RESUMO
Four new azo-based supramolecular materials containing thiacalixarene core substituted by variable alkoxy groups (TFA1 -TFA4 ) have been designed and synthesized for the mesomorphic and photoswitching properties. The liquid crystalline behavior were accomplished by using DSC, POM, and XRD studies. All azo-based thiacalixarene based materials with short and higher chain length display columnar hexagonal mesophase with broad temperature range. The thermal behavior of all the materials was investigated by DSC and TGA study. The structural and conformational study of the lower rim functionalized materials was confirmed by using different techniques. These thiacalixarene moulded liquid crystalline compounds shows columnar self-assembly type behavior and higher thermal stability. The introduction of bi-substituted azo-ester network towards the lower rim of thiacalixarene core has impact on the electron delocalization and liquid crystalline properties. The photoswitching properties suggested cis and trans azo-isomerization under radiation of UV light and higher thermal back relaxation time. The mesogenic behaviour of compound TFA2 and TFA4 were demolished by the influence of cis and trans isomerization. The structure-property correlation is studied to understand the variation in mesogenic properties with the substitution of variable alkoxy side chain.
RESUMO
A 52-year-old unvaccinated and splenectomized man presented with fever, altered sensorium, bilateral flank pain and chest discomfort accompanied with paroxysmal atrial fibrillation with a rapid ventricular response. An abdominal computed tomography scan was performed, which revealed a right renal infarct and splenosis. Transthoracic echocardiography was performed, which demonstrated an echodense structure on the mitral valve with mitral regurgitation and a vegetation on the aortic valve with aortic regurgitation. Subsequently, he was found to have pneumococcal infective endocarditis, pneumococcal pneumonia and bacterial meningitis, namely Austrian syndrome. He underwent an early aortic valve and mitral valve repair but still had a poor clinical outcome. Renal infarction has a mortality of approximately 13.2%, which is strongly influenced by the underlying diseases and infectious complications. Medical and surgical treatment initiated in a timely manner is often inadequate. The authors report the first case of Austrian syndrome presenting with renal infarction as a clue to an embolic event associated with infective endocarditis in this study.