No description available.

Triazenes are molecules characterized by having the triazeno group (–N=N–N<). They are known as photoactive molecules due to trans-cis photoinduced isomerization around the N=N bond. Their nucleophilic character makes them good ligands to metal centers. A study on the potential ability of photochromic organic ligand triazenes to undergo reversible cis-trans photoisomerization and, in turn, photoreversible complexation with metal cations was carried out in aqueous solutions. Metal-triazenide complexes are instantaneously formed upon addition of metal cations to trans-triazenes dissolved in aqueous solutions. For silver-triazenide and mercury-triazenide complexes, the metal-to-ligand ratios are 1:1 and 1:2, respectively. Unfortunately, target metal-triazenide complexes do not photoisomerize upon 355 nm laser excitation. Triazenes are also known to be unstable materials under acidic conditions. A study on the effects of cyclodextrins (CDs) on the rate of acid-catalyzed decomposition of 1,3-diphenyl-triazenes was carried out in 2% MeOH aqueous buffer solutions by means of spectroscopic methods. CDs inhibit triazenes decomposition through inclusion complex formation. The inclusion complexes render the guest triazene significantly less basic as a consequence of the less polar nature of the CD cavity (a microsolvent effect). For any given triazene, the inhibition effect is dependent on both the size of the cyclodextrin cavity and the substituents on the cavity rims. Binding constants for 1:1 host:guest complexes increase in the order α-CD < ß-CD ~ TM-ß-CD < HP-ß-CD; in the case of α CD, formation of 2:1 complexes is also observed.

Triazenes are molecules characterized by having the triazeno group (–N=N–N<). They are known as photoactive molecules due to trans-cis photoinduced isomerization around the N=N bond. Their nucleophilic character makes them good ligands to metal centers. A study on the potential ability of photochromic organic ligand triazenes to undergo reversible cis-trans photoisomerization and, in turn, photoreversible complexation with metal cations was carried out in aqueous solutions. Metal-triazenide complexes are instantaneously formed upon addition of metal cations to trans-triazenes dissolved in aqueous solutions. For silver-triazenide and mercury-triazenide complexes, the metal-to-ligand ratios are 1:1 and 1:2, respectively. Unfortunately, target metal-triazenide complexes do not photoisomerize upon 355 nm laser excitation. Triazenes are also known to be unstable materials under acidic conditions. A study on the effects of cyclodextrins (CDs) on the rate of acid-catalyzed decomposition of 1,3-diphenyl-triazenes was carried out in 2% MeOH aqueous buffer solutions by means of spectroscopic methods. CDs inhibit triazenes decomposition through inclusion complex formation. The inclusion complexes render the guest triazene significantly less basic as a consequence of the less polar nature of the CD cavity (a microsolvent effect). For any given triazene, the inhibition effect is dependent on both the size of the cyclodextrin cavity and the substituents on the cavity rims. Binding constants for 1:1 host:guest complexes increase in the order α-CD < ß-CD ~ TM-ß-CD < HP-ß-CD; in the case of α CD, formation of 2:1 complexes is also observed.

Universiẗat, Diss., 2003--Tübingen.

