Table 2. PF-BTB Infrared Bands Assignment^a.

experimental bands (cm–1)	literature data17,21 (cm–1)	assignment
3049	3047	νC–H aromatic OP
3006	3024	νC–H trans-vinyl OP
2922	2920	νaliphatic
2849	2852	νaliphatic
1690	1679	νC=N (benzothiadiazole)
1602	1594	νC=C aromatic
1534	1561	νC=C aromatic
1463	1423	νC=C aromatic
1096	1108	δC–H aromatic IP
963	965	δC–H trans-vinyl IP
802	837	δC–H aromatic OP
747	784	unknown

^aIP = in-plane, OP = out-of-plane.