Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 31Citation - Scopus: 36Integration of Triboluminescent Eud4tea Crystals To Transparent Polymers: Impact Sensor Application(American Chemical Society, 2017) İncel, Anıl; Eanes, Mehtap; McMillen, Colin D.; Demir, Mustafa MuammerLanthanide-based organometallic materials are well-known candidate triboluminescent (TL) materials that can show bright emission when a mechanical force is applied. These materials are usually in the form of crystalline powders, and it is often useful to integrate these samples into a polymer matrix in order to achieve processability, enabling coating from a solution/molten state or fabrication as a complex-shaped matrix. In this work, micrometer-sized europium tetrakis (dibenzoylmethide) triethylammonium (EuD4TEA) crystals were synthesized and integrated with various transparent polymers (PMMA, PS, PVDF, and PU) using two approaches: (i) blending and (ii) surface impregnation. In the former method, the crystalline particles were molecularly dissolved; therefore, a TL response cannot be achieved. More than 10 wt % TL crystals in the composite is needed to obtain TL signals. However, TL signal was achieved at 2.5 wt % when a composite was prepared by the latter approach. TL intensity shows exponential decay with consecutive mechanical action. The TL emission of PU-based surface impregnated composite expires with long-lived emission, and maximum TL response with respect to applied force was measured between 2.45 and 42.0 N.Article Citation - WoS: 7Citation - Scopus: 7Hydrothermal Synthesis of New Rare Earth Silicate Fluorides: a Novel Class of Polar Materials(Academic Press Inc., 2012) McMillen, Colin D.; Eanes, Mehtap; Stritzinger, Jared T.; Kolis, Joseph K.Polar crystals provide an interesting avenue for materials research both in the structures they form and the properties they possess. This work describes the hydrothermal synthesis and structural characterization of three novel silicate fluorides. Compound (1), LiY 3(SiO 4) 2F 2 crystallizes in space group C2/c, with a=17.651(4) Å, b=4.8868(10) Å, c=11.625(2) Å and β=131.13(3)°. BaY 2(Si 2O 7)F 2 (2) crystallizes in space group P-1, with a=5.1576(10) Å, b=6.8389(14) Å, c=11.786(2) Å, α=93.02(3)°, β=102.05(3)° and γ=111.55(3) °. Finally, the structure of Ba 2Y 3(SiO 4) 2F 5 (3) was determined in the polar orthorhombic space group Pba2, having unit cell parameters a=8.8864(18) Å, b=12.764(3) Å and c=5.0843(10) Å. The structures are compared based on their building blocks and long range polarities. Aligned silicate tetrahedra segregated into a single layer in (3) impart the observed polarity.Article Citation - WoS: 5Citation - Scopus: 5Hydrothermal Synthesis and Characterization of One Dimensional Chain Structures of Monolacunary Keggin Polyoxoanions Substituted With Copper(Elsevier Ltd., 2015) Eanes, Mehtap; Önen, Banu; McMillen, Colin D.Two novel polymeric polyoxometallates constructed from transition metal substituted heteropolytungstates, [(4,4’bpyH2)2(4,4’bpyH)][PCuW11O39]·H2O (1), and [(4,4’bpyH2)(pyH)3][PCuW11O39]·2H2O (2), (4,4’bpy = 4,4’bipyridine, py = pyridine) have been synthesized under hydrothermal conditions and characterized by IR, TGA, single crystal X-ray diffraction and magnetic measurements. The product formation showed a high sensitivity toward experimental factors including pH and stirring. Compounds 1 crystallizes in the monoclinic space group P2(1)/n with a = 13.503(3) Å, b = 26.726(5) Å, c = 15.168(3) Å, = 99.61(3)° and Z=4. The second compound also crystallizes in space group P2(1)/n, but with a = 13.519(3) Å, b = 20.431(4) Å, c =18.655(4) Å, = 96.52(3)° and Z=4. Compound 1 exhibits a zigzag chain structure, while compound 2 exhibits a straight chain structure. Compound 2 is the first example of a polyoxometallate containing 1D chains of transitionmetal- substituted heteropolytungstate designed with two significantly different organic units as the countercations. The Cu2+ ions in 1 exhibit paramagnetic behavior.