Search results for "ligand"
showing 10 items of 2559 documents
Zn2+ and Cu2+ complexes of a fluorescent scorpiand-type oxadiazole azamacrocyclic ligand: crystal structures, solution studies and optical properties
2020
A ligand comprised of a macrocyclic pyridinophane core having a pendant arm containing a secondary amine group linked through a methylene spacer to a pyridyl–oxadiazole–phenyl (PyPD) fluorescent system has been prepared (L). The crystal structures of [ZnL](ClO4)2 and [CuL](ClO4)2 show that M2+ is coordinated to all the nitrogen atoms of the macrocyclic core, the secondary amine of the pendant arm and the nitrogen atom of the pyridine group of the fluorescent moiety, the latter bond being clearly weaker than the one with the pyridine of the macrocycle. Solution studies showed the formation of a highly stable Cu2+ complex with 1 : 1 stoichiometry, whereas with Zn2+ least stable complexes were…
From 1D coordination polymers to Metal Organic Frameworks by the use of 2-pyridyl oximes.
2020
The synthesis and characterization of coordination polymers and metal&ndash
Bidentate [N, N] nickel complexes with salen type ligands for polymerization of methyl methacrylate
2008
Otrzymano kompleksy niklu [N,N]NiBr2, które po aktywacji związkiem glinoorganicznym zastosowano w polimeryzacji metakrylanu metylu (MMA). Dwukleszczowe ligandy [N,N] uzyskano zastępując w ligandach salenowych grupy hydroksylowe podstawione do pierścieni fenylowych różnymi grupami alkoksylowymi (OMe lub OCH2C6H5). Metyloalumoksan (MAO) okazał się skutecznym aktywatorem kompleksów niklu w polimeryzacji MMA. Same kompleksy bez aktywatora nie wykazywały żadnej aktywności. Stwierdzono, że aktywność badanych układów katalitycznych rośnie ze wzrostem stosunku molowego Al/Ni. W wyniku polimeryzacji w stosowanych warunkach otrzymano poli(metakrylan metylu) (PMMA) z przewagą triad syndiotaktycznych c…
Interaction of methyltin(IV) compounds with carboxylate ligands. Part 1: formation and stability of methyltin(IV)–carboxylate complexes and their rel…
2006
Quantitative data on the stability of mono-, di- and trimethyltin(IV)-carboxylate complexes (acetate, malonate, succinate, malate, oxydiacetate, diethylenetrioxydiacetate, tricarballylate, citrate, butanetetracarboxylate and mellitate) are reported at t=25°C and I → 0 mol l - 1 . Several mononuclear, mixed proton, mixed hydroxo and polynuclear species are formed in these systems. As expected, the stability trend is mono- > di- > trimethyltin(IV) and mono < di < tri < tetra < hexa for the organotin moieties and carboxylate ligands investigated, respectively. Moreover, ligands containing, in addition to carboxylic,-O-and-OH groups show a significantly higher stability with respect to analogou…
Suitability of MMGBSA for the selection of correct ligand binding modes from docking results
2019
The estimation of the correct binding mode and affinity of a ligand into a target protein using computational methods is challenging. However, docking can introduce poses from which the correct binding mode could be identified using other methods. Here, we analyzed the reliability of binding energy estimation using the molecular mechanics‐generalized Born surface area (MMGBSA) method without and with energy minimization to identify the likely ligand binding modes within docking results. MMGBSA workflow (a) outperformed docking in recognizing the correct binding modes of androgen receptor ligands and (b) improved the correlation coefficient of computational and experimental results of rescor…
Oxygen Atom Transfer Catalysis by Dioxidomolybdenum(VI) Complexes of Pyridyl Aminophenolate Ligands
2021
A series of new cationic dioxidomolybdenum(VI) complexes [MoO2(Ln)]PF6 (2-5) with the tripodal tetradentate pyridyl aminophenolate ligands HL2-HL5 have been synthesized and characterized. Ligands HL2-HL4 carry substituents in the 4-position of the phenolate ring, viz. Cl, Br and NO2, respectively, whereas the ligand HL5, N-(2-hydroxy-3,5-di-tert-butylbenzyl)-N,N-bis(2-pyridylmethyl)amine, is a derivative of 3,5-di-tert-butylsalicylaldehyde. X-ray crystal structures of complexes 2, 3 and 5 reveal that they have a distorted octahedral geometry with the bonding parameters around the metal centres being practically similar. Stoichiometric oxygen atom transfer (OAT) properties of 5 with PPh3 wer…
Novel platinum(II) complexes with heterociclyc ligands: Synthesis and structural chracterization.
2008
An array of mononuclear complexes of Pt(II) with triazine and (benzimidazolyl)pyridine heterocycles is reported. The mononuclear complexes [PtCl2(Kdptdn)] [dbtdn=5,6- diphenyl-3-(2-pyridyl)-1,2,4-triazine-4’,4’’-disulfonate sodium salt hydrate], [PtCl2(bbp)] [bbp=2,6-bis(2-benzimidazolyl)pyridine] and [PtCl2(H2dpt)]PtCl4 [dpt=5,6-diphenyl-3-(2- pyridyl)-1,2,4-triazine] have been prepared and structurally characterized. Both neutral and ionic complexes are present, with bifunctional Pt(II) moieties, whose size and shape enable them to behave as novel scaffolds for DNA binding.
Progestogens and risk of breast cancer: a link between bone and breast?
2015
This article reviews the data supporting the role of receptor activator of the nuclear factor kappa (RANK) and its ligand, RANKL, in progestogen-induced breast cancer. Both experimental and clinical studies have been included. The expression of both RANK and RANKL has been described in epithelial cells of both mice and humans. Experiments of gain and loss of function in mice have shown that RANK/RANKL mediate alveologenesis during pregnancy or the estrous cycle. Moreover, the participation of the RANK/RANKL has been detected in models of breast carcinogenesis associated with progestogens-like medroxyprogesterone acetate. Recent clinical studies have found that the expression of RANK is asso…
Osteoprotegerin (OPG) and RANKL expression and distribution in developing human craniomandibular joint.
2005
Abstract During embryogenesis the bone tissue of craniomandibular joint (CMJ) is formed through two pathways: intramembranous ossification and endochondral ossification. The development process is under the control of regulatory factors.The osteoprotegerin (OPG) and the receptor activator of nuclear factor (NF)-κB ligand are key regulators of osteoclastogenesis. The aim of this study is the localization of OPG and RANKL mRNA and protein in the foetal CMJ by immunohistochemistry (IHC) and in situ hybridization (ISH). The main results were: OPG and RANKL mRNA and protein were co-localized in the same cell types; OPG and RANKL were specially immunolocated in osteogenic cells; immunolabeling wa…
Silicate modulates the cross-talk between osteoblasts (SaOS-2) and osteoclasts (RAW 264.7 cells): inhibition of osteoclast growth and differentiation
2012
It has been shown that inorganic monomeric and polymeric silica/silicate, in the presence of the biomineralization cocktail, increases the expression of osteoprotegerin (OPG) in osteogenic SaOS-2 sarcoma cells in vitro. In contrast, silicate does not affect the steady-state gene expression level of the osteoclastogenic ligand receptor activator of NF-κB ligand (RANKL). In turn it can be expected that the concentration ratio of the mediators OPG/RANKL increases in the presence of silicate. In addition, silicate enhances the growth potential of SaOS-2 cells in vitro, while it causes no effect on RAW 264.7 cells within a concentration range of 10-100 µM. Applying a co-cultivation assay system,…