Table 1 Comparison of observed and calculated vibrational modes of meropenem before degradation

575/603

O-H b in carboxylic group

635/668

O-H b in carboxylic group

653/668

def. pyrrolidine ring + C-O-H b in carboxyl group

690/705

def. pyrrolidine ring + C-O-H b in carboxyl group

695/715

breathing β-lactam ring + C=O b in dimethylcarbomoyl group

771/768

carbonyl group b in carboxylic group

784/810

breathing β-lactam ring + C-N s between N and methyl group in dimethylcarbomoyl group

991/959

C-C between β-lactam and dimethylcarbomoyl group + C-N in β-lactam

994/989

C-C s in basis ring + CH₃ w at pyrrolidine ring

1049/1056

1049/1056

C-C in β-lactam ring + CH t/w in trans-hydroxyethyl group

1074/1075

CH t/w in trans-hydroxyethyl group

1135/1143

CH t/w + C-N s in pyrrolidine ring

1143/1147

CH₂t and methyl t in dimethylcarbomoyl group

1160/1153

CH t in CH₂ and methyl group in dimethylcarbomoyl group

1202/1188

1202/1188

C-N s in pyrrolidine ring + C-O-H b in carboxyl group

1221/1210

C-H w at β-lactam ring

1289/1265

1289/1263

C-N s at 4 CH₃ + C-H w

1330/1307

C-C s between pyrrolidine ring and C at COH group

1375/1335

C-H w in CH in trans-hydroxyethyl group + CH w in pyrrolidine ring

1417/1388

1417/1391

C-C s between carboxyl group and pyrrolidine ring + C-N s in basis ring + C-H sc in CH₃ in trans-hydroxyethyl group and methyl group

1430/1388

C-N s between CO and CH₃ in dimethylcarbomoyl group

1438/1421

C-