Azulene complexes

Recently, an IR spectroscopic study showed that the diiron system [111] corresponding to 128 does not undergo such photoisomerization, because this system under irradiation only generates the respective syw-biradical and not a triplet species necessary for the formation of a photoproduct corresponding to 130 [136]. Actual publications report on the application of the system for solar energy storage [137]. 

Higher fulvalene complexes are rarely mentioned in the literature [90]. Higher metallocene oligomers are part of a review by O Hare et al. [95]. 

Azulene is an isomer of pentafulvalene and consists of a cyclopentadienyl and a cycloheptatrienyl unit, which are anellated resulting in a fulvene substructure. 

Multinuclear ruthenium complexes with azulene ligands were reported by Nagashima etal, [141], who investigated their catalytic behavior in hydrosilylation reactions. 

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In contrast to the reaction with indene, a triruthenium complex having a face-capping azulene ligand was isolated from the reaction of Ru3(CO)i2 with azulene, while formation of a tetrametallic azulene complex was also observed.It has been shown by means of X-ray diffraction studies that the azulene is coordinated to one of the ruthenium centers through its Cs ring in an / -fashion similar to the /t3-indene complex, and the seven-membered... 

Similar to the 3-azulene complex 111, complex 115 also catalyzes hydrosilylation of acetophenone. In addition, complex 115 has been shown to catalyze ring-opening polymerization of and cyclic siloxanes using... 

Formally there are five nonequivalent double bonds and, as a consequence, a number of different coordination modes have been reported [51]. The complexes are usually obtained by reaction of the ligand with metal complexes such as iron carbonyls. For example, the constitution of the dinuclear iron azulene complex 131 has been identified on the basis of its crystal structure analysis [138]. The interesting complex 132 with two azulene moeties was obtained by the reaction of triisopropyliron (from isopropylmagnesium bromide and FeClj) and azulene (Scheme 10.46) [139]. 

Polycyclic aromatic hydrocarbons, indole and quinoline derivatives, naphthylamines, azulenes Silica gel G Formation of oxidation products via the initially formed iodine complexes [15]... 

Parallel to this use of relatively simple approximations of the molecular orbital theory to the study of complex molecules Berthier has investigated the possible utilization of more refined molecular orbital procedures in the study of necessarily smaller molecules. We owe him the first application of the SCF method to the study of fulvene and azulene and also a pioneering extension, presented in 1953, of the SCF method to the study of molecules with incomplete electronic shells. 

Additions of suifinic acids to polyenes ( hydrosulfonylation ), however, proceed with very strong acids or under catalysis of Pd complexes (equation 17). With copper(Il) arenesulfinates, azulene has been oxidatively sulfonylated in the 1- and 2-positions of the five-membered ring (equation 18). The sulfonylmercuration has also been applied with success to conjugated dienes (equation 19). 

Nagashima reported the hydrogenation of di-, tri- and tetranuclear ruthenium complexes bearing azulenes below 100 °C revealed that only the triruthenium compounds reacted with H2 via triruthenium dihydride intermediates.398 This indicates that there exists a reaction pathway to achieve facile activation of dihydrogen on the face of a triruthenium carbonyl moiety.399... 

The reaction of salt 369 with acetic anhydride affords a cyclized product characterized as 2-methyl-1,3,3a,9-tetra-zacyclopentant[ ]azulene 370 (Scheme 38) <1999J(P1)1339>. The reaction of l,2-diamino-l,3-diazaazulenium compound 369 with diethyl ethoxymethylenedicarboxylate (DEEM) provides a complex reaction mixture, one of the isolated products being compound 21, which is isolated in 29% yield when the reaction is carried out in ethanol, but in 47% yield, when acetonitrile is used as solvent (Scheme 38) <1999J(P1)1339>. 

The interpretation of these effects as the formation of a proton addition complex was further supported by Plattner et al. (1952) by means of spectroscopic and conductimetric investigations. In these interactions the change of the absorption spectrum is characteristic, since the blue colour of the azulene in organic solvents is changed to a yellow colour in... 

In calculations on proton addition complexes of azulene and methyl-azulenes by means of the HMO method, Heilbronner and Simonetta (1952) took the effect of methyl groups into aecount by adjustment of the a and j8 values, as had already been done by PuUmann and collaborators (1950) in calculating the spectra of the methylazulenes. These calculations correctly reproduce the effeet of a methyl group on the basicity of azulene. In contrast to the ease of naphthalene, the position of addition of the proton remains independent of the position of the methyl group ... 

Molybdenum hexacarbonyl reacts with azulenes to give complexes of the type [Mo2(CO)6(azulene)], of unknown structure (29). 

Prolonged treatment of manganese carbonyl with azulenes gives unstable complexes of the type [Mn2(CO)6(azulene)2], the structures of which are uncertain (29). 

Interaction of azulenes (= az) with Fe(CO)6 or Fe3(CO)i2 gives reddish-brown complexes of the type [Fe2(CO)6(az)] (29) with azulene itself a com-... 

In the reactions of azulene with trimethylsilylruthenium carbonyl complexes in refluxing heptane, there occurs a migration of organosili-con groups from metal to ligand to give complexes of silylated azulenes (94) ... 

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