Nearest-Neighbor Interactions and Their Influence on the Structural Aspects of Dipeptides
Table 7
Frequenciesa (in cm−1) and IR intensities (in km/mol) of various vibrational modesb obtained from the theoretical vibrational spectra of the dipeptides in gas and aqueous phases. Intensities are given in brackets.
Dipeptides
Phases
(C4=O11)
(N6–H10)
(C4–N6)
(N5–H)
(N5–H)
Sis (N5–H)
(C7–H)
(C3–H)
Sec-Val
Aqueous
1699 (573)
3433 (160)
1552 (673)
3384 (9)
3464 (12)
1667 (59)
2977 (6)
2941 (6)
Gas
1749 (273)
3469 (57)
1554 (406)
3382 (2)
3463 (7)
1675 (43)
2968 (10)
2937 (2)
Sec-Leu
Aqueous
1696 (533)
3442 (155)
1550 (555)
3383 (8)
3464 (11)
1670 (61)
2975 (9)
2942 (7)
Gas
1747 (266)
3458 (66)
1559 (359)
3382 (3)
3465 (3)
1676 (44)
2962 (7)
2939 (2)
Sec-Asp
Aqueous
1706 (623)
3415 (169)
1554 (597)
3383 (11)
3464 (13)
1667 (56)
2972 (16)
2941 (6)
Gas
1758 (260)
3429 (80)
1553 (268)
3376 (9)
3467 (6)
1675 (58)
2951 (24)
2938 (3)
Sec-Ser
Aqueous
1704 (533)
3420 (179)
1550 (555)
3381 (12)
3463 (14)
1668 (58)
3027 (8)
2942 (6)
Gas
1754 (275)
3454 (76)
1548 (380)
3382 (3)
3464 (3)
1676 (41)
3028 (3)
2940 (2)
Sec-Gln
Aqueous
1697 (628)
3440 (162)
1548 (583)
3381 (9)
3461 (12)
1668 (55)
2970 (21)
2940 (6)
Gas
1748 (277)
3457 (73)
1551 (447)
3383 (3)
3466 (4)
1676 (42)
2978 (4)
2939 (2)
Sec-His
Aqueous
1704 (507)
3416 (175)
1546 (621)
3384 (12)
3465 (13)
1669 (58)
3027 (8)
2940 (6)
Gas
1754 (239)
3450 (77)
1548 (413)
3382 (3)
3464 (3)
1676 (43)
3021 (5)
2940 (2)
Sec-Pyl
Aqueous
1698 (537)
3430 (161)
1556 (609)
3384 (10)
3464 (12)
1667 (62)
2976 (4)
2940 (6)
Gas
1747 (264)
3458 (73)
1560 (380)
3382 (3)
3465 (3)
1676 (41)
2988 (17)
2938 (2)
The frequencies below 1800 cm−1 are scaled with 1.01 and for those above 1800 cm−1 a correction factor 0.9679 is used.
bVibrational modes: ν: stretching; Sis: scissoring; s: symmetric; as: asymmetric.
