Trinuclear Diamagnetic Nickel(II) Complexes with Bridging 3‐Arylpyrazolato Ligands

Abstract

Orange-red trinuclear nickel(II) complexes are obtained by reacting Ni(ClO 4 ) 2 (H 2 O) 6 with 3(5)-arylpyrazoles in the presence of a base. Herein, the diamagnetic nickel centers are coordinated in a square-pyramidal manner by four pyrazolato ligands, each of which bridges two nickel sites. The structurally unique complexes were investigated by NMR,

Reaction of chloroauric acid with histidine in microdroplets yields a catalytic Au–(His)2complex

“…S10 †). Under the double layer interaction of the airwater interface, it promotes the formation of a coordination bond between Au + and negative NHC ligand with the large p bond between the two nitrogen atoms of 'pyrrole-like' and 'pyridine-like' character, which is consistent with what Thiel 62 reported and recently reviewed by Glorious. 1 Most commonly, this strategy involves a redox process for chloroauric acid 18 and a-elimination or oxidative addition at the carbene carbon of histidine, 7 to form the metal-based NHC complex with the basepromoted transformation of imidazole complex to carbene derivatives (Fig.…”

Coordination of Nickel(II) by 3‐(2‐(Diphenylphosphanyl)phenyl)‐1H‐pyrazole

“…The two bridging pyrazolato ligands and the two central nickel(II) cations form a six‐membered ring that occupies a boat conformation with a Ni1–Ni2 distance of 3.421 Å. There is a whole bunch of nickel complexes with bridging pyrazolato ligands in the literature, mainly bi‐ and some trinuclear19 compounds. The ligand systems used for the synthesis of dinuclear complexes in most cases bear additional donor units to prevent the formation of polymeric structures such as catena‐(bis(μ 2 ‐pyrazolato)nickel(II) and MOF‐type solids 20.…”

Influencing the Dimensionality of Ni/Co‐Bipyrazole‐Based Coordination Frameworks through Anions and Thermal Activation

“…Chemicals and Materials. 1H,1'H-4,4-bipyrazole (H 2 BPZ) [31] and hexakis(μ 2 -3-phenylpyrazolato)trinickel(II) [32] were prepared using previously reported methods. Ni(SiF 6 ) • (H 2 O) 6 was obtained through the reaction of Ni (1.0 g, 17.0 mmol) with hexafluorosilicic acid (6.4 mL, 20.0 mmol) in 5 mL water stirred at 100 °C for 20 h. After hot filtration the pure product was obtained by precipitation with acetone (4.96 g, yield: 95 %).…”