Pyrazolato complexes

Monomethyl pyrazolato complexes, with Ti(IV), 4, 335 Mono(A-heterocyclic carbene) ligands, in silver(I) complexes, 2, 210... 

Figure 10. Drawing of the dinucleating ligands utilized in the magnetostructural correlations on copper(ll) pyrazolato complexes.

The metal-pyrazolate saga has been known since the pioneering work of Buchner in the nineteenth century. In the last few years, a definitive characterization of several binary complexes has been possible due to the advent of the recent method of ab initio structure determination from X-ray powder diffraction data. In this respect, it is likely that a number of new molecules and/or crystalline phases, which have so far escaped a complete characterization, will be structurally analyzed, thus confirming the variability of the coordination modes and stoichiometries attributable to simple pyrazolato complexes. 

HOMOGENEOUS CATALYTIC OXIDATION OF ORGANIC SUBSTRATES BY COPPER-PYRAZOLATO COMPLEXES... 

Indeed, some copper-pyrazolato complexes allowed the catalytic oxidation of organic substrates such as primary and secondary amines, isocyanides and phosphines in mild conditions. 

In an attempt to gain more insight into the reactions of copper(I) pyrazolato complexes with dioxygen, we decided to use different pyrazoles, whose donor capabilities were modified by introducing substituents in the 3,5-positions. 

The water-soluble pyrazolato complex (Rh(p-Pz)(CO)(TPPTS)]2 was used as precursor for olefin hydroformylation in an aqueous heptane solvent system 9]. Without additional ligand, olefin isomerization dominated hydroformylation at 7 bar CO/H2 (1 1) giving large amounts of 2-hexene. Isomerization was suppressed most effectively at 49.8 bar, leading to aldehyde chemoselectivities >90% and a 2.4-3.S njiso ratio. It was demonstrated that aerobic recycling of the aqueous catalyst phase by... 

A thorough DPT investigation of diverse pathways in the intramolecular hydroamination of (177), catalysed by the iridium chloropyrazole complex (178) and affording pyrrolidine (179), has defined the mechanism that features turnover-limiting reductive cycloamine elimination from an iridium-hydrido-alkyl intermediate. The vital role of a supportive hydrogen-bonded network (180) and cooperative activation of aminoalkenes with iridium-pyrazolato complexes have also been identified. " ... 

Metal basicity and cooperative effects in the reactions of dinuclear pyrazolato rhodium complexes 98PAC779. 

Complex [(CXI )Ir(/j,-pz)(/i,-SBu )(/j,-Ph2PCH2PPh2)Ir(CO)] reacts with iodine to form 202 (X = I) as the typical iridium(II)-iridium(II) symmetrical species [90ICA(178)179]. The terminal iodide ligands can be readily displaced in reactions with silversalts. Thus, 202 (X = I), upon reaction with silver nitrate, produces 202 (X = ONO2). Complex [(OC)Ir(/i,-pz )(/z-SBu )(/i-Ph2PCH2PPh2)Ir(CO)] reacts with mercury dichloride to form 203, traditionally interpreted as the product of oxidative addition to one iridium atom and simultaneous Lewis acid-base interaction with the other. The rhodium /i-pyrazolato derivative is prepared in a similar way. Unexpectedly, the iridium /z-pyrazolato analog in similar conditions produces mercury(I) chloride and forms the dinuclear complex 204. 

Barber J., Elduque, A., Gimenez, R., Lahoz, F.J., Oro, L.A. and Serrano, J.L. (1998) (Pyrazolato)gold complexes showing room-temperature columnar mesophases. Synthesis, properties, and structural characterization. Inorganic Chemistry, 37, 2960-2967. 

Torralba, M.C., Ovejero, P., Mayoral, M.J., Cano, M Campo, J.A., Heras, J.V., Pinilla, E. and Torres, M.R. (2004) Silver and Gold Trinudear Complexes Based on 3-Substituted or 3,5-Disubstituted Pyrazolato Ligands. X-Ray Crystal Structure of cyclo-Tris p,-[3,5-bis(4-phenoxyphenyl)-lH-pyrazolato-KN ... 

Pyrazolato-bridged bis(tacn) ligands and their dinickel complexes are mentioned in Sections 6.3.4.12.6 and 6.3.4.12.7. 

Table 6 Crystallographically characterized alkali metal pyrazolato, triazolato, and tetrazolato complexes...

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