2D Cd(II)-MOF of Pyridyl-Imidazoquinazoline: Structure, Luminescence, and Selective Detection of TNP and Fabrication of Semiconducting Devices

Abstract

Pyridyl-substituted imidazoquinolines are highly fluorescent probes and are useful for the design of smart materials. A hitherto unknown pyridyl-quinazoline] has been designed and structurally confirmed by single-crystal X-ray crystallography. The presence of C−H•••π and π•••π interactions in CP 1 makes it a threedimensional (3D) supramolecular structure. The excellent luminescent behavior of CP 1 is selectively quenched by trinitrophenol (TNP) even in the presence of potentially intrusive nitroaromatic explosives (NAEs). A limit of detection (LOD) of 2.75 × 10 −7 M for TNP is achieved (3σ/m). In addition, the CP 1 displays electrical conductivity on an electronic device with the metal−semiconductor (MS) junction. Current vs voltage (I−V plot) correlation reveals the substantial enhancement of electrical conductivity upon illumination (Λ: 1.12 × 10 −3 S m −1 (dark), 6.33 × 10 −3 S m −1 (light)) along with a decrease in energy barrier (Φ B : 0.53 (dark), 0.42 (light)). The plots of log V vs log I show a non-Ohmic feature at a higher voltage (log V ≥ 0) both in the dark and the light phase, which is the characteristic of a Schottky diode barrier (SDB).

Rational synthesis of a pyridyl-imidazoquinazoline based multifunctional 3D Zn(ii)-MOF: structure, luminescence, selective and sensitive detection of Al3+ and TNP, and its semiconducting device application

“…A thin film device consisting of metal (Al)–semiconductor (synthesized compound) (MS) junction ( TFD 1 ) has been fabricated (details given in ESI†). 66 The I – V plot (Fig. 7b) of the device was recorded at room temperature (26 °C) in the absence of light and also in the presence of photo-irradiation (intensity of light was ∼100 mW cm −2 ) at an applied bias voltage sequentially within the limit of ±2 V to investigate its electrical properties.…”

“…6). 66 Even in the presence of several lower pH solutions ( pH = 2-7) (Fig. S19, ESI †), the emission intensity of 1 remains unchanged, which implies structural durability under acidic conditions.…”

“…S16, ESI †)) and this is one of the highest values for MOF-based sensor materials reported so far. 65,66,86,[88][89][90][91] The progressive addition of TNP was followed in the time-resolved instrument to evaluate the lifetime of the composite [1 + Al 3+ ] and it was observed that the fluorescence lifespan of 1 remained unchanged with the progressive addition of TNP (Fig. S18, ESI †).…”

“…Until now, examples of MOFs with such an all-in-one function have yet to be explored. 65,66 We therefore consider the aforementioned challenges as our reason for utilizing a single framework for multiple applications and have developed a 3D Zn(II)-MOF derived from a novel heterocyclic ligand, 6-( pyridin-4-yl)-5,6-dihydrobenzo [4,5]imidazo [1,2-c]quinazoline ( pdiq), and a bridging linker, 2,5-thiophene dicarboxylate (2,5-H 2 tdc) (Fig. 1a).…”

Synthesis and crystal structures of two tri- and tetra-heterometallic Ni(ii)–Mn(ii)/Ni(ii)–Co(iii) complexes from two different Ni(ii)-containing metalloligands: effective catalytic oxidase activity and Schottky device approach

“…Most of the research groups have investigated the electrical properties of homonuclear transition metal complexes and simultaneously, heteronuclear complexes have been less explored. [37][38][39] Herein, we report the development and proper identification of two heteronuclear complexes, [(NiLA) 2 (CH 3 COO) 2 (SCN) 2 (Co) 2 ] (1), and [(NiLB) 2 (SCN) 2 Mn (2), by utilizing two structurally similar metalloligands, [NiLA 2 ] and [NiLB 2 ], developed by using N 2 O 2 donor Schiff bases H 2 LA and H 2 LB respectively. The structural details of both complexes have been verified using singlecrystal data analysis.…”