Chemical analysis, coordination compounds

Experiment 15 Synthesis of a Coordination Compound and Its Chemical Analysis... 

Dimercury(I) n complexes are formed between aromatic compounds and Hg2(AsF6)2 in liquid S02 as solvent.113,121 Insoluble complexes with the ratio arene Hg2+ = 1 1 (arene = benzene, naphthalene, 2-methylnaphthalene, 2,6-dimethylnaphthalene, acenaphthene, fluor-anthrene, phenanthrene, anthracene, 9,10-dimethylanthracene or 1,3-dinitrobenzene) or 1 2 (arene = 9,10-benzophenanthrene) have been characterized by elemental analysis and, in some cases, by Raman spectrometry.113,120 The 13CNMR data allow the estimation of formation constants for the hexamethylbenzene, p-xylene and 1,4-dichlorobenzene complexes together with the chemical shifts for the bound substrates in these cases.121 Probably the coordination compounds of dimercury(I) salts with carbazole, dibenzofuran and diben-zothiophene are also n complexes.122... 

Synthesis of a coordination compound and its chemical analysis beaker, Erlenmeyer flask, evaporating dish, volumetric flask, pipet, analytical balance, testtubes/cuvettes, spectrophotometer... 

To continue this introduction to MO models, we look next at a coordination compound. Consider the 18-electron complex Cr(CO)6 which has octahedral geometry (Figure 1.9). Here the metal acts as a Lewis acid but now one that can accommodate more than a single pair of electrons. How does this factor complicate the analysis A chemically informative fragment analysis generates a Cr atom and six CO ligands. 

Electron spectroscopy for chemical analysis (ESCA) has also been apphed successfully for elucidating oxidation states and coordination numbers of gold compounds, but the number of studies is stiU very limited. 

Water could play a structure-directing role in the synthesis of microporous compounds, but such examples are very rare. The most remarkable one is the synthesis of VPI-5 by using dipropylamine as SDA.[111] However, chemical analysis indicated that the organic amine content in the framework of VPI-5 is very small (about one dipropylamine molecule/2.5 cells). The channels of VPI-5 were filled with a large number of water molecules instead of dipropylamine molecules. There are 7 water molecules in one cell of VPI-5. Two of them (I, II) coordinated to the A1 atom in the framework, and four of them (III-VI) formed three helical water molecule chains in the 18-membered-ring channel of VPI-5 via intermolecular H-bonds. These three helical water molecule chains connected all 6-coordinated A1 atoms. The last water molecule (VII) was located in the center of the channel. Therefore, it was proposed that these water molecules played a structure-directing role in the creation of the framework of VPI-5. The synthesis of VPI-5... 

Coordination compounds find application in many different areas, for example, as antidotes for metal poisoning and in chemical analysis. 

From on-line coupled TG-MS and TG-FTIR measurements, in combination with quantitative chemical analysis, the chemical formula for an unknown bismuA oxalate compound was deduced to be Bi(NH4)(C204)2 3.71(6)H20 by Vanhoyland et al. [78], Solution of the crystallographic structure on the basis of X-ray powder data proved this formula to be correct. Bi is 8-fold coordinated by oxygen from the oxalate anions. Because these BiOg polyhedra do not share any edges or vertexes, an open framework is formed with water and ammoniiun molecules between. As a result, water can easily be removed, which is clearly indicated by the rapid initial mass loss in the TG cxu e. 

Organometallic and Coordination Compounds. - Crystallization of ferrocene and ruthenocene substituted in the 1- and T-positions by two nitronyl nitroxide radicals gave the new crystal phases p-1 (besides the known phase a-1, a-2, and a-2 whose structures were determined by X-ray analysis and were investigated by C and H NMR spectroscopy with MAS NMR. The solid state Sn CP MAS NMR spectra of a series of triaryltin chlorides of the form ArsSnCl have been acquired. The indirect spin-spin coupling constants (J( Sn- C1)), quadrupolar-dipolar shifts (6( Sn- Cl)), and the Sn chemical shift tensors were extracted. " Powders of the zinc and copper(II) dimethyl-(MDtc), diethyl-(EDtc), and morpholinedithiocarbamate (MfDtc) complexes quantitatively absorb hexamethyleneimine (Hmi) to produce the adducts... 

New instrumental surface techniques (24) have been introduced to study adhesion during the last ten years. Among them, ESCA (or electron spectroscopy for chemical analysis) techniques (25) have given us insights about the structure of the polymeric interface within the first 50A. New applications of ESCA are discussed by Briggs (26). A combination of ESCA and AES (27) has been used to investigate the interfacial bonding between aluminum and chromium(III) fumarato-coordination compounds. 

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