Table 1.

Definition and contribution of all descriptors obtained from the PLS models.

Serial no.	Descriptor	Type of descriptor	Meaning	Contribution
1	B04[O-Cl]	2D atom pair	Presence or absence of oxygen and chlorine (O-Cl) at the topological distance 4	+ve
2	nRCONHR	Functional group counts	Number of secondary amides (aliphatic)	–ve
3	F01[C-N]	2D atom pair	Frequency of C-N at the topological distance 1	–ve
4	ETA_dBeta (Δβ)	Extended Topochemical Atom (ETA)	A measure of relative unsaturation content. It can be expressed using the following equation: $\Delta \beta =\sum {\beta }_{ns}-\sum {\beta }_s$ Where ${\beta }_{ns}$ represents VEM non-sigma contribution of a non-hydrogen vertex and ${\beta }_s$ represents VEM sigma contribution for a non-hydrogen vertex (Roy, 2015).	+ve
5	B05[C-N]	2D atom pair	Presence/absence of carbon and nitrogen (C-N) at topological distance 5	+ve
6	B06[N-N]	2D atom pair	Presence/absence of nitrogen and nitrogen (N-N) at topological distance 6	+ve