Chemistry - A European Journal p. 4149 - 4159 (2017)
Update date:2022-09-26
Topics:
W?hrle, Tobias
Gündemir, Rafet
Frey, Wolfgang
Knecht, Friederike
K?hn, Andreas
Laschat, Sabine
A series of MIDA (N-methylimino diacetic acid) boronates carrying 4-alkoxy, 3,4-bisalkoxy, or 3,4,5-trisalkoxyphenyl substituents were synthesized and their mesomorphic properties characterized by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) techniques such as small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). Most derivatives were liquid crystalline. In the case of mono- and bisalkoxy-substituted derivatives, C6 chains already induced smectic A (SmA) mesophases despite the bulky MIDA head group. With increasing chain length, columnar hexagonal (Colh) phases replaced SmA phases in the disubstituted series. Quantum chemical calculations on a series of MIDA boronates show that the B?N bond is a dative bond with a positive charge on the boron atom and negative charges on the nitrogen and oxygen atoms. In addition, no π-interaction between the aryl moiety and B?N bond was found, thus the mesogenic unit is electronically decoupled from the MIDA head group. These theoretical findings were supported by IR and Raman spectra as well as by asingle crystal structure analysis of 4-ethoxyphenyl MIDA boronate. Calculations of the electrostatic potential of the MIDA boronate reveal a special polarity pattern that can support the formation of a two-dimensional network and is likely to explain the liquid crystalline self-assembly. The absence of any electronic cross-talk between the MIDA head group and B-aryl or B-alkyl substituents allows the efficient tailoring of the mesophase type through variation of the substituents.
View MoreBeijing Stable Chemcial Co.ltd
Contact:86-10-63785052
Address:A1301 Technological Edifice. No.4 FuFeng Road,FengTai District, Beijing. China
Shijiazhuang Yunxuan Im&Export Co.,Ltd.
Contact:+86-311-83037514
Address:No.6 Hongbin Road
Wuhan Yitongtai Science and Technology Co.,Ltd.
Contact:+86-27-88933550
Address:27th Fl. Bldg. 1, Shuian International Mansion, Heping Ave, Wuhan, Hubei, China
Laizhou City Laiyu Chemical CO.,Ltd
Contact:+86-535-2719337/2719339
Address:Chenggang road zhuyou laizhou City Shangdong China
Contact:0833-5590788/5590338/5590055
Address:Victory in the town of Red Star Village,Mount Emei City,industrial concentration area storage processing logistics parkpark
Doi:10.1021/j150648a020
(1984)Doi:10.1016/S0040-4020(01)80037-5
(1989)Doi:10.1016/S0022-2860(97)00253-6
(1998)Doi:10.1002/anie.200502985
(2006)Doi:10.1021/jo00178a032
(1984)Doi:10.1248/cpb.33.674
(1985)