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

Copper(I) acylpyrazolonate derivatives of formula [Cu(Q)(PPh3)2] (HQ = HQC2F5 =  1-phenyl-3-methyl-4-pentafluoropropanoylpyrazol-5-one, HQCF3,CF3 = 1-(4-trifluoromethyl)phenyl-3-methyl-4-trifluoroacetylpyrazol-5-one, HQnaph = 1-phenyl-3-methyl-4-(1-naphthoyl)pyrazol-5-one, HQfur = 1-phenyl-3-methyl-4-furylpyrazol-5-one, HQthi = 1-phenyl-3-methyl-4-thienoylpyrazol-5-one, HQCF3,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(Qfur)(PPh3)2] and [Cu(Qthi)(PPh3)2] and of [Cu(QC2F5)(PPh3)2] show their copper atoms in distorted tetrahedral environments. Apart from the derivative [Cu(Qnaph)(PPh3)2], they are fluxional in chloroform solution, dissociating partially to the [Cu(Q)(PR3)] fragment and free PR3, or existing in solution as [Cu(O2–Q)(PR3)2] or [Cu(O–Q)(PR3)2] species, with CuO2P2 or CuOP2 metal environments, in equilibrium with each other. By contrast, in [Cu(QCF3,py)(PPh3)2] the QCF3,py ligand is coordinated to copper through the nitrogen atoms of the pyrazole and pyridine rings. The latter compound reacts with Zn(BF4)2 · xH2O and [Ru(p-cymene)Cl2]2 affording ionic heterobimetallic adducts.

New phosphino–copper(I) acylpyrazolonate derivatives have been synthesized and characterized in the solid state and solution. They are monomeric compounds where the acylpyrazolonates act as O2- or N2-donor ligands depending on their substituents. In the latter case, the ligand is also able to coordinate other metal centres through the carbonyl arms, affording heterobimetallic derivatives.Figure optionsDownload as PowerPoint slide