RESUMO
The exploration of smart sensors is of great significance for the selectivity, sensitivity, and ability to show the low detection limit for the target analyte. Here, we have used the linker H2L (5-((anthracen-9-ylmethyl)amino)isophthalic acid) for the construction of {[Cd(L)(DMF)(H2O)2]·H2O}n (1) which is in order with the chromophore anthracene moiety and the free -NH functionality as a guest interaction site. This framework showed the luminescence recovery "turn-on" detection of the Al3+ ion in an aqueous solution. An exhaustive mechanism study disclosed that the Lewis acid-base-type interaction between the Al3+ ion and the -NH functionality of the linker in the framework revealed that the absorbance caused an enhancement for the "turn-on" sensing event. Besides the "turn-on" sensing event, the "turn-off" sensing phenomenon of 1 is also noticed when it detects the hazardous oxo-anions (MnO4- and CrO42-) with limit of detection values of 17.08 and 19.91 ppb, respectively. The detection of these diverse analytes are very fast (10 s) and they can also be recognized through a colorimetric response. The sensing mechanisms for these analytes are established by photoinduced electron transfer, Forster resonance energy transfer, and inert filter effect along with theoretical investigation. Furthermore, to show the sensing application of 1 in a versatile podium, a MOF gel composite, 1@AA (AA = Agar-Agar), was developed from 1 with AA. Interestingly, 1@AA showed the colorimetric detection of these analytes under UV light. Therefore, sensor 1 behaves as a smart sensory material for the recognition of the above analytes through a simultaneous "turn-on" and "turn-off" effect.
RESUMO
The electrochemical deposition of Si has been carried out in an ionic liquid medium in the presence of water in a limited dry nitrogen environment on highly oriented pyrolytic graphite (HOPG) at room temperature. It has been found that the presence of water in ionic liquids does not affect the available effective potential window to a large extent. Silicon has been successfully deposited electrochemically in the overpotential regime in two different ionic liquids, namely, BMImTf2N and BMImPF6, in the presence of water. Although a Si thin film has been obtained from BMImTf2N; only distinguished Si crystals protected in ionic liquid droplets have been observed from BMImPF6. The most important observation of the present investigation is that the Si precursor, SiCl4, instead of undergoing hydrolysis, even in the presence of water, coexisted with ionic liquids, and elemental Si has been successfully electrodeposited.
