New β-diketones with oligoether side-chains and their complexes with barium and copper. Crystal and molecular structure of bis(1-phenyl-7,10-dioxaundecane-1,3-dionato)copper(II) at 150 K

Abstract

A range of new β-diketones of formula RC(O)CH₂C(O)(CH₂)₃(OCH₂CH₂)_nOMe (n= 1, R = Me, Ph, 2,4,6-Me₃C₆H₂ or Bu^t; n= 2, R = Me) has been prepared and spectroscopically characterised. Complexes of these β-diketones with barium(II) and with copper(II)(n= 1, R = Me or Ph) have been prepared and are shown to be involatile because the polyether chain binds to a different metal atom from that to which the β-diketonate function is bound, thus forming polymers. The complex [Cu{PhC(O)CHC(O)(CH₂)₃O(CH₂)₂OMe}₂] crystallises in the space group P2₁/c with a= 9.109(9), b= 11.189(8), c= 14.453(6)Å, β= 103.64(9)° and Z= 2. The structure was refined to R= 0.065, using 990 independent reflections. The copper atoms exhibit Jahn–Teller distorted six-co-ordinate geometry with the oxygen atoms of two bidentate β-diketonates occupying the equatorial positions (Cu–O 1.92 Å) and two terminal oxygen atoms from the polyether chains of different neighbouring molecules occupying the axial sites (Cu ⋯ O 3.065 Å).