Bis(saccharinato)palladium(II) and platinum(II) complexes with 2,2′-bipyridine: Syntheses,structures, spectroscopic,fluorescent and thermal properties

New palladium(II) and platinum(II) complexes, cis-[Pd(bpy)(sac)₂] (1) and cis-[Pt(bpy)(sac)₂] (2), where sac = saccharinate, bpy = 2,2′-bipyridine, have been synthesized and characterized by elemental analysis, UV–Vis, IR, ¹H NMR and ¹³C NMR. The structures of the DMSO solvated complexes are determined by X-ray diffraction. Both complexes are isomorphous and the metal ions are coordinated by two N-bonded sac ligands, and two nitrogen atoms of pyridyl groups of bpy in a cis fashion. The mononuclear species interact each other through weak intermolecular C–H?O hydrogen bonds, C–H?π and π?π interactions leading to three-dimensional supramolecular networks. All complexes exhibit a high thermal stability in the solid state, and are fluorescent in the solution.     

Allyl sulfonium salt as a novel initiator for active cationic polymerization of epoxide by shooting with radicals species

A rapid cationic polymerization of cyclohexene oxide that completed within a few minutes was achieved by a new initiation system that involves (1) a copper‐catalyzed reduction of benzoyl peroxide by an ascorbic acid derivative that generates free radicals and (2) capture of the radicals by allyl sulfonium salt having hexafluoroantimonate (SbF) as a counter anion, followed by fragmentation of sulfonium radical cation, from which a super acid HSbF₆ was produced to initiate the rapid polymerization. The key factor in designing an efficient allyl sulfonium salt was attachment of an electron withdrawing ester group at the allyl group, of which ability to stabilize the formed radical can enhance the efficiency in trapping radicals by the allylic salt. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4178–4183, 2010     

Using digital stories to reduce misconceptions and mistakes about fractions: an action study

The aim of this study is to determine the mistakes and misconceptions about fractions of the fourth-grade students in a primary school and to eliminate these mistakes and misconceptions through digital stories. The study has been conducted with a total of 25 students in the fourth-grade of a private primary school in Turkey. An action research method based on qualitative research approach has been used in the study. In the preparation of activities related to digital stories, the mistakes and misconceptions that students have regarding fractions are taken into account. As a data collection tool, the Determination of Misconceptions Form consisting of 30 open ended questions about the fractions prepared by the researchers and the observation notes taken during the implementation process have been used. In addition, semi-structured interviews have been conducted to identify views of teachers and students about activities designed with digital stories. The implementation has been carried out for 5 weeks. Qualitative data analysis techniques have been used in analysing the data. As a result of the research, it has emerged that teaching implementations designed with digital stories have eliminated the mistakes and misconceptions that a large majority of students have about fractions. Most of the students who had a limited perception about the concept of fraction before implementation have fully perceived the definition of fractions after the activities designed with digital stories. Likewise, most of the students who incorrectly modelled the operations with fractions before the implementation, have been able to use the correct model for the operations with fractions after the-implementation fractions. When opinions about the activities designed with digital stories have been examined, it has been found that most students’ express positive opinions on digital story use in lessons and found digital stories fun, instructive and constructive.     

Approximation of Invariant Subspaces in Some Dirichlet-Type Spaces

The Hilbert space \(\mathcal {D}_{2}\) is the space of all holomorphic functions f defined on the open unit disc \(\mathbb {D}\) such that \({f}^{'}\) is in the Hardy Hilbert space \(\mathbf {H}^2.\) In this paper, we prove that the invariant subspaces of \(\mathcal {D}_{2}\) with respect to multiplication operator \(M_{z}\) can be approximated with finite co-dimensional invariant subspaces. We also obtain a partial result in this direction for the classical Dirichlet space.     

The Picard Theorem on S-metric spaces

Recently, the notion of an S-metric space is defined and extensively studied as a generalization of a metric space. In this paper, we define the notion of the S∞-space and prove its completeness. We obtain a new generalization of the classical "Picard Theorem".     

N‐alkoxy pyridinium ion terminated polystyrenes: A facile route to photoinduced block copolymerization

Photoactive N‐alkoxy 4‐phenyl pyridinium and N‐alkoxy isoquinolinium ion terminated polystyrenes with hexafluoroantimonate counter anion were prepared and characterized. For this purpose, mono‐ and dibrominated polystyrenes were prepared by atom transfer radical polymerization (ATRP). The reaction of these polymers with silver hexafluoroantimonate in the presence of 4‐phenylpyridine N‐oxide and isoquinoline N‐oxide in dichloromethane produced desired polymeric salts with the corresponding functionalities. Irradiation of these photoactive polystyrenes produced alkoxy radicals at chain ends capable of initiating free radical polymerization of methyl methacrylate (MMA). This way, depending on the number of functionality, AB or ABA type block copolymers were formed which were characterized with the aid of gel permeation chromatography and ¹H NMR spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 423–428, 2007.     

Trans‐bis(saccharinato)cadmium(II) Complexes with 2‐Aminomethylpyridine and 2‐Aminoethylpyridine — Synthesis,Crystal Structures,Spectral and Thermal Characterization of trans‐[Cd(sac)2(ampy)2] and trans‐[Cd(sac)2(aepy)2]

Two trans‐bis(saccharinato) (sac) complexes of cadmium(II ) with 2‐aminomethylpyridine (ampy) and 2‐aminoethylpyridine (aepy) were synthesized and characterized by means of elemental analysis, FT‐IR spectroscopy and thermal analysis. In addition, their solid‐state structures were determined by single crystal X‐ray diffraction studies. The [Cd(sac)₂(ampy)₂] ( 1 ) and [Cd(sac)₂(aepy)] ( 2 ) complexes consist of neutral monomeric units and crystallize in the orthorhombic (Pbca) and monoclinic (P2₁/c) crystal systems, respectively. The cadmium(II ) ions in 1 and 2 sit on inversion centres andexhibit distorted octahedral coordination by two sac anions and two aminopyridine ligands. The sac ligands in both complexes are N‐coordinated and located in trans positions, while the ampy and aepy ligands act as a bidentate ligand forming two symmetrically chelate rings around cadmium(II ). IR spectra and thermal decompositions of the complexes are also discussed.     

An investigation of electrorheological properties of calcium carbonate suspensions in silicone oil

In this study, electrorheological behavior of suspensions prepared from 0.9 and 5.0 µm calcium carbonate particulates, dispersed in insulating silicone oil medium was investigated. Sedimentation stabilities of suspensions (c = 5 wt %) prepared using these calcium carbonate powders were determined to be 6 and 4 days, respectively. Electrorheological activity of all the suspensions was observed to increase with increasing electric field strength, concentration and decreasing shear rate. Shear stress of calcium carbonate suspensions increased linearly with increasing concentrations of the particles and with the applied electric field strength. Electric field viscosity of all the suspensions was decreased sharply with increasing shear rate and particle size, showing a typical shear thinning non-Newtonian visco-elastic behavior. Effects of elevated temperature and polar promoter onto electrorheological activity of calcium carbonate/silicone oil system were also investigated.__________From Kolloidnyi Zhurnal, Vol. 67, No. 2, 2005, pp. 268–273.Original English Text Copyright © 2005 by Yilmaz, Ünal, Yavuz.This article was submitted by the authors in English.