Synthesis and thermal, emission and dielectric properties of liquid crystalline Eu(III), Sm(III) and Tb(III) complexes based on mesogenic 4-pyridone ligands functionalized with cyanobiphenyl groups

Thermal and Emission Properties of a Series of Lanthanides Complexes with N-Biphenyl-Alkylated-4-Pyridone Ligands: Crystal Structure of a Terbium Complex with N-Benzyl-4-Pyridone

“…Generally, the prepared complexes’ thermal properties are similar for different lanthanide ions; the effect of changing the lanthanide ions on the thermal behavior is minimal, as previously reported for other lanthanide complexes with various 4-pyridone ligands [ 9 , 11 , 12 ].…”

“…In fact, the absence of the polar cyano group, by the replacement of the cyanobiphenyl unit with the biphenyl unit in the construction of the 4-pyridone ligands, is the strongest argument for the monotropic nature of the SmA phase and the lack of mesogenic properties for the analogs with shorter spacer (9 carbon atoms, complexes 3 – 5a ). Unlike the lanthanide complexes presented in this study, the related complexes with cyanobiphenyl mesogenic groups show enantiotropic SmA phases, even for shorter spacers (8, 9 or 10 carbon atoms) [ 11 , 12 ].…”

“…It is important to mention that no emission from the ligands in the emission spectra of the prepared complexes was observed. The emission spectra of the related lanthanide complexes with the 4-pyridone ligands having cyanobiphenyl terminal units in place of biphenyl units are characterized by the blue emission originating from the cyanobiphenyl group, which is dominant in the case of the Tb(III) and Sm(III) complexes [ 11 , 12 ]. Unlike these complexes with 4-pyridone terminated with cyanobiphenyl units, their related lanthanide complexes having the 3,4,5-tris(alkoxy)benzyl mesogenic groups attached to the 4-pyridone platform exhibited the characteristic emission light, red for Eu(III), orange for Sm(III) and green for Tb(III), respectively.…”

“…Based on these considerations, the lanthanide complexes with monodentate 4-pyridone ligands represent a recently developed class of lanthanidomesogens with several strong and appealing features, such as high thermal stability and their easily adjustable mesomorphic behavior [ 9 , 10 , 11 , 12 ]. These new materials’ mesogenic properties can be tuned by specifically choosing the mesogenic groups attached to the 4-pyridone ring.…”

Polyfunctional Nanosystems on Amphiphilic and Hybrid Platform: Self-Assembly, Mesogenic Properties and Application

“…При исследовании мезогенных свойств металлсодержащих термотропных ЖК в настоящее время главное внимание уделяется установлению температуры и тепловых эффектов фазовых переходов, определению типа мезофазы. С этой целью успешно используется поляризационная микроскопия, дифференциальная сканирующая калориметрия, термогравиметрический анализ [91][92][93][94][95]. При синтезе термотропных ЖК широко используют соли переходных металлов, имеющие незаполненные d-и f-подоболочки.…”