Poly borates structures

A Survey of Structural Types of Borates and Poly borates... 

A Survey of Structural Types of Boratre and Poly borates Mg2[B205] H2O = Mg2(0H)[B204(0H)] = mme,r szaibelyite(iorTaetascharite) ... 

Recently, Lipton et al. [25] have used zinc-67 NMR to investigate [Zn(HB(3,5-(CH3)2pz)3)2] complexes which have been doped with traces of paramagnetic [Fe(HB(3,4,5-(CH3)3pz)3)2]. The low-temperature Boltzmann enhanced cross polarization between XH and 67Zn has shown that the paramagnetic iron(II) dopant reduces the proton spin-lattice relaxation time, Tj, of the zinc complexes without changing the proton spin-lattice relaxation time in the Tip rotating time frame. This approach and the resulting structural information has proven very useful in the study of various four-coordinate and six-coordinate zinc(II) poly(pyrazolyl)borate complexes that are useful as enzymatic models. 

Although the poly(pyrazolyl)borate complexes of iron(II) have been well known for many years, [1] it is only recently that the complexes with the tris(l-pyrazolylmethane ligand, HC(pz)3, [45-48] have been studied in detail. It should be noted that poly(pyrazolyl)methane ligands, such as the tris(l-pyrazolylmethane ligand, are neutral, whereas the poly(pyrazolyl)bo-rate ligands, such as the tris(l-pyrazolyl)borate ligand, HB(pz)3", are monoanions. As a consequence, the metal(II) poly(pyrazolyl)methane complexes are dications and often have quite different properties from those of the analogous metal(II) poly(pyrazolyl)borate molecular complexes. But, in spite of these differences there are often very close structural similarities between the dicationic complexes and the neutral complexes. Therefore the study of the pyrazolylmethane complexes will parallel that of the borate complexes discussed above. 

Several explosive salts including the acetylide, azide, borate, bromate, chlorate, chromate, iodate (and ammonium iodate double salt), nitrite, perchlorate (and ammonium perchlorate double salt), periodate, permanganate, picrate and trinitrobenzoate were prepared. The 3 latter salts and the acetylide, azide and bromate are impact-sensitive detonators [1], It appears probable that many of the explosively unstable compounds [2], formed in various ways from interaction of mercury or its compounds with ammonia or its salts, may have the common polymeric structure now recognised for Millon s base [3], This is a silica-like network of N+ and Hg in 4- and 2-coordination, respectively, with OH and water in the interstitial spaces. Individually indexed compounds are Poly(dimercuryimmonium acetylide)... 

Poly(pyrazolyl)borate complexes of Sn(II) and Pb(II) 92SL469. Synthesis, structure, and properties of vicinal hydroxy-, mercapto-, and hydroselenoaldimines of the pyrazole series 92MI22. 

The solid-state structure of the heteroleptic compound [Tp Bal (HMPA)2] is shown in Fig. 21.111 The steric bulk of the poly(pyrazolyl)bo-rate ligand is apparent in this figure, effectively blocking oligomerization from occurring. This is even more apparent in the bis(3,5-dimethylpoly (pyrazolyl)borate) complex Ba[HB(3,5-Me2pz)3]2 shown in Fig. 22, where two poly(3,5-dimethylpyrazolylborate) ligands have sterically saturated the coordination sphere of the barium center. The shortest intermolecular distance is 5.23 A.112... 

Table 6. Poly(l-pyrazolyl)borates of Structure 21 with n = 2...

Numerous physical studies of poly(l-pyrazolyl)borate complexes have been carried out, some as part of structure determinations, others to study different phenomena inherent in the complexed transition metal. 

A large number of poly(l-pyrazolyl) borate complexes had their structure determined by X-ray crystallography these are listed in Table 8. It should be remembered, however, that in some instances the structure in solution will have a different denticity of the poly(l-pyrazolyl)borate ligand than that found in the crystal. 

Table 8. Listing of Poly(l-pyrazolyl)borate Complexes of Known Crystal Structures...

Davies, G.M., Aarons, R. J., Motson, GR., et al. (2004) Structural and near-IR photophysical smdies on ternary lanthanide complexes containing poly(pyrazolyl)borate and 1,3-diketonate Ugands. Dalton Transactions, 1136. 

The tris(pyrazolyl)boratothallium(I) compounds are the most widely studied among thallium poly(pyrazolyl)borates. An excellent recent review article has appeared that covers the synthesis, structures, properties, and applications of tris(pyrazolyl)boratothallium(I). ... 

A tris(imidazolyl)borate (138) complex of thallium(I) has been synthesized.The solid-state structure of hydrotris(imidazolyl)boratothallium(I) consists of one-dimensional, twisted, ladderlike strands, and three-coordinate thallium centers. Due to the position of the nitrogen donors, the tris(imidazolyl)borate ligand is not capable of forming metal chelates as are observed in tris(pyrazolyl)borates. Poly(benzotriazolyl)borate ligands have some features of both tris(pyrazo-lyl)borate and tris(imidazolyl)borate systems. Thallium(I) complexes of bis-, tris-, and tetrakis (benzotriazolyl)borates are reported. These adducts have been synthesized by treating the corresponding potassium derivative with an equimolar quantity of thallium(I) formate. ... 

The fundamental feature in all poly(pyrazolyl)borate complexes is the six-membered ring within a more general structure R R B(//-pz)2M(L) , (1). 

Poly(imidazolyl)borates H B(im)4 ra (Scheme 4) can be prepared by analogy with that reported for poly(pyrazolyl)borates.164 HraB(im)4 ra can be used to model the histidine imidazole coordination in metalloproteins. H B(im)4 ra complexes have been widely described,165 but only few metal derivatives are structurally authenticated i.e., the ionic lithium salt of tetrakis(imidazolyl)borate,166... 

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