0000000001301782
AUTHOR
Pedro Molina
Combined study of anion recognition by a carbazole-based neutral tripodal receptor in a competitive environment
Anion recognition studies have been carried out on a series of neutral synthetic receptors in which carbazole-2-carboxamide has been used as building block. Different ligands which include one to three carbazole units in their structure have been prepared. Binding experiments have been performed under competitive conditions in DMSO and DMSO-water solutions. The tripodal receptor offered a better host-guest association due to the synergistic effect of a well arranged set of hydrogen bonds. A selective response towards the biologically important pyrophosphate anion has been achieved. This selectivity is enhanced when studies are carried out with an increasing water content, which gets as high…
Host–Guest Chemistry: Oxoanion Recognition Based on Combined Charge‐Assisted C−H or Halogen‐Bonding Interactions and Anion⋅⋅⋅Anion Interactions Mediated by Hydrogen Bonds
Several bis-triazolium-based receptors have been synthesized and their anion-recognition capabilities have been studied. The central chiral 1,1'-bi-2-naphthol (BINOL) core features either two aryl or ferrocenyl end-capped side arms with central halogen- or hydrogen-bonding triazolium receptors. NMR spectroscopic data indicate the simultaneous occurrence of several charge-assisted aliphatic and heteroaromatic C-H noncovalent interactions and combinations of C-H hydrogen and halogen bonding. The receptors are able to selectively interact with HP2 O7 (3-) , H2 PO4 (-) , and SO4 (2-) anions, and the value of the association constant follows the sequence: HP2 O7 (3-) >SO4 (2-) >H2 PO4 (-) . The …
Spin crossover in iron(II) complexes with ferrocene-bearing triazole-pyridine ligands.
In the search for new multifunctional spin crossover molecular materials, here we describe the synthesis, crystal structures and magnetic and photomagnetic properties of the complexes trans-[Fe(Fctzpy)2(NCX)2]·CHCl3 where Fc-tzpy is the ferrocene-appended ligand 4-(2-pyridyl)-1H-1,2,3-triazol- 1-ylferrocene, X = S (1) and X = Se (2). Both complexes display thermal- and light-induced (LIESST) spin crossover properties characterised by T1/2 = 85 and 168 K, ΔS = 55 and 66 J K−1 mol−1 , ΔH = 4.7 and 11.1 kJ mol−1 and TLIESST = 47 K and 39 K for 1 and 2 respectively. The crystal structure of 1 and 2 measured at 275 K is consistent with the iron(II) ion in the high-spin state while the crystal st…
A pyrroloquinazoline derivative with anti-inflammatory and analgesic activity by dual inhibition of cyclo-oxygenase-2 and 5-lipoxygenase
Abstract In a previous study, we reported a new pyrroloquinazoline derivative, 3-(4′-acetoxy-3′,5′-dimethoxy)benzylidene-1,2-dihydropyrrolo[2,1- b ]quinazoline-9-one (PQ), which inhibited human purified 5-lipoxygenase activity and prostaglandin E 2 release in lipopolysaccharide-stimulated RAW 264.7 cells. In the present work, we show that PQ inhibits cyclo-oxygenase-2 activity in intact cell assays (human monocytes) and purified enzyme preparations (ovine isoenzymes) without affecting cyclo-oxygenase-1 activity. This behaviour was confirmed in vivo by using the zymosan-injected mouse air pouch model, where PQ caused a marked reduction in cell migration and leukotriene B 4 levels at 4 h, as …
Ion pair recognition receptor based on an unsymmetrically 1,1'-disubstituted ferrocene-triazole derivative.
The ferrocene-triazole derivative 4, available from 1,1'-bis(diazido)ferrocene by sequential functionalization through click-type chemistry and the Staudinger reaction, is elaborated as a lab-on-a-molecule for the selective sensing of HP(2)O(7)(3-) and Hg(2+). Receptor 4 behaves as a ratiometric fluorescent probe for HP(2)O(7)(3-) with a good selectivity over other anions, whereas in the presence of Hg(2+) it modifies the fluorescent emission of the pyrene unit, acting as a selective on-off fluorescent sensor for Hg(2+) with a low detection limit. The most salient feature of compound 4 is its behavior as an excellent electrooptical ion pair recognition receptor able to simultaneously recogn…
Synthesis, Structure and Anion Sensing Properties of a Dicationic Bis(imidazolium)-Based Cyclophane
The preparation and sensing properties of a tetracyclic cyclophane receptor containing two imidazolium rings as anion binding sites and two fluorene rings as fluorescent signaling units, are reported. The receptor behaves as a selective fluorescent chemosensor molecule for inorganic phosphates. H-NMR spectroscopical data clearly indicate the simultaneous occurrence of charge-assisted aromatic and aliphatic C−H noncovalent interactions. PCM/DFT calculations have been carried out to predict the structures of the complexes formed with one and two molecules of PF , HPO and HPO .
2,4,5-Trimethylimidazolium Scaffold for Anion Recognition Receptors Acting Through Charge-Assisted Aliphatic and Aromatic C–H Interactions
A series of two-armed 2,4,5-trimethylimidazolium-based oxoanion receptors, which incorporate two end-capped photoactive anthracene rings, being the central core an aromatic or heteroaromatic ring, has been designed. In the presence of HP2O7(3-), H2PO4(-), and SO4(2-) anions, (1)H- and (31)P NMR spectroscopical data clearly indicate the simultaneous occurrence of several charge-assisted aliphatic and aromatic C-H noncovalent interactions, i.e., significant downfield shifts were observed for the imidazolium C(2)-CH3 protons, the methylene N-CH2 protons, and the inner aromatic proton or the outer heteroaromatic protons. Density functional theory calculations confirm the occurrence of these non…
A novel cyclo-oxygenase-2 inhibitor modulates catabolic and antiinflammatory mediators in osteoarthritis.
ITB (6-(p-bromophenyl)amino-7-(p-chlorophenyl)indazolo[2',3':1,5]-1,2,4-triazolo[4,3-a]-1,3,5-benzotriazepine) is a novel inhibitor of cyclo-oxygenase-2 (COX-2) with antiinflammatory activity in animal models. In the present study, we investigated the effect of this compound on the production of catabolic or antiinflammatory mediators in osteoarthritis (OA) cartilage. In OA cartilage explants, ITB inhibited the production of prostaglandin E(2) (PGE(2)), tumour necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase-13 (MMP-13) in a concentration-dependent manner, whereas nitrite was partially reduced. On the contrary, ITB increased the production of interleukin (IL)-10 and the expres…
Inhibition of leukocyte functions by the alkaloid isaindigotone from Isatis indigotica and some new synthetic derivatives.
The alkaloid isaindigotone (1a) and seven derivatives have been synthesized to study their influence on several leukocyte functions and the generation of inflammatory mediators. Isaindigotone (1a) was found to be a scavenger of superoxide generated either by the hypoxanthine/xanthine oxidase system or stimulated human neutrophils. Isaindigotone (1a) and its acetylated derivative (1b) also inhibited 5-lipoxygenase activity and leukotriene B(4) production in these cells, whereas none of the compounds affected degranulation. In RAW 264.7 macrophages stimulated with lipopolysaccharide, synthetic derivatives exerted higher inhibitory effects on prostaglandin E(2) (PGE(2)) and nitric oxide (NO) g…
Solid-phase synthesis and inhibitory effects of some pyrido[1,2-c]pyrimidine derivatives on leukocyte formations and experimental inflammation.
A number of pyrido[1,2-c]pyrimidines bearing a nitrogen, oxygen, or sulfur functionality at C-1 were synthesized on solid-phase using the iminophosphorane methodology and tested for their effects on leukocyte functions in vitro and antiinflammatory activity. Compound 5c was found to be a strong scavenger of superoxide anion and an inhibitor of chemiluminescence induced by 12-O-tetradecanoylphorbol 13-acetate in human neutrophils. These pyrido[1,2-c]pyrimidines inhibited the generation of PGE(2) by COX-2 in RAW 264.7 macrophages stimulated with lipopolysaccharide. Compounds 7, 5f, 6, and 8 inhibited enzyme activity, whereas the remaining compounds also acted on the induction phase. In additi…
[3.3]Ferrocenophanes with guanidine bridging units as multisignalling receptor molecules for selective recognition of anions, cations, and amino acids.
The synthesis, electrochemical, and optical properties of a new [3.3]ferrocenophane framework in which two ferrocene subunits, with similar electronic environments, are linked through two substituted guanidine moieties, are reported. The receptors 4-7 have been prepared in good yields by the reaction of bis(carbodiimide) 3 with primary amines. This architecture is exceptionally "tunable" because a variety of "legs" may be appended to the basic [3.3]ferrocenophane scaffold to give a wide range of signaling units. These receptors show remarkable ion-sensing properties, due to the presence of a redox active unit (ferrocene), and an amphoteric binding site (guanidine). In this nitrogen-rich str…
CCDC 1456591: Experimental Crystal Structure Determination
Related Article: Paula Sabater, Fabiola Zapata, Antonio Caballero, Israel Fernández, Carmen Ramirez de Arellano, and Pedro Molina|2016|J.Org.Chem.|81|3790|doi:10.1021/acs.joc.6b00468
CCDC 1417554: Experimental Crystal Structure Determination
Related Article: Tania Romero-Morcillo, Francisco Javier Valverde-Muñoz, Lucía Piñeiro-López, M. Carmen Muñoz, Tomás Romero, Pedro Molina, José A. Real|2015|Dalton Trans.|44|18911|doi:10.1039/C5DT03084F
CCDC 893127: Experimental Crystal Structure Determination
Related Article: Francisco Otón , María del Carmen González , Arturo Espinosa , Carmen Ramírez de Arellano , Alberto Tárraga , and Pedro Molina|2012|J.Org.Chem.|77|10083|doi:10.1021/jo301570u
CCDC 1417556: Experimental Crystal Structure Determination
Related Article: Tania Romero-Morcillo, Francisco Javier Valverde-Muñoz, Lucía Piñeiro-López, M. Carmen Muñoz, Tomás Romero, Pedro Molina, José A. Real|2015|Dalton Trans.|44|18911|doi:10.1039/C5DT03084F
CCDC 1417555: Experimental Crystal Structure Determination
Related Article: Tania Romero-Morcillo, Francisco Javier Valverde-Muñoz, Lucía Piñeiro-López, M. Carmen Muñoz, Tomás Romero, Pedro Molina, José A. Real|2015|Dalton Trans.|44|18911|doi:10.1039/C5DT03084F
CCDC 1821490: Experimental Crystal Structure Determination
Related Article: Paula Sabater, Faviola Zapata, Pedro Molina, Ibon Alkorta, Jose Elguero, Antonio Caballero, Carmen Ramirez de Arellano|2018|Chem. Sel.|3|3855|doi:10.1002/slct.201800809
CCDC 1448934: Experimental Crystal Structure Determination
Related Article: Lidia Gonzalez, Fabiola Zapata, Antonio Caballero, Pedro Molina, Carmen Ramirez de Arellano, Ibon Alkorta, Jose Elguero|2016|Chem.-Eur.J.|22|7533|doi:10.1002/chem.201600379
CCDC 1448935: Experimental Crystal Structure Determination
Related Article: Lidia Gonzalez, Fabiola Zapata, Antonio Caballero, Pedro Molina, Carmen Ramirez de Arellano, Ibon Alkorta, Jose Elguero|2016|Chem.-Eur.J.|22|7533|doi:10.1002/chem.201600379