Characterization of Molecular Complexes of 1,4-Naphthoquinone Derivatives

Abstract  

The structures of sulphur atom tethered quinone containing flexible carboxylic acid (3-methyl-1,4-dioxo-1,4-dihydronaphthalen-2-ylsulfanyl)acetic acid (1) and its molecular complex with 4,4′-bipyridine (3) are determined. The compound 1 crystallizes in P-1 (triclinic, a = 7.5378(6) ?, b = 7.6413(7) ?, c = 10.3101(9) ?; α = 89.779 (7)°, β = 81.042 (5)°, γ = 89.101(7)°) and the molecular complex 3 crystallises in P2(1)/n (monoclinic, a = 9.3383(7) ?, b = 3.970(3) ?, c = 42.130(3) ?, β = 91.056(5)°) space groups, respectively. The R₂²(8) type hydrogen bonding between dicarboxylic acid groups present in the parent compound 1 is lost on interaction with 4, 4′-bipyridine; in the molecular complex 3 R₂²(7) type of O···H–C and O–H···N interactions are present between the pyridine rings and carboxylic acid groups. The molecular complex (4) derived from 3-carboxymethylsulfanyl-1,4-dihydroxynaphthalen-2-yl-sulfanyl) acetic acid (2) with triphenylphosphine oxide in 1:2 ratio, crystallises in C2/c space group have monoclinic, a = 26.0494(13) ?, b = 10.5402(5) ?, c = 17.1023(8) ?, β = 108.719 (5)°). The triphenylphosphine oxide molecules are preferentially held by O–H···O interactions between carboxylic acid and P=O bond.