Publications by authors named "Guilherme M D M Rubio"

Acyclic diamino carbenes (ADCs) are interesting alternatives to their more widely studied N-heterocyclic carbene counterparts, particularly due to their greater synthetic accessibility and properties such as increased sigma donation and structural flexibility. ADC gold complexes are typically obtained through the reaction of equimolar amounts of primary/secondary amines on gold-coordinated isocyanide ligands. As such, the reaction of diamine nucleophiles to isocyanide gold complexes was expected to lead to bis-ADC gold compounds with potential applications in catalysis or as novel precursors for gold nanomaterials.

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Self-assembly processes guide disordered molecules or particles into long-range organized structures due to specific supramolecular interactions among the building entities. Herein, we report a unique evaporation-induced self-assembly (EISA) strategy for four different silica nanoparticle systems obtained through peptide functionalization of the particle surface. First, covalent peptide-silica coupling was investigated in detail, starting with the grafting of a single amino acid (L-serine) and expanded to specific small peptides (up to four amino acids) and transferred to different particle types (MCM-48-type MSNs, solid nanoparticles, and newly developed virus-like nanoparticles).

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Most of potential diagnostic and therapeutic nanoparticles fail to reach clinical trials because assessment of their 'drug-like' properties is often overlooked during the discovery stage. This compromises the results of cell culture and animal experiments, making them insufficient to evaluate the lead candidates for testing on patients. In this study, we demonstrate the potential of high-resolution inductively coupled plasma mass spectrometry (ICP-MS) as a nanoparticle qualification tool.

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N-heterocyclic carbenes (NHCs) have received significant attention as gold nanoparticle stabilizers due to their strong binding affinity towards gold. However, their tunability is limited by the difficulty in obtaining nonsymmetric NHCs. In this regard, N-acyclic carbenes (NACs) are attractive alternatives due to their high synthetic versatility, allowing easy tuning of their steric and electronic properties towards specific applications.

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Solvothermal reactions between a pyridine based amide functionalized dicarboxylic acid, 4,4'-{(pyridine-2,6-dicarbonyl)bis(azanediyl)}dibenzoic acid (H2L), and zinc(ii) nitrate in the absence and presence of a base produced the binuclear metallomacrocyclic compound [Zn2(L)2(H2O)4]·2(H2O)·6(DMF) (1) and the metallomacrocyclic based two dimensional MOF [Zn5(L)4(OH)2(H2O)4]n·8n(DMF)·4n(H2O) (2), respectively. Compound 1 bears two tetrahedral Zn(ii) centres, whereas the 2D framework 2 includes a penta-nuclear Zn(ii) cluster as a secondary building block unit, with two of the metal cations assuming a tetrahedral type geometry and the remaining three an octahedral type geometry. The topological analyses reveal that compound 1 has a 2-connected uninodal net and framework 2 has a 2, 8-connected binodal net.

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Article Synopsis
  • A pyridine-based amide functionalized tetracarboxylic acid, known as HL, was synthesized and explored for its interactions with zinc(II) and cadmium(II) ions, leading to the development of two different 2D coordination polymers.
  • These polymers were thoroughly characterized using various techniques including elemental analysis and X-ray diffraction, revealing distinct coordination environments around the metal ions: tetrahedral for Zn and octahedral/pentagonal bipyramidal for Cd.
  • Both coordination polymers demonstrated catalytic abilities for deacetalization-Knoevenagel condensation reactions while maintaining stability for multiple uses, showcasing their potential as efficient heterogeneous catalysts in chemical processes.
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N-Heterocyclic carbene-stabilized metal nanoparticles have drawn much attention over the last decade due their strong carbon metal bond. Although several reports show increased stability of such N-heterocyclic carbene-stabilized metal nanoparticles, only limited examples of water-soluble N-heterocyclic carbene stabilized metal nanoparticles are known to date. However, water dispersibility and stability in biologically relevant solvents would be a prerequisite for any biological applications.

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Although N-heterocyclic carbenes (NHCs) have been demonstrated as suitable ligands for the stabilisation of gold nanoparticles (AuNPs) through a variety of methods, the manner in which such AuNPs form is yet to be fully elucidated. We report a simple and fast one-step synthesis of uniform chiral (l/d)-histidin-2-ylidene stabilised gold nanoparticles using the organometallic Au(i) complex as a well defined starting material. The resulting nanoparticles have an average size of 2.

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The reactions of 3,3'-{(pyridine-2,6-dicarbonyl)bis(azanediyl)}dibenzoic acid (HL) with zinc(II), cadmium(II), and samarium(III) nitrates were studied, and the obtained compounds, [Zn(1κ:2κ-L)(HO)] (), [Cd(1κ :2κ -L)(HO)] 6 HO  CHO 1.5 DMF (), and [Sm(1κ:2κOO:3κ-L)(NO)(HO)(dmf)]  DMF (), were characterized by elemental analysis, FTIR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction. Compounds and have 1D zigzag- and double-chain-type structures, respectively, whereas features a dinuclear metallomacrocyclic complex.

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Five isostructural lanthanide MOFs, [Ln(1κOO',2κO'',3κO''',4κO''''-μ-L)(NO)(DMF)]·n(DMF) {Ln = La (1), Ce (2), Nd (3), Sm (4) and Dy (5); L = 5-[2-{2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene}hydrazinyl]isophthalate; DMF = N,N'-dimethyl formamide}, based on dicarboxyl-functionalized arylhydrazone of barbituric acid were synthesized under solvothermal conditions. They were characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric and X-ray diffraction analyses. Crystal structure analysis revealed that these frameworks possess a similar type of two dimensional (2D) structure with a dinuclear {Ln(COO)} unit acting as a secondary building block.

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