A cadmium(ii)-based MOF, Cd-MDIP, was successfully prepared by hydrothermal reaction between the tetra-carboxylic ligand 5,5'-methylenebisophthalic acid (H4MDIP) and cadmium perchlorate. The X-ray crystal structure analysis showed that there are two uncoordinated carboxyl groups in each ligand and a 1D elliptical channel along the [001] direction. Because of the existence of uncoordinated carboxyl groups within open frameworks, Cd-MDIP exhibited a high sensitivity (Stern-Volmer constant KSV = 4.13 × 104 L mol-1) and a low detection limit (80 nM) for Fe3+ ions in pure water, which is much lower than the national standard for Fe3+ in daily drinking water (5.4 μM) set by the Ministry of Environmental Protection of P. R. China. Most importantly, Cd-MDIP also featured the ultrahigh adsorption of Fe3+ in aqueous solution that cannot be destroyed even by EDTA/base. Importantly, the MOF material (Cd-MDIP⊃Fe3+) after adsorbing Fe3+ could act as the first example of an excellent bi-metallic Lewis-acid catalyst for the cyanosilylation reaction of aromatic aldehydes in a size-selective fashion, and its efficiency was almost 10-times higher than that of the original Cd-MDIP.

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Herein, we developed the dual-function template method to fabricate hollow magnetic nano-spheres (denoted as HMNPs-Cn, n = 16, 18) with a mesoporous shell and hollow interior structure using alkyl chain trimethoxysilane templating. The microstructure of the HMNPs-Cn was investigated by means of XRD, FT-IR, EDS, SEM, TEM and N2-BET analyses. The shorter chain template directed formation of HMNPs-C16 with size of 119 nm, having disordered inkbottle type mesopores and saturation magnetization of 50.01 emu/g. It can be observed that, mitomycin C (MMC) loaded HMNPs-Cn hollow spheres showed a clear pH-dependent drug release behavior, having a higher release rate in acidic environments of pH 5.7. For the pH 5.7 and 7.4 release, the diffusion through HMNPs-Cn hollow spheres is the rate limiting step, the release kinetic for HMNPs-C16-MMC composites follows pseudo-first-order attributable to its special pore structure. For this reason the inner cavity of HMNPs-C16 could be labeled with radioisotope 99Tcm to study the magnetic targeting distribution of HMNPs-C16 in vivo, and its cytotoxicity against in vitro HeLa cells was also studied. These results indicate the potential of HMNPs-C16 in the magnetic targeted drug delivery system.

Herein, we developed the dual-function template method to fabricate hollow magnetic nano-spheres (denoted as HMFe-Si-Cn, n=16, 18) with a mesoporous shell and hollow interior structure using alkyl chain trimethoxysilane templating. The shorter chain template directed formation of HMFe-Si-C16 with size of 119 nm, having disordered inkbottle type mesopores and saturation magnetization of 50.01 emu/g higher than that of HMFe-Si-C18 with cylindrical type mesopores. By contrast, Mitomycin C (MMC) loading efficiency of HMFe-Si-C16 was higher owing to the fact that the pore size, surface area, and pore volume of HMFe-Si-C16 were larger than those of HMFe-Si-C18. Besides, MMC loaded HMFe-Si-Cn hollow spheres showed a clear pH-dependent drug release behavior, having a higher release rate in acidic environments of pH 5.7. For the pH 5.7 and 7.4 release, the release kinetic for HMFe-Si-C16-MMC composites follows pseudo-first-order attributable to its special pore structure. For this reason the inner cavity of HMFe-Si-C16 could be labeled with radioisotope 99Tcm to study the magnetic targeting distribution of HMFe-Si-C16 in vivo, and its cytotoxicity against in vitro HeLa cells was also studied. These results indicate the potential of HMFe-Si-C16 in the magnetic targeted drug delivery system.