Issue 29, 2015

A series of multi-dimensional metal–organic frameworks with trans-4,4′-azo-1,2,4-triazole: polymorphism, guest induced single-crystal-to-single-crystal transformation and solvatochromism

Abstract

In this work, a flexible multi-dentate trans-4,4′-azo-1,2,4-triazole (atrz) ligand has been employed, and a series of novel coordination polymers, namely [Fe(μ-atrz)(NCS)2(H2O)2]n (1), [Fe(μ-atrz)(NCS)2(H2O)2]n (2), {[Fe(μ-atrz)(μ-Cl)(H2O)2]·Cl·H2O}n (3), {[Fe(μ-atrz)(atrz)2(H2O)2]·2Br·4H2O}n (4), {[Fe(μ-atrz)(atrz)2(H2O)2]·(BF4)2·2H2O}n (5), {[Cu(μ-atrz)3]·(BF4)2·2H2O}n (6), {[Cu(μ-atrz)3]·(BF4)2}n (7), {[Cu24-atrz)(μ2-OH)2(H2O)4]·SO4·3.75H2O}n (8), {[Zn(μ-atrz)(NCS)2]·0.5H2O}n (9) and {[Zn(μ-atrz)(NCS)2]}n (10) have been isolated. 1 and 2 present one-dimensional (1D) polymorphic iron(II)–triazole frameworks, in which bicycle-pedal motion of the azo moieties of atrz can be observed. Further, when different iron(II) salts are used, 1D iron(II)–triazole frameworks 3–5 with different 1D bridging motifs can be isolated. 6 has a 3D nano-porous CuII framework with dimensions of 11.709(1) Å × 12.201(1) Å. Interestingly, 6 exhibits guest induced single-crystal-to-single-crystal (SC-SC) structural transformation to obtain another 3D nano-porous CuII framework 7 with dimensions of 11.621(6) Å × 16.674(1) Å. 8 has a 2D cationic CuII framework constructed with infinite (CuO)n chains and unique μ4-bridging atrz ligands. Anion exchange experiment indicates an anion-induced structural transformation from the 3D CuII framework 6 to the 2D CuII framework 8 confirmed by PXRD patterns. Further, when Zn(NCS)2 is used in the reaction system, 9 can be isolated which exhibits guest induced SC-SC transformation to obtain 10 accompanied by a color change from red (9) to pale pink (10). Variable temperature magnetic susceptibility measurements (2–300 K) reveal anti-ferromagnetic interactions between central iron(II) ions for 1–5. The polymorphic iron(II) frameworks, guest induced single-crystal-to-single-crystal transformation and solvatochromism also reveal great potential for the construction of flexible frameworks employing 4,4′-azo-1,2,4-triazole as basic building blocks.

Graphical abstract: A series of multi-dimensional metal–organic frameworks with trans-4,4′-azo-1,2,4-triazole: polymorphism, guest induced single-crystal-to-single-crystal transformation and solvatochromism

Supplementary files

Article information

Article type
Paper
Submitted
14 Apr 2015
Accepted
30 May 2015
First published
22 Jun 2015

CrystEngComm, 2015,17, 5396-5409

A series of multi-dimensional metal–organic frameworks with trans-4,4′-azo-1,2,4-triazole: polymorphism, guest induced single-crystal-to-single-crystal transformation and solvatochromism

B. Ding, Y. Y. Wang, S. X. Liu, X. X. Wu, Z. Z. Zhu, J. Z. Huo and Y. Y. Liu, CrystEngComm, 2015, 17, 5396 DOI: 10.1039/C5CE00724K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements