Title: Hybrid organic-inorganic architectures: Blue and red shift in optical properties

Abstract

The progress in organic-inorganic hybrid materials towards the development of new materials of intriguing optical properties can be potential due to its optical responses of organic units with inorganic counterpart, paves new avenue to study innovating optical systems. In the present work, a new assembly of luminescent hybrid inorganic-organic molecule was synthesised via condensation of six units of 10-octyl-10H-phenothiazine-3-carbaldehyde (R-PTZ-CHO, R- octyl chain) with hexakis cyclotriphosphazene hydrazide (CTP-Hyd). Herein, the synthesis of new inorganic heterocyclic hydrazideprecursor, CTP-Hyd has been developed to append the PTZ units on the periphery of robust inorganic CTP ring. The luminescent hybrid material obtained by the facile synthesis was characterized at each step by battery of analysis such as FT-IR, multi-nuclear NMR including 1H, 13C and 31P spectra as well as HRMS/MALDI TOF data. Moreover, the photophysical properties of the above hybrid material were characterized by UV-vis absorption, photoluminescence and time resolved photoluminescence spectral data. Indeed, the hybrid molecule shows extraordinary solvent compatibility and depicts tunable emission around yellow-green region. To extend our studies on above type of structures, phenothiazine moietyconjugated with(4-aminobenzoyl) hydrazidehas been assembled on periphery of CTP core with aromatic spacer unit. Conversely, optical absorption data of the same molecule was occurred to exhibit the blue shift rather than red shift. The above data has been compared with control substrate of aromatic molecule to deduce the observed blue shift in photophysical properties. Also, the characterization by physicochemical studies was found to deduce the proposed structure of new molecule with good thermal stability.