Synthesis and Characterization of New Niobium Hydridotris(3,5-dimethylpyrazol-1-yl)borato Complexes

Abstract

Reaction of the binuclear alkoxide species [Nb(Cl)3(OR)2]2 (R = Me, Et) with potassium hydridotris(3,5-dimethylpyrazol-1-yl)borate, KTp*, leads to Tp*Nb(O)(Cl)(OR) (R = Me (1), Et (2)). These complexes react with Me3SiCl or PCl3 to give Tp*Nb(O)(Cl)2 (3). The binuclear complex [{Tp*Nb(O)(Cl)}2(μ-O)] (4) was prepared by the controlled hydrolysis of 1 or 2. Finally, complex 3 reacts with (Me3Si)2NMe or LiN(SiMe3)2·Et2O to give Tp*Nb(O)(HNSiMe3)2 (5) as the only isolated niobium product. Compounds 4 and 5 were characterized by X-ray diffraction.

(Acetylacetonato-κ2O,O′)chloridotrimethanolatoniobium(V)

“…The O-Nb-O angles vary between 80.74 (6) and 100.82 (7) ° while the trans Cl-Nb-O angle is 167.60 (5) °. All the bond distances and angles are similar to other relevant niobium(V) structures (Sokolov et al, 1999;2005;Antinolo et al, 2000 andDahan et al, 1976). The niobium compounds pack in a head-to-tail fashion along the bc plain.…”

“…For applications of acetylacetone in industry, see: Steyn et al (1992Steyn et al ( , 1997; Otto et al (1998); Roodt & Steyn (2000); Brink et al (2010); Viljoen et al (2008Viljoen et al ( , 2009aViljoen et al ( ,b, 2010; Steyn et al (2008). For related niobium complexes, see: Sokolov et al (1999Sokolov et al ( , 2005; Antinolo et al (2000); Dahan et al (1976).…”

(Acetylacetonato-κ2O,O′)dichloridobis(methanolato-κO)niobium(V)

“…The O-Nb-O angles vary between and 81.36 (7) and 172.65 (7) °, while the trans Cl-Nb-Cl angle is 167.34 (2) °. All the bond distances and angles are similar to other relevant niobium(V) structures (Herbst et al, 2010;2011;Sokolov et al, 1999;2005;Antinolo et al, 2000 andDahan et al, 1976).…”

“…For applications of acetylacetone-type ligands in industry, see: Steyn et al (1992Steyn et al ( , 1997Steyn et al ( , 2008; Otto et al (1998); Roodt & Steyn (2000); Brink et al (2010); Viljoen et al (2008Viljoen et al ( , 2009aViljoen et al ( ,b, 2010. For related niobium complexes, see: Sokolov et al (1999Sokolov et al ( , 2005; Antinolo et al (2000); Dahan et al (1976).…”

Synthesis, structures and ring-opening polymerization studies of new zinc chloride and amide complexes supported by amidinate heteroscorpionate ligands

“…from early to late transition metals. 2 In recent years, the chemistry based on the design of these particular types of intriguing heteroscorpionate ligands has been considerably extended in terms of catalytic applications. 3 In this context, our research group has contributed widely to the design of new heteroscorpionate ligands 4 related to the bis(pyrazol-1yl)methane system, 5 with several pendant donor arms such as carboxylate 6 and dithiocarboxylate, 6 cyclopentadienyl 7 and, more recently, enantiopure 4 heteroscorpionate ligands based on the isocyanate, 8 isothiocyanate, 8 and myrthenal fragments.…”