Funcionalització d'o-carborans iodats per obtenir estructures dendrimèriques útils en aplicacions mèdiques

L'1,2-dicarba-closo-dodecaborà, l'o-carborà, és un clúster icosaèdric format per deu vèrtexs de bora–hidrogen i dos vèrtexs de carboni–hidrogen en posició adjacent. Aquesta molècula és químicament molt versàtil, ja que presenta una reactivitat diferenciada segons el tipus de vèrtex, la qual cosa en permet la derivatització en funció de l'aplicació mèdica desitjada. Al nostre grup de recerca, tenim una gran experiència en reaccions de substitució electrofílica sobre els àtoms de bor, sobretot per tal d'obtenir derivats B-iodats de l'o-carborà que continguin un elevat nombre d'àtoms de iode per molècula. Aquesta condició els converteix en bons candidats per ser usats com a agents de contrast opacs als raigs X en ciments ossis polimèrics de metilmetacrilat. Els enllaços de bor–iode d'aquests carborans poden ser posteriorment derivatitzats amb diferents grups orgànics funcionals, tot formant nous vèrtex de bor– carboni i obtenint, així, molècules útils com a nuclis d'estructures de tipus dendró. El creixement dendrimèric d'aquests nuclis es du a terme mitjançant reaccions d'acoblament amb altres clústers de carborà funcionalitzats, tot obtenint molècules amb un elevat contingut en àtoms de bor, molt útils com a agents anticancerosos en la tècnica BNCT (Boron Neutron Capture Therapy).The 1,2-dicarba-closo-dodecaborane, o-carborane, is an icosahedral cluster consisting of ten boron-hydrogen vertices and two carbon-hydrogen adjacent vertices. This molecule is chemically versatile, has a differential reactivity depending on the type of vertex, and this enables the functionalization according to the desired medical application. Our research group has extensive experience in electrophilic substitution reactions on the boron atoms, especially to obtain boron-iodinated carborane derivatives, which contain a large number of iodine atoms per molecule. This condition makes them good candidates for use as X-ray contrast agents in methyl methacrylate bone cements. These boron-iodine bonds may be subsequently functionalized with various organic functional groups forming new boron-carbon vertices and producing useful molecules as dendron nuclei. The growth of these dendrimeric cores is carried out by coupling reactions with other functionalized carboranes yielding molecules with high boron content, useful as anticancer agents in BNCT (Boron Neutron Capture Therapy)

Negatively charged metallacarborane redox couples with both members stable to air

It was possible to synthesize and isolate redox couples in which both partners are negatively charged. The handy framework is [3,3'-Co(1,2-closo-C2B9H11)2]-. The E½ potential can be tuned by adjusting the nature and number of substituents on B and C. The octaiodinated species [3,3'-Co(1,2-closo-C2B9H7I4)2]- is the most favorable as it is isolatable and stable in air

Metal·locarborans i biologia molecular: la sorprenent interacció de dos mons aparentment independents

La capacitat d'autoassemblatge dels metal·locarborans ha estat molt investigada recentment. La seva habilitat per formar membranes monocapa ens induí a l'estudi de la interacció d'aquestes membranes sintètiques amb membranes biològiques. Aquest treball evidencia que l'anió cobaltabisdicarballur, [3,3'-Co(C2B9H11)2]− (COSAN), i el seu derivat diiodat, [3,3'-Co(8-I-C2B9H10)2]− (I2-COSAN), poden interaccionar amb membranes biològiques i creuar-les, de manera que s'acumulen a l'interior de cèl·lules vives. En aplicar aquests compostos a diferents tipus de cèl·lules en cultiu, s'indueix una inhibició completa, però alhora reversible, de la proliferació cel·lular, amb una recuperació total de l'activitat de divisió cel·lular un cop extret el metal·locarborà del medi.Metallacarborane’s self-assembly has been recently widely investigated. Its ability to form monolayer membranes led us to study the interaction of these synthetic membranes with biological membranes. This work evidences that the cobaltibisdicarbollide anion, [3,3’-Co(C2B9H11)2]− (COSAN), and its di-iodinated derivative, [3,3’-Co(8-I-C2B9H10)2]− (I2-COSAN), can interact with biological membranes and cross them, accumulating inside living cells. When applying these compounds to different cells in culture, complete but reversible cell proliferation suppression is induced, with a total recovery of the cell division activity after removal of the metallacarborane from the media

