01930nas a2200205   4500008004100000022001400041245007500055210006900130260000900199300001600208490000700224520124400231100001801475700002401493700002201517700003001539700001801569700003001587856010701617       2025                        eng d  a1948-718500a(Chiro)optical Properties of π-Extended Spiro-Double Carbo[7]helicene0 aChirooptical Properties of πExtended SpiroDouble Carbo7helicene  cNOV   a11657-116640 v163 a<p>
	Helical nanographenes are a fascinating class of pi-extended chiral nanocarbons, where structural helicity imparts intrinsic chirality and unique optoelectronic properties to the rigid carbon framework. In this work, we synthesized a hexa-peri-hexabenzocoronene-based pi-extended spiro-double carbo[7]helicene. The helical distortion of the structure was unambiguously confirmed by X-ray crystallography. The optical properties were explored through UV-Vis absorption, fluorescence, and phosphorescence measurements, complemented by density functional theory (DFT) calculations. Remarkably, the pi-extended spiro-double carbo[7]helicene exhibited thermally activated delayed fluorescence (TADF) at room temperature and phosphorescence at low temperatures. Chiral HPLC successfully resolved the enantiomers into three fractions: (PP), (MM), and the meso forms (PM)/(MP), and chiroptical studies of the pure enantiomers revealed a moderately high g lum value of 1.58 x 10-3. Finally, the origin of the observed dissymmetry factors was rationalized by analyzing the transition electric dipole moments (TEDM) and transition magnetic dipole moments (TMDM) derived from time-dependent density functional theory (TD-DFT) calculations.</p>
1 aKumar, Viksit1 aDongre, Sangram, D.1 aVandhanam, Aparna1 aJadhav, Ashok, Badrinaray1 aKumar, Jatish1 aBabu, Sukumaran, Santhosh  uhttps://library.ncl.res.in/content/chirooptical-properties-%CF%80-extended-spiro-double-carbo7helicene