Reactions in ultra-small droplets by tip-assisted chemistry

The confinement of chemical reactions within small droplets has received much attention in the last few years. This approach has been proved successful for the in-depth study of naturally occurring chemical processes as well as for the synthesis of different sets of nanomaterials with control over their size, shape and properties. Different approaches such as the use of self-contained structures or microfluidic generated droplets have been followed over the years with success. However, novel approaches have emerged during the last years based on the deposition of femtolitre-sized droplets on surfaces using tip-assisted lithographic methods. In this feature article, we review the advances made towards the use of these ultra-small droplets patterned on surfaces as confined nano-reactors

Design and Synthesis of a Noninnocent Multitopic Catechol and Pyridine Mixed Ligand : Nanoscale Polymers and Valence Tautomerism

The design and synthesis of a new redox-active ligand combining catechol and pyridine units have allowed the achievement of cobalt-based nanoscale coordination polymer particles in a single-step exhibiting a switchable valence tautomeric behavior and thermal hysteresis. The combination of polymerizing capabilities with redox-active responses in a unique ligand leads to the formation of nanoparticles exhibiting a gradual valence tautomeric interconversion in the 35-370 K temperature range. Using one single ligand to obtain these nanoparticles facilitates possible nanostructure formation methodologies. (Chemical Equation Presented)

Antitumour activity of coordination polymer nanoparticles

Altres ajuts: the ICN2 is funded by the CERCA programme / Generalitat de Catalunya.Nanoscale coordination polymers (NCPs) have fascinated researchers over the last years. Their intrinsic theranostic properties of metal ions and organic ligands, the encapsulation of several drugs/biomolecules with excellent yields and the surface functionalisation, enhancing their biocompatibility and targeting, have remarkably impacted in prospective drug delivery alternatives in medicine. Moreover, the properties and characteristics of these nanoparticles (NPs) can be fine-tuned thanks to the synthetic flexibility of coordination chemistry. For all these reasons, the number of examples published has grown exponentially over the last years, embracing different disciplines such as molecular electronics, sensors or nanomedicine, among others. Specifically, significant advances in antitumoural applications are reported, one of the areas where this novel family of NPs has experienced a considerable advance. NCPs have accomplished a high sophistication degree and efficiency as theranostic nanoplatforms (i.e., drug delivery carriers and bioimaging probes) with long residence time in the bloodstream, targeting capacities and remarkable cellular internalisation. In this review, an introduction emphasizing the advantages of NPs for cancer treatment is included. Later on, the most representative examples of NCPs for antitumoural applications are described grouped into six mean representative areas: i) encapsulation approaches, ii) stimuli-responsive NCPs, iii) metal chemotherapy, iv) photodynamic therapy (PDT), v) unconventional therapeutic approaches and vi) theranostics. Particular emphasis is given to understand the encapsulation/release properties of these particles at the nanoscale and their interaction with biological environments, highlighting any limitation and challenges that these systems are facing from a clinical translation perspective and envisioning possible future trends and areas that will deserve further attention for the following years

Síntesis de nuevos catecoles como precursores de materiales adhesivos bioinspirados

