Coordination Polymers with Grinding‐Size‐Dependent Mechanoresponsive Luminescence Induced by π···π Stacking Interactions

Abstract

Two new coordination polymers {[Zn(L)(dma)] 2 ·H 2 O} n (1) and {[Cd(L)(H 2 O) 3 ]·dma·H 2 O} n (2) {H 2 L = 5-[(pyren-9-ylmethyl)amino]isophthalic acid, dma = N,N-dimethylacetamide} were synthesized by the reaction of H 2 L and zinc(II) or cadmium(II) nitrate in mixed solvents. Single-crystal XRD analyses show that polymers 1 and 2 have 1D chain structures. Due to [a]

Nature of the N‐Substituted Alkyl Chain Influencing Emission Properties of Naphthalene Diimide (NDI) Via Excimer, and Exciplex Formation

“…Initially, the P‐XRD pattern of the NDI compounds was compared before and after grinding resulting in the shift of d values to the lower 2θ values with an increase in sharpness of peaks. In the case of π ‐stacking, a small change in d values from 4.41 to 4.38, and 4.04 to 4.06 were respectively observed for NDI ‐ OL and NDI ‐ OD which indicates intermolecular interactions indeed changes after grinding (Figure 5a) [49] . Measurement of the emission spectra of NDI ‐ OL before grinding shows a major peak at 464 nm and comparatively less intense peaks at 417 and 566 nm, which after grinding, the 566 nm peak shift to 570 with an increase in intensity (Figure 5b).…”

“…In the case of πstacking, a small change in d values from 4.41 to 4.38, and 4.04 to 4.06 were respectively observed for NDI-OL and NDI-OD which indicates intermolecular interactions indeed changes after grinding (Figure 5a). [49] Measurement of the emission spectra of NDI-OL before grinding shows a major peak at 464 nm and comparatively less intense peaks at 417 and 566 nm, which after grinding, the 566 nm peak shift to 570 with an increase in intensity (Figure 5b). In the case of NDI-OD, before grinding a poor monomer emission with a shoulder peak around 566 nm was seen which forms a broad emission with two maxima around 460 and 540 nm after grinding.…”

Two d10 2D Cathode-Ray Scintillation Coordination Polymers with High Efficiency and High-Voltage Stability

“…Zn-SCP and Cd-SCP have UV–vis spectra similar to that of H 2 Nyaia at 200–400 nm . The UV–vis absorption peaks of Cd-SCP in the range of 500–600 nm can be assigned to the π -stacking interactions in the structure . The coordination of Zn 2+ and Cd 2+ leads to a decrease of the rotation freedom and an increase of the rigidity degree of the ligand, resulting in a blue shift of the fluorescence emission peak compared with the ligand. , …”

Construction of multi-hydroxyl/ketone lanthanide metal–organic frameworks for understanding mechanochromic luminescence and high proton conductivity

“…First of all it is obvious that metalmetal interactions do not exist in these two types of structures. [29][30][31] Moreover, in [Zr 16 -Eu 1−x Tb x ] with only square acid as a ligand, there are no C-H⋯π and π-π interactions, [32][33][34][35] while in [Zr 16 -BPDC-Eu 1−x Tb x ], the BPDC between the same layer is separated by Zr 16 clusters and the BPDC between different layers is more than 15 Å apart, which means that still there is no intermolecular interaction as mentioned above. The XRD of the amorphous state shows that the strong grinding may lead to the Zr 16 clusters between the layers to slip, but [Zr 16 -Eu 1−x Tb x ] does not produce the MCL phenomenon as a result, so the slip may not affect the luminescence properties in this system.…”