We synthesized a new Pt/Zn-based coordination polymer, {Zn[Pt(CN) 2 (5,5'-dcbpy)]⋅4H 2 O} n , (5,5'-H 2 dcbpy = 5,5'-dicarboxy-2,2'-bipyridine), which exhibits reversible colour changes in response to temperature change or exposure to chemical vapours and liquids. Such chromic behaviour shows promise for sensing not only changes in temperature but also for detecting 10 chemical solvents and vapours. The single crystal X-ray structure indicates that one-dimensional coordination polymeric chains formed by an alternating arrangement of [Zn(H 2 O) 3 ] 2+ and [Pt(CN) 2 (5,5'-dcbpy)] 2-stacked to produce moderate metallophilic interactions between the Pt(II) ions. Thermogravimetric analysis and water vapour adsorption measurements show that both the crystal water and water coordinated to Zn(II) ions can be removed and re-adsorbed reversibly by 15 heating or under vacuum. Emission spectra at various temperatures and/or in the presence of vapours or liquids reveal that the complex exhibits thermochromic and solvatochromic-like behaviours, with the emission band shifting between 616 and 671 nm. IR spectroscopy and powder X-ray diffraction measurements suggest that this multichromic behaviour is a result of the cooperative phenomena of water adsorption/desorption around the Zn(II) ions and the modification 20 of the metallophilic interaction.

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Reactions of a Pt(II)-diimine-based metalloligand Na 2 [Pt(CN) 2 (4,4'-dcbpy)] (4,4'-H 2 dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) with alkaline-earth metal salts Mg (NO 3 exhibit any chromic behaviour. Combination analysis of powder X-ray diffraction, thermogravimetry, and IR spectroscopy suggests that the dimensionality of the coordination network contributes considerably to both the structural flexibility and luminescence properties; that is, the low-dimensional flexible coordination network formed in MPt-4 complexes with smaller alkaline-earth metal ions enables a structural rearrangement induced by thermal and mechanical stimuli and vapour adsorption, resulting in 25 the observed multichromic behaviour.