Borate, poly -, alkali metal

Pyrazoles, and some indazoles, substituted on the nitrogen by B, Al, Ga, In, Si, Ge, Sn, P and Hg are known. Poly(pyrazol-1 -yl)borates have been studied by Trofimenko (72CRV497) who found that they were excellent ligands (Section 4.04.2.1.3(vi)). The parent ligands (282), (283) and (284) are available by the reaction of an alkali metal borohydride with pyrazole, the extent of substitution depending on the reaction temperature (Scheme 22). 

During the time of the Olin reports, the first examples of oligomeric boron-bridged (l-pyrazolyl)borate systems appeared from the laboratory of Trofimenko at DuPont Chemicals 24 He reported the synthesis of poly(l-pyrazolyl)borates (6) (Fig. 5) from the reactions of alkali metal borohydrides with the pyrazole ligand. The (l-pyrazolyl)borate ligand was obtained from two pyrazole units when bridged by a BR2 unit on one side and by a metal or onium ion on the other. Even though reports... 

B. POTASSIUM HYDROTRIS(1 -PYRAZOLYL)BORATE— ALKALI METAL POLY(l-PYRAZOLYL)BORATES... 

Another approach which has been taken by many researchers for chain extension of polyesters is the use of di or poly-epoxy compounds. Diepoxides, usually of molecular weight between 100 and 1200 have been used, often with catalysts such as tetrasodium ethylenediaminetetraacetate [195], alkali metal halides [200], or alkali metal borates [207]. N,N -bis(glycidyl ester)pyromellitimides have been investigated [170, 171], as have digycidyltetrahydrophthalate [172], di- or poly-substituted diphenylpropane and related substances [205]. It has also been suggested that, for ease of handling and addition, such compounds may be combined with a titanium dioxide carrier [209]. 

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