Strikingly different molecular organization and molecular order of tetracatenar mesogens in columnar mesophases revealed by XRD and 13C NMR†

Reddy, M. Guruprasad; Lobo, Nitin P.; Roy, Arun; +2 Co-Authors

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/7577

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DC Field	Value	Language
dc.contributor.author	Reddy, M. Guruprasad	-
dc.contributor.author	Lobo, Nitin P.	-
dc.contributor.author	Roy, Arun	-
dc.contributor.author	+2 Co-Authors	-
dc.date.accessioned	2020-11-16T04:11:20Z	-
dc.date.available	2020-11-16T04:11:20Z	-
dc.date.issued	2020-11	-
dc.identifier.citation	Physical Chemistry Chemical Physics , 2020, Vol. 22, p23986-23997	en_US
dc.identifier.issn	1463-9076(Print)	-
dc.identifier.issn	1463-9084(Online)	-
dc.identifier.uri	http://hdl.handle.net/2289/7577	-
dc.description	Restricted Access.	en_US
dc.description.abstract	or a successful design of functional mesogens, it is paramount to understand factors that contribute to molecular organisation such as molecular shape, the non-covalent interactions of the constituent moieties as well as nanosegregation of incompatible molecular parts. In this study on four tetracatenar mesogens, we show that by a slight change in the length of the terminal chain, the molecular organization changes from lamellar to columnar phase and that the orientational order experiences profound change between the lamellar, the center rectangular columnar and the hexagonal columnar mesophases. We consider here, mesogens that exhibit lamellar and columnar mesophases with five phenyl rings in the central rod-like core which are subjected to XRD and high resolution solid state 13C NMR investigations in their mesophases. The XRD studies indicate that the lower homologs exhibit a lamellar mesophase while the higher homologs show either a centre rectangular columnar phase or a 2D hexagonal columnar mesophase. 13C NMR investigations reveal interesting and strikingly different molecular orientations in each of these phases. For example, values of order parameters of one of the phenyl rings in the core region of the mesogens vary from 0.75 and 0.77 for the lamellar mesogens to 0.45 and 0.17 for the centre rectangular columnar and the hexagonal columnar mesogens respectively. While these values indicate that the mesogenic molecules are oriented along the magnetic field as expected in the lamellar phases, the very low order parameter in the hexagonal columnar phase arises due to molecules distributed azimuthally in layers and undergoing motion about the columnar axis which itself is oriented orthogonal to the magnetic field. Such cutting edge information extracted from the combined use of XRD and 13C NMR studies on tetracatenar mesogens is expected to be of significant use for the study of π–conjugated polycatenar systems where functional properties depend on the molecular orientation and order.	en_US
dc.language.iso	en	en_US
dc.publisher	Royal Society of Chemistry	en_US
dc.relation.uri	https://doi.org/10.1039/D0CP03933K	en_US
dc.rights	2020 Royal Society of Chemistry	en_US
dc.title	Strikingly different molecular organization and molecular order of tetracatenar mesogens in columnar mesophases revealed by XRD and 13C NMR†	en_US
dc.type	Article	en_US
dc.additional	Supplementary Information Available	en_US
Appears in Collections:	Research Papers (SCM)

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