753139.fig.002a
(a)
753139.fig.002b
(b)
753139.fig.002c
(c)
753139.fig.002d
(d)
Figure 2: Optimized structures using WB97XD/6-31++G(d,p) of (a) ethylene glycol (EG) dimer, (b) diethylene glycol (DEG) dimer, (c) triethylene glycol (TEG) dimer, and (d) dipropylene glycol (DPG) dimer (colour legend: red = oxygen, black = carbon, whitish grey = hydrogen, and black-dotted line is hydrogen-bond).