Design and Theoretical Study of D–A–π–A Organic Sensitizers with [1,2,5]Thiadiazolo[3,4-c]pyridine, [1,2,5]Selenadiazolo[3,4-c]pyridine, and [1,2,5]Oxadiazolo[3,4-c]pyridine π Component

Table 3

Enthalpies of formation for D–A- (DA-) blocks.

D–A- (DA-) block	, kcal/mole
ac	60.6
bc	83.1
ad	50.1
bd	68.6
e	16.6
f	−4.2
g	34.1