[Zn3(HCOO)6]: A Porous Diamond Framework Conformable to Guest Inclusion

Zheming Wang; Yanjuan Zhang; Mohamedally Kurmoo; Tao Liu; Serge Vilminot; Bin Zhao; Song Gao

doi:10.1071/CH06176

RESEARCH FRONT

[Zn₃(HCOO)₆]: A Porous Diamond Framework Conformable to Guest Inclusion

Zheming Wang ^A ^E , Yanjuan Zhang ^A ^B , Mohamedally Kurmoo ^C ^E , Tao Liu ^A , Serge Vilminot ^D , Bin Zhao ^B and Song Gao ^A ^E

+ Author Affiliations

- Author Affiliations

^A College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

^B Department of Chemistry, Qufu Normal University, Shandong 273165, China.

^C Laboratoire de Chimie de Coordination Organique, UMR7140-CNRS, Université Louis Pasteur, 67000 Strasbourg, France.

^D Institut de Physique et Chimie des Matériaux de Strasbourg, UMR7540 CNRS-ULP, 23 rue du Loess, BP 43, Université Louis Pasteur, 67037 Strasbourg, France.

^E Corresponding authors. Email: zmw@pku.edu.cn; kurmoo@chimie.u-strasbg.fr; gaosong@pku.edu.cn

Australian Journal of Chemistry 59(9) 617-628 https://doi.org/10.1071/CH06176
Submitted: 25 May 2006 Accepted: 20 July 2006 Published: 19 October 2006

Abstract

We report the syntheses, crystal structures, and the thermal properties of [Zn₃(HCOO)₆](CH₃OH)_1.5(H₂O)_0.5 (1_parent), [Zn₃(HCOO)₆] (2_empty), and six guest-inclusion compounds [Zn₃(HCOO)₆](I₂) (3_iodine), [Zn₃(HCOO)₆](C₄H₈O) (4_THF), [Zn₃(HCOO)₆](C₄H₄O) (5_furan), [Zn₃(HCOO)₆](C₆H₆) (6_benzene), [Zn₃(HCOO)₆](CH₃CN) (7_acetonitrile), and [Zn₃(HCOO)₆]((CH₃)₂CO) (8_acetone) as well as the H₂ and N₂ adsorption of 2_empty. The frameworks of all the compounds are similar, and consist of Zn-centred ZnZn₄ tetrahedral nodes of a distorted diamond structure. It is robust by virtue of the diamond structure and it displays permanent porosity in which the pores, occupying about 30% of the volume, can be reversibly emptied and refilled with solvents and gases without loss of crystallinity. The crystal-to-crystal transformation is assured by performing the guest-inclusion process by exposure of 2_empty to the vapours of the guests following the complete desolvation of 1_parent. Conformity is evidenced by the change in the lattice parameters proportional to the size of the guests. The framework is thermally stable up to 140°C at which it is transformed exothermically to a more compact form, β-Zn(HCOO)₂, that is stable to 270°C. Due to the flexibility and amphiphilic nature of the pores, consisting of both C–H and O arrays at the surface, 2_empty can take up a wide spectrum of both polar and non-polar guests of different size. The guests are confined in zig-zag molecular arrays within the channels where weak hydrogen bonds provide the main host–guest interaction. Except for acetonitrile, which sits in the central part of the channels, all the guests appear to line the wall of the channels.

References

[Zn3(HCOO)6]: A Porous Diamond Framework Conformable to Guest Inclusion

Abstract

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[Zn₃(HCOO)₆]: A Porous Diamond Framework Conformable to Guest Inclusion