The 1:1 adduct of 2,5-dihydroxy-1,4-benzoquinone with 4,4′-bipyridine

2,5-Dihydroxy-1,4-benzoquinone (DHBQ) and 4,4'-bipyridine (BPY) crystallize in a 1:1 ratio as a neutral molecular adduct, C6H4O4.C10H8N2, in space group C2/c, with half of each molecule in the asymmetric unit. The molecules are linked by a strong O-H . . .N hydrogen bond [O . . .N 2.6323 (15) Angstrom] and a weak C-H . . .O hydrogen bond [C . . .O 3.2082 (17) Angstrom] to form infinite stacks of parallel one-dimensional hydrogen-bonded ribbons. The two rings of the bipyridine are twisted at 28.3 degrees with respect to each other, and the benzoquinone ring is inclined at an angle of 18.3 degrees with respect to the plane of the neighbouring pyridine ring. The 4,4'-bipyridine molecule lies on a twofold axis and the benzoquinone molecule lies across an inversion centre.