Thermoinduced structural-transformation and thermochromic luminescence in organic manganese chloride crystals.

Meng-En Sun,Xi-Yan Dong,Shuang-Quan Zang,Yao Li

doi:10.1039/c8sc04711a

Abstract

The [Mn2Cl9]5- mode of red emissive (C4NOH10)5Mn2Cl9·C2H5OH under thermal treatment will be cleaved into [MnCl4]2- in the green emissive (C4NOH10)2MnCl4 with the departure of ethanol. The rapid conversion of luminescence from red to green provides new insight into the luminescence origin and thermal stability of organic-inorganic metal halide hybrids.

Highlights

All publication charges for this article have been paid for by the Royal Society of Chemistry
The reported manganese halides focus on monomanganese species,1a,9 manganese chain structure1b,10 and layer structure,[11] the oligomeric cluster of manganese(II) remains quite limited,[12] which deserved careful investigation due to the structural uniqueness
The crystal structural analysis revealed that the manganese dimer in octahedral coordination decomposed into mono manganese species in tetrahedral mode, accompanied by the departure of guest ethanol molecules

Summary

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All publication charges for this article have been paid for by the Royal Society of Chemistry. We assembled a binuclear red-emissive manganese chloride cluster crystal (C4NOH10)5Mn2Cl9$C2H5OH (1) using morpholine as the organic counter cation. The crystal structural analysis revealed that the manganese dimer in octahedral coordination decomposed into mono manganese species in tetrahedral mode, accompanied by the departure of guest ethanol molecules. Compound 1 was prepared by mixing manganese chloride (MnCl2) and morpholine hydrochloride (C4NOH10Cl) (2 : 5 molar ratio) in ethanol at room temperature (R.T.) (Scheme 1). The [Mn2Cl9]5À dimers are faceshared through three coordination chloride ions and embedded periodically in the matrix of organic cations C4NOH10+. C4NOH10+ counter ions and ethanol molecules are hydrogen-bonded with [Mn2Cl9]5À dimers in compound 1 (ESI Fig. S1†). For compound 2, the Mn2+ cations occupy the tetrahedral centre coordinated by four chloride ions (Fig. 1b).

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Conclusions