Synthesis, structure, electrochemical and magnetic properties of 2,6-bis(5-trifluoromethylpyrazol-3-yl)pyridine and its NiII complexes

Reactivity of an Unusual Divalent Chromium Aggregate Supported by a Multifunctional Bis(pyrazolate) Pincer Ligand

“…Similar [ML] 4 structures have been observed for Ni(II) and Cu(II) using 2,6‐bis(5‐trifluoromethylpyrazol‐3‐yl)pyridine . The deprotonated βN is an intermolecular Lewis base and is an aggregate building functionality.…”

Protic NNN and NCN Pincer‐Type Ruthenium Complexes Featuring (Trifluoromethyl)pyrazole Arms: Synthesis and Application to Catalytic Hydrogen Evolution from Formic Acid

“…The spontaneous loss of the proton may be ascribed to the increased Brønsted acidity of the pyrazole arms with the highly electron‐withdrawing CF 3 group. In fact, most of the known CF 3 ‐LH 2 complexes, which have been investigated mainly as materials with photophysical properties, are isolated in their fully deprotonated form, except for the nickel complex [Ni(CF 3 ‐LH 2 ) 2 ] 2+ and its derivatives . As shown in Scheme , 1 a was rationally obtained by the reaction of [RuCl 2 (PPh 3 ) 3 ] with CF 3 ‐LH 2 in the presence of an equimolar amount of a base in moderate yield.…”

“…To further explore the electronic tuning of the protic pincer‐type complexes with the CF 3 pendants, we synthesized the NCN pincer‐type ruthenium(II) complexes. The ligand precursor, a 1,3‐bis(CF 3 ‐pyrazolyl)benzene, was obtained according to the synthetic protocol for the pyridine analogue CF 3 ‐LH 2 . Unlike the synthesis of the NCN pincer‐type complexes with t Bu pendants, the reaction of the acetato complex [RuCl(OAc)(PPh 3 ) 3 ] and the pincer proligand was sluggish.…”

“…In fact, most of the known CF 3 -LH 2 complexes,w hich have been investigated mainly as materials with photophysical properties, are isolated in their fully deprotonated form, [15] except for the nickel complex [Ni(CF 3 -LH 2 ) 2 ] 2 + and its derivatives. [16] As shown in Scheme2, 1a was rationally obtained by the reactiono f [RuCl 2 (PPh 3 ) 3 ]w ithC F 3 -LH 2 in the presence of an equimolar amount of ab ase in moderate yield. The 19 FNMR spectrum of 1a exhibitst wo singlets assignable to the inequivalent CF 3 groups in the pincer ligand.…”

“…The ligand precursor,a1,3-bis(CF 3 -pyrazolyl)benzene, was obtained according to the synthetic protocol for the pyridine analogue CF 3 -LH 2 . [16] Unlike the synthesis of the NCN pincer-type complexes with tBu pendants, [9] the reaction of the acetato complex [Ru-Cl(OAc)(PPh 3 ) 3 ]and the pincer proligand was sluggish. Addition of an excess of acetate anion wast hus required to accelerate the cyclometalation, [19] which resulted in the formation of the NCN pincer-type bis(pyrazole) complex [Ru(OAc)(CF 3 -L NCN H 2 )(PPh 3 ) 2 ]( 5)b earing an acetato ligand (Scheme 6).…”