Fluorine complexes

The main binary tin fluorides are stannous fluoride and stannic fluoride. Because the stannous ion,, is readily oxidized to the stannic ion,, most reported tin and fluorine complexes are of tin(IV) and fluorostannates. Stannous fluoroborates have also been reported. 

Figure 8.7 Thermal behavior of no fluorinated complexes [AuCI (CNC6H40C H2 + i)] (labeled as no F), and the corresponding fluorinated derivatives 6a (F-3) and 6b (F-2).

An analogous fluorinated complex derivative measured under the same conditions also is less soluble and exhibits similar pressure differences of the initial solubility with and without olefln addition (Fig. 18). This gives rise to the assumption that the observed negative modifler effect generally is valid also for other derivatives. 

Fluorine complexes behave in the same way. Boron, in the first period, still does not show the normal coordination number and only forms BF, while the larger aluminium ion forms Na3AlF6 with a higher coordination number. The carbon ion in CF4 is, however, so small that the coordination number is limited to four and complex formation is completely absent. On the other hand, the larger Si4+ ion gives normal complexes such as K2SiF6, etc. 

Table 15 Distances and Angles in Some Antimony(III)-Oxygen (Fluorine) Complexes...

Ring fluorination of pyridine and its benzo derivatives is suggested to occur through nucleophilic attack of fluoride ion on an initial pyridine fluorine complex (87TL255, 91BCJ1081, 93AHC(58)29l). In electron-deficient pyridines and their benzo derivatives, fluorination on the pyridine ring is kinetically competitive with annular and side chain fluorination. 

In addition to the simple halides, boron forms fluorine complexes containing the fluoroboratc ion (BF4 ) Subhalidcs of boron arc known (B2X4) of the structure ... 

The compound [Ca(hfac)2(H20)2]2153 (Fig. 38) is a centrosymmetric dimer in the solid state, while the analogous barium complex, [Ba(hfac)2 (H20)]x,153 exists as a polymer. Both compounds have M-F interactions similar to those described for [Ba2(hfac)4(Et20)L The smaller size of calcium is probably responsible for the structural differences between these two water adducts. The volatility of these fluorinated complexes is certainly decreased by the M-F interactions, as well as by the overall oligomeric structure of the compounds. What relationship metal ligand interactions of this type play in the incorporation of BaF2 in films prepared from these compounds has not yet been elucidated. Interestingly, no base-free fluorinated /3-diketonate compounds have been structurally characterized. 

Thus the fluorine complexes are less covalent and more ionic than the bromine coordinated species due to the larger F/Si electronegativity difference. However, the complexation energies of CH3F are similar to those of CH3Br to Me3Sr (ca. 30 kcal mol . Table 5). The overview of complexation energies in Table 5 indicates that benzene and toluene compete well with these alkyl halides. 

GTE), which acts as a cofactor of insuhn in all insulin-dependent systems. Food intake is the main Cr source for humans l,l,l-Trifluoro-2,4-pentadione (tfacH) is one of the most commonly used chelating agents for the GC measurement of chromium, due to its quantitative reaction with the analyte, its volatility and thermal stability and its relative inertness towards undesirable on-column reactions. Furthermore, the exceptional sensitivity of ECD to the fluorinated complex and the ease of synthesis for calibration purposes, all these have made of tfacFI the most commonly used chelating agent for several decades . ... 

The world s production of elemental fluorine amounted to around 1990 to 17 000 tons per year it is concentrated in North America, Europe, and Japan. This production is exclusively electrochemical, because F2 is the most highly oxidizing stable species known and so it cannot be industrially obtained by the action of another oxidant. To be exact there are chemical reactions, which produce elemental fluorine, like K NiFg + KF —> K3NiF6 + 1/2F2 (at 673 K, [44]). But then it has to be taken into account that elemental fluorine was needed to prepare the fluorine complex of Ni(IV). And the preparation method described in [45] is only of laboratory scale. 

Living polymerizations. Of greater interest, however, is the fact that fluorophenyl-substituted bis(phenoxy-imine) Ti complexes easily show extremely narrow Mv/M ratios, around 1, indicative of living polymerization behavior.1132,1134,1140,1160 At 50 °C, the perfluorophenyl-substituted complex 137 is more active than the corresponding non-fluorinated complex 136 (4 x 104 vs. 3 x 103 gpK(mmolM) 1 h 1 bar-1 entries 67 and 4 in Table 18), and yields a PE with an extremely narrow molecular mass distribution 1.13).1134 Analogous perfluorophenyl Zr... 

The MAO-activated complexes 188-191 have been also tested in ethylene/propylene co-polymerization.1139 The perfluorinated complexes 188 and 189 resulted in somewhat higher activities and molecular masses than the corresponding non-fluorinated complexes 190 and 191 (188 4/w = 64 000 189 / / w 193 000 vs. 190 Mw = 4000 191 Mw = 9000). Moreover, the fluorinated complexes 188 and 189 incorporate propylene better than the non-fluorinated complexes 190 and 191 ((188 P = 12.9 mol% 189 P = 9.5mol% vs. 190 P = 6.0mol%, 191 P = 7.2mol%). This finding has been correlated to the higher electrophilicity of the metal in the fluorinated complexes.1... 

Espinet has also studied gold(I) isonitrile complexes [55]. In the substituted complexes (Figure 27) it is seen that the alkoxy chain length produces little variation in the transition temperatures and the Sa phase dominated. However, for the chlorogold(I) complexes, then the crystal and Sa phase are stabilized in the 3-fluorinated complexes (i. e. = F) compared to the unfluorinated complexes in the... 

Cleavage of [Ir(F-mppy)2Cl]2 by 2,2 -bipyridine gives [Ir(F-mppy)2(bpy)] 1. Relative to the ppy derivative, the fluorinated complex exhibits an increased emission energy, excited-state lifetime, and quantum yield of emission.9... 

The structure of [Pt(Me)3(Tp )] was compared with that of the distorted octahedral Pt(IV) complex containing the Tp CF3 ligand. The study supports a substantially weaker coordination for the fluorinated Tp ligand, the Pt-N being significantly longer and the Pt-Me slightly shorter in the fluorinated complex.524... 

HalogenofuUerenes can also be generated with chlorine, the next higher homolog. The synthetic methods are similar to those for fluorination. Both chlorine and halogenochlorides may be employed, but as with fluorine, complex mixtures are often obtained instead of separable compounds. Moreover chloro-fullerenes are less stable than their fluoro-analogs, they are prone to hydrolysis... 

Nemoto et al. at Nissan reported the first CVD growth of BSCCO films using fluorocarbon-based chelates [240]. Triphenyl bismuth and the hexafluoroacetylacetonato complexes of Sr, Ca, and Cu were used as precursors in oxygen at a 20 Torr system pressure with a substrate temperature of 600°C to give amorphous, insulating films. After an air anneal at 830°C for 1 h, the films were c-axis oriented Bi-2212 with 7(. = 50 K. Researchers at Advanced Technology Materials deposited amorphous BSCCO(F) films at 500 °C under 2 Torr pressure using the fluorinated complexes Ca(fod)2, Sr(fod)2, and Cu(hfa)2 as well as Bi(ph)3 as precursors [241]. Fluorine was... 

Measurements have been made of the room-temperature luminescence quantum yields of various Cr ammine and ethylenediamine complexes in water. Most emission was phosphorescence, but some fluorinated complexes emitted delayed fluorescence. The range of quantum yields was accounted for in terms of processes degrading the state. Radiationless decay rates for the transition... 

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