The design, synthesis and characterization of novel conjugated polymers are described. Using a coupling reaction recently developed within our labs, polymers were constructed through triazene linkages generated by joining N-heterocyclic carbenes (NHCs) with organic azides. This triazene reaction produced polymer of sufficiently high molecular weight as to be spin-coated and rendered conductive upon doping with iodine. The reaction also has potential for executing post-polymerization modifications. This was evidenced through rapid functionalization of poly(4-methylazido-styrene) via triazene formation using a commercially available N-heterocyclic carbene (NHC). A formal anion metathesis of benzobis(imidazolium)s was used to transform neutral block copolymers into block ionomers. Further investigation of the block ionomers revealed their solvent mediated self assembly. The gradual change of organic to aqueous media caused the adoption of a three-dimensional micelle conformation as determined by transmission electron microscopy and dynamic light scattering. Through the exploitation of carbene-carbon disulfide adducts, new chain transfer agents were generated. After 2-dithiocarboxylate-imidazolium adduct formation, alkylation was performed with benzyl bromide. The resulting charged chain transfer agent was tested for its ability to moderate radical addition fragmentation (RAFT) polymerizations of styrene. A considerable increase in transfer kinetics as compared to that of commonly used RAFT agents was observed whilst retaining low polydispersity and molecular weight control. The rate enhancement is presumably due to the electron withdrawing imidazolium activating the thionyl towards the nucleophilic radical while retaining effective fragmentation. Ion coordinating macrocycles were affixed to a poly(methacrylate) scaffold for employment as electrolyte extractants. Polymer bound calix[4]pyrrole was found to complex fluoride and chloride with sufficient strength as to extract tetrabutylammonium salts from water. Enhanced extraction abilities were observed when calix[4]pyrrole was used in conjunction with benzo-15-crown-5. Methacrylate polymers containing both macrocycles affected the removal of aqueous potassium fluoride from a biphasic water/dichloromethane mixture. To provide evidence for the presence of potassium fluoride within the dichloromethane layer, ¹⁹F NMR and flame emission spectroscopy were used. / text

Zugl.: Karlsruhe, Univ., Diss., 2009

Les déficiences en transporteur vésiculaire de l'acétylcholine (VAChT) sont l'un des symptômes précoces de perte neuronale lors de la maladie d'Alzheimer, perte fortement corrélée avec la gravité de la démence associée. Comme le (2R,3R)-5-IBVM est le radioligand de référence du VAChT utilisé en imagerie TEMP, la synthèse par fluoro-de-diazenation a conduit à son analogue fluoré, le 5-FBVM, ainsi qu’à ses énantiomères. Par étude 3D-QSAR, confirmée par évaluation in vitro, chaque énantiomère du 5-FBVM montre une affinité pour le VAChT similaire au 5-IBVM. D'autres travaux ont permis d'améliorer le rendement en 5- FBVM par fluoro-de-triazénation du précurseur triazène, le 5-TVB, en utilisant seulement de l’éthérate de trifluorure de bore qui joue le double rôle d’acide de Lewis et d’agent fluorant, dans le tétrachlorure de carbone, sous irradiation micro-onde. L’optimisation de la fluoro-detriazénation en étudiant différents paramètres expérimentaux compatibles avec un radiomarquage a permis d’obtenir le 5-[18F]FBVM. Ce résultat encourageant devrait conduire à l’obtention du 5-[18F]FBVM. / Deficiencies in vesicular acetylcholine transporter (VAChT) are among the earliest neuronal changes preceding clinical symptoms of Alzheimer's disease, and show a strong correlation with the severity of dementia. As (2R,3R)-5-IBVM is the lead and the only SPECT radioligand for VAChT human imaging, we synthesized by fluoro-de-diazoniation its fluoro analog 5-FBVM with corresponding enantiomers, and confirmed by 3D QSAR and in vitro studies that both enantiomers of 5-FBVM are of the same order affinity as 5-IBVM. Furthermore, we greatly improved 5-FBVM yield via fluoro-de-triazenation of the corresponding triazene precursor 5-TBV using boron trifluoride etherate under non-protic acid conditions in tetrachloromethane under optimized microwave irradiation. By testing different reaction parameters in numerous experimental attempts to find fluoro-de-triazenation conditions which can be transposed to radiofluorination, we may accomplished 5-[18F]FBVM. This encouraging result warrants to optimize 5-[18F]FBVM yield via promising methods obtained in cold chemistry.

