Structures of three DNA cross-linking agents, ethane-1,2-di(methylsulfonate), propane-1,3-di(methylsulfonate) and n-butane-1,4-di(methylsulfonate).

(I): C4H10O6S2, Mr = 218.25, P2(1)/c, a = 7.2611 (9), b = 5.8726 (4), c = 10.6628 (19) A, beta = 103.95 (1) degree, V = 441.3 (2) A3, Z = 2, Dm = 1.65, Dx = 1.642 Mg m-3, lambda(Cu K alpha) = 1.54184 A, mu = 5.43 mm-1, F(000) = 228, R = 0.0336 and wR = 0.0346 for 745 unique reflections with F greater than or equal to 3 sigma (F), T = 298 K. (II): C5H12O6S2, Mr = 232.28, P2(1)/c, a = 11.030 (1), b = 8.452 (1), c = 11.162 (1) A, beta = 104.65 (1) degree, V = 1006.8 (3) A3, Z = 4, Dm 1.54, Dx = 1.532 Mg m-3, lambda(Cu K alpha) = 1.54184 A, mu = 4.79 mm-1, F(000) = 488, R = 0.0418 and wR = 0.0430 for 1666 unique reflections with F greater than or equal to 3 sigma(F), T = 298 K. (III): C6H14O6S2, Mr = 246.30, P1, a = 5.6147 (9), b = 6.8343 (6), c = 7.5434 (6) A, alpha = 110.61 (1), beta = 92.08 (1), gamma = 76.15 (1) degree, V = 262.7 (3) A3, Z = 1, Dm = 1.56, Dx = 1.557 Mg m-3, lambda(Cu K alpha) = 1.54184 A, mu = 4.79 mm-1, F(000) = 130, R = 0.0397 and wR = 0.0425 for 907 unique reflections with F greater than or equal to 3 sigma(F), T = 298 K. All three compounds have a common conformation in the C.O.SO2.CH3 part of the molecules due to weak O...H interactions. Compounds (I) and (III) have a trans conformation about the central C--C bond, whereas (II) is cis.