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A range of novel BODIPY derivatives with a tripodal aromatic core was synthesized and characterized spectroscopically. These new fluorophores showed promising features as probes for in vitro assays in live cells and offer strategic routes for further functionalization towards hybrid nanomaterials. Incorporation of biotin tags facilitated proof‐of‐concept access to targeted bioconjugates as molecular probes. Computational explorations using DFT and TD‐DFT calculations identified the most stable tripodal linker conformations and predicted their absorption and emission behavior. The uptake and speciation of these molecules in living prostate cancer cells was imaged by single‐ and two‐photon excitation techniques coupled with two‐photon fluorescence lifetime imaging (2P FLIM). [ABSTRACT FROM AUTHOR]

Three‐dimensional fluorescent graphene frameworks with controlled porous morphologies are of significant importance for practical applications reliant on controlled structural and electronic properties, such as organic electronics and photochemistry. Here we report a synthetically accessible approach concerning directed aromatic stacking interactions to give rise to new fluorogenic 3D frameworks with tuneable porosities achieved through molecular variations. The binding interactions between the graphene‐like domains present in the in situ‐formed reduced graphene oxide (rGO) with functional porphyrin molecules lead to new hybrids via an unprecedented solvothermal reaction. Functional free‐base porphyrins featuring perfluorinated aryl groups or hexyl chains at their meso‐ and β‐positions were employed in turn to act as directing entities for the assembly of new graphene‐based and foam‐like frameworks and of their corresponding coronene‐based hybrids. Investigations in the dispersed phase and in thin‐film by XPS, SEM and FLIM shed light onto the nature of the aromatic stacking within functional rGO frameworks (denoted rGOFs) which was then modelled semi‐empirically and by DFT calculations. The pore sizes of the new emerging reduced graphene oxide hybrids are tuneable at the molecular level and mediated by the bonding forces with the functional porphyrins acting as the "molecular glue". Single crystal X‐ray crystallography described the stacking of a perfluorinated porphyrin with coronene, which can be employed as a molecular model for understanding the local aromatic stacking order and charge transfer interactions within these rGOFs for the first time. This opens up a new route to controllable 3D framework morphologies and pore size from the Ångstrom to the micrometre scale. Theoretical modelling showed that the porosity of these materials is mainly due to the controlled inter‐planar distance between the rGO, coronene or graphene sheets. The host‐guest chemistry involves the porphyrins acting as guests held through π‐π stacking, as demonstrated by XPS. The objective of this study is also to shed light into the fundamental localised electronic and energy transfer properties in these new molecularly engineered porous and fluorogenic architectures, aiming in turn to understand how functional porphyrins may exert stacking control over the notoriously disordered local structure present in porous reduced graphene oxide fragments. By tuning the porosity and the distance between the graphene sheets using aromatic stacking with porphyrins, it is also possible to tune the electronic structure of the final nanohybrid material, as indicated by FLIM experiments on thin films. Such nanohybrids with highly controlled pores dimensions and morphologies open the way to new design and assembly of storage devices and applications incorporating π‐conjugated molecules and materials and their π‐stacks may be relevant towards selective separation membranes, water purification and biosensing applications. [ABSTRACT FROM AUTHOR]

Abstract: Molecular imaging has become a powerful technique in preclinical and clinical research aiming towards the diagnosis of many diseases. In this work, we address the synthetic challenges in achieving lab‐scale, batch‐to‐batch reproducible copper‐64‐ and gallium‐68‐radiolabelled metal nanoparticles (MNPs) for cellular imaging purposes. Composite NPs incorporating magnetic iron oxide cores with luminescent quantum dots were simultaneously encapsulated within a thin silica shell, yielding water‐dispersible, biocompatible and luminescent NPs. Scalable surface modification protocols to attach the radioisotopes 64Cu (t1/2=12.7 h) and 68Ga (t1/2=68 min) in high yields are reported, and are compatible with the time frame of radiolabelling. Confocal and fluorescence lifetime imaging studies confirm the uptake of the encapsulated imaging agents and their cytoplasmic localisation in prostate cancer (PC‐3) cells. Cellular viability assays show that the biocompatibility of the system is improved when the fluorophores are encapsulated within a silica shell. The functional and biocompatible SiO2 matrix represents an ideal platform for the incorporation of 64Cu and 68Ga radioisotopes with high radiolabelling incorporation. [ABSTRACT FROM AUTHOR]