This work was accomplished with the interest in the synthesis of ortosubstituted ligands, with special prominence to the moiety __CF3, __Br and __NO2 and later the complexação with Hg(II). The first obtained result was the crystalline structure of the ligand (1), it crystallizes in the system crystalline monoclínico, space group Cc, with the given following crystallographic the a = 15,3122(12)Å, b = 4,8544(3)Å, c = 19,2804(15)Å, ß = 104,205(2)°, V = 1389,32(18)Å3, Z = 4, R1 = 0,0330 and wR2 = 0,0988. The molecular structure of the -ligand (1) it confirms the expected stereochemistry trans in relation to the doble bond in the diazoamine moiety. The interplanar angle [8,3(1)°] between the terminal phenyl rings indicate that the whole molecule is almost planar (r.m.s deviation = 0,0929 Å). The molecule shows intramolecular N__H...(F1,F2) bifurcated, and non-classical N__H...F hydrogen bonds. The unequal distribution of the double bond character among the N atoms of the diazoamine group, indicates a delocalization of the π electrons over the N=N__N(H) moiety towards the terminal 2-trifluormethylphenyl substituents. The subsequent results resulted in crystalline structures of compounds involving the ion Hg(II) (2), (3) and (4). The data in relation to the crystalline structures are gathered in the sequence, respectively: (2) it crystallizes in the system crystalline monoclinic, space group: C2/c, the a = 23,0736(5)Å, b = 107,82604(2)Å, c = 14,7387(3)Å, ß = 99,6590(10)°, V = 2623,70(10)Å3, Z = 4, R1 = 0,0232 and wR2 = 0,1187; (3) it crystallizes in the system crystalline monoclinic, space group C2/c, the a = 20,8663(6) Å, b = 9,9525(4) Å, c = 15,6013(5) Å, ß = 118,007(2)°, V = 2860,52(17) Å3, Z = 4, R1 = 0,0666 and wR2 = 0,1435 and the last obtained result is regarding the compound (4) it crystallizes in the system crystalline monoclinic, space group C2/C, The a = 22,5163(3) Å, b = 8,2234 (1)Å, c = 15,1037 (2) Å, β = 111,282(1), V = 2605,9(11), Z = 4, R1 = 0,078 e wR2 = 0,232. The compounds above mentioned present a behavior similar plenty crystallographic, because they are gathered in the same crystalline system and they are part of the same space group, however a particularity of each compond is detached in what refers to the electronic effects of the groups linked substituintes to the rings terminal phenila, that so much presents angles different interplanares as well as strong effect estérico in relation to Hg(II) shielding it of other ligands. / Este trabalho foi realizado com o interesse na síntese de pré-ligantes ortosubstituídos, com especial destaque aos grupamentos __CF3, __Br e __NO2 e posteriormente a complexação com Hg(II). O primeiro resultado obtido foi a estrutura cristalina do pré-ligante (1), cristaliza no sistema cristalino monoclínico, grupo espacial Cc, com os seguintes dados cristalográficos a = 15,3122(12)Å, b = 4,8544(3)Å, c = 19,2804(15)Å, β = 104,205(2)°, V = 1389,32(18)Å3 , Z = 4, R1 = 0,0330 e wR2 = 0,0988. A estrutura molecular do pré-ligante (1) confirma a esperada estereoquímica trans em relação à dupla ligação. O ângulo interplanar de 8,3(1)° entre os anéis de arilas terminais indica que a molécula é quase planar (r.m.s = 0,0929 Å). A molécula apresenta ligação de hidrogênio intramolecular N__H... (F1,F2) bifurcadas e ligações de hidrogênio não-clássicas N__H...F. A distribuição desigual do caráter da dupla ligação entre os átomos de N do grupo diazoamínico, indica a deslocalização dos elétrons π na cadeia N=N__N(H) em direção aos substituintes terminais 2-trifluormetilfenil. Os resultados posteriores demonstraram as estruturas cristalinas de complexos (2), (3) e (4) envolvendo o íon Hg(II). Os dados em relação às estruturas cristalinas estão reunidos na seqüência, respectivamente (2) cristaliza no sistema cristalino monoclínico, grupo espacial C2/c, a = 23,0736(5)Å, b = 7,82604(2)Å, c = 