Inorganic−Organic Hybrid Materials: Layered Zinc Hydroxide Salts with Intercalated Porphyrin Sensitizers

Abstract

Layered materials provide a two-dimensional interlayer space suitable for accommodating molecules with a designed functionality. In this study, inorganic−organic hybrids were prepared by intercalation of anionic porphyrin sensitizers into the host structure of layered zinc hydroxide salts. The inorganic host offers stabilization and protection, whereas the guest species provide the photofunction. The properties and arrangement of porphyrin molecules in the interlayer space were studied by a combination of experimental techniques and molecular simulations. Intercalation of porphyrins led to a gallery height that is comparable with the size of porphyrin molecules. Molecular simulations showed that the interlayer space is filled with disordered porphyrin units. The porphyrin sulfonate groups interact with the brucite-like layers via dominant electrostatic interactions similarly to layered double hydroxides. The photophysical experiments proved that intercalated anionic Pd porphyrins produce singlet oxygen, O2(1Δg), with long effective lifetimes, suggesting that layered zinc hydroxide salts are good carriers of porphyrin sensitizers.

Ab initio simulations of the intercalation of iron(III) porphyrinates in Zn 2 Al-LDH: Structural analysis and evaluation of their basic and acid sites

“…Due to the good agreement of our simulations and the ones reported by Kovar et al, it can be inferred that the presence of water molecules in the interlayer region does not affect the structural stabilization of the porphyrinates. Furthermore, Demel et al also obtained a good agreement between the simulation and the experimental data of the intercalation of LHS with zinc porphyrin (Demel et al, 2010). Those simulations did not consider the presence of water molecules in the interlayer region, thus also corroborating our previous remark.…”

Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound

“…The compound further undergoes a 26% of weight loss in the region of 240–500°C which is attributed to the dehydroxylation of the hydroxide layers as well as partial decomposition of the intercalated CFX anions. The final step records a 35% weight loss with the major peak occurs around 827°C (temperature range 680–928°C) which is ascribed to the complete decomposition of amorphous mixture of salts generated during the initial drug decomposition [15]. …”

“…A wide variety of guest molecules has been intercalated into the interlayer region of LHS, mainly via ion exchange process, ranging from anionic dyes [14], porphyrin sensitizers [15] and an anti corrosive compound [16]. In particular, LHS has demonstrated the ability to extend the release period of bioactive molecules [17] and drug molecules [18], prompting more investigations towards potential applications of LHS in drug delivery systems.…”

Layered zinc hydroxide salts: Delamination, preferred orientation of hydroxide lamellae, and formation of ZnO nanodiscs

“…Coprecipitation is a well-suited method for the synthesis of LZH salts [10,13,45,46]. Elemental analysis confirms the composition [Zn 5 (OH) 8 …”

“…Layered hydroxide salts have similar anionexchange properties as LDH with a new functionality brought by synergic effects of intercalated anions and hydroxide layers of a specific composition. Thus, layered hydroxide salts are suitable carriers of singlet oxygen photosensitizers [10] and supports for catalysts [11], they can be used as reinforcement in polymer nanocomposites [12] or drug delivery systems [13], or they have specific magnetic [4,6,7,14], magnetic-resonance-contrasting [15], photoluminescence, and catalytic properties [16].…”