ABSTRACT
The active sites of [FeFe]-hydrogenase promoted by Fe/E (E = S, Se) clusters have attracted considerable interest due to their significance in understanding the interconversion of hydrogen with protons and electrons. As an extension of the study on Fe/Se clusters related to H-cluster model compounds of [FeFe]-hydrogenase, a series of tertiary phosphine substituted Fe/Se carbonyls were successfully prepared. The treatment of Fe2(µ-SePh)2(CO)6 (A) and excess PR3 resulted in the ferrous bis(selenolate) carbonyls Fe(SePh)2(CO)2(PR3)2 (PR3 = PPhMe2, 1; PMe3, 2) in moderate yields. In striking contrast, the reaction of Fe2(µ-SeCH2Ph)2(CO)6 (B) with the same PR3 ligand resulted in the PR3-disubstituted models Fe2(µ-SeCH2Ph)2(CO)4(PR3)2 (PR3 = PPhMe2, 3; PMe3, 4) as the principal products. The more interesting finding is that two independent isomers (anti- and syn-) can be isolated according to different reaction temperatures. Further reactions of 3 or 4 with PR3 under UV irradiation afforded the first PR3-trisubstituted 2Fe2Se derivatives Fe2(µ-SeCH2Ph)2(CO)3(PR3)3 (PR3 = PPhMe2, 5; PMe3, 6). 6 could be further converted into the tetrasubstituted product Fe2(µ-SeCH2Ph)2(CO)2(PMe3)4 (7), while no further substitution was observed with 5 and excess of PPhMe2. All the prepared compounds were fully characterized by elemental analysis, various spectroscopic techniques and X-ray crystallography. In addition, some electrochemical properties of these models were studied by cyclic voltammetry (CV) in MeCN. Compounds 4, 6 and 7 were found to be catalysts for the H2 evolution reaction under electrochemical conditions.
Subject(s)
Hydrogenase , Iron-Sulfur Proteins , Crystallography, X-Ray , Hydrogen/chemistry , Hydrogenase/chemistry , Iron-Sulfur Proteins/chemistry , Models, Molecular , ProtonsABSTRACT
Six novel organotin phosphonate complexes, [(Me3Sn)4(HL1)4]n1, [(Me3Sn)2(HL2)2]n2, [(Me3Sn)2L3(H2O)]n3, [(Ph3Sn)(HL1)]64, [(Ph3Sn)2L2]n5 and [(Ph3Sn)2L3]66, derived from phosphonic acid ligands [NaHL1 = 1-C10H7OPO2(OH)Na, H2L2 = 1-C10H7PO(OH)2, H2L3 = 2-C10H7PO(OH)2], have been synthesized and characterized by elemental analysis, FT-IR, NMR (1H, 13C, 31P and 119Sn) spectroscopy and X-ray crystallography. The structural analysis reveals that complexes 1 and 5 display 1D infinite zig-zag chain structures, and complex 2 shows 1D right-handed helical chain structure, while complex 3 displays 1D left-handed helical chain structure. Complexes 4 and 6 are 24-membered macrocyclic rings interconnected by P, O and Sn atoms. Additionally, the molecules of complexes 1 and 3 are further linked through intermolecular π···π and O-H···O interaction into supramolecular structures, respectively. Furthermore, we preliminarily estimated in vitro cytostatic activity of complexes 1-6 against the human cervix tumor cells (HeLa), human hepatocellular carcinoma cells (HepG-2) and human normal breast cells (HBL-100). Importantly, the anti-proliferative properties and possible pathway of complex 6 are investigated, and the results demonstrate that complex 6 could induce apoptotic cell death via an overload of intracellular reactive oxygen species (ROS) levels and the dysfunctional depolarization of mitochondrial membranes.
Subject(s)
Cytostatic Agents/chemistry , Cytostatic Agents/pharmacology , Organotin Compounds/chemistry , Organotin Compounds/pharmacology , Phosphorous Acids/chemistry , Apoptosis/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Crystallography, X-Ray , Cytostatic Agents/chemical synthesis , Female , HeLa Cells , Humans , Ligands , Liver Neoplasms/pathology , Magnetic Resonance Spectroscopy , Male , Molecular Structure , Organotin Compounds/chemical synthesis , Phosphorous Acids/pharmacology , Reactive Oxygen Species/metabolism , Spectroscopy, Fourier Transform Infrared , Tin/chemistry , Uterine Cervical Neoplasms/pathologyABSTRACT
BACKGROUND: This study will explore the efficacy and safety of horizontal muscle augmentation (HMA) combined inferior oblique muscle shortening (IOMS) for the treatment of pediatric strabismus (PS). METHODS: Literature search for studies will be carried out in the following databases: Cochrane Library, MEDILINE, EMBASE, CINAHL, Web of Science, PsycINFO, CBM, and CNKI. We will search all these databases without language and publication status restrictions. Two independent authors will perform selection of studies, data collection and management, risk of bias evaluation. A third author will be consulted with the help of discrepancies. RESULTS: This study will provide a synthesis of existed evidence for HMA combined IOMS for the treatment of PS. CONCLUSION: The results of this study will provide evidence to evaluate the efficacy and safety of HMA combined IOMS for the treatment of PS, which can help to guide clinical decision-making. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019149716.
Subject(s)
Exercise Therapy/methods , Strabismus/rehabilitation , Child , Humans , Oculomotor Muscles , Randomized Controlled Trials as Topic , Research DesignABSTRACT
In this paper, we synthesized a series of curcumin analogs and evaluated their cytotoxicity against HepG2 cells. The results exhibited that the hydroxyl group at 3,3'-position play an essential role in enhancing their anti-proliferation activity. More importantly, 3,3'-hydroxy curcumin (1b) caused apoptosis in HepG2 cells with the ROS generation, which may be mainly composed of hydroxyl radicals (HO) and H2O2. The more cytotoxic activity and ROS-generating ability of 1b may be due to the more stable in (RPMI)-1640 medium and more massive uptake than curcumin. Then the generation of ROS can disrupt the intracellular redox balance, induce lipid peroxidation, cause the collapse of the mitochondrial membrane potential and ultimately lead to apoptosis. The results not only suggest that 3,3'-hydroxy curcumin (1b) may cause HepG2 cells apoptosis through ROS-mediated pathway, but also offer an important information for design of curcumin analog.