Scorpionate ligand

These lithium derivatives were found to be excellent reagents for the introduction of the new amidinate scorpionate ligands into Group 4 metal complexes, and a series of neutral titanium and zirconium complexes were prepared according to Scheme 189 and fully characterized. 

As in the synthesis of bdmpza by Otero et al., the scorpionate ligand bis(3,5-di-fert-butylpyrazoI-l-yI)acetate Hbdtbpza (3c) can be synthesized from bis(3,5-fert-butylpyrazoI-l-yI)methane (bdtbpzm) (2c) by... 

Fig. 11 zinc complexes of N-donor imino, NHC, and scorpionate ligands... 

The first such complex, Tp Ni(NO) (87), was very recently obtained from KTp and [NiBr(NO)(PPh3)2], along with an analogue (88) based on the "soft-scorpionate" ligand hydrotris(2-seleno-l-mesitylimidazolyl)borate (Scheme 9).37 In the same time frame Tpph2Ni(NO) (89) was independently... 

More recently, both our group and Perez s group have demonstrated that Ag complexes 22 and 33 containing scorpionate ligands are effective for C-H insertion... 

The sterically crowded, monoanionic scorpionate ligand tris(3-tert-butyl-5-methylpyrazol-l-yl)borate (Tp,Bll Me) provides a unique environment for the isolation of discrete rare-earth metal complexes with YMe AlMe4) and... 

In a related approach by Zuo and Zhou the same type of donor corner, [TpFe(CN)3], where Tp is a scorpionate ligand with a three-fold axis of symmetry (hydrotris(pyrazolyl)borate), is combined with a higher connectivity acceptor linker, [Cu]2+. As the Cu center adopts a square pyramidal (CN)4Cu(H20) local coordination, the cluster structure observed is one with eight donor corners and... 

Both ligand classes are modelled on long established ligands, the pincer ligands with amino, phosphane or ether sidechains on a pyridine or benzene base for the mer geometry [64-66] and the scorpionate ligands (tris-pyrazolylborates) for the fac geometry [67-69]. 

After the early reviews in 19712 and 19723 on poly(pyrazolyl)borate chemistry and pyrazole-derived ligands, and the boron pyrazole compounds chemistry described in 1986,4 Trofimenko reported in 1986s and in 19936 a summary on the coordination chemistry of poly(pyrazolyl)-borates. In 1999 Trofimenko described the coordination chemistry of scorpionate ligands in a book.7... 

The presence of sufficient pyrazolate ion (pz) is necessary to convert the R2B(pzx) species quickly to the [R2B(pzx)2], otherwise the R2B(pzx) species will dimerize to the stable pyrazabole R2B (/r-pzx)2BR2 (2), which are not readily convertible to scorpionate ligands.34 35... 

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