14,7387(3)Å, β = 99,6590(10)°, V = 2623,70(10)Å3 , Z = 4, R1 = 0,0232 e wR2 = 0,1187; (3) cristaliza no sistema cristalino monoclínico, grupo espacial C2/c, a = 20,8663(6) Å, b = 89,9525(4) Å, c = 15,6013(5) Å, β = 118,007(2)°, V = 2860,52(17) Å3, Z = 4, R1 = 0,0666 e wR2 = 0,1435 e o último resultado obtido é referente ao complexo (4) cristaliza no sistema cristalino monoclínico, grupo espacial C2/c, a = 22,5163(3) Å, b = 8,2234 (1)Å, c = 15,1037 (2) Å, β = 111,282(1), V = 2605,9(11), Z = 4, R1 = 0,078 e wR2 = 0,232. Os complexos acima mencionados apresentam um comportamento cristalográfico bastante semelhante, pois estão reunidos no mesmo sistema cristalino e fazem parte do mesmo grupo espacial, porém uma particularidade de cada composto é destacada no que se refere aos efeitos eletrônicos dos grupos substituintes ligados aos anéis arila terminais da cadeia triazenídica, que tanto apresentam ângulos interplanares distintos assim como forte efeito estérico em relação ao Hg(II) blindando-o de outros ligantes.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work shows the crystaline/molecular structure of two mercury(II) complexes with a same monocateneted triazene ligand previolsly deprotonated. The reaction between mercury(II) acetate, 1-(3-nitrophenyl)-3-(3-trifluorometilphenyl)triazene and triphenylphosphine in a methanol of yields the complex [Hg(CF3C6H4NNNC6H4NO2)2(C18H15P)] (1). (1) cristallizes in triclinic system, space group P 1, Z = 2, with cell parameters a = 11.8334(3) Å, b = 13.7747(3) Å, c = 15.3909(4) Å, α = 75.9550(10)°, β = 70.8900(10)°, γ = 65.9750(10)°. The refinament of this estructure converges to the follow discordance indexes R1 = 0.0525 e wR2 = 0.1342. The coordination sphere of mercury(II) ion is formed by two deprotonated triazenido ligands and a triphenilphosphine molecule imposing a trigonal-distorted coordination geometry to the metallic center. Intermolecular interactions of C-H···O type are observed in this structure originating chains of molecules guided parallel to the crystallographic direction [101]. These chains for your time settle of form centrosimetric some relative ones to the other ones, forming bidimensional supramolecular arrangement binding intermolecular interactions type C-H···F. The reaction between mercury(II) acetate, 1-(3-nitrophenyl)-3-(3- trifluorometilphenyl)triazene and pirydine in a methanol of yields the complex [Hg(CF3C6H4NNNC6H4NO2)2(C5H5N)] (2). (2) cristallizes in monoclinic system, space group P21/c, Z = 4, with cell parameters a = 13,5586(3) Å, b = 19,2937(5) Å, c = 12,9152(3) Å, β = 90,9610(10)°. The refinement of this structure converged to the discordance indexes R1 = 0,0470 and wR2 = 0,1365. The coordination sphere of mercury(II) ion is formed by two deprotonated triazenido ligands and a pyridine molecule imposing a T-distorted coordination geometry to the metallic center. The molecular structure reveals disordered fluorine and oxygen atoms related to the the trifluoromethyl and nitro substituents, respectively. A discussion of intermolecular interactions via C-H···O and C-H···F is not possible at this stage of the structure analysis. On the other hand, the crystal structure of (2) in contrast to other examples of this class of compounds, does not present intermolecular metal-arene π interactions between the Hg(II) ion and terminal aryl substituents of the triazenide ligand. Beside the X-ray structure analysis, both the complexes (1) and (2) were also characterized by melting point determination and infrared spectroscopy. / Este trabalho apresenta a determinação da estrutura cristalina/molecular de dois complexos de mercúrio(II) com um mesmo ligante triazeno monocatenado previamente desprotonado. A reação entre acetato de mercúrio(II) e o ligante 1-(3-nitrofenil)-3-(3-trifluorometilfenil)triazeno e trifenilfosfina em metanol forma o complexo