Copper(I) monophosphine complexes with functionalized acylpyrazolonate ligands: Syntheses of heterobimetallic Cu–Zn and Cu–Ru adducts

Abstract

Copper(I) acylpyrazolonate derivatives of formula [Cu(Q)(PPh 3) 2] (HQ = HQ C2F5 = 1-phenyl-3-methyl-4-pentafluoropropanoylpyrazol-5-one, HQ CF3,CF3 = 1-(4-trifluoromethyl)phenyl-3-methyl-4-trifluoroacetylpyrazol-5-one, HQ naph = 1-phenyl-3-methyl-4-(1-naphthoyl)pyrazol-5-one, HQ fur = 1-phenyl-3-methyl-4-furylpyrazol-5-one, HQ thi = 1-phenyl-3-methyl-4-thienoylpyrazol-5-one, HQ CF3,py = 1-(2-pyridyl)-3-methyl-4-trifluoromethylpyrazol-5-one) have been synthesized and characterized, both in the solid state and in solution. The isomorphous crystal structures of [Cu(Q fur)(PPh 3) 2] and [Cu(Q thi)(PPh 3) 2] and of [Cu(Q C2F5)(PPh 3) 2] show their copper atoms in distorted tetrahedral environments. Apart from the derivative [Cu(Q naph)(PPh 3) 2], they are fluxional in chloroform solution, dissociating partially to the [Cu(Q)(PR 3)] fragment and free PR 3, or existing in solution as [Cu(O 2–Q)(PR 3) 2] or [Cu(O–Q)(PR 3) 2] species, with CuO 2P 2 or CuOP 2 metal environments, in equilibrium with each other. By contrast, in [Cu(Q CF3,py)(PPh 3) 2] the Q CF3,py ligand is coordinated to copper through the nitrogen atoms of the pyrazole and pyridine rings. The latter compound reacts with Zn(BF 4) 2 · xH 2O and [Ru( p-cymene)Cl 2] 2 affording ionic heterobimetallic adducts.