Table 2.

Hydrogen bond length of DOX and graphene system molecules (Å). The annotation of O1 to O4 have shown in Figure 1.

Models	O1·········· ·H	O2··· ···H	O3··· ···H	O4······ ···H	N··· ···H
DOX	1.812	1.986	1.738	2.305	-
G-DOX	1.501	1.906	1.648	2.426	-
GO-OH-DOX	1.598	1.869	1.753	2.370	-
GO-O-DOX	1.515	1.826	1.682	2.373	-
GO-OH-O-DOX	1.551	2.039	1.626	-	1.903