O=C1c2ccccc2C(=O)c2c1ccc(C1C(=O)c3ccccc3C1=O)c2-c1c(C2C(=O)c3ccccc3C2=O)ccc2c1C(=O)c1ccccc1C2=O
The donor in a hydrogen bond is usually a strongly electronegative atom such as N, O, or F that is covalently bonded to a hydrogen bond. How many hydrogen bond donors does the molecule have?