Synthesis, Structure, and Proton-Transfer Reactions of Brønsted Acidic Pyridylpyrazole Complexes of Ruthenium

Abstract

A reaction of [{Cp*Ru(μ3-Cl)}4] (Cp*: η5-C5(CH3)5) with 5-phenyl-3-(2-pyridyl)-1H-pyrazole (PhpypzH) afforded a chelating pyrazole complex [Cp*RuCl(PhpypzH)] (2) bearing an NH proton at the β-position to the metal. Treatment of 2 with an equimolar amount of silver nitrite followed by anion exchange with KOTf (OTf: OSO2CF3) gave the pyrazolato–nitrosyl complex [Cp*Ru(NO)(Phpypz)](OTf) (3) through a proton shift from the pyrazole ligand to the nitrite ion. In contrast, simple ligand exchange took place in the reaction of silver nitrite and [Cp*RuCl(bipy)] (bipy: 2,2′-bipyridine) without the protic chelate ligand to give the nitro complex [Cp*Ru(NO2-κN)(bipy)] (4). Protonation of 4 with triflic acid led to the formation of the nitrosyl complex [Cp*Ru(NO)(bipy)](OTf)2 (5). The pyrazolato complex 3 was also obtained by the reaction of [Cp*Ru(NO)Cl2] with PhpypzH and KOTf in water. Reversible protonation of 3 resulted in the formation of the dicationic pyrazole complex [Cp*Ru(NO)(PhpypzH)](OTf)2 (6). The detailed structures of 2–4 and 6 have been determined by X-ray crystallography.

3-Phenyl-5-(2-pyridyl)pyrazolato Complexes of Lithium, Magnesium, Calcium, and Zinc

“…Selected bond lengths (pm): N2-N3 135.1(2), N2-C6 135.3(2), C6-C7 138.2(2), C7-C8 140.8(2), N3-C8 134.4(2), C5-C6 146.6(2), C8-C9 147.4 (2). oxidation states with the main focus on late transition metals such as cobalt [11,12], nickel [12,13], and copper [12,14] as well as molybdenum [10], ruthenium [15,16], palladium [17 -19], and platinum [19,20]. Recently, the coordination behavior of the extended ligand 2,6-bis(5-phenyl-1H-pyrazol-3-yl)pyridine towards d 10 metal cations was also investigated [21].…”

Formation of a dinuclear copper(II) complex through the cleavage of C<private-char description='Single_Bond' name='Single_Bond' value='Single_Bond'/>N bond of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole

“…The dinuclear copper(II) complex was formed from the reaction of two moles of 3-(pyridin-2-yl)-1H-pyrazole with Cu(II) ion to form a Cu(PyPzH) 2 2+ moiety. Then, deprotonation of one of the 3-(pyridin-2-yl)-1H-pyrazole ligand renders the molecule to form a Cu(II)(PyPzH)(PyPz) + moiety [9]. Further coordination of pyrazolato moiety in the Cu(II)(PyPzH)(PyPz) + with another Cu(II)(PyPzH)(PyPz) + moeity afforded the dinuclear complex which see two unit of 3-(pyridin-2-yl)-pyrazolato moieties acted as bridges.…”

Untitled

“…Curcumin, chemically, ((1E, 6E)-1, 7-Bis (4-hydroxy-3-methoxyphenyl)-1, 6 heptadiene-3, 5-dione) and Gefitinib, chemically, (N (3 chlorofluorophenyl) 7 methoxy 6 (3 morpholinopropoxy) quinazolin -4-amine) 1,2,3,4 . Whereas curcumin is a polyphenolic compound with molecular weight 368.39 g/mol and gefitinib is a quinazolamine with molecular weight 446.90 g/mol.…”