TABLE 1: ELEMENTAL ANALYSIS, COLOUR AND FORMULA OF Cr(III) COMPLEXES
Note also that the coordination number ofa complex often increases as the charge on the metal ion becomeslarger.
TABLE 2: IR SPECTRAL DATA OF Cr(III) COMPLEXES OF LIGA 1, 2, 3
It will be shown that the polymer chains initially produced within the mesopores of the Cr-MCM-41 material form nanofibres of polyethylene with a length of several microns and a diameter of 50 to 100 nanometers.
Due to these applications it is highly desirable to synthesise and characterise transition metal complexes with such ligands. In present paper we report the synthesis and characterisation of complexes with thiosemicarbazone (L1) and semicarbazone (L2) derived from 2-benzoylpyridine according to scheme 1 and scheme 2 and with ligand (L3) derived from 2-benzoylthiophene and thiosemicarbazone according to Scheme 3.
TABLE 4: EPR SPECTRAL DATA OF Cr(III) COMPLEXES OF LIGAND 1, 2
EPR Spectra: The X-band EPR spectra of the complexes (Fig. 5a & 5b) under study recorded as polycrystalline sample at room temperature. The giso values obtained from the EPR spectra are recorded in Table 4. In The X- band spectra of all Chromium(III) complexes in solid state a broad signal in vicinity of giso≈2.0 is observed. No hyperfine line is observed so D and E parameters can not be calculated. The proposed geometry of all the Cr(III) complexes is octahedral.
The IR spectra of acetato complexes of Cr(III) of both the ligands show appearance of bands at 1420-1448, as vC=O and 1200-1202cm-1 as vC-O. The difference of v5 and v1 is 248 and 220cm-1 corresponds to monodentate behaviour of acetate group 28.
10/01/2018 · Synthesis of oximes from (arene)Cr ..
T1 - Atom transfer as a preparative tool in coordination chemistry. Synthesis and characterization of Cr(V) nitrido complexes of bidentate ligands
FIG. 5a & 5b: EPR SPECTRA OF [Cr(L1)2(NO3)2]NO3 AND [Cr(L1)2(OAc)2]OAc COMPLEXES
SYNTHESIS AND SPECTROSCOPIC CHARACTERISATION OF Cr…
Preparation and properties of some Cr(III) complexes
into consideration as a possible reason of antidiabetic activities of some Cr(III) complexes, ..
Substituted dipyridophenazine complexes of Cr(III): Synthesis, ..
Abstract The synthesis of some α-methylene-γ-lactones employing allylic Cr and Sn complexes is described.
Synthesis of Fe–Li–Cr Multinuclear Complexes as …
Synthesis, characterization, and reactivity of PPN[Cr…
Syntheses and characterisation of platinum(0) complexes
The catalyst particles also gradually break up during ethylene polymerization resulting in the formation of crystalline and amorphous polyethylene with a low bulk density and a melt flow index between 0.56 and 1.38 g per 10 min; this indicates the very high molecular weight of the polymer.
1,2-Amino Alcohols and Their Heterocyclic Derivatives …
Combined DRS-ESR spectroscopies were used to monitor the reduction process of Cr6+/5+ and the oxidation and coordination environment of Crn+ species during catalytic action.
Aerobic Copper-Catalyzed Organic Reactions - …
The polymerization activity is dependent on the Cr loading, precalcination temperature and the support characteristics; a 1 wt % [Cr(acac)3]-AlMCM-41 catalyst pretreated at high temperatures was found to be the most active material with a polymerization rate of 14 000 g polyethylene per gram of Cr per hour.
Allen was born in 1984 in Kutztown, Pennsylvania
The combined ground and excited state studies demonstrate enhanced ground state oxidative properties (4-dmcbpy shifts 1/2 +0.22 V), microsecond time-scale storage of ∼1.7 eV in excited states, and ancillary ligand-tunable light absorption properties in this family of complexes.
Journal of Nanoscience and Nanotechnology
After calcination, Cr3+ is almost completely oxidized to Cr6+, which is anchored onto the surface as dichromate, some chromate and traces of small amorphous Cr2O3 clusters and square pyramidal Cr5+ ions.
Nanocomposites: synthesis, structure, properties and …
Hydrogen bonding between surface hydroxyls and the acetylacetonate (acac) ligands is the only type of interaction between [Cr(acac)3] complexes and SiMCM-41, while the deposition of [Cr(acac)3] onto the surface of AlMCM-41 takes place through either a ligand exchange reaction or a hydrogen-bonding mechanism.
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