The complex Ru(bpy)2L2+, where bpy=2,2′‐bipyridine, L=4‐(phenylethynyl)‐2,2′‐bipyridine, was prepared in its racemic and resolved forms (Δ and Λ). The phenylethynyl unit on the bipyridine for the ...complex acts as a binding site for α‐cyclodextrin in water (1:1 complex, K=3390 L mol−1) or β‐cyclodextrin (2:1 complex, K1=887 L mol−1, K2=8070 L mol−1). The presence of the cyclodextrin provides partial protection to the complex under light‐activated water oxidation conditions.
The protectors: A cyclodextrin has been used to protect a specifically designed ruthenium(II) polypyridyl photosensitizer against photodecomposition in water. The enhanced photostability comes from its inclusion at the easiest‐to‐reduce bipyridine ligand, which is consequently the first to be decomposed upon illumination.
Metal-organic frameworks (MOFs) are promising multifunctional porous materials for biomedical and environmental applications. Here, we report synthesis and characterization of a new MOF based on the ...tetrahedral secondary building unit Zn
O(CBAB)
(NUIG4), where CBABH
= 4-((4-carboxybenzylidene)amino)benzoic acid. NUIG4 belongs to the family of MOFs with primitive cubic pcu topology, being a rare example with 4-fold interpenetration. The pore architecture enables unprecedentedly high doxorubicin (DOX) loading capacity (1955 mg DOX/g NUIG4) with pH-controlled release. Solid-state NMR and
modeling confirmed formation of aromatic π-π stacking interactions between DOX and the framework. Preliminary cell-line experiments suggested a protective effect of NUIG4 on healthy HDF cells against DOX toxicity. NUIG4 also displays potential for adsorptive small-molecule gas separation, with a BET surface area of 1358 m
g
and high selectivity of 2.75 for C
H
over CO
.
A great parallel exists between metal complexes of cyclopentadienyl and arene ligands on one side and metal complexes of the nido derivatives of the icosahedral o-carborane clusters. With few ...exceptions, the metal complexation in the cluster can be viewed as the substitution of one or more bridging hydrogen atoms by the metal. Therefore, a necessary requirement for the complexation is the deprotonation of the nido cluster to generate a coordination site for that metal. The reaction to remove these protons, which most probably is one of the most commonly done processes in boron and metallaborane chemistry, is barely known, and no quantitative data are available on the magnitude of their pK a values. With the purpose of determining the acidity of nido-carboranes, a procedure to calculate the pK a values of nido boron clusters is presented in this paper for the first time. To this objective, some nido clusters have been selected and their geometry and NMR-spectroscopic properties have been studied, giving a good correlation between the theoretical and experimental data in both geometry distances and 11B NMR spectroscopy. Of notice is the result that proves that the singular carbon atom in the thermodynamic isomer of C2B10H13- is definitely part of the cluster and that its connection with the C2B3 face would be better defined by adding additional interactions with the two boron atoms nearest to the second cluster carbon. The pK a values of the nido species have been calculated by correlating experimental pK a values and calculated reaction Gibbs energies ΔG s. Some pK a values of importance are −4.6 and +13.5 for 7,8-C2B9H13 (1) and 7,8-C2B9H12- (2), respectively.
El treball que es presenta en aquesta tesi doctoral és la continuació i ampliació de la feina feta en el nostre grup en els darrers anys sobre el metal·lacarborà cobalto-bis(dicarballur). Amb la ...finalitat de la seva aplicació com a components de materials moleculars, calia com a objectiu inicial la síntesi i caracterització de nous derivats en els àtoms de carboni i de bor del clúster, així com l'estudi teòric d'alguns d'aquests compostos que presentaven propietats que no s'havien observat fins al moment. A partir d'aquests compostos s'han buscat aplicacions en els camps del tractament de residus nuclears, motors sintètics moleculars i en el camp de la biomedicina. Finalment i per ampliar el coneixement en el camp dels carborans, s'han fet estudis teòrics del pKa de nido-carborans, s'ha estudiat tant teòrica com experimentalment la reacció de cloració de l'anió Ph-CB9H9- i s'ha participat en l'elaboració d'un treball d'interaccions intermoleculars entre molècules de iode i fosfino-carborans.Pel que fa a la síntesi de derivats en els àtoms de carboni, s'han obtingut productes substituïts amb àtoms de fòsfor i de sofre. En el primer cas l'àtom de fòsfor fa de pont entre les dues caixes de dicarballur de manera semblant als derivats del ferrocè anomenats ferrocenofans. Pel que fa als derivats de l'anió cobalto-bis(dicarballur) amb sofre s'han obtingut derivats disubstituïts amb funcions tioèter a partir dels disulfurs orgànics apropiats, i altres en què l'àtom o àtoms de sofre estan pinçant les dues caixes de dicarballur. Les substitucions en els vèrtexs de bor s'han treballat en tres vies diferents. La primera és l'halogenació de l'anió cobalto-bis(dicarballur) amb àtoms de clor, brom i iode emprant diferents mètodes, tant en dissolució com en estat sòlid. S'ha estudiat en més detall la reacció de cloració per la importància dels seus compostos en l'extracció de radionúclids. La segona via que s'ha treballat consisteix en la formació d'enllaços B-C utilitzant les condicions de reacció ben establertes per l'acoblament C-C com la reacció de Kumada o la de Heck. La tercera via parteix ja d'un oxo-derivat de l'anió 1, el zwitterió 8-OC4H8O-1,2-(C2B9H11)2- (43). Aquest té l'oxigen enllaçat al B(8) fet que el fa que estigui carregat positivament, i per tant susceptible a l'atac de nucleòfils. S'han sintetitzat i caracteritzat un ampli ventall de compostos utilitzant diversos nucleòfils com alcohols, àcids, reactius de grignard, tiols, carborans i tiocarborans. Alguns dels compostos sintetitzats en aquest treball s'han aplicat en diversos camps. Els derivats clorats del cobalto-bis(dicarballur) s'han provat com a agents sinèrgics en