Hg(CF3C6H4NNNC6H4NO2)2(C18H15P)] (1). (1) cristaliza no sistema triclínico, grupo espacial P 1, Z = 2, com parâmetros de cela a = 11,8334(3) Å, b = 13,7747(3) Å, c = 15,3909(4) Å, α = 75,9550(10)°, β = 70,8900(10)°, γ = 65,9750(10)°. O refinamento desta estrutura convergiu aos índices de discordância R1 = 0,0525 e wR2 = 0,1342. A esfera de coordenação do íon mercúrio(II) é formada por dois ligantes triazenidos desprotonados e uma molécula de trifenilfosfina, impondo uma geometria de coordenação trigonal-distorcida ao centro metálico. Interações intermoleculares do tipo C-H···O são observadas nesta estrutura originando cadeias de moléculas orientadas paralelamente à direção cristalográfica [101]. Estas cadeias por sua vez arranjam-se de forma centrossimétrica umas relativas às outras, formando um arranjo supramolecular bidimensional através de interações intermoleculares do tipo C-H···F. A reação entre acetato de mercúrio(II) e o ligante 1-(3-nitrofenil)-3-(3-trifluorometilfenil)triazeno e piridina em metanol forma o complexo [Hg(CF3C6H4NNNC6H4NO2)2(C5H5N) (2). (2) cristaliza no sistema monoclínico, grupo espacial P21/c, Z = 4, com parâmetros de cela a = 13,5586(3) Å, b = 19,2937(5) Å, c = 12,9152(3) Å, β = 90,9610(10)°. O refinamento desta estrutura convergiu aos índices de discordância R1 = 0,0470 e wR2 = 0,1365. A esfera de coordenação do íon mercúrio(II) é formada por dois ligantes triazenidos desprotonados e uma molécula de piridina, impondo uma geometria de coordenação T-distorcida ao centro metálico. A estrutura molecular revela uma desordem dos átomos de flúor e de oxigênio dos grupos substituíntes m-trifluorometil e m-nitro, respectivamente, prejudicando uma possível discussão de interações intermoleculares secundárias do tipo C-H···O e C-H···F. Por outro lado, a estrutura cristalina de (2) em contraste com outros exemplos desta classe de combinações, não apresenta interações intermoleculares secundárias do tipo metal-areno π incluindo o íon mercúrio(II) e átomos de carbono dos anéis fenila terminais dos ligantes triazenidos. Além da análise estrutural por difração de raios-X, ambos os complexos (1) e (2) também foram caracterizados por ponto de fusão e espectroscopia de infra-vermelho.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work is associated with the crystal and molecular structure analysis of two free triazene 1-oxide molecules and a complex with K+ involving a p-carboxyfenil-substituted single protonated triazene 1-oxide ligand. 1-metil-3-(p-carboxyphenyl)triazene 1-oxide (1) crystallizes in the monoclinic system, space group C2/c, with cell parameters a = 27.2046(8) Å, b = 5.0218(1) Å, c = 14.4503(5) Å, β= 113.13(1)°, V = 1815.47(9)Å3, Z = 8, R1 = 0.0325, wR2 = 0.0977. The crystal structure demonstrate that the molecule deviate slightly from planarity (r.m.s. 0.0192 Å). The molecules are associated in form of a bidimensional supramolecular array in the [100] and [001] crystallographic directions via classic hydrogen bonds, N H···O e O H···O. 1,3-bis(4-carboxyphenyl)triazene (2) crystallizes in the monoclinic system, space group P21/c, with cell parameters a = 23.168(2) Å, b = 3.7398(4) Å, c = 19.751(2) Å, β= 100.912(6)°, V = 1680.3(3)Å3, Z = 4, R1 = 0.0764, wR2 = 0.2425. The crystal structure show that the molecule deviates significantly from planarity (r.m.s. 0.2071 Å). Also in this case, the molecules (2) are associated in form of a bidimensional supramolecular array constituted by helix chains including classic hydrogen bonds with water molecules, operated by a 21 axial screw-axis along the [010] crystallographic direction, and a c axial glide-plane in the [001] crystallographic direction. The complex 3-(4-carboxyphenyl)-1-metiltriazene 1-oxide of potassium tetrahydratade (4) crystallizes in the monoclinic system, space group P21/c, with cell parameters a = 12.695 Å, b = 8.123 Å, c = 13.520 Å, β = 