Crystal structure of the iron(III) chloride complex with 2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolylidene-1)-5,5-dimethyl-2,3,5, 6-tetrahydroimidazo[2.1-a]isoquinolin-3-one

The iron(III) complex with 2-(3,3-dimethyl-1,2,3,4- tetrahydroisoquinolylidene-1)-5,5-dimethyl-2,3,5,6-tetrahydroimidazo[2.1-a] isoquinolin-3-one (L) was studied by X-ray diffraction. The complex (LH)· [FeCl4]·C3H6O has a cation-anion structure. The proton in the HL+ cation is located at the N(2) nitrogen atom in position 1 of the imidazolone fragment. The cation contains a hydrogen bond (O(1)-H(1), 1.31(5) Å; N(3)-H(1), 1.37(5) Å; O(1)⋯N(3), 2.67 Å; O(1)H(1)N(3), 167(4)°) in which the position of the H(1) atom corresponds to the average of two equiprobable half-populated positions at the O(1) and N(3) atoms. The π-electron density in the imidazolone moiety is delocalized. The C-C bond length between the imidazolone and dihydroisoquinoline moieties (1.42(1) Å) is much greater than the standard C=C double bond length. The FeCl4 - anion has a usual geometry.