Özkar, Saim
Various guests have been investigated in zeolite hosts in our laboratory over the past five years. From analysis of in situ spectroscopic observations (FT-IR, UV-vis, Mossbauer, DOR-MAS NMR) of the reaction sequences and structural features of precursors and products (EXAFS, Rietveld refinement of powder XRD data), the molecule size cavities and channels of zeolites respectively are viewed as providing macrospheroidal and macrocylindrical, multisite multidentate coordination environments toward encapsulated guests. By thinking, in particular, about the alpha- and beta-cages of the zeolite Y host effectively as a "zeolate' ligand composed of interconnected and perfectly organized anionic aluminosilicate 'crown ether-like" rings, the materials chemist is able better to understand and exploit the reactivity and coordination properties of the zeolite internal surface for the anchoring and self-assembly of a wide range of encapsulated guests (e.g., metal atoms, metal cations, metal clusters, coordination compounds, metal carbonyls, organometallics, metal oxides, and semiconductor nanoclusters. This approach helps with the design of synthetic strategies for creating novel guest-host inclusion compounds having possible applications in diverse areas of materials science, such as size/shape selective catalysis, nonlinear optics, quantum electronics, and photonics. To present this 'crown ether-zeolate ligand analogy", we will focus attention on structurally well-defined examples of metal-zeolate bonding, involving mainly metal carbonyls and molecular metal oxides, housed within the diamond network of interlaced 13-angstrom supercages (alpha-cages) of zeolite Y, mainly taken from our recent work. A coordination chemistry view of metal-zeolate bonding in intrazeolite metal organic chemical vapor deposition type precursors and semiconductor nanocluster products is presented in a separate publication.20


Zeolite confined nanostructured dinuclear ruthenium clusters: preparation, characterization and catalytic properties in the aerobic oxidation of alcohols under mild conditions
Zahmakiran, Mehmet; Özkar, Saim (Royal Society of Chemistry (RSC), 2009-01-01)
Zeolite confined nanostructured dinuclear ruthenium clusters as a novel material were prepared by a simple three step procedure: (i) the ion-exchange of Ru3+ ions with the extra-framework Na+ ions in zeolite-Y, (ii) reduction of the Ru3+ ions within the cavities of zeolite with borohydride ions in aqueous solution all at room temperature, (iii) drying the isolated samples under aerobic conditions at 100 +/- 1.0 degrees C. The composition, morphology and structure of zeolite confined nanostructured dinuclear...
Green synthesis of silver nanoparticles: biomolecule-nanoparticle organizations targeting antimicrobial activity
Roy, Anupam; Bulut, Onur; Some, Sudip; Mandal, Amit Kumar; Yilmaz, M. Deniz (Royal Society of Chemistry (RSC), 2019-01-23)
Since discovery of the first antibiotic drug, penicillin, in 1928, a variety of antibiotic and antimicrobial agents have been developed and used for both human therapy and industrial applications. However, excess and uncontrolled use of antibiotic agents has caused a significant growth in the number of drug resistant pathogens. Novel therapeutic approaches replacing the inefficient antibiotics are in high demand to overcome increasing microbial multidrug resistance. In the recent years, ongoing research has...
Photocatalytic microbial inactivation over Pd doped SnO2 and TiO2 thin films
ERKAN, Arcan; BAKIR, Ufuk; Karakaş, Gürkan (Elsevier BV, 2006-12-15)
The photocatalytic antimicrobial activity over TiO2, SnO2 and their Pd doped thin film samples were determined against Escherichia coli, Staphylococcus aereus, Saccharomyces cerevisiae and Aspergilus niger spores. Higher antimicrobial activity was observed with TiO2 than SnO2 thin films and, Pd addition contributes to an increase in the activity of both semiconductor oxides. The highest microbial inactivation was achieved with 1% PdO/TiO2 against E. coli with a 98% decrease in survival after 2 h illuminatio...
Adsorption of volatile organic compounds on soil and prediction of desorption breakthroughs
Yeo, SD; Tuncer, E; Akgerman, A (Informa UK Limited, 1997-01-01)
Vapor extraction of volatile organic compounds from soil was investigated by performing adsorption and desorption experiments of trichloroethylene, trichloroethane, and chlorobenzene on soil particles. The adsorption breakthrough curves were obtained using a dynamic response technique based on frontal analysis chromatography. The shape of the breakthrough curves indicated that the adsorption process was close to an ideal adsorption system of no mass transfer resistance, no axial dispersion, and infinitesima...
Influence of Terminal Carboxyl Groups on the Structure and Reactivity of Functionalized m-Carboranethiolate Self-Assembled Monolayers
Goronzy, Dominic P.; Stanek, Jan; Avery, Erin; Guo, Han; Bastl, Zdenek; Dusek, Michal; Gallup, Nathan M.; Gun, Saliha; Kucerakova, Monika; Levandowski, Brian J.; Machacek, Jan; Sicha, Vaclav; Thomas, John C.; Yavuz, Adem; Houk, K. N.; Danışman, Mehmet Fatih; METE, ERSEN; Alexandrova, Anastassia N.; Base, Tomas; Weiss, Paul S. (American Chemical Society (ACS), 2020-08-01)
The structure and function of self-assembled monolayers (SAMs) at the nanoscale are determined by the steric and electronic effects of their building blocks. Carboranethiol molecules form pristine monolayers that provide tunable two-dimensional systems to probe lateral and interfacial interactions. Additional omega-functionality, such as carboxyl groups, can be introduced to change the properties of the exposed surfaces. Here, two geometrically similar isomeric m-carborane analogues of m-mercaptobenzoic aci...
Citation Formats
G. OZIN and S. Özkar, “ZEOLATES - A COORDINATION CHEMISTRY VIEW OF METAL-LIGAND BONDING IN ZEOLITE GUEST HOST INCLUSION-COMPOUNDS,” CHEMISTRY OF MATERIALS, pp. 511–521, 1992, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/70000.