106.71°, V = 1335.3Å3, Z = 4, R1 = 0.0554, wR2 = 0.1705. The single crystal structure analysis demonstrate that the coordination sphere of the K+ ion include eight oxygen atoms belonging to the carboxyphenyl deprotonated triazene ligand, and seven water molecules. The coordination geometry identified correspond an S8 molecule with a distorted boat conformation. Additionally, molecule (1) were characterized by melting point and spectroscopic methods (IR, UV/VIS and multinuclear NMR), molecule (2) by melting point and complex (4) by melting point and spectroscopic methods (IR and UV/VIS). In connection with biological activity, molecule (1) demonstrate bacteriostatic activity (concentration of 16μg/mL), and acts as bactericide (concentration of 32μg/mL) in relation to the bacterium S. agalactiae. 1-(4-etoxyphenyl)-3-(4-carboxyphenyl)triazene (3) (concentration of 1,25mM) demonstrate 17,03% cleavage ability in relation to the plasmidial DNA pUC18. / Este trabalho apresenta a determinação da estrutura cristalina/molecular de dois compostos triazenos livres e um complexo de K+ com ligante triazeno 1-óxido protonado. O composto 1-metil-3-(p-carboxifenil)triazeno 1-óxido (1) cristaliza no sistema monoclínico, grupo espacial C2/c , com parâmetros de cela a = 27,2046(8)Å, b = 5,0218(1)Å, c = 14,4503(5)Å, β= 113,13(1)°, V = 1815,47(9)Å3, Z = 8, R1 = 0,0325, wR2 = 0,0977. A estrutura cristalina do pró-ligante (1) revela que a molécula é praticamente plana (r.m.s. 0,0192Å) e que, o conjunto de moléculas unidas por ligações de hidrogênio, na cela elementar, formam cadeias independentes na direção cristalográfica [100], sendo que estas cadeias independentes unem-se, também, por ligações de hidrogênio na direção cristalográfica [001]. Estas ligações são do tipo clássicas N H----O e O H----O, e se relacionam por operações de simetria formando um arranjo bidimensional. O composto 1,3-bis(4-carboxifenil)triazeno (2) cristaliza no sistema monoclínico, grupo espacial P21/c, com parâmetros de cela a = 23,168(2)Å, b = 3,7398(4)Å, c = 19,751(2)Å, β= 100,912(6)°, V = 1680,3(3)Å3, Z = 4, R1 = 0,0764, wR2 = 0,2425. A estrutura cristalina do pró-ligante (2) revela que a molécula não é planar (r.m.s. 0,2071Å) e que, as moléculas unem-se por ligações de hidrogênio na direção cristalográfica [010] e com as moléculas de água na direção cristalográfica [001]. As ligações de hidrogênio são do tipo clássicas N H-----O, O H-----O, O H-----N, que se relacionam por operações de simetria formando uma arranjo bidimensional. O complexo 3-(4-carboxilatofenil)-1-metiltriazeno 1-óxido de potássio tetraidratado (4) cristaliza no sistema monoclínico, grupo espacial P21/c, com parâmetros de cela a = 12,695Å, b = 8,123Å, c = 13,520Å, β = 106,71°, V = 1335,3Å3, Z = 4, R1 = 0,0554, wR2 = 0,1705. Na estrutura cristalina do complexo (4), a esfera de coordenação do íon K+ é formada por oito átomos de oxigênio, um do ligante triazeno 1-óxido protonado, um da molécula de água terminal e seis das moléculas de água em ponte. O polímero originado, com número de coordenação oito, apresenta uma distorção da estrutura semelhante ao enxofre elementar S8 na conformação de barco com a simetria ideal C2v. Além das análises estruturais em monocristal, o pró-ligante (1) foi caracterizado adicionalmente por ponto de fusão, espectrometria no infravermelho, ressonância magnética nuclear de +H e 13C e também na região do ultravioleta, o pró-ligante (2) ponto de fusão, e o complexo (4) por ponto de fusão e espectrometria na região do infravermelho e ultravioleta. Em relação à atividade biológica, o pró-ligante (1) revela capacidade bacteriostática na concentração de 16μg/mL e bactericida em 32μg/mL frente a bactéria S. agalactiae, e o pró-ligante 1-(4-etoxifenil)-3- (4-carboxifenil)triazeno (3) é capaz de clivar o DNA plasmidial pUC18, na proporção de 17,03%, com a concentração de 1,25mM.