Abstract: The encapsulation of CdSe nanocrystals within single‐walled carbon nanotube (SWNT) cavities of varying dimensions at elevated temperatures under strictly air‐tight conditions is described for the first time. The structures of CdSe nanocrystals under confinement inside SWNTs was established in a comprehensive study, combining both experimental and DFT theoretical investigations. The calculated binding energies show that all considered polymorphs [(3:3), (4:4), and (4:2)] may be obtained experimentally. The most thermodynamically stable structure (3:3) is directly compared to the experimentally observed CdSe structures inside carbon nanotubes. The gas‐phase DFT‐calculated energy difference between “free” 3:3 and 4:2 structures (whereby 3:3 models a novel tubular structure in which both Cd and Se form three coordination, as observed experimentally for HgTe inside SWNT, and 4:2 is a motif derived from the hexagonal CuI bulk structure in which both Cd and Se form 4 or 2 coordination) is surprisingly small, only 0.06 eV per formula unit. X‐ray powder diffraction, Raman spectroscopy, high‐resolution transmission electron microscopy, and energy‐dispersive X‐ray analyses led to the full characterization of the SWNTs filled with the CdSe nanocrystals, shedding light on the composition, structure, and electronic interactions of the new nanohybrid materials on an atomic level. A new emerging hybrid nanomaterial, simultaneously filled and beta‐ d‐glucan coated, was obtained by using pristine nanotubes and bulk CdSe powder as starting materials. This displayed fluorescence in water dispersions and unexpected biocompatibility was found to be mediated by beta‐ d‐glucan (a biopolymer extracted from barley) with respect to that of the individual inorganic material components. For the first time, such supramolecular nanostructures are investigated by life‐science techniques applied to functional nanomaterial characterization, opening the door for future nano‐biotechnological applications. [ABSTRACT FROM AUTHOR]

Functional porphyrins have attracted intense attention due to their remarkably high extinction coefficients in the visible region and potential for optical and energy-related applications. Two new routes to functionalised SWNTs have been established using a bulky ZnII-porphyrin featuring thiolate groups at the periphery. We probed the optical properties of this zinc(II)-substituted, bulky aryl porphyrin and those of the corresponding new nano-composites with single walled carbon nanotube (SWNTs) and coronene, as a model for graphene. We report hereby on: i) the supramolecular interactions between the pristine SWNTs and ZnII-porphyrin by virtue of π-π stacking, and ii) a novel covalent binding strategy based on the Bingel reaction. The functional porphyrins used acted as dispersing agent for the SWNTs and the resulting nanohybrids showed improved dispersibility in common organic solvents. The synthesized hybrid materials were probed by various characterisation techniques, leading to the prediction that supramolecular polymerisation and host-guest functionalities control the fluorescence emission intensity and fluorescence lifetime properties. For the first time, XPS studies highlighted the differences in covalent versus non-covalent attachments of functional metalloporphyrins to SWNTs. Gas-phase DFT calculations indicated that the ZnII-porphyrin interacts non-covalently with SWNTs to form a donor-acceptor complex. The covalent attachment of the porphyrin chromophore to the surface of SWNTs affects the absorption and emission properties of the hybrid system to a greater extent than in the case of the supramolecular functionalisation of the SWNTs. This represents a synthetic challenge as well as an opportunity in the design of functional nanohybrids for future sensing and optoelectronic applications. [ABSTRACT FROM AUTHOR]

This study reports on the supramolecular assemblies formed between planar carbon systems (PCSs) such as thermally reduced graphene oxide (TRGO) and its small-molecule model system coronene and a series of d- and l-α amino acid derivatized naphthalenediimides (NDIs) where the halogen substituents (X = F, Cl, Br, I) are varied systematically. Confocal fluorescence microscopy of NDIs, NDI•coronene, and NDI•TRGO complexes is performed proving the uptake and stability of such complexes in the cellular environment and suggesting their potential as prostate cancer imaging agents. 1H NMR and UV-vis spectroscopy studies support the formation of charge transfer complexes whereby the increasing polarizability and general electronegativity of the aryl halide substituted at the NDI periphery influence the magnitude of the association constants in the ground state between NDI and coronene. Complexation between NDIs and PCSs also results in stable photoexcited assemblies within the solution (coronene) as well as the dispersed phased (TRGO). Fluorescence emission titrations and 2-photon time correlated single photon counting measurements suggest the existence of dynamic quenching mechanisms upon the excitation of the fluorophore in the presence of the carbon substrates, as these methods are sensitive proves for the subtle changes in the NDI environment. The series of halogenated species used exerts supramolecular control over the degree of surface assembly on the TRGO and over the interactions with the coronene molecule, and this is of relevance to the assembly of future biosensing platforms as these materials can both be viewed as congeners of graphene. Finally, MTT assays carried out in PC-3 cells demonstrate that the stable noncovalent functionalization of TRGO and coronene with either l or d NDIs remarkably improves the cellular viability in the presence of such graphene-like materials. These phenomena are of particular relevance for the understanding of the direct donor-acceptor interactions in solutions which govern the design of nanomaterials with future biosensing and bioimaging applications. [ABSTRACT FROM AUTHOR]

Stimulated emission depletion (STED) super‐resolution imaging and multiphoton fluorescence lifetime imaging techniques are used to image the aggregation of ZnII porphyrin arrays onto flat and conductive, as well as insulating, surfaces. New synthetic routes using directed‐ as well as self‐assembling methods of new, luminescent hybrids incorporating these functional porphyrins and pristine single‐walled carbon nanotubes (SWNTs) are reported. Multi‐domain imaging and spectroscopy techniques shed light on the potential implications of the covalent and supramolecular functionalization approaches in solution, dispersion, on surfaces and in the solid state. For more information, see the Full Paper by S. I. Pascu et al. on page 9772 ff. [ABSTRACT FROM AUTHOR]