Diverse dissolution–recrystallization structural transformations and sequential Förster resonance energy transfer behavior of a luminescent porous Cd-MOF

Abstract

Metal-organic frameworks (MOFs) with light-harvesting building blocks provide an excellent platform to study energy transfer in networks with well-defined structures. Here, we report the synthesis, dissolution-recrystallization structural transformation (DRST) and the Förster resonance energy transfer (FRET) properties of a 2D microporous MOF {[Cd(L)(Hdabco)]·5DMAc·6HO} (Cd-MOF, 1). Complex 1 can be dissolved in water and three other products with different dimensions recrystallized from the aqueous solution under diverse reaction conditions were obtained. Due to the porosity and excellent blue luminescence properties of complex 1, we also studied the FRET process between 1 and guest dyes. Two distinct organic dye molecules viz., acridine orange (AO) and rhodamine B (RhB), are encapsulated in 1 which has honeycomb-type nanochannels, and their influence on fluorescence emission has also been studied. The microporous complex 1 in (AO + RhB)@1 serves as an energy funnel that harvests high energy excitation and channels it onto AO and then onto RhB. The steady-state fluorescence and fluorescence dynamics of emission reveal successfully the process of stepwise vectorial energy transfer. Therefore, MOFs could be a class of promising host materials to be further explored in the field of energy transfer between MOF-host and organic guests.

Multichromic Metal-Organic Framework for Multimode Photonic Sensing

“…Conversely, we discovered that the RhB@ZIF-71 exhibits good luminescence ( Figure S14 and Figure 6) in non-polar solvents, and even show sensing property previously not achievable by pure RhB alone. To date, most of the RhB@MOF studies [17][18][19][20][21][22][23][24] have focused on the field of solvatochromism, and many of these systems possess the similar sensing behaviour.…”

“…In this study, we demonstrate a facile method to synthesize a multi-stimuli responsive Guest@MOF luminescent material, by embedding the well-known luminescent dye rhodamine B (RhB) into zeolitic imidazolate framework-71 (ZIF-71). Although a number of RhB@MOF systems have been reported, [17][18][19][20][21][22][23][24] there are certain limitations, such as the use of complex synthesis steps, no control of RhB aggregates, inadequate explanation of the underlying mechanisms, and monotonous functionality (basically only solvatochromism). In contrast, our RhB@ZIF-71 not only shows solvatochromic response with its sensitivity far surpassing all reported examples, [17][18][19][20][21][22][23][24] but also exhibits exceptional mechanochromic and thermochromic sensing properties that are unknown to date.…”

Multichromic Metal-Organic Framework for Multimode Photonic Sensing

“…Conversely, we discovered that the RhB@ZIF-71 exhibits good luminescence ( Figure S14 and Figure 6) in non-polar solvents, and even show sensing property previously not achievable by pure RhB alone. To date, most of the RhB@MOF studies [17][18][19][20][21][22][23][24] have focused on the field of solvatochromism, and many of these systems possess the similar sensing behaviour.…”

“…In this study, we demonstrate a facile method to synthesize a multi-stimuli responsive Guest@MOF luminescent material, by embedding the well-known luminescent dye rhodamine B (RhB) into zeolitic imidazolate framework-71 (ZIF-71). Although a number of RhB@MOF systems have been reported, [17][18][19][20][21][22][23][24] there are certain limitations, such as the use of complex synthesis steps, no control of RhB aggregates, inadequate explanation of the underlying mechanisms, and monotonous functionality (basically only solvatochromism). In contrast, our RhB@ZIF-71 not only shows solvatochromic response with its sensitivity far surpassing all reported examples, [17][18][19][20][21][22][23][24] but also exhibits exceptional mechanochromic and thermochromic sensing properties that are unknown to date.…”

Structural Transformation Pathways of Alkaline Earth Family Coordination Polymers Containing 3,3′,5,5′‐Biphenyl Tetracarboxylic Acid

“…Very few studies exemplify the step-by-step crystal growth process. [18,19] Due to large radii, high and various coordination numbersof alkaline earth metal ions, the relatedCPs are difficult to be predesigneda nd directional synthesized. Especially for Sr 2 + and Ba 2 + ,t hey have received much less attention compared to other transition metal ions.…”