Spectroelectrochemical Investigation of the Interaction of Adenine with Pyridoxine at Physiological pH

Table 1

Experimental Raman shift values (cm⁻¹) for adenine in solution.

Experimental Raman (cm^−1) [34]	B3LYP/6-31G (d, p) [34]	Experimental Raman values (cm^−1) [21]	B3LYP/6-31^2+G (d, p) [21]	This work, Raman values (cm^−1)	Vibrational assignment [21]
1639	1641	1674	1665	1680	sciss NH2, υ (C6-N10), υ (C5-C6)
1612	1617	1613	1643	1610	υ (N3-C4), υ (N1-C6), υ (C5-N7), υ (N7-C8), δ (N9-H)
1599	1584	1597	1613	1597	sciss NH2
1482	1502	1483	1524	1485	υ (N7-C8), δ (C8-H), sciss NH2
1474	1487	1463	1510		υ (C2-N3), υ (N1-C6), δ (C2-H), sciss NH2
1419	1416	1419	1441	1420	υ (C4-N9), (C4-C5), (C6-N10), (N7-C8), δ (C2-H)
1389	1400	1372	1423	1373	δ (C2-H, N9-H), υ (C8-N9, C4-N9)
1345	1350	1333	1372	1335	δ (C2-H, C8-H, N9-H), υ (C6-N1, C8-N9, N3-C4)
1328	1342	1333	1365	1335	υ (C5-N7, N1-C2), δ (C2-H, C8-H),
1290	1317	1308	1341	1308	υ (C2-N3, N1-C2, C5-C6, C5-N7)
1240	1250	1248	1272	1250	δ (C8-H, N9-H), υ (N7-C8)
1229	1228	1234	1246	1234	rock NH2, υ (C5-N7, N1-C2, C2-N3)
1127	1129	1162	1148	1165	δ (C8-H, N10-H11), υ (C4-N9, N3-C4, C6-N10)
1032	1065	1126	1085	1128	υ (C8-N9), δ (N9-H, C8-H),
1005	1000	1025	1012	1025	rock NH2
958	953		974		wag (C2-H) o.p.
927	925	942	942	942	def R5
887	882	899	899	893	def R6, R5 (υ C5-N7)
848	831	839	849		wag (C8-H) o.p.
802	793	797	805	773	def R6 (wag C4-C5-C6), wag (C8-H) o.p.
717	713	723	726	722	Ring breath whole molecule (distorted)
	672		685		def R5, R6 (τ C4-C5-C6, wag N3-C4-N9) o.p.
655	658		666		def R5 (wag C5-N7-C8), wag C8-H, N9-H,) o.p.
610	607	623	618	622	def R6 and R5
566	568	560	576	560	wag (C2-H, N9-H) o.p.
	528		540		τ (NH2) o.p.
	521	536	530	533	def R6—i.p./o.p.
513	514	536	520	533	wag (N9-H), def R6, R5—i.p./o.p.
	504		518	474	wag (N9-H), τ (NH2) o.p.
	298		300	375	def R6, R5 (wag N1-C2-N3-C4, C5-N7-C8-N9), wag C6-N10) o.p.

υ = stretching; δ = bending; τ = torsion; rock = rocking; def = deformation; sciss = scissoring; wag = wagging; R5 = five-membered ring; R6 = six-membered ring; breath = breathing; i.p. = in plane; o.p. = out plane.