Die Photolyse von [Cp″Fe(CO)2]2 1 (Cp″ = C5H3tBu2‐1,3) und P4 ergibt durch sukzessive PP‐Bindungsspaltung und Decarbonylierung die P4‐Komplexserie [Cp″2Fe2P4(CO)4 − n] 2 (n = O), 3 (n = 1), 4 (n = 2), 5 (n = 3) und 6 (n = 4) mit unterschiedlichen P4‐Liganden. 4 und 6 wurden zusätzlich durch eine Kristallstrukturanalyse charakterisiert.
Poly(4‐hydroxybenzoate) was prepared from 4‐acetoxybenzoic acid, 4‐pivaloyloxybenzoic acid, and 4‐trimethylsiloxy benzoyl chloride by condensation without the addition of a catalyst. Although various reaction conditions were used the products were always crystalline. The morphology of the as‐polymerized crystals has been studied by transmission electron microscopy as a function of molecular weight and end‐group type. It was possible to detect morphological features during the course of reaction from oligomers to polymer which enabled us to determine the mechanisms that are likely to control chain growth for different regimes of polymerization kinetics.
The (trimethylsi1oxy)benzoyl chlorides 1 -7 are easily to obtain under mild conditions from silylated hydroxybenzoic acids by means of thionyl chloride. Whereas these acid chlorides are stable at room temperature, they undergo condensation polymerization at temperatures above 100°C. Reactions with various nucleophils, such as thioalcohols, phenols, amines, N,O-bis(sily1ated) amino acids and N-silylated lactams were investigated. With hexamethyldisilazane and thionyl chloride the (trimethylsi1oxy)benzonitriles 21, 22 are accessible, and by means of trimethylsilyl azide the (trimethylsi1oxy)phenyl isocyanates 23 -25 were obtained. Conversion with phenyl carbazate and subsequent silylation lead to the 2-(trirnethylsiloxy)phenyl-l,3,4-oxadiazol-5-ones 27a -c.
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