TY - JOUR
T1 - Easier to Twist than Bend
T2 - The Scope of the Bridge Formation Approach to Naphthalenophane Synthesis
AU - Bedi, Anjan
AU - Shimon, Linda J.W.
AU - Bogoslavsky, Benny
AU - Gidron, Ori
N1 - Publisher Copyright:
© 2020 Georg Thieme Verlag. All rights reserved.
PY - 2020/9/8
Y1 - 2020/9/8
N2 - Twisting anthracene and higher acenes can alter their optical, magnetic, and electronic properties. To test the effect of twisting on the lower homologue, naphthalene, we synthesized tethered naphthalenophanes bearing alkyl bridges. Both X-ray structure and DFT calculations show that hexyl and butyl bridges induce a 6° and 12° end-to-end twist on the naphthalene unit, respectively. Attempts to increase the twisting further using shorter tethers resulted in an elimination product. Enantiomerically pure naphthalenophanes display strong chiroptical properties, which intensify with increasing twist. Attempts to induce bending, rather than twisting, using the same synthetic methodology, resulted in intermolecular dimerization, yielding macrocyclic naphthalenes. This work highlights the importance of steric hindrance in the synthesis of curved cyclophanes using the bridge formation approach.
AB - Twisting anthracene and higher acenes can alter their optical, magnetic, and electronic properties. To test the effect of twisting on the lower homologue, naphthalene, we synthesized tethered naphthalenophanes bearing alkyl bridges. Both X-ray structure and DFT calculations show that hexyl and butyl bridges induce a 6° and 12° end-to-end twist on the naphthalene unit, respectively. Attempts to increase the twisting further using shorter tethers resulted in an elimination product. Enantiomerically pure naphthalenophanes display strong chiroptical properties, which intensify with increasing twist. Attempts to induce bending, rather than twisting, using the same synthetic methodology, resulted in intermolecular dimerization, yielding macrocyclic naphthalenes. This work highlights the importance of steric hindrance in the synthesis of curved cyclophanes using the bridge formation approach.
KW - acenes
KW - chirality
KW - curved aromatic molecules
KW - cyclophanes
UR - http://www.scopus.com/inward/record.url?scp=85123471276&partnerID=8YFLogxK
U2 - 10.1055/s-0040-1721102
DO - 10.1055/s-0040-1721102
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AN - SCOPUS:85123471276
SN - 2625-1825
VL - 2
SP - 323
EP - 329
JO - Organic Materials
JF - Organic Materials
IS - 4
ER -