En nuestro grupo de investigación y en colaboración con el Doctor Daniel Ruiz-Molina del Centro de Investigación en Nanociencia y Nanotecnología (CIN2) de este campus universitario, hemos iniciado un proyecto que se plantea lograr biomimetizar ciertas proteínas adhesivas de moluscos, cuya adherencia se debe a la presencia de la funcionalidad catecol. El objetivo es poder desarrollar nuevos materiales adhesivos basados en esa funcionalidad, siendo necesaria por lo tanto el desarrollar protocolos sintéticos para la obtención de compuestos tipo catecol convenientemente sustituidos. Concretamente, en el presente trabajo de Master en Experimentación Química se ha conseguido la síntesis de los nuevos catecoles 1 y 2, que incorporan en su estructura una cadena alquílica acabada con la funcionalidad tiol, con el fin de poder desarrollar más adelante superficies o nanopartículas de oro adhesivas. Para la síntesis del 4-(3'-mercaptopropil)catecol 1 se ha puesto a punto una ruta de obtención partiendo del producto comercial eugenol, consistente en 3 etapas sintéticas y con un rendimiento global cercano al 70%. También se ha desarrollado una ruta sintética para el 4-(7'-mercaptopropil)catecol 2 que parte del 3,4-dimetoxibenzaldehído, y consta de 6 etapas, presentando un rendimiento global del 25%.En el present treball de Màster en Experimentació Química s'ha aconseguit la síntesi de nous catecols 1 i 2 amb la finalitat d'aconseguir desenvolupar més endavant superfícies o nanopartícules d'or adhesives. Per la síntesi del 4-(3'-mercaptopropil)catecol 1 s'ha posat a punt una ruta d'obtenció partint del producte comercial eugenol, consistent en 3 etapes sintètiques y amb un rendiment global proper al 70%. També s'ha desenvolupat una ruta sintètica pel 4-(7'-mercaptopropil)catecol 2 que parteix del 3,4-dimetoxibenzaldehído, y consta de 6 etapes, presentant un rendiment global del 25%

Two-step synthesis of heterometallic coordination polymers using a polyazamacrocyclic linker

A new macrocyclic linker 1,4,7,10-tetraazacyclododecane-1,7-bis(4-acetamidobenzoic)-4,10-diacetic acid (HL1) was synthesized and characterized. This linker was used to create two heterometallic coordination polymers following a two-step synthesis. This synthesis consisted of first combining this polyazamacrocyclic linker with Ni(ii) or Mn(ii) ions to obtain the corresponding metallomacrocyclic complexes showing non-coordinated carboxylic groups. In a second step, these metallated macrocycles were used as building units to construct two heterometallic Ni(ii)-Zn(ii) and Mn(ii)-Zn(ii) coordination polymers when combined with Zn(ii) ions. In addition, a third Zn(ii)-Zn(ii) coordination polymer could also be synthesized by direct mixing of HL1 with Zn(ii) ions. Interestingly, the Mn(ii)-Zn(ii) coordination polymer exhibits a reversible type-I "crystal-to-amorphous transformation" upon water sorption/desorption

Mussel-inspired lego approach for controlling the wettability of surfaces with colorless coatings

The control of surface wettability with polyphenol coatings has been at the forefront of materials research since the late 1990s, when robust underwater adhesion was linked to the presence of L-DOPA-a catecholic amino acid-in unusually high amounts, in the sequences of several mussel foot proteins. Since then, several successful approaches have been reported, although a common undesired feature of most of them is the presence of a remnant color and/or the intrinsic difficulty in fine-tuning and controlling the hydrophobic character. We report here a new family of functional catechol-based coatings, grounded in the oxidative condensation of readily available pyrocatechol and thiol-capped functional moieties. The presence of at least two additional thiol groups in their structure allows for polymerization through the formation of disulfide bonds. The synthetic flexibility, together with its modular character, allowed us to: (I) develop coatings with applications exemplified by textiles for oil-spill water treatment; (II) develop multifunctional coatings, and (III) fine-tune the WCA for flat and textile surfaces. All of this was achieved with the application of colorless coating

Clip-off Chemistry : Synthesis by Programmed Disassembly of Reticular Materials

Bond breaking is an essential process in chemical transformations and the ability of researchers to strategically dictate which bonds in a given system will be broken translates to greater synthetic control. Here, we report extending the concept of selective bond breaking to reticular materials in a new synthetic approach that we call Clip-off Chemistry. We show that bond-breaking in these structures can be controlled at the molecular level; is periodic, quantitative, and selective; is effective in reactions performed in either solid or liquid phases; and can occur in a single-crystal-to-single-crystal fashion involving the entire bulk precursor sample. We validate Clip-off Chemistry by synthesizing two topologically distinct 3D metal-organic frameworks (MOFs) from two reported 3D MOFs, and a metal-organic macrocycle from metal-organic polyhedra (MOP). Clip-off Chemistry opens the door to the programmed disassembly of reticular materials and thus to the design and synthesis of new molecules and materials. Clip-off Chemistry, a new approach to synthesizing molecules and materials based on the programmed de-reticulation and controlled etching at the molecular level in reticular materials, is introduced. Using this strategy, we have transformed two 3D metal-organic frameworks (MOFs) into two topologically distinct 3D MOFs, and one metal-organic polyhedra into a metal-organic macrocycle

pH-Responsive Relaxometric Behaviour of Coordination Polymer Nanoparticles Made of a Stable Macrocyclic Gadolinium Chelate

