RT Journal Article
T1 Chiral Coalition in Helical Sense Enhancement of Copolymers: The Role of the Absolute Configuration of Comonomers
A1 Arias, Sandra
A1 Rodríguez Riego, Rafael
A1 Riguera Vega, Ricardo
A1 Quiñoá Cabana, Emilio
A1 Freire Iribarne, Félix Manuel
K1 Chiral Communication
K1 Helical Polymers
K1 Poly(phenylacetylene)s
K1 Chiral Conflict
K1 Sergeants and Soldiers effect
AB Both the role of the absolute configuration and the tendency of a chiral monomer to promote a certain helical scaffold in a polyphenylacetylene (PPA) —that depends on the conformational composition at the pendant group— have been evaluated to study the communication between two chiral monomers within a copolymer chain. 19 different PPA copolymer series —47 copolymers altogether— were prepared to explore the existence of a chiral to chiral communication mechanism in helical copolymers. From the data obtained, we found that communication between two different chiral monomers within a copolymer chain emerge when the two monomers exhibit two special features: (a) a different conformational composition —one chiral monomer must exist in a single low energy conformation ("chiral Sergeant") and the other must present an equilibrium between two different conformers ("chiral Soldier")—, and (b) both chiral monomers must promote a similar scaffold in the PPA, either cis-cisoidal or cis-transoidal. In the selected systems, the chiral Soldier includes the 4-ethynylanilide (para position) of either (R)- or (S)-2-methoxy-2-phenylacetic acid [(R)- or (S)-1], pendants characterized by their conformational flexibility once polymerized (equilibrium between synperiplanar and antiperiplanar conformations). The chiral Sergeant contains the same chiral groups but linked to the backbone in meta position [3-ethynylanilide of (R)- or (S)-2-methoxy-2-phenylacetic acid, (R)- or (S)-2] and is selected on the basis of its restricted antiperiplanar conformation. Incorporation of a very small amount (1%) of the Sergeant [either (R)- or (S)-2] to a chain composed just by the Soldier transforms the originally axially racemic chain into a helix with strong sense preference (either M or P) that is determined by the absolute configuration of the Soldier. For instance, both poly-[(R)-10.9-co-(R)-20.1] and poly-[(R)-10.9-co-(S)-20.1] adopt M helical structures due to the absolute configuration of the soldier, although the extent of the chiral amplification induced by the Sergeant is different as a consequence of a different communication mechanism between the (R)-Sergeant/(R)-Soldier and the (S)-Sergeant/(R)-Soldier
PB American Chemistry Society
SN 0002-7863
YR 2017
FD 2017-12-14
LK http://hdl.handle.net/10347/16391
UL http://hdl.handle.net/10347/16391
LA eng
NO Arias, S., Rodríguez, R., Quiñoá, E., Riguera, R., & Freire, F. (2018). Chiral Coalition in Helical Sense Enhancement of Copolymers: The Role of the Absolute Configuration of Comonomers. Journal Of The American Chemical Society, 140(2), 667-674. http://dx.doi.org/10.1021/jacs.7b09965
NO NOTICE: This is the peer reviewed version of the following article: Arias, S.; Rodríguez, R., Quiñoá, E.; Riguera, R.; Freire, F.. Chiral Coalition in Helical Sense Enhancement of Copolymers: the Role of the Absolute Configuration of Comonomers Promoting the Helical Scaffold. J. Am. Chem. Soc. 2018, 140, 667-674. This article may be used for noncommercial purposes in accordance with ACS Terms and Conditions for self-archiving
NO We thank the Ministerio de Ciencia e Innovacion ([CTQ2014-61470-EXP, CTQ2015-70519-P, FPI ́ (R.R.)], Fundacion Gil Da ́ vila fellowship (S.A.), Xunta de Galicia (Centro Singular de Investigación de Galicia accreditation 2016-2019, GRC2014/040), and the European Union (European Regional Development Fund-ERDF) for financial support
DS Minerva
RD 22 abr 2026