的基于NHC的齐齐巴宾烃（10.7 kcal·mol，B3LYP）而言，该值要低得多。结果，3的双自由基特征（y）（y = 0.62）也明显高于氢取代的CHs（y = 0.41 - 0.43）。对于3，在CASSCF（22.24 kcal·mol）和CASPT2（11.17 kcal·mol）中发现ΔE更高，双自由基特征（d）为44.6％。