l'extracció selectiva de radionúclids amb resultats interessants en quant a la millora de la selectivitat quan s'usen aquests compostos. També s'ha provat la incorporació del metal·lacarborà cobalto-bis(dicarballur) en màquines moleculars, i més concretament en rotors del tipus rotaxà. S'han sintetitzat i caracteritzat nous rotaxans a fi d'estudiar l'efecte intramolecular o intermolecular del clúster de bor en la dinàmica d'aquest tipus de molècules. D'altra banda s'han utilitzat alguns dels oxo-derivats en el vèrtex B(8) en la investigació antimicrobiana i en el tractament en cèl·lules tumorals. Finalment, tot i que els objectius d'aquest treball es centraven en el metal·lacarborà cobalto-bis(dicarballur) també s'ha fet un estudi teòric de carborans tenint en compte que aquests són part del cobalto-bis(dicarballur). En primer lloc s'ha volgut ampliar l'estudi de cloració fet a l'anió 1 sobre un altre clúster de bor. L'anió Ph-CB9H9- (86) mostra l'interès de tenir dos punts de reactivitat molt diferent, els vèrtex aromàtics C-H i els del clúster B-H. Per altra banda s'ha buscat un mètode teòric per tal de calcular l'acidesa de nido-carborans mitjançant una metodologia ràpida i senzilla. Per últim s'ha realitzat un estudi que tracta les interaccions entre els fosfinocarborans i el iode. És interessar observar el cas del compost 1-Me-2-PPh2-1,2-C2B10H10 (99) on l'addició de iode no provoca una disminució de la interacció entre ambdós àtoms, indicant la formació d'una estructura del tipus P···I-I···P. Aquest tipus d'estructura també es troba en estat sòlid tal com demostra l'estructura de raigs X.
The work presented in this manuscript is the continuation and extension of the work done in our group during the last years on the cobaltabisdicarbollide metallacarborane. To apply these molecules as components of molecular materials, the initial objectives were the synthesis and characterization of new derivatives of cobaltabisdicarbollide on the carbon and boron vertices of the cluster, as well as a theoretical study of some of these compounds that presented properties not previously observed. The second objective was the application of some of these compounds to different fields such as the treatment of nuclear waste, molecular synthetic motors and in biomedicine. Finally, work on carboranes has also been done as these are part of metallacarboranes. Theoretical calculations of pKa values of nido-carboranes have been done. It has been studied both theoretically and experimentally the chlorination reaction of the anion Ph-CB9H9-. Also the intermolecular interaction between iodine molecules and phosphino-carboranes has been studied by computational methods.Concerning the synthesis of carbon functionalized compounds, products substituted with phosphorus and sulphur have been obtained. In the first case the phosphorus is bridging the two dicarbollide cages in a way similar to the already known ferrocene derivatives called ferrocenophanes. Sulphur derivatives of cobaltabisdicarbollide have been obtained as disubstituted molecules with thioether groups obtained from the appropriate organic disulfides. C,C bridging molecules in which one or two sulphur atoms bridge both dicarbollide cages have also been obtained. Boron substituted vertices have been studied in three different ways. The first concerns halogenation of cobaltabisdicarbollide anion with chlorine, bromine and iodine atoms by using different methods, such as solution or solid state reactions. It has been studied more deeply the chlorination reaction because of the importance of these compounds on the extraction of radionuclides. The second way studied concerning the derivatization of 1 refers to the formation of B-C bonds by using either Kumada reaction or Heck reaction conditions. The third way of cobaltabisdicarbollide derivatization has as the starting product the oxo-derivative of 1, the zwitterion 8-OC4H8O-1,2-(C2B9H11)2- (43). This compound has an oxygen atom bonded to the B(8) vertex with a positive charge and this position is susceptible to the attack by nucleophiles. We have synthesized and characterized a wide range of compounds by using different nucleophiles such as alcohols, acids, Grignard reagents, thiols, carboranes and thiocarboranes. Some compounds synthesized during this work have been used in different applications. Chlorinated derivatives of cobaltabisdicarbollide have been tested as synergic agents in the selective extraction of radionuclides for nuclear waste treatment. It has been tested the incorporation of metallacarborane cobaltabisdicarbollide in molecular machine structures, and more precisely in rotors like organic molecules called rotaxanes. We have synthesized and characterized new rotaxanes specially designed to study intramolecular or intermolecular effects of the boron cluster in the dynamics of this kind of molecules. Moreover, some oxo-derivatives at the B(8) vertex of cobaltabisdicarbollide have been applied in the research of antimicrobial and antitumoral treatments. Finally and although the aims of this work were centered on cobaltabisdicarbollide, some theoretical and experimental studies on carboranes have been done taking into account that these are part of the cobaltacarborane. Firstly we would like to improve the understanding of the chlorination reaction, extending the work done for 1 to other boron clusters. Anion Ph-CB9H9- (86) was selected because it has two very different reactivity points, aromatic C-H groups and B-H cluster vertices. On the other hand we have described a theoretical method to calculate the acidity of nido-carboranes by means of a fast, reliable and simple methodology. Finally, the last part of the manuscript was focused on interactions between phosphino-carboranes and iodine. It is remarkable the behaviour of compound 1-Me-2-PPh2-1,2-C2B10H10 (99), where upon addition of iodine the decrease of the interaction can't be observed. This behaviour can be explained by the formation of a P···I-I···P moiety, which can be observed in solid state by its x-ray crystal structure.
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