Lead tetrakis preparation

Lead tetrakis(trifluoroacetate), Pb(OCOCF3)4, which is prepared from red lead oxide (Pb304), trifluoroacetic acid, and trifluoroacetic anhydride [435], has very limited applications. It converts alkylbenzenes into benzylic trifluoroacetates [435] and benzene and its derivatives into phenyl trifluoroacetates [435, 449]. 

Spirostannanes can also be prepared by organoboration of tetrakis(trimethylsilyl-ethynyl)tin with acyclic trialkylboranes BR3 to give the stannaspiro[4,4]nona-l,3,6,8-tetraenes117 74 (R = ethyl, neopentyl). A stannacyclopentadiene was prepared by this type of organoboration of alkynylstannanes123. Treating bis(trimethylsilylethynyl)dimethyltin with a trialkylboron leads to the substituted stannacyclopentadiene 75. 

The synthesis of [RuL] where H2L = 2,3-naphthalocyanine has been reported. Reactions with suitable bridging ligands lead to oligomers, electrical conductivity data for which have been compared with those of related compounds. The tetrakis(tert-butyl) derivative [Ru ( BU4L)] has been prepared by the thermal decomposition of the [Ru( Bu4L)(Lax)2] (Lax = NH3, 3-Clpy). ... 

The analogous reaction of Cjq with bis-o-quinodimefhane (Scheme 4.6) leads to a bridged system [41], which can be regarded as a part of a band polymer containing the C50 unit and exhibits a significantly decreased solubility. The bis-o-quino-dimethane was prepared in situ from l,2,4,5-tetrakis(bromomethyl)benzene 40. Scheme 4.6 shows one of the possible conformers of the bisadduct 41. 

The tetrakis complexes are easily obtained by the addition of an excess of the appropriate pyridine, in absolute ethanol or methanol, to a solution in the same solvent of the anhydrous nickel salt.147 The bis adducts are prepared by using stoichiometric amounts of the anhydrous reactants783 or by heating the corresponding tetrakis complexes at temperatures in the range 80-110 °C.784 820 Thermal decomposition of the bis and tetrakis adducts leads to the mono adducts. Using hydrated nickel salts as starting material may cause the formation of complexes with coordinated water molecules. 

In this respect, red lead acts as lead tetraacetate in situ [434], Lead oxide, Pb304, is also used in the preparation of lead tetraacetate and tetrakis(trifluoroacetate) [435]. 

A,7V-polyazolylmethanes can be prepared by reaction of azoles with methylene chloride in an autoclave at 150 °C (Scheme ll).20 At 200 °C this reaction leads to 4,4 -dipyrazolylmethane, which upon reaction with boranes gives a pyrazaboles polymer. Some derivatives have been prepared from the reaction of potassium salts of the azole and methylene iodide. The ligand (tetrakis-(l-pyrazolyl)methane was prepared analogously. In selected cases a basic medium was employed.21... 

Tetrakis(carboxylato)dimetal complexes have been prepared from Cr, Cu, Mo, Re, Rh, Ru, Tc, and W. For leading references, see FA Cotton, RA Walton. Multiple Bonds Between Metal Atoms. New York Wiley, 1982. 

An attempt to prepare tetrakis(pentafluorophenyl)lead analogously from lead dichloride, pentafluorophenyllithium, and pentafluoroiodobenzene failed, although the action of pentafluorophenylmagnesium bromide on lead dichloride in the presence of benzyl chloride gave the mixed organolead compound ... 

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