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Two new methyl viologen halocadmium charge-transfer salts with isostructures, [(MV)(CdI)]·3HO ( 1) and (MV)(CdI)·HO ( 2) (MV = methyl viologen, i.e., 1,1′-dimethyl-4,4′-bipyridinium), have been structurally determined. 1 and 2 consist of CdI clusters, MV dications, lattice waters with isostructures, and C-H···I hydrogen bonds are presented in 1 but absent in 2, furthermore, their relative stabilities based on were investigated by DFT calculations. Both compounds display photoluminescences in the visible region under visible-light excitations, and their thermochromism effects are observed. But their photoluminescence and thermochromic behaviors differ greatly with the presence or absence of hydrogen bonds. Moreover, their absorption spectra have also been discussed. [ABSTRACT FROM AUTHOR]

Under the template of methyl viologen (MV2+ = methyl viologen) and ethyl viologen (EV2+ = ethyl viologen), two new viologen/iodobismuthate hybrids, (MV)5(Bi2I10)(Bi2I9)2 (1) and (EV)3(Bi4I18) (2) have been structurally determined. The highly interesting feature of 1 lies in its combination of two kinds of dimeric iodobismuthate clusters, i.e. (Bi2I10)4− and (Bi2I9)3− in one lattice induced by MV2+, which are constructed from edge- and face-sharing BiI6 octahedra respectively. But the (Bi4I18)6− tetramer in 2 is based on edge- and vertex-sharing BiI6 octahedra. C–H···I hydrogen bonds contribute to the formation of quasi-3-D networks. The smaller gap of 1 might be led by more versatile C–H···I hydrogen bond interactions due to the presence of mixed type iodobismuthate clusters. Two hybrids display reversible thermochromism behaviors. Theoretical calculation suggests that the terminal iodine is dominated in electron transfer of thermochromisms, rather than bridged iodine. [ABSTRACT FROM AUTHOR]

Two new copper(I) iodide-based hybrids, i.e. (Py3P–O–PPy3)(Cu2I4) (1) and (Py3P–O–PPy3)(Cu4I6) (2) (Py = pyrrolidine), have been prepared, in which the tripodal diphosphonium (Py3P–O–PPy3)2+ is in situ generated in the one-pot synthesis. The disordered (Cu4I6)2− tetramers are rare with two sets of tetracuprate centers. Interestingly, 1 exhibits sensitive luminescence mechanochromism, which is ascribed to the disturbed cuprophilic Cu⋯Cu interactions and the crystalline packing adjustment by destroying C–H⋯I hydrogen bonds during mechanical force. In particular, the luminescence thermochromism is unique, whose fluorescence intensity is strengthened with the elevated temperature. This could be due to the S2–S1 internal conversion on the linear P–O–P backbone, which will be bent upon heating. Simultaneous luminescence thermo/mechanochromism can also be monitored in 1. However, no luminescence thermo/mechanochromic performances can be detected in 2, so the luminescence thermo/mechanochromism of 1 could be quenched with DMF. The conclusions in this work might provide a new large-scale synthesis strategy for intelligent responsive luminescent materials. [ABSTRACT FROM AUTHOR]

The development of new‐type memristors with special performance is of great interest. Herein, an inorganic‐organic hybrid crystalline polyoxometalate (POM) with usual dynamic structures is reported and used as active material for fabricating memristor with unique temperature‐regulated resistive switching behaviors. The hybrid POM not only exhibits tunable thermochromic properties, but also thermal‐induced reversible aggregation and disaggregation reactions, leading to reversible structural transformations in SCSC fashion. Further, the memory device using the hybrid POM as active layer exhibits uncommon performance, which can keep resistive switching silent in the low temperature range of 30–150 °C, but show nonvolatile memory behavior in the high temperature range of 150–270 °C. Particularly, the silent and working states at three special temperatures (30, 150 and 270 °C) can be monitored by chromism. The correlation between structure and resistive switching property of the material has been discussed. The work demonstrates that crystalline inorganic‐organic hybrid POMs are promising materials for making memristors with superior performance. [ABSTRACT FROM AUTHOR]

