COc1ccc2[n-]c([S+]([O-])Cc3ncc(C)c(OC)c3C)nc2c1.COc1ccc2[n-]c([S+]([O-])Cc3ncc(C)c(OC)c3C)nc2c1.[Mg+2]
The electronegative atoms usually involved in hydrogen bonding are oxygen, nitrogen and fluorine. How many hydrogen bond acceptors does the molecule contain?