Fluorescent Sulfonate-Based Inorganic-Organic Hybrid Nanoparticles for Staining and Imaging.

Sulfonate-based inorganic-organic hybrid nanoparticles (IOH-NPs) with the general saline composition [Gd(OH)]2+n/2[ Rdye(SO3) n] n- showing optical absorption and emission in the blue to red spectral regime are presented for the first time. All IOH-NPs are prepared via straightforward aqueous synthesis and instantaneously result in colloidally highly stable suspensions with mean particle diameters of 40-50 nm and high zeta potentials (-20 to -40 mV at pH 7.0). Specifically, the IOH-NPs comprise [Gd(OH)]2+2[CSB]4-, [Gd(OH)]2+2[DB71]4-, [Gd(OH)]2+[NFR]2-, [Gd(OH)]2+[AR97]2-, and [Gd(OH)]2+2[EB]4- showing blue, orange, red, and infrared absorption and emission ([CSB]: Chicago Sky Blue; [DB71]: Direct Blue 71; [NFR]: Nuclear Fast Red; [AR97]: Acid Red 97; [EB]: Evans Blue). The novel IOH-NPs are characterized by electron microscopy, dynamic light scattering, infrared spectroscopy, energy-dispersive X-ray analysis, thermogravimetry, elemental analysis, and fluorescence spectroscopy. In vitro studies based on HeLa and HUVEC cells were exemplarily performed with [Gd(OH)]2+2[EB]4- IOH-NPs and show intense fluorescence and only moderate toxicity at concentrations of 1 to 10 µg/mL. Based on aqueous synthesis, good colloidal stability, absence of severely toxic metals (e.g., Cd2+, Pb2+), use of molecular dyes that are already known for staining in cell biology and histology, extremely high dye load per nanoparticle (70-80 wt %), and blue to red absorption and fluorescence, the sulfonate-based IOH-NPs can be highly interesting for staining, fluorescence microscopy, and optical imaging.

Saline hybrid nanoparticles with phthalocyanine and tetraphenylporphine anions showing efficient singlet-oxygen production and photocatalysis.

The inorganic-organic hybrid nanoparticles Gd43+[AlPCS4]34- and La43+[TPPS4]34- ([AlPCS4]4-: aluminium(iii) chlorido phthalocyanine tetrasulfonate; [TPPS4]4-: tetraphenylporphine sulfonate) are shown for the first time. Both were obtained via aqueous synthesis and contain extremely high contents of [AlPCS4]34- (81 wt%) and [TPPS4]34- (83 wt%). They show efficient singlet oxygen (1O2) production upon daylight and red-light irradiation. Photocatalysis is evidenced via dye degradation as a proof-of-the-concept and proceeds with daylight and even red-light illumination.

A highly luminescent octanuclear gold(i) carbide cluster.

The ligand [{Me3SiC[triple bond, length as m-dash]CC(NDipp)2}Li(thf)3] (Dipp = 2,6-diisopropylphenyl) was used for salt metathesis reactions with [AuCl(tht)] (tht = tetrahydrothiophene) to obtain the dinuclear alkyne functionalized bisamidinate [{Me3SiC[triple bond, length as m-dash]CC(NDipp)2}2Au2]. This compound serves as a building block for the polynuclear carbide bridged gold(i) amidinate complex [Au8{µ3-(η1:η2-C[triple bond, length as m-dash]C)}2(Me3SiC[triple bond, length as m-dash]CC(NDipp)2)4(tht)2], which is the first gold(i) complex with a µ3-η1:η2 carbide coordination. Both gold(i) compounds show distinct aurophilic interactions and are remarkably stable at ambient conditions. Photophysical investigations revealed intense luminescence with notable high quantum yields both in the solid state and in solution.

Bright luminescence in lanthanide coordination polymers with tetrafluoroterephthalate as a bridging ligand.

Ten new coordination polymers of the general compositions ∞²[Ln(III)(tfBDC)(NO3)(DMF)2]·DMF with Ln(III) = Eu(3+) (1), Gd(3+) (2), Tb(3+) (3), Ho(3+) (4), Tm(3+) (5), ∞²[Ln(III)(tfBDC)(CH3COO)(FA)3]·3FA with Ln(III) = Sm(3+) (6), Eu(3+) (7) and ∞²[Ln(III)(tfBDC)(NO3)(DMSO)2] with Ln(III) = Ho(3+) (8), Er(3+) (9) and Tm(3+) (10) were synthesized and structurally characterized by X-ray single crystal diffraction (tfBDC(2-) = 2,3,5,6-tetrafluoroterephthalate, DMF = N,N'-dimethylformamide, FA = formamide, DMSO = dimethyl sulfoxide). 1-5 crystallize in the monoclinic space group C2/c with Z = 8, 6 and 7 in P1̄ with Z = 2 and 8-10 in Pbca with Z = 8. All crystal structures contain binuclear lanthanide nodes that are connected by 2,3,5,6-tetrafluoroterephthalates (tfBDC(2-)) to form two-dimensional polymeric structural units. Despite this common structural feature the coordination within these binuclear units is quite different in detail, e.g. CN = 9 for 1-7 and CN = 8 for 8-10. The emission spectra of the europium (1, 7) and terbium (3) compounds reveal bright red and green emission in the visible region. The resulting high quantum yields of 53% (1) and 67% (3) at room temperature show that the replacement of organic ligands with C-H groups by perfluorinated ligands leads to compounds with intense emission, as vibrational quenching is reduced. On the other hand, the influence of the coordinating solvent and additional ligands cannot be neglected, as the replacement of DMF by FA and NO3(-) by CH3COO(-) in 7 leads to a reduced quantum yield of only 10%. Thermoanalytical investigations show that all compounds are stable up to 100-150 °C, before a stepwise release of solvent molecules starts followed by a decomposition of the coordination polymer.