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Lu YC, Hsu YT, Yang TY, Liou IC, Wang SW, Huang PC, Lee JJ, Lai LL, Hsu HF. Converting non-Mesogenic to Mesogenic Stacking of Amino- s-Triazine-Based Dendrons with p-CN Phenyl Unit by Eliminating Peripheral Dipole. NANOMATERIALS 2022; 12:nano12020185. [PMID: 35055204 PMCID: PMC8782037 DOI: 10.3390/nano12020185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/20/2021] [Accepted: 12/31/2021] [Indexed: 12/04/2022]
Abstract
Three new amino-s-triazine-based dendrons, 1a, 1b, and 1c, containing an aryl-CN moiety in the dendritic skeleton were prepared in 72–81% yields (1a: R1 = − N(n-C8H17)2, R2 = n-OC8H17, 1b: R1 = R2 = − N(n-C8H17)2, 1c: R1 = − N(n-C8H17)2, R2 = − N(n-C4H9)2). Dendrons 1a with N(n-C8H17)2 and n-OC8H17 peripheral substituents, surprisingly, did not show any mesogenic phase during the thermal process. However, non-mesogenic 1a can be converted to mesogenic 1b or 1c by eliminating the peripheral dipole arising from the alkoxy substituent; dendron 1b only comprising the same N(n-C8H17)2 peripheral groups showed a ~25 °C mesogenic range on heating and ~108 °C mesogenic range on cooling. In contrast, dendron 1c possessing different N(n-CmH2m+1)2 (m = 8 versus m = 4) peripheral units, having similar stacking as 1b, exhibited a columnar phase on thermal treatment, but its mesogenic range (~9 and ~66 °C on heating and cooling, respectively) was much narrower than that of 1b, attributed to 1c’s less flexible alkyl chains in the peripheral part of dendron. Dendron 1a with the alkoxy substituent in the peripheral skeleton, creating additional dipole correspondingly, thus, leads to the dendritic molecules having a non-mesogenic stacking. Without the peripheral dipole for intermolecular side-by-side interaction, dendrons 1b and 1c exhibit a columnar phase on thermal treatment because of the vibration from the peripheral alkyl chain.
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Affiliation(s)
- Yao-Chih Lu
- Department of Applied Chemistry, National Chi Nan University, No. 1 University Rd., Puli, Nantou 545, Taiwan; (Y.-C.L.); (T.-Y.Y.); (I.-C.L.); (S.-W.W.)
| | - Yu-Tsz Hsu
- Department of Chemistry, Tamkang University, No. 151, Yingzhuan Rd., New Taipei City 251, Taiwan;
| | - Tsung-Yen Yang
- Department of Applied Chemistry, National Chi Nan University, No. 1 University Rd., Puli, Nantou 545, Taiwan; (Y.-C.L.); (T.-Y.Y.); (I.-C.L.); (S.-W.W.)
| | - I-Chun Liou
- Department of Applied Chemistry, National Chi Nan University, No. 1 University Rd., Puli, Nantou 545, Taiwan; (Y.-C.L.); (T.-Y.Y.); (I.-C.L.); (S.-W.W.)
| | - Sheng-Wei Wang
- Department of Applied Chemistry, National Chi Nan University, No. 1 University Rd., Puli, Nantou 545, Taiwan; (Y.-C.L.); (T.-Y.Y.); (I.-C.L.); (S.-W.W.)
| | - Po-Chia Huang
- National Synchrotron Radiation Research Center, No. 101, Hsin-Ann Rd., Hsinchu 300, Taiwan; (P.-C.H.); (J.-J.L.)
| | - Jey-Jau Lee
- National Synchrotron Radiation Research Center, No. 101, Hsin-Ann Rd., Hsinchu 300, Taiwan; (P.-C.H.); (J.-J.L.)
| | - Long-Li Lai
- Department of Applied Chemistry, National Chi Nan University, No. 1 University Rd., Puli, Nantou 545, Taiwan; (Y.-C.L.); (T.-Y.Y.); (I.-C.L.); (S.-W.W.)
- Correspondence: (L.-L.L.); (H.-F.H.)
| | - Hsiu-Fu Hsu
- Department of Chemistry, Tamkang University, No. 151, Yingzhuan Rd., New Taipei City 251, Taiwan;
- Correspondence: (L.-L.L.); (H.-F.H.)
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Khan BC, Mukherjee PK. Isotropic to smectic-A phase transition in taper-shaped liquid crystal. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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