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

Table 2

Raman shift values (cm⁻¹) for aqueous solution of pyridoxine.

Experimental Raman values (cm^−1) [23]	IR (ab initio) [23]	Experimental Raman values (cm^−1) [35]	DFT/6-311++G (d, p) [35]	This work, Raman values (cm^−1)	Vibrational assignment [21, 35]
1646		1618	1611	1645	υ (C-C)/ring stretch
1630	1600	1565	1576	1630	υ (C-C), δ (H15–C10–H16), δ (C9–N7–H20)
1520	1542		1501	1545	δ (C-H ring) + υ (C-C)
1451	1465	1460	1459	1452	δ (C4–O8–H13) + δ (C-C-O) + υas (CH3), δ (C3–C9–H19)
1389		1378	1376	1385	υ (C1–C2, C2–C4) + δ (CH3)
1360	1351		1362	1361	δ (C11–O12–H23) + δ (C-O-H) + (CH2) twist
1326	1325	1316	1341	1327	δ (C9–N7–H20) + δ (C3–C9–H19) + δ (C–H) i.p. + ring τ + δ (H17-C1-O6), υ (C-N)
1295	1288	1280	1287	1297	υ (C5–N7)/(C-C) + τ (C5–CH3) + δ (C10–H)
1234	1256	1236	1242	1235	δ (C-O-H)/(C-C-H), δ (N–H) i.p.
1219	1178		1178	1091	υ (C11–O12) + δ (C11–H), δ (C-O-H)
1054	1061	1054	1067	1052	Ring stretch + τ (H17–C1–O6–H24) + υ (C-C-O)
966	972	986	988	967	δ (N–H) o.p. + δ (C–C) + υ (C-O)
		928	904	929	τ (C-C-N-H)
			895	865	τ (C-C-N-H)
753	756	751	751	751	τ (H19–C9–N7–H20) + δ (C6–C1–O6) + υ (C1–C2–C3)
692	655	695	706	690	τ (C2–C3–C9–H19) + stretch quadrant (C2–C4–C5–N7) + τ (C3-C2-C4-C5)
			585	590	τ (C-C-C-N)
533	539	519	520	518	δ (OH–C4–C5–CH3) + τ (H19–C9–N7–H20), υ (C-C) + υ (C-O)
477	453	482	494	474	τ (H19–C9–N7–H20) + δ (C-C-O)/(C-C-H)
403	404	391	411	387	δ (H17–C1–O6–H24) + τ (H21–C11–O12-H23), υ (C-O)

υ = stretch; δ = bending; τ = torsion; twist = twisting; i.p. = in plane; o.p. = out plane.