The development of new‐type memristors with special performance is of great interest. Herein, an inorganic‐organic hybrid crystalline polyoxometalate (POM) with usual dynamic structures is reported and used as active material for fabricating memristor with unique temperature‐regulated resistive switching behaviors. The hybrid POM not only exhibits tunable thermochromic properties, but also thermal‐induced reversible aggregation and disaggregation reactions, leading to reversible structural transformations in SCSC fashion. Further, the memory device using the hybrid POM as active layer exhibits uncommon performance, which can keep resistive switching silent in the low temperature range of 30–150 °C, but show nonvolatile memory behavior in the high temperature range of 150–270 °C. Particularly, the silent and working states at three special temperatures (30, 150 and 270 °C) can be monitored by chromism. The correlation between structure and resistive switching property of the material has been discussed. The work demonstrates that crystalline inorganic‐organic hybrid POMs are promising materials for making memristors with superior performance. [ABSTRACT FROM AUTHOR]

The hybridization of 1,4-bis(isoquinoline)butane (BIQBT2+) cation with iodobismuthate under different solvents produce two isomers α-[(BIQBT)(BiI4)2]n (α-1, in CH3OH/H2O mixed solvent, Triclinic system with P-1 space group) and β-[(BIQBT)(BiI4)2]n (β-1, in CH3OH, Monoclinic system with P21/c space group). The 1-D (BiI4)nn− chains are constructed from the opposite edge-sharing BiI6 octahedra. The (BIQBT)2+ in α-isomer adopts the planar configuration, and that in β-isomer presents the chair-like configuration, as a result, different packing modes (intercalating quasi-3-D mode for α-1 and interlocking 2-D mode for β-1) are observed. Interestingly, from α-1 to β-1, distortion degree of BiI6 octahedron and π–π stacking interaction decrease, but hydrogen bonds number increase. Consequently, due to different packing mode, photoluminescence/thermochromisms can be found in α-1, but those of β-1 are vanished, Theoretical calculation was conducted to disclose the structure/thermochromism correlation. [ABSTRACT FROM AUTHOR]

Diphenyliodonium cations were firstly introduced into halobismuthate system to synthesize two new hybrids, i. e. (DPI) 4 (Bi 2 I 10 ) ( 1 ) and (DPI) 4 (Bi 2 Br 10 )·H 2 O ( 2 ) (DPI = diphenyliodonium). Two hybrids are isostructures containing (Bi 2 X 10 ) 4- halobismuthate dimmers and diphenyliodonium cations. Hypervalent I(III)⋯X interactions and C H⋯X (X I, Br) hydrogen bonds stabilize the structures and contribute to the structural extending from 0-D clusters to 2-D layer/1-D chain. The broader absorption spectra and lower energy gap of 1 were led by strong I⋯I interactions. Two compounds display thermochromism behaviors, whose mechanisms were verified by theoretical calculations. [ABSTRACT FROM AUTHOR]

A new halocadmium/methyl viologen hybrid (MV)(CdI)(CdI) ( 1) (MV = methyl viologen) has been structurally determined. In 1, two kinds of dimeric halocadmium clusters constructed from edge/vertex-sharing CdI tetrahedra respectively, i.e., CdI and CdI dimmers were observed, which were templated by methyl viologen cation (MV). A highly interesting feature of 1 is the presence of mixed type dimeric halocadmium clusters in one crystal lattice templated by one kind of cation. 1 displays photoluminescences, and its thermochromism behavior is observed, whose mechanism was verified by theoretical calculations. [ABSTRACT FROM AUTHOR]

Two new two- and three-dimensional transition-metal-organic frameworks, namely, [Ni(imbz)] ( 1), [Cu(imbz)·4HO] ( 2), (imbz = 4-(imidazole-1-yl)-benzoic acid), have been hydrothermally synthesized and structurally determined. Compound 1 is a 2-D (4, 4)-network framework consisting of square grid with dimensions of ca. 11.4158(11) × 11.4158(11) Å, and 2 exhibits a 3-D framework encapsulating four guest solvent waters. Interestingly, both compounds exhibit tunable photoluminescences upon thermochromisms, i.e., upon heating, two compounds undergo color changes from blue to green (for 1) and dark blue to light blue (for 2) accompanied by a reduction or disappear of the fluorescent intensities. Graphical Abstract: Two new two- and three-dimensional transition-metal-organic frameworks exhibiting tunable photoluminescences upon thermochromisms have been structurally determined. They present 2-D (4, 4)-network framework and 3-D framework encapsulating four guest solvent waters.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]