Copper and calcium complexes with the anionic O2-donor 4-tert-butylacetyl-3-methyl-1-phenylpyrazol-5-onato (Q–). Influence of hydrogen-bond interactions on lattice architecture in the crystal structures of [CuQ2(H2O)] and [CaQ2(EtOH)2]

Abstract

By interaction of 4-tert-butylacetyl-3-methyl-1-phenylpyrazol-5-one (HQ) with Cu(O₂CCH₃)₂·H₂O in EtOH, the derivative [CuQ₂(H₂O)] 1 has been synthesized. It possesses a square-pyramidal structure with the asymmetric β-diketonate ligands arranged in an “anti” configuration to each other and with a molecule of H₂O at the apex of polyhedron. Both protons of H₂O are involved in an intermolecular hydrogen-bonding network with pyridinic nitrogen atoms of Q donors belonging to two neighbouring complexes. Compound 1 reacts with substituted phenanthrolines (2,9-Me₂Phen with 4,7-Ph₂Phen) in Et₂O to give [CuQ₂(2,9-Me₂Phen)] and [CuQ₂(4,7-Ph₂Phen)] derivatives. During the reaction of 1 with an excess of 2,9-Me₂Phen in EtOH reduction of copper(II) to copper(I) was observed with formation of the ionic diamagnetic copper(I) derivative [Cu(2,9-Me₂Phen)]Q. Ethylenediamine (en) reacted with 1 affording the ionic complex [Cu(en)₃]Q₂·2H₂O. By interaction of 1 with N-methylimidazole (N-MeIm) the compound [CuQ₂(N-MeIm)₂] has been isolated. Finally the P-donors triphenylphosphine and tricyclohexylphosphine (PCy₃) reduced copper(II) affording the copper(I) derivatives [CuQ(PPh₃)₂] and [CuQ(PCy₃)₂]. The reaction between HQ and CaCl₂ in basic (KOH) EtOH produced the derivative [CaQ₂(EtOH)₂]. It contains the calcium atom in an axially distorted octahedral environment with the two β-diketonate ligands in “anti” positions and the EtOH molecules trans to each other. The O–Ca–O axis is bent [172.86(6)°]. The protons of the solvent molecules are involved in a hydrogen-bonding network with the nitrogen atoms of Q donors of other molecular units, and the structure is constituted of infinite chains. The derivatives [CaQ₂(ROH)₂] have been obtained in alcoholic ROH solvents when R = Me, Et or Prⁱ, whereas the [CaQ₂(H₂O)₂] complex formed when R = Bu^t, HCCCH₂ or Prⁱ(Bu^t)CH. The interaction between [CaQ₂(EtOH)₂] and 1,10-phenanthroline afforded the adduct [Ca(Q)₂(Phen)₂].