Bond lengths and angles in the X-ray structure of zwitterion 7a.

Bond	Bond length Å	Bond order	Angle	Angle value, °
C5–N1	1.326(4)	1.851	N1C5N4	105.7(3)
C5–N4	1.352(4)	1.701	C1N1C2	109.7(3)
C3–N4	1.378(4)	1.552	C5N1N2C3	0.4(4)
C3–N2	1.303(4)	1.983	N1N2C3N4	−1.4(4)
N1–N2	1.374(4)	1.385	N4C5N1C6	176.4(3)
N4–C23	1.448(4)	1.149	C5N4C23C24	−77.0(4)
N1–C6	1.509(4)	0.851	N2C3C17C22	−38.5(5)
C3–C17	1.460(5)	1.376	—	—
C5–C10	1.493(4)	1.208	—	—
S13–O14	1.460(3)	—	—	—