Search results for "carboranes"
showing 10 items of 15 documents
Synthesis of quadruped-shaped polyfunctionalized o-carborane synthons
2011
[EN] o-Carborane derivatives with precisely defined patterns of substitution have been prepared from 8,9,10,12-I-4-1,2-closo-C2B10H8 by replacing the iodine atoms, bonded to four adjacent boron vertices in the cluster, with allyl, and subsequently 3-hydroxypropyl groups. The resulting structures, comprising four pendant arms and two reactive vertices located on opposite sides of a central o-carborane core, can be envisaged as versatile precursors for dendritic growth
Photoluminescence in Carborane–Stilbene Triads : A Structural, Spectroscopic, and Computational Study
2016
A set of triads in which o- and m-carborane clusters are bonded to two stilbene units through Ccluster -CH2 bonds was synthesized, and their structures were confirmed by X-ray diffraction. A study on the influence of the o- and m- isomers on the absorption and photoluminescence properties of the stilbene units in solution revealed no charge-transfer contributions in the lowest excited state, as confirmed by (TD)DFT calculations. The presence of one or two B-I groups in m-carborane derivatives does not affect the emission properties of the stilbenes in solution, probably due to the rather large distance between the iodo substituents and the fluorophore. Nevertheless, a significant redshift o…
Iodinatedortho-Carboranes as Versatile Building Blocks to Design Intermolecular Interactions in Crystal Lattices
2009
[EN] The crystal structures of numerous iodinated ortho-carboranes have been studied, which has revealed the diversity of intermolecular interactions that these substances can adopt in the solid state. The nature-mostly as it relates to hydrogen and/or halogen bonds-and relative strength of such interactions can be adjusted by selectively introducing substituents onto the cluster, thus enabling the rational design of crystal lattices. In this work we present the newly determined crystal structures of the following iodinated ortho-carboranes: 9-I-1,2-closo-C2B10H11, 4,5,7,8,9,10,11,12-I-8-1,2-closo-C2B10H4, 3,4,5,6,7,8,9,10,11,12-I-10,-1,2-closo-C2B10H2, 1-Me-8,9,10,12-I-4-1,2-closo-C2B10H7,…
Relaxed but highly compact diansa metallacyclophanes.
2011
A series of monoansa [μ-1,1′-PR-3,3′-Co(1,2-C2B9H10)2]− and diansa [8,8′-μ-(1″,2″-benzene)-μ-1,1′-PR-3,3′-Co(1,2-C2B9H9)2]− (R = Ph, tBu) cobaltabisdicarbollidephanes have been synthesized, characterized and studied by NMR, MALDI-TOF-MS, UV-visible spectroscopy, cyclic voltammetry, and DFT calculations. Single crystal X-ray diffraction revealed a highly relaxed structure characterized by the title angle α of 3.8° ([7]−), this being the smallest angle α for a metallacyclophane. In such compounds, the metal-to-phosphorus distance is less than the sum of their van der Waals radii. The availability of a phosphorus lone pair causes an electron delocalization through the metal, as shown by the ab…
Intramolecular Communication in Anionic Oxidized Phosphanes through a Chelated Proton
2015
Oxidation of the 1,2-(PR2 )2 -1,2-closo-C2 B10 H10 (R=Ph, iPr) platform with hydrogen peroxide in acetone is a two-step procedure in which partial deboronation of the closo cluster and oxidation of the phosphorus atoms occur. Based on NMR spectroscopic and kinetic data, we demonstrate that the phosphorus atoms are oxidized in the first step, followed by cluster deboronation. DFT calculations and natural-bond orbital (NBO) analysis were used to obtain insight into the electronic structures of diphosphane ortho-carborane derivatives.
Adsorptive Separation of CO2 by a Hydrophobic Carborane-Based Metal-Organic Framework under Humid Conditions
2023
We report that the carborane-based metal-organic framework (MOF) mCB-MOF-1 can achieve high adsorptive selectivity for CO2:N2 mixtures. This hydrophobic MOF presenting open metal sites shows high CO2 adsorption capacity and remarkable selectivity values that are maintained even under extremely humid conditions. The comparison of mCB-MOF-1' with MOF-74(Ni) demonstrates the superior performance of the former under challenging moisture operation conditions.
Design of carborane molecular architectures with electronic structure computations: From endohedral and polyradical systems to multidimensional netwo…
2009
11 pags, 6 figs. -- 19th International Conference on Physical Organic Chemistry (ICPOC-19) 13–18 July 2008, Santiago de Compostela, Spain
A Discrete P⋅⋅⋅II⋅⋅⋅P Assembly: The Large Influence of Weak Interactions on the31P NMR Spectra of Phosphane–Diiodine Complexes
2006
Thioethers, except derivatives of [7-R-7,8-C2B9H11] , are more weakly coordinating ligands than phosphanes. This difference is evidenced by the I I distances in the spokeshaped charge-transfer (CT) complexes R2S·I2 and R3P·I2 (Figure 1). The I I distance is sensitive to the strength of the interaction between the s* LUMO orbital on I2 and the HOMO orbital of the donor atom: the stronger the donor, the longer the I I distance. In these spoke CT complexes, the I I distance varies from 3.2 0.2 7 in R3P·I2 adducts [5] to 2.80 0.05 7 in R2S·I2 adducts, [6] indicating the weaker donor character of the thioether group. Whereas extended I2 arrays, spoke adducts of I2, polyiodides, and other structu…
Icosahedral carboranes as scaffolds for congested regioselective polyaryl compounds: the distinct distance tuning of C–C and its antipodal B–B
2019
Four-fold aryl substituted o-carborane derivatives with defined patterns of substitution at the antipodal region of the cluster carbon atoms have been achieved. It is proven that this region is congested but lacks steric hindrance. Also, the two antipodal sites Cc–Cc and B9–B12 are affected very distinctly by electron donor substituents.
Towards purely inorganic clusters in medicine: Biocompatible divalent cations as counterions of cobaltabis(dicarbollide) and its iodinated derivatives
2021
Monovalent cations, Cs+, and alkylammonium ([NR4]+) salts have traditionally been used to precipitate the anions of boranes, carborane and metallocarborane clusters. In contrast, in the body and in living organisms in general, divalent cations have a special relevance. In this work, we isolate for the first time the cobaltabis(dicarbollide) salts of the biocompatible divalent cations of biological importance that can have application both in biology and in materials science. The preparation of Ca2+, Mg2+ and Fe2+ salts of anionic iodinated nido-[C2B9H12]− and cobaltabis(dicarbollide) as well as its di-, tetra- and octa-iodinated derivatives are reported. Ca2+ and Mg2+ are hard Lewis acids a…