FT-IR, Laser-Raman, UV-Vis, and NMR Spectroscopic Studies of Antidiabetic Molecule Nateglinide

Table 2

The experimental and computed UV-Vis parameters and electronic transitions in methanol of nateglinide.

The experimental parameters	Calculated parameter for Monomer 2	The calculated parameters for Monomer 1 (td = (nstates = 6) B3LYP/6–31 + G(d, p) scrf = (cpcm,solvent = methanol) maxdis k  = 22 GB geom = connectivity)
(nm)	Transitions	(nm)	(nm)	Excitation energy (eV)	Oscillator strength	Major contributions [31]
	⟶	236.49	236.51	5.2421	0.0046	H-1->LUMO (35%), HOMO->L + 1 (41%) H-2->LUMO (3%), H-1->L + 1 (4%), H-1->L + 2 (5%), HOMO->LUMO (9%)
	⟶	228.64	228.14	5.4345	0.0144	H-3->LUMO (50%), H-3->L + 2 (18%) H-7->LUMO (2%), H-7->L + 2 (2%), H-6->LUMO (3%), H-6->L + 2 (3%), H-1->LUMO (4%), HOMO->LUMO (7%)
	⟶	219.7	221.79	5.5902	0.0065	H-2->L + 2 (25%), H-2->L + 4 (39%) H-2->LUMO (3%), H-2->L + 3 (5%), H-2->L + 5 (6%), H-1->L + 2 (4%), H-1->L + 4 (5%)
	⟶	216.37	219.16	5.6571	0.0741	HOMO->LUMO (66%) H-3->LUMO (6%), H-2->LUMO (6%), H-2->L+ 4 (2%), H-1->L + 1 (5%), HOMO->L+ 1 (6%), HOMO->L + 2 (3%)
212	⟶	212.63	216.85	5.7175	0.0120	H-2->LUMO (67%), H-1->LUMO (12%) H-3->LUMO (6%), H-2->L + 4 (5%), HOMO->LUMO (2%)
	⟶	210.78	207.28	5.9814	0.0257	H-1->LUMO (13%), H-1->L + 1 (18%), HOMO->L + 2 (50%) H-2->LUMO (4%), H-1->L + 2 (6%)