Polypyrazolylborates metal complexes

Polypyrazolylborates metal complexes, 2, 87,245-257 bidcntatc. 2,246 biological applications, 2.255 preparation. 2, 246 tridentate, 2,247 Polypyrazolylgallates... 

Valinomycin metal complexes, 969 Vanadium complexes acetylacetone exchange reactions, 380 1,4-diaza-l,3-butadiene, 209 dioxygen mononuclear, 321 hydrazido(2-), 148 hydroxamic adds, 506 phthalocyanines, 865 polypyrazolylborates, 248 porphyrins, 824 dioxygen adducts, 325... 

Trofimenko69 has reviewed the preparation of polypyrazolylborate ligands and the syntheses of metal complexes containing such ligands. An update has also appeared.70... 

Of the 33 papers presented at the symposium 32 are included in this volume. They are of two general types. One type discusses inorganic compounds exhibiting a specific property, most frequently electrical or photochemical. The second type reviews recent developments in the synthetic chemistry of a class of inorganic compounds— most often transition metal or lanthanide complexes— which are of potential interest to persons looking for new systems with unusual properties. Classes of compounds covered by this second type include metal alkyls, metal alk-oxides, metal alkylamides, metal chelates, and metal clusters as well as metal complexes with polyboranes, polyphosphines, macrocyclic derivatives, di- and triketones, and polypyrazolylborates as ligands. 

Complexes of molybdenum form the largest set of any of the transition metals. Many of these compounds display spectroscopic properties, isomerism and structural features that illustrate the coordination chemistry of polypyrazolylborate complexes. In addition, this system illustrates that trispyrazolylborate ligands are more bulky than their formal analogue C5H5. 

Polypyrazolylborates. This area of chemistry has developed considerably. [LnTp3] have nine-coordinate stmctnres for early lanthanides (e g. Pr, Nd), bnt eight-coordinate for the later metals (e g. Yb). Seven-coordinate bis complexes [Ln(Tp)2Cl] are formed nsing totally moisture-lfee conditions, bnt these readily add a Lewis base, for example, water forming [Ln(Tp)2Cl(H20)]. A very wide range of componnds, many of Sm, En, and Yb, in both the -1-2 and -T3 states, has been synthesized with Tp , this time with a maximum of two Tp bound. In triflate complexes... 

Poly(l-pyrazolyl)borates ( scorpionates ) are well-established, versatile, and easily accessible ligands in coordination chemistry, which have found widespread applications ranging from analytical chemistry to homogeneous catalysis and materials science . Table 5 shows many of the polypyrazolylborate complexes with different metals published in the last decade. 

The bonding of polypyrazolylborates to metal is determined primarily by the number of pyrazolyl groups attached to boron. Dipyrazolylborates are necessarily bidentate, and they form with divalent transition metal ions complexes, 1, that are similar to -diketonates but that are always monomeric for steric reasons. The major difference between dipyrazolylborates and -diketonates is that the R2B(pz)2M ring is not planar but is puckered in the boat form as in Structure 2. This results in asym-... 

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