Two novel boron-based flexible scorpionate ligands based on 7-azaindole, Li[HB(azaindolyl)(2)(1-naphthyl)] and Li[HB(azaindolyl)(2)(mesityl)] {Li[(Naphth)Bai] and Li[(Mes)Bai] respectively}, have been prepared (mesityl = 2,4,6-trimethylphenyl). These salts have been isolated in two forms, either as dimeric structures which contain bridging hydride interactions with the lithium centres or as crystalline material containing mono nuclear bis-acetonitrile solvates. The newly formed ligands have been utilised to prepare a range of group nine transition metal complexes with the general formula [M(COD){κ(3)-NNH-HB (azaindolyl)(2)(Ar)}] (where M = rhodium, iridium; Ar = 1-naphthyl, mesityl; COD = 1,5-cyclooctadiene) and [Rh(NBD){κ(3)-NNH-HB (azaindolyl)(2)(Ar)}] (where NBD = 2,5-norbornadiene; Ar = 1-naphthyl, mesityl). These new complexes have been compared to the previously reported compounds which contain the related scorpionate ligands Li[HB(azaindolyl)(2)(phenyl)] and K[HB(azaindolyl)(3)] {Li[(Ph)Bai] and K[Tai] respectively}. Structural characterisation of the complexes [Rh(COD){κ(3)-NNH-HB (azaindolyl)(2)(mesityl)}], [Ir(COD){κ(3)-NNH-HB (azaindolyl)(2)(mesityl)}] and [Rh(NBD){κ(3)-NNH-HB (azaindolyl)(2)(naphthyl)}] confirm the expected κ(3)-NNH coordination mode for these new ligands. Spectroscopic analysis suggests strong interactions of the B-H functional group with the metal centres in all cases.
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http://dx.doi.org/10.1039/c0dt01576h | DOI Listing |
Molecules
December 2024
Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Complesso Universitario di Monserrato, S.P. 8 Km 0.700, I-09042 Monserrato, Italy.
By combining Er and Yb ions with 3,6-dithiophene-anilate (ThAn) and scorpionate hydrotris(pyrazol-1-yl)borate (HBpz) ligands new luminescent dinuclear complexes are obtained. The two materials formulated as [((HB(pz))Yb)(μ-thAn)]·4DCM·1.3HO and [((HB(pz))Er)(μ-thAn)]·4DCM·1.
View Article and Find Full Text PDFMolecules
November 2024
Escola Superior de Tecnologia do Barreiro, Instituto Politécnico de Setúbal, Rua Américo da Silva Marinho, 2839-001 Lavradio, Portugal.
Cancer remains a formidable challenge, requiring the constant pursuit of novel therapeutic agents and strategies. Scorpionates, known for their unique coordination properties, have recently gained attention for their anticancer potential. Traditionally applied in catalysis, these compounds have demonstrated notable cytotoxicity across various cancer cell lines, often surpassing the efficacy of conventional chemotherapeutics.
View Article and Find Full Text PDFInorg Chem
December 2024
Institute of Inorganic Chemistry (AOC), Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, Karlsruhe 76131, Germany.
A series of seven-coordinated monoporphyrinate rare-earth(III) complexes featuring a novel tripodal tin-chelated trisphosphineoxide scorpionate ligand with the general formula [(TPP)Ln(PPhO)Sn] (Ln = Y, La, Dy, Er, Ho, Yb; TPP = 5,10,15,20-tetraphenylporphyrinate) were synthesized by reactions of the potassium tripodal scorpionate ligand [Sn(PPhO)K] with porphyrinate rare-earth metal chlorides [(TPP)LnCl(dme)] (Ln = Y, Dy, Er, Ho, Yb) or porphyrinate lanthanum borohydride [(TPP)LaBH(thf)]. The complexes were characterized by single-crystal X-ray diffraction, NMR spectroscopy, and ion mobility mass spectrometry. All complexes emit weak red TPP-based fluorescence, accompanied by near-infrared emission of Er, Ho (rather weak), and Yb (relatively intense with a quantum yield of 1% in dichloromethane solution) of the corresponding complexes.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Universidad Rey Juan Carlos, Departamento de Biología y Geología, Física y Química Inorgánica, Móstoles, 28933, Madrid, Spain.
Scorpionate ligands have emerged as pivotal components in the field of coordination chemistry and catalysis since the seminal work by Trofimenko in the late 1960s. These species have demonstrated an extraordinarily rich tridentate coordination chemistry, enhancing the stability of metal complexes. In addition, they offer the possibility of modifying the chemical and electronical features as κ-ligands, providing a wide variety of potential substrates with multiple donor atoms.
View Article and Find Full Text PDFEJNMMI Radiopharm Chem
November 2024
Department of Nuclear Medicine, Odense University Hospital, Kløvervaenget 47, Odense, DK-5000, Denmark.
Background: The highly potent Auger electron emitter antimony-119 (Sb) and the SPECT-isotope antimony-117 (Sb) comprise a true theranostic pair particularly suitable for cancer theranostics. Harnessing this potential requires development of a chelator that can rapidly form a stable complex with radioactive antimony ions at the low concentrations typical of radiopharmaceutical preparations. Stable Sb(III) complexes of hydrotris(methimazolyl)borate (TMe) are known, prompting our investigation of this chelator.
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