Multimetallic Complexes and Functionalized Nanoparticles Based on Unsymmetrical Dithiocarbamate Ligands with Allyl and Propargyl Functionality

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A robust dithiocarbamate tether allows novel gadolinium units based on DOTAGA (q=1) to be attached to the surface of gold nanoparticles (2.6–4.1 nm diameter) along with functional units offering biocompatibility, targeting and photodynamic therapy. A dramatic increase in relaxivity (r1) per Gd unit from 5.01 mm−1 s−1 in unbound form to 31.68 mm−1 s−1 (10 MHz, 37 °C) is observed when immobilised on the surface due to restricted rotation and enhanced rigidity of the Gd complex on the nanoparticle surface. The single‐step synthetic route provides a straightforward and versatile way of preparing multifunctional gold nanoparticles, including examples with conjugated zinc–tetraphenylporphyrin photosensitizers. The lack of toxicity of these materials (MTT assays) is transformed on irradiation of HeLa cells for 30 minutes (PDT), leading to 75 % cell death. In addition to passive targeting, the inclusion of units capable of actively targeting overexpressed folate receptors illustrates the potential of these assemblies as targeted theranostic agents.

Section: Introductionmentioning

confidence: 99%

Combined Magnetic Resonance Imaging and Photodynamic Therapy Using Polyfunctionalised Nanoparticles Bearing Robust Gadolinium Surface Units

Chabloz

Perry

Yoon

et al. 2020

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“…Since 2008, we have focused on the functionalisation of gold nanoparticles (GNPs) with transition metal units . Much of this work has focused on the use of dithiocarbamate (R 2 NCS 2 − ) tethers rather than the usual thiol(ate) or disulfide attachment methodologies.…”

Section: Introductionmentioning

confidence: 99%

“…Since 2008, we have focusedo nt he functionalisation of gold nanoparticles (GNPs) with transition metal units. [14][15][16][17][18] Much of this work has focusedo nt he use of dithiocarbamate (R 2 NCS 2 À )tethers rather than the usual thiol(ate) or disulfide attachment methodologies. Competition experiments by us [19] and others [20] have shown that dithiocarbamates are able to displace thiol(ate)s from the surface of the nanoparticle, but not vice versa.…”

Section: Introductionmentioning

confidence: 99%

Polyfunctionalised Nanoparticles Bearing Robust Gadolinium Surface Units for High Relaxivity Performance in MRI

Chabloz

Wenzel

Perry

et al. 2019

The first example of an octadentate gadolinium unit based on DO3A (hydration number q=1) with a dithiocarbamate tether has been designed and attached to the surface of gold nanoparticles (around 4.4 nm in diameter). In addition to the superior robustness of this attachment, the restricted rotation of the Gd complex on the nanoparticle surface leads to a dramatic increase in relaxivity (r1) from 4.0 mm−1 s−1 in unbound form to 34.3 mm−1 s−1 (at 10 MHz, 37 °C) and 22±2 mm−1 s−1 (at 63.87 MHz, 25 °C) when immobilised on the surface. The one‐pot synthetic route provides a straightforward and versatile way of preparing a range of multifunctional gold nanoparticles. The incorporation of additional surface units for biocompatibility (PEG and thioglucose units) and targeting (folic acid) leads to little detrimental effect on the high relaxivity observed for these non‐toxic multifunctional materials. In addition to the passive targeting attributed to gold nanoparticles, the inclusion of a unit capable of targeting the folate receptors overexpressed by cancer cells, such as HeLa cells, illustrates the potential of these assemblies.

“…Although hydrophilic alkynes thus appear to be ideally suited to this study, the intrinsic nucleophilicity of their polar groups towards transition metals needs to be taken into account. Several studies have shown the preference of ruthenium and osmium triphenylphosphine hydride complexes to react with nucleophilic oxygen‐, nitrogen‐ and sulfur‐donor groups, even in the presence of terminal alkynes . Thus, when both functionalities are present on the same ligand, the alkyne insertion seems often to be less favoured compared to coordination of the other donors, especially when a bidentate chelate results …”

Section: Resultsmentioning

confidence: 99%

“…Several studies have shown the preferenceo fr uthenium and osmium triphenylphosphineh ydride complexes to react with nucleophilic oxygen-,n itrogen-and sulfur-donor groups,e ven in the presenceo ft erminal alkynes. [39,40] Thus, when both functionalities are present on the same ligand,t he alkyne insertions eems often to be less favouredc ompared to coordination of the other donors, especially when ab identate chelate results. [40,41] For theser easons, terminal alkynes were designed to possess hydrophilic properties combined with an absence of nucleophilic character.T he inexpensive 4-ethynylbenzyl alcohol was thus coupled to ap olyethylene glycol( PEG) chain via a simple esterification reaction.…”

Section: Detection Of Co In Cellsmentioning

confidence: 99%

Highly Sensitive and Selective Molecular Probes for Chromo‐Fluorogenic Sensing of Carbon Monoxide in Air, Aqueous Solution and Cells

Toscani

Marín‐Hernández

Robson

et al. 2019

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Optical sensing offers a low‐cost and effective means to sense carbon monoxide in air and in solution. This contribution reports the synthesis of a new series of vinyl complexes [Ru(CH=CHR)Cl(CO)(TBTD)(PPh3)2] (R=aryl, TBTD=5‐(3‐thienyl)‐2,1,3‐benzothiadiazole) and shows them to be highly sensitive and selective probes for carbon monoxide in both solution and air. Depending on the vinyl substituent, chromogenic and fluorogenic responses signalled the presence of this invisible, odourless, tasteless and toxic gas. Adsorbing the complexes on silica produced colorimetric probes for the ′naked eye′ detection of CO in the gas phase with a limit of detection as low as 8 ppm in some cases, while the release of the TBTD fluorophore allowed detection at much lower concentrations through the fluorescence response. Structural data were obtained by single‐crystal X‐ray diffraction techniques, while the photophysical behaviour was explored computationally using TD‐DFT experiments. The systems were also shown to be selective for CO over all other gases tested, including water vapour and common organic solvents. By introducing a poly(ethylene)glycol chain to the vinyl functionality, water compatibility was achieved and these non‐cytotoxic complexes were employed in the sensing of CO in HeLa cells, offering a simple and rapid system for sensing this gasotransmitter in this challenging medium.