Search results for "Cyana"
showing 10 items of 585 documents
Influence of the central metal ion in controlling the self-assembly and magnetic properties of 2D coordination polymers derived from [(NiL)2M]2+ node…
2014
Three new 2D coordination polymers (CPs) 2∞[(NiL)2Ni(μ1,5-N(CN)2)2]n (1), 2∞[(NiL)2Cd(μ1,5-N(CN)2)2]n (2) and 2∞[(NiL)2Zn(μ1,5-N(CN)2)2]n (3) have been synthesized by reacting a [NiL] “metalloligand” (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine) with three different metal(II) (Ni, Cd and Zn) perchlorates and sodium dicyanamide, with identical molar ratios of the reactants. All three products have been characterized by IR and UV-Vis spectroscopies, elemental analyses, powder and single crystal X-ray diffraction and variable temperature magnetic measurements. The isomorphous compounds 1 and 2 consist of similar [(NiL)2M(μ1,5-N(CN)2)] (M = Ni for 1 and Cd for 2) angular trinuclear un…
An original 1D Cu–Co heterometallic compound: synthesis, structure and magnetic properties
2006
A novel heterobimetallic system, 1∞[LCuIICoII(NCS)2] (1), was obtained by reacting the neutral mononuclear complex [LCu] with cobalt(II) acetate in the presence of potassium thiocyanate (L is the dianion of the Schiff base resulting from the 2 ∶ 1 condensation of 3-methoxysalicylaldehyde with 1,3-propanediamine). The crystallographic investigation of 1 reveals a one-dimensional alternating zig-zag chain-like structure, made of dinuclear {LCuCo} units linked by thiocyanate bridges. The copper(II) ion is pentacoordinate to the N2O2 donor set of the Schiff base ligand in the basal plane, with the apical position occupied by the sulfur atom. The cobalt ion displays a strongly distorted (4 + 2) …
Synthesis, structural aspects and magnetic properties of an unusual 2D thiocyanato-bridged cobalt(II)–Schiff base network
2010
Abstract A new two-dimensional (2D) thiocyanato-bridged cobalt(II) network formulated as [LCo2(NCS)2]n (1), has been synthesized with the Schiff base ligand N,N′-bis(3-methoxysalicylidenimino)-1,3-diaminopropane (H2L) and thiocyanate anions. This novel layered compound has been completely characterized by elemental analysis, FT-IR, UV–Vis spectroscopy and the structure has been established by single crystal X-ray diffraction studies. The structure of 1 consists of a doubly phenoxo-bridged dimer comprising two different cobalt(II) centers with different coordination geometries (octahedral and tetrahedral). The 2D network is accomplished by bridging thiocyanate ligands, connecting the dimeric…
Magnetic and catalytic properties of a new copper(II)–Schiff base 2D coordination polymer formed by connected helical chains
2011
Abstract A dicyanamide bridged 2D polynuclear complex of copper(II) having molecular formula [Cu2(L)(μ1,5-dca)2]n (1) has been synthesized using the Schiff base ligand N,N′-bis(salicylidene)-1,3-diaminopentane, (H2L) and sodium dicyanamide (dca). The complex presents a 2D hexagonal structure formed by 1,5-dca singly bridged helical chains connected through double 1,5-dca bridges. The chelating characteristics of the H2L Schiff base ligand results in the formation of copper(II) dimer with a double phenoxo bridge presenting a very strong antiferromagnetic coupling in the copper(II) derivative (1) (J = −510 cm−1). The dimeric asymmetric unit of 1 is very similar to the active site of the catec…
Single ion magnet behaviour in a two-dimensional network of dicyanamide-bridged cobalt(II) ions
2015
A novel two-dimensional coordination polymer of the formula [Co(dca)2(atz)2]n (1) resulted from assembling trans-bis(2-amino-1,3,5-triazine)cobalt(II) motifs by dicyanamide spacers. Variable-temperature dc and ac magnetic susceptibility measurements of 1 show that the high-spin cobalt(II) ions act as single ion magnets (SIMs).
Identification and Evaluation of Hazardous Pyrolysates in Bio-Based Rigid Polyurethane-Polyisocyanurate Foam Smoke
2021
In this study, rigid polyurethane (PU) and polyisocyanurate (PIR) foam samples made from renewable material (tall oil fatty acid) based polyols were analyzed by pyrolysis gas chromatography mass spectrometry (Py-GC/MS) to obtain information about the full relative smoke content, with a focus on substance identification by their functional groups and hazardousness. The relative content of gaseous products produced during the thermal degradation was evaluated between the two samples, differenced by their assigned isocyanate (NCO) index value—150 and 300. The main thermal degradation components of the rigid PU-PIR foam were found to originate from the decomposition of isocyanate, primarily for…
Optical determination of pH on surfaces using immobilized Fluorescent dyes.
1993
The attachment of pH-sensitive Fluorescent dyes on to hydroxylapatite for measuring the pH of small volumes is described. Fluorescein and acridine were used, both activated with reactive functions, such as isothiocyanate or succinimidyl ester groups, to enhance the possibility of a covalent linkage to the surface. First investigations were carried out on synthetic hydroxylapatite as the surface material. After the preparation of a particular surface with the fluorescent dye, steady-state and time-resolved fluorescence spectroscopies were employed for estimating the pH value of a solution applied to the surface. In this paper we present the results of our investigations done with both method…
A topology-constrained distance network algorithm for protein structure determination from NOESY data.
2005
This article formulates the multidi- mensional nuclear Overhauser effect spectroscopy (NOESY) interpretation problem using graph theory and presents a novel, bottom-up, topology-con- strained distance network analysis algorithm for NOESY cross peak interpretation using assigned resonances. AutoStructure is a software suite that implements this topology-constrained distance net- work analysis algorithm and iteratively generates structures using the three-dimensional (3D) protein structure calculation programs XPLOR/CNS or DY- ANA. The minimum input for AutoStructure in- cludes the amino acid sequence, a list of resonance assignments, and lists of 2D, 3D, and/or 4D-NOESY cross peaks. AutoStru…
Dynamic covalent urea bonds and their potential for development of self-healing polymer materials
2019
Self-healing polymer materials have drawn rapidly increasing interest over the last decade, and have been studied and used in an ever-increasing range of applications. Herein, we successfully make the covalent urea bond – a pinnacle of stability due to strong resonance effects – dynamic in nature through mediation of zinc salts. The dynamic covalent character of urea in the presence of zinc ions is confirmed through dissociation reaction experiments and quantum chemical calculations of small-molecule model urea compounds. In line with our experiments, the modelling results suggest that the presence of zinc ions speeds up the reaction of urea dissociation by two orders of magnitude via the f…
CCDC 247405: Experimental Crystal Structure Determination
2005
Related Article: J.Carranza, J.Sletten, C.Brennan, F.Lloret, J.Cano, M.Julve|2004|Dalton Trans.||3997|doi:10.1039/b412034p