Redox-Active Metallacarborane-Decorated Octasilsesquioxanes. Electrochemical and Thermal Properties

Polyanionic and electroactive hybrids based on octasilsesquioxanes bearing metallacarborane units are developed. They show remarkable solubility in organic solvents and outstanding thermal stability. The metallacarboranes act as independent units simultaneously undergoing the reversible redox process.We acknowledge support by MINECO [Grants CTQ2013- 44670-R, CTQ2012-32436, and CTQ2015-64436-P and the “Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2015-0496)] and Generalitat de Catalunya (Grant 2014/ SGR/149). J.C.-G. thanks to the CSIC for an intramural grant. V.S.-A. thanks MICINN (Grant CTQ2010-16237) for the FPI grant.Peer reviewe

Reversibly Switchable Fluorescent Molecular Systems Based on Metallacarborane-Perylenediimide Conjugates

Altres ajuts: Universitat Autònoma de Barcelona predoctoral PIF fellowshipIcosahedral metallacarboranes are θ-shaped anionic molecules in which two icosahedra share one vertex that is a metal center. The most remarkable of these compounds is the anionic cobalt-based metallacarborane [Co(CBH)], whose oxidation-reduction processes occur via an outer sphere electron process. This, along with its low density negative charge, makes [Co(CBH)] very appealing to participate in electron-transfer processes. In this work, [Co(CBH)] is tethered to a perylenediimide dye to produce the first examples of switchable luminescent molecules and materials based on metallacarboranes. In particular, the electronic communication of [Co(CBH)] with the appended chromophore unit in these compounds can be regulated upon application of redox stimuli, which allows the reversible modulation of the emitted fluorescence. As such, they behave as electrochemically-controlled fluorescent molecular switches in solution, which surpass the performance of previous systems based on conjugates of perylendiimides with ferrocene. Remarkably, they can form gels by treatment with appropriate mixtures of organic solvents, which result from the self-assembly of the cobaltabisdicarbollide-perylendiimide conjugates into 1D nanostructures. The interplay between dye π-stacking and metallacarborane electronic and steric interactions ultimately governs the supramolecular arrangement in these materials, which for one of the compounds prepared allows preserving the luminescent behavior in the gel state

Diethyl 2,2'-[1,3-phenylenebis(methylthio)]dibenzoate

The title molecule, C26H26O4S2, assumes C2 symmetry with two C atoms and two H atoms of the central phenyl ring located on the twofold axis. The S atoms are synplanar with the benzene moiety, so the observed geometry is suitable for CS2 coordination. The o-(ethoxycarbonyl)phenylthiomethyl moiety is approximately planar and its orientation is almost perpendicular with respect to the central phenyl group

Di- and triheteronuclear metal cluster anions containing transition metals

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24896/1/0000323.pd

Bis[1,3-bis(2-hydroxyphenyl)-1,3-propanedionato]bis(ethanol)zinc(II), C34H34O10Zn

Mr=668.0, triclinic, P1, a=13.028 (2), b=11.872(2), c=10.971(2) A, a=102.28 (1), β = 87.14(1), a=112.53(2)º, V = 1530.6(7)A3, Z = 2, Dx = 1.45 Mg m-3, (Mo Ka)=0.71069 A, µ= 0.889 mm-1, F(000)=696, T=295 K. Final R = 0.06 for 3025 observed reflections. The structure consists of chains of molecules parallel to [011] linked by hydrogen bonds. The Zn2+ ion is surrounded by six O atoms in a distorted octahedral shape. The 1,3-bis(2-hydroxyphenyl)-1,3, propanedionato anions act as bidentate ligands. The six-membered Zn-propanedione rings have half-chair form