Saturated N‐Heterocyclic Carbene Based Thiele's Hydrocarbon with a Tetrafluorophenylene Linker. Issue 72 (28th November 2019) - Kundu, Gargi
Abstract: The synthesis of a SIPr [1, 3‐bis(2, 6‐diisopropylphenyl)‐imidazolin‐2‐ylidene] derived Kekulé diradicaloid with a tetrafluorophenylene spacer (3 ) has been described. Two synthetic routes have been reported to access 3 . The cleavage of C−F bond of C6 F6 by SIPr in the presence of BF3 led to double C−F activated compound with two tetrafluoro borate counter anions (2 ), which upon reduction by lithium metal afforded 3 . Alternatively, 3 can be directly accessed in one step by reacting SIPr with C6 F6 in presence of Mg metal. Compounds 2 and 3 were well characterized spectroscopically and by single‐crystal X‐ray diffraction studies. Experimental and computational studies support the cumulenic closed‐shell singlet state of 3 with a singlet‐triplet energy gap (Δ E S–T ) of 23.7 kcal mol −1 . Abstract : The synthesis of SIPr [1, 3‐bis(2, 6‐diisopropylphenyl)‐imidazolin‐2‐ylidene] based Thiele's hydrocarbon with a C6 F4 linker (3 ) has been accomplished. Single‐crystal X‐ray studies and computational studies revealed that 3 possesses cumulenic closed‐shell singlet state with a singlet‐triplet energy gap (Δ E S–T ) of 23.7 kcal mol −1 .