Integration of Porous Coordination Polymers and Gold Nanorods into Core–Shell Mesoscopic Composites toward Light-Induced Molecular Release

Abstract

Besides conventional approaches for regulating in-coming molecules for gas storage, separation, or molecular sensing, the control of molecular release from the pores is a prerequisite for extending the range of their application, such as drug delivery. Herein, we report the fabrication of a new porous coordination polymer (PCP)-based composite consisting of a gold nanorod (GNR) used as an optical switch and PCP crystals for controlled molecular release using light irradiation as an external trigger. The delicate core-shell structures of this new platform, composed of an individual GNR core and an aluminum-based PCP shell, were achieved by the selective deposition of an aluminum precursor onto the surface of GNR followed by the replication of the precursor into aluminum-based PCPs. The mesoscopic structure was characterized by electron microscopy, energy dispersive X-ray elemental mapping, and sorption experiments. Combination at the nanoscale of the high storage capacity of PCPs with the photothermal properties of GNRs resulted in the implementation of unique motion-induced molecular release, triggered by the highly efficient conversion of optical energy into heat that occurs when the GNRs are irradiated into their plasmon band. Temporal control of the molecular release was demonstrated with anthracene as a guest molecule and fluorescent probe by means of fluorescence spectroscopy.

Metal‐Organic Frameworks: Coordination Polymer Nanoparticles and Macrostructures

“…The potential of these materials as new light-induced molecular release systems was demonstrated by the release of anthracene (used as fluorescent probe molecule) under near-infrared irradiation. 91 Potential of using the pseudomorphic replacement process in order to integrate PCPs with other functional materials was also demonstrated by Zhang et al This group synthesized core-shell heterostructures composed of vertically standing arrays of ZnO nanorods coated with ZIF-8 crystals. These novel semiconductor@PCP composites are considered as promising new types of photoelectrochemical sensors with efficient molecule selectivity.…”

Coordination Programming: A New Concept for the Creation of Multifunctional Molecular Systems

“…Furukawa, Kitagawa, and co-workers reported the fabrication of a new porous coordination polymer (PCP)-based composite consisting of a gold nanorod (GNR) used as an optical switch and PCP crystals for controlled molecular release using light irradiation as an external trigger ( Figure 14). 43 Temporal control of the molecular release was demonstrated using anthracene as a guest molecule and fluorescent probe by means of fluorescence spectroscopy.…”

Application of metal and metal oxide nanoparticles@MOFs

“…These unique features have led researchers to explore combining MOFs with other functional materials to form novel composites with advanced properties [6]. Indeed, ceramics, metal nanoparticles, polymers and biomolecules have been combined with MOFs to afford new materials that have demonstrated unprecedented performance in the areas of catalysis [7], molecular separations [8], sensing [9], plasmonics [10], gas storage [11], controlled guest release [12,13], and protection of biomacromolecules [14]. The most widely studied of these composite systems are based on integrating metal and metal oxide nanoparticles with MOFs.…”