Table 2. X-Ray and Optimized DFT (B3LYP-D3BJ/Def2SVP Level of Theory) Bond Lengths (in Å), and Bond Orders for the Phenyl Ring of PDA-Ring in Compounds 3 and 4.

	Compound 3			Compound 4
	Bond distance			Bond distance
Bond	X-ray	DFT	Bond order	X-ray	DFT	Bond order
C2α–N	1.313(3)	1.320	1.24	1.315(3)	1.326	1.28
C2α–C2α′	1.479(2)	1.489	0.95	1.488(4)	1.487	0.98
C2α–C2βa	1.431(1)	1.431	1.17	1.432(1)	1.429	1.19
C2β–C2γa	1.415(2)	1.419	1.25	1.416(2)	1.418	1.26
C2γ–C2γ′	1.385(3)	1.399	1.32	1.389(5)	1.399	1.33

^aBond distance average.