A urea adduct of bis(hinokitiolato)copper(II)

Bis(μ(2)-3-isopropyl-7-oxocyclohepta-1,3,5-trien-1-olato)bis[(3-isopropyl-7-oxocyclohepta-1,3,5-trien-1-olato)copper(II)]-urea-acetone (1/6/2), [Cu(2)(C(10)H(11)O(2))(4)]·6CH(4)N(2)O·2C(3)H(6)O, where 3-isopropyl-7-oxocyclohepta-1,3,5-trien-1-olate is the systematic name for the hinokitiolate anion, contains three novel structural features. First, it contains a bis(hinokitiolato)copper(II) dimer, [Cu(hino)(2)](2), unlike any other, demonstrating that linkage isomerism is another avenue by which Cu(hino)(2) can transmute from one form to another. Second, [Cu(hino)(2)](2) is hydrogen bonded to two urea molecules, indicating that hydrogen bonding cannot yet be discounted from any proposed mechanism of action for the antimicrobial and antiviral properties of bis(hinokitiolato)copper(II). Finally, corrugated urea layers crosslinked by [Cu(hino)(2)](2) dimers are observed, suggesting that a new family of host-guest materials, i.e. metallo-urea clathrates, exists to challenge our understanding of crystal engineering and crystal growth and design. Selected details of the structure are that the [Cu(hino)(2)](2) dimers possess crystallographic inversion symmetry, the Cu atoms have square-pyramidal coordination geometries, the basal Cu-O bonds are in the range 1.916 (2)-1.931 (2) Å, the apical Cu-O bond length is 2.582 (2) Å, the hinokitiolate bite angles are in the range 83.41 (7)-83.96 (8)°, the urea-Cu(hino)(2) interactions have an R(2)(2)(8) motif, and the urea layers result from the close packing of R(8)(6)(28) 'butterflies' and R(8)(6)(24) 'strips of tape'.