Lanthanide-containing nanoscale particles have been widely explored for various biomedical purposes, however, they are often prone to metal leaching. Here we have created a new coordination polymer (CP) by applying, for the first time, a stable Gdchelate as building block in order to prevent any fortuitous release of free lanthanide(III) ion. The use of the Gd-DOTA-4AmP complex as a design element in the CP allows not only for enhanced relaxometric properties (maximum r=16.4 mmsat 10 MHz), but also for a pH responsiveness (Δr=108 % between pH 4 and 6.5), beyond the values obtained for the low molecular weight Gd-DOTA-4AmP itself. The CP can be miniaturised to the nanoscale to form colloids that are stable in physiological saline solution and in cell culture media and does not show cytotoxicity

Síntesi de nous compostos tipus catecol amb aplicació en materials funcionals

En el nostre grup d'investigació i en col·laboració amb el grup d'investigació del doctor Daniel Ruiz-Molina del Centre d'investigació en Nanociència i Nanotecnologia (CIN2) d'aquest campus universitari, hem iniciat un projecte que es planteja aconseguir biomimetitzar certes proteïnes adhesives de mol·luscs, en que la seva adherència es deu a la presència de la funcionalitat catecol. Aprofitant aquesta propietat adhesiva dels catecols, l'objectiu és poder desenvolupar nous materials per a recobriments hidro- i oleofòbics, i nous materials adhesius sent necessari el desenvolupament de protocols sintètics per a l'obtenció de compostos tipus catecol convenientment substituïts. En el present treball de recerca s'ha aconseguit la síntesi del nou catecol 10, que presenta en la seva estructura una cadena alquílica parcialment fluorada amb la finalitat de fer-ne recobriments hidro- i oleofòbics, i l'optimització i escalat del catecol 2, que presenta una cadena alquílica, amb la finalitat de fer-ne recobriments hidrofòbics. També s'ha explorat en la síntesi de catecols amb una funcionalitat tiol amb la finalitat de poder desenvolupar superfícies o nanopartícules d'or adhesives. Partint del producte comercial 17, s'ha aconseguit obtenir 10 en tres etapes sintètiques i un rendiment global del 57% i 2 en dues etapes sintètiques i un rendiment global del 63% a escala multigram, millorant la metodologia sintètica existent que consistia en quatre etapes sintètiques i un 48% de rendiment global

Síntesi de la molècula ML-10 i del seu precursor immediat per poder obtenir 18F-ML-10, d'ús en tècniques PET

El 18F-ML-10 és un radiofàrmac utilitzat com a traçador de cèl·lules apoptòtiques mitjançant la tècnica del PET (Positron Emission Tomography). En el present treball de recerca s'ha dut a terme la síntesi de dos precursors del 18F-ML-10, i del producte final no marcat isotòpicament, el ML-10. S'ha plantejat una síntesi convergent per l'obtenció del compost final 3, partint del malonat de di-tert-butil i l'1,5-pentandiol. Tant el precursor tosilat 1 com el mesilat 2 s'han sintetitzat en 3 etapes amb un 29% i un 36% de rendiment, respectivament. El compost 3, utilitzat com a referència en la síntesi del 18F-ML-10, s'ha sintetitzat en 2 etapes a partir del precursor 2 amb un rendiment total de la síntesi del 31%. El procés de radiomarcació s'està portant a terme a l'Institut d'Alta Tecnologia - Parc de Recerca Biomèdica de Barcelona (IAT-PRBB), on posteriorment es faran estudis neurològics i oncològics on el seguiment de processos apoptòtics és clau