126 research outputs found
A Phosphine Functionalized Ī²āDiketimine Ligand for the Synthesis of Manifold Metal Complexes
One-size-fits-all: A Ī²-diketimine ligand and its corresponding anion, forming a PNNP-type pocket, can stabilize various coordination polyhedral. A complete series of complexes forming seven different coordination polyhedral and coordination numbers ranging from 2 to 6 were realized.
A bis(diphenyl)-phosphine functionalized Ī²-diketimine (PNac-H) was synthesized as a flexible ligand for transition metal complexes. The newly designed ligand features symmetrically placed phosphine moieties around a Ī²-diketimine unit, forming a PNNP-type pocket. Due to the hard and soft donor atoms (N vs. P) the ligand can stabilize various coordination polyhedra. A complete series ranging from coordination numbers 2 to 6 was realized. Linear, trigonal planar, square planar, tetrahedral, square pyramidal, and octahedral coordination arrangements containing the PNac-ligand around the metal center were observed by using suitable metal sources. Hereby, PNac-H or its anion PNacā acts as mono-, bi- and tetradendate ligand. Such a broad flexibility is unusual for a rigid tetradentate system. The structural motifs were realized by treatment of PNac-H with a series of late transition metal precursors, for example, silver, gold, nickel, copper, platinum, and rhodium. The new complexes have been fully characterized by single crystal X-ray diffraction, NMR, IR, UV/Vis spectroscopy, mass spectrometry as well as elemental analysis. Additionally, selected complexes were investigated regarding their photophysical properties. Thus, PNac-H proved to be an ideal ligand platform for the selective coordination and stabilization of various metal ions in diverse polyhedra and oxidation states
Alkali Metal Complexes of a Bis(diphenylphosphino)methane Functionalized Amidinate Ligand: Synthesis and Luminescence
A novel bis(diphenylphosphino)methane (DPPM) functionalized amidine ligand (DPPMāC(N-Dipp)H) (Dipp=2,6-diisopropylphenyl) was synthesized. Subsequent deprotonation with suitable alkali metal bases resulted in the corresponding complexes [M{DPPMāC(N-Dipp)}(Ln)] (M=Li, Na, K, Rb, Cs; L=thf, EtO). The alkali metal complexes form monomeric species in the solid state, exhibiting intramolecular metal-Ļ-interactions. In addition, a caesium derivative [Cs{PPhCH-C(N-Dipp)}] was obtained by cleavage of a diphenylphosphino moiety, forming an unusual six-membered ring structure in the solid state. All complexes were fully characterized by single crystal X-ray diffraction, NMR spectroscopy, IR spectroscopy as well as elemental analysis. Furthermore, the photoluminescent properties of the complexes were thoroughly investigated, revealing differences in emission with regards to the respective alkali metal. Interestingly, the hexanuclear [Cs{PPhCH-C(N-Dipp)}] metallocycle exhibits a blue emission in the solid state, which is significantly red-shifted at low temperatures. The bifunctional design of the ligand, featuring orthogonal donor atoms (N vs. P) and a high steric demand, is highly promising for the construction of advanced metal and main group complexes
Dvojni lijekovi primakina i nesteroidnih protuupalnih lijekova: Sinteza, hvatanje slobodnih radikala, antioksidativno djelovanje i keliranje Fe2+ iona
Novel primaquine conjugates with non-steroidal anti-inflammatory drugs (PQ-NSAIDs, 4a-h) were prepared, fully chemically characterized and screened for radical scavenging and antioxidant activities. The synthetic procedure leading to twin drugs 4a-h involved two steps: i) preparation of NSAID benzotriazolides 3a-h from the corresponding NSAID (ibuprofen, ketoprofen, fenoprofen, ketoprofen hydroxy and methylene analogues, diclofenac or indomethacin) and benzotriazole carboxylic acid chloride (BtCOCl, 1), ii) reaction of intermediates 3a-h with PQ. The prepared PQ-NSAIDs exerted moderate activities in the DPPH free radical test and -carotene-linoleic acid assay. Moreover, ketoprofen derivatives 4d and 4b demonstrated a notable Fe2+ chelating ability as well. On the other hand, negligible antiproliferative and antituberculotic effects of conjugates 4a-h were observed.U radu je opisana sinteza novih konjugata primakina s nesteroidnim protuupalnim lijekovima (PQ-NSAIDs, 4a-h), njihova potpuna karakterizacija te testiranje sposobnosti hvatanja slobodnih radikala i antioksidativnog djelovanja. Sintetski postupak za pripravu dvojnih lijekova 4a-h ukljuÄuje dva koraka: i) pripravu NSAID-benzotriazolida 3a-h iz odgovarajuÄih nesteroidnih protuupalnih lijekova (ibuprofena, ketoprofena, fenoprofena, hidroksi i metilenskih analoga ketoprofena, diklofenaka i indometacina) i klorida 1-benzotriazol karboksilne kiseline (BtCOCl, 1), ii) reakciju intermedijera 3a-h s primakinom. Novi PQ-NSAID konjugati pokazuju umjerenu sposobnost hvatanja slobodnih radikala u DPPH testu te umjereno antioksidativno djelovanje u pokusu s -karotenom i linoleinskom kiselinom. Osim toga, derivati ketoprofena 4d i 4b imaju primjetnu sposobnost keliranja Fe2+ iona. Svi konjugati 4a-h pokazuju vrlo slabo antiproliferativno i antituberkulotsko djelovanje
Ketorolak-dekstran konjugati: sinteza, in vitro i in vivo vrednovanje
Ketorolac is a non-steroidal anti-inflammatory drug. Dextran conjugates of ketorolac (KD) were synthesized and characterized to improve ketorolac aqueous solubility and reduce gastrointestinal side effects. An N-acylimidazole derivative of ketorolac (KAI) was condensed with a model carrier polymer, dextran of different molecular masses (40000, 60000, 110000 and 200000). IR spectral data confirmed formation of ester bonding. Ketorolac contents were evaluated by UV-spectrophotometric analysis. The molecular mass was determined by measuring viscosity using the Mark-Howink-Sakurada equation. In vitro hydrolysis studies were performed in aqueous buffers (pH 1.2, 7.4, 9) and in 80% (V/V) human plasma (pH 7.4). At pH 9, a higher rate of ketorolac release from KD was observed as compared to aqueous buffer of pH 7.4 and 80% human plasma (pH 7.4), following first-order kinetics. In vivo biological screening in mice and rats indicated that conjugates retained analgesic and anti-inflammatory activities with significantly reduced ulcerogenicity compared to the parent drug.U radu je opisana sinteza konjugata dektrana i protuupalnog lijeka ketorolaka (KD). Konjugati su pripravljeni da bi se poveÄala topljivost ketorolaka u vodi i smanjila njegova nusdjelovanja u gastrointestinanom traktu. Ketorak je prvo preveden u N-acilimidazolni derivat (KAI) koji je kondenziran s polimernim nosaÄem, dekstranom razliÄitih molekulskih masa (40000, 60000, 110000 i 200000). IR-spektri potvrdili su nastajanje esterske veze. Udio ketorolaka u konjugatu odreÄen je UV-spektrofotometrijskom analizom. Molekulske mase odreÄene su mjerenjem viskoznosti koristeÄi Mark-Howink-Sakurada jednadžbu. Hidroliza in vitro praÄena je u puferskim otopinama (pH 1,2, 7,4 i 9) i u 80% V/V humanoj plazmi (pH 7,4). Pri pH 9 primjeÄeno je znaÄajno brže oslobaÄanje ketorolaka iz KD nego u puferskoj otopini pH 7,4 i krvnoj plazmi. OslobaÄanje je prati kinetiku prvog reda. In vivo bioloÅ”ka ispitivanja na miÅ”evima i Å”takorima ukazuju da konjugati imaju analgetsko i protuupalno djelovanje, a znaÄajno smanjeno ulcerogeno djelovanje
New localities of the subendemic species Berberis croatica, Teucrium arduini and Micromeria croatica in the Dinaric Alps
New localities of three subendemic species (Berberis croatica, Teucrium arduini and Micromeria croatica) have been found in the Dinaric Alps. Berberis croatica was found at ten new locations, nine of them in Croatia and one in Bosnia and Herzegovina. Teucrium arduini was found on Mt UÄka, Mt Velebit, Mt Biokovo and Mt Sniježnica, at nine new locations while Micromeria croatica was found at four new locations, only on Mt Velebit
Human G ProteināCoupled Receptor Gpr-9-6/Cc Chemokine Receptor 9 Is Selectively Expressed on Intestinal Homing T Lymphocytes, Mucosal Lymphocytes, and Thymocytes and Is Required for Thymus-Expressed ChemokineāMediated Chemotaxis
TECK (thymus-expressed chemokine), a recently described CC chemokine expressed in thymus and small intestine, was found to mediate chemotaxis of human G proteinācoupled receptor GPR-9-6/L1.2 transfectants. This activity was blocked by antiāGPR-9-6 monoclonal antibody (mAb) 3C3. GPR-9-6 is expressed on a subset of memory Ī±4Ī²7high intestinal trafficking CD4 and CD8 lymphocytes. In addition, all intestinal lamina propria and intraepithelial lymphocytes express GPR-9-6. In contrast, GPR-9-6 is not displayed on cutaneous lymphocyte antigenāpositive (CLA+) memory CD4 and CD8 lymphocytes, which traffic to skin inflammatory sites, or on other systemic Ī±4Ī²7āCLAā memory CD4/CD8 lymphocytes. The majority of thymocytes also express GPR-9-6, but natural killer cells, monocytes, eosinophils, basophils, and neutrophils are GPR-9-6 negative. Transcripts of GPR-9-6 and TECK are present in both small intestine and thymus. Importantly, the expression profile of GPR-9-6 correlates with migration to TECK of blood T lymphocytes and thymocytes. As migration of these cells is blocked by antiāGPR-9-6 mAb 3C3, we conclude that GPR-9-6 is the principal chemokine receptor for TECK. In agreement with the nomenclature rules for chemokine receptors, we propose the designation CCR-9 for GPR-9-6. The selective expression of TECK and GPR-9-6 in thymus and small intestine implies a dual role for GPR-9-6/CCR-9, both in T cell development and the mucosal immune response
- ā¦