Poly borato alkyl derivatives

A. Poly(pyrazolyl)borato Alkyl Derivatives of the Group 2 Elements... 

Poly(pyrazolyl)borato alkyl derivatives of the Group 13 elements (Al, Ga, In, Tl) have been synthesized for all members with the exception of thallium. 

Of the group 14 elements (Si, Ge, Sn and Pb), only tin is known to form a variety of poly(pyrazoIyl)borato alkyl derivatives. For example, the reactions between K[pzTp] and the silicon derivatives Me SiCl4 (n = 1-3) have not given tractable products (115). Similarly, the reaction between K[pzTp] and Me2GeCl2 gives a complex that has been spectroscopically characterized as [pzTp]2GeMe2, but which readily decomposes. 

Gold (continued) pentafluoride, structure, 27 103 peroxides, 6 343-344 phthalocyanine, preparation of, 7 64 polyhalogen complex of, 3 153 poly(pyrazolyl)borato alkyl derivatives, 42 320-321... 

III. Terminal Alkyl Derivatives of the s- and p-Block Metals Supported by Poly(pyrazolyl)borato Ligation... 

Alkyl derivatives of the Group 2 metals (Be, Mg, Ca, Sr, Ba) supported by poly(pyrazolyl)borato ligation have only been isolated for the lighter congeners, beryllium and magnesium. 

In contrast to the scarcity of stable poly(pyrazolyl)borato alkyl complexes of Si, Ge, and Pb, such derivatives are common for tin. The first poly(pyrazolyl)borato tin alkyl derivatives to be prepared were the parent derivatives, namely five-coordinate [Bp]SnMe Cl3 and six-coordinate [Tp]SnMe Cl3 (n = 0-3), obtained by the reactions of MenSnCl4 with K[Bp] and K[Tp], respectively [Eqs. (25) and (26)] (116). 

In addition to tin alkyl derivatives with one poly(pyrazolyl)borato ligand, bis[(poIy)pyrazolylborato] complexes of the types [Tp]2SnR2 and [R2Bp]2SnR2 have also been prepared (123,124). 

ALKYL, HYDRIDE, AND HYDROXIDE DERIVATIVES OF THE s- AND p-BLOCK ELEMENTS SUPPORTED BY POLY(PYRAZOLYL)BORATO LIGATION MODELS FOR CARBONIC ANHYDRASE, RECEPTORS FOR ANIONS, AND THE STUDY OF CONTROLLED CRYSTALLOGRAPHIC DISORDER... 

Bis and tris(pyrazolyl)hydroborato ligands are generally prepared as the potassium derivatives by the direct reaction of KBH4 with the appropriate pyrazole (RR pzH), as illustrated in Scheme 1 for the parent system (13). The reaction is extremely general and has been applied to a number of different derivatives, which have included the incorporation of chiral (14, 15) and tethered (16) substituents. However, if the alkyl substituents of the pyrazole are inequivalent (i.e., R + R ), a potential problem may be encountered with the formation of isomeric products, in which either of the R and R substituents may occupy the 3-position of the poly(pyrazolyl)borato ligand. Nevertheless, if the difference in steric demands of R and R is large, there is a strong... 

Alkyl, Hydride, and Hydroxide Derivatives in the s- and p-Block Elements Supported by Poly(pyrazolyl)borato Ligation Models for Carbonic Anhydrase, Receptors for Anions, and the Study of Controlled Crystallographic Disorder Gerard Parkin... 

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