01858nas a2200265   4500008004100000022001400041245009300055210006900148260000800217300001500225490000700240520100900247653002401256653002401280653000801304653002701312653001801339100001701357700002501374700001601399700001701415700001701432700001901449856012401468       2023                        eng d  a2192-650600aEnhancing diradical character of chichibabin's hydrocarbon through fluoride substitution0 aEnhancing diradical character of chichibabins hydrocarbon throug  cAUG  ae2023002730 v883 a<p>
	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 BF3 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 (?ES-T) of 3.7 kcal mol(-1), which is substantially lower with respect to the hydrogen substituted NHC-based Chichibabin's hydrocarbons (10.7 kcal mol(-1), 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 ?ES-T was found to be higher in CASSCF (22.24 kcal mol(-1)) and CASPT2 (11.17 kcal mol(-1)) for 3 and the diradical character (d) is 44.6 %.</p>
10aC-F Bond Activation10aChichibabin & PRIME10aDFT10aN-Heterocyclic carbene10as Hydrocarbon1 aKundu, Gargi1 aDash, Soumya, Ranjan1 aKumar, Ravi1 aVanka, Kumar1 aGhosh, Aryya1 aSen, Sakya, S.  uhttps://library.ncl.res.in/content/enhancing-diradical-character-chichibabins-hydrocarbon-through-fluoride-substitution02304nas a2200229   4500008004100000022001400041245011900055210006900174260000900243490000700252520151600259653001001775653002401785653002701809653001901836653001301855100001701868700002001885700001901905700001901924856013101943       2024                        eng d  a0947-653900aAccess to NHC-Boryl mono- and bis-selenide and utility as mild selenium transfer reagent including to the C-F bond0 aAccess to NHCBoryl mono and bisselenide and utility as mild sele  cJAN 0 v303 a<p>
	Reactions of 5-SIDipp &amp; sdot; BH3 (5-SIDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene) (1) with diphenyldiselenide provide access to 5-SIDipp-boryl mono- (5-SIDipp &amp; sdot; BH2SePh) (2) and bis-selenide (5-SIDipp &amp; sdot; BH(SePh)2) (3). The facile cleavage of the B-Se bond makes 2 a neutral source of selenium nucleophiles in substitutions reactions with benzyl bromides, and provide access to the corresponding selenoethers. The direct transformations of one of the C(sp2)-F bonds of C5F5N and C6F5CF3 to C-Se bonds have also been achieved by the use of 2 without employing transition-metal catalysts. While it was previously established that C6F6 could undergo complete defluoroselenation under harsh conditions, we successfully achieved partial defluorination of C6F6 by employing 2 as a mild selenide transfer reagent. During the formation of C-Se bonds through the cleavage of C-F bonds, the potential by-product NHC &amp; sdot; BH2F undergoes ring expansion of the NHC, leading to the formation of the six-membered diaazafluoroborinane (7). Access to NHC &amp; sdot; boryl mono- and bis-selenides from NHC &amp; sdot; BH3 has been achieved. The boryl mono selenide has been demonstrated to function as a selenium transfer reagent, enabling the synthesis of selenoethers from benzyl bromide. Additionally, it can also facilitate the conversion of the challenging aromatic C-F bond to a C-Se bond, resulting in concomitant ring expansion of NHC &amp; sdot; haloborane.image</p>
10aboron10aC-F Bond Activation10aN-Heterocyclic carbene10aRing expansion10aSelenium1 aKundu, Gargi1 aAmrutha, P., R.1 aTothadi, Srinu1 aSen, Sakya, S.  uhttps://library.ncl.res.in/content/access-nhc-boryl-mono-and-bis-selenide-and-utility-mild-selenium-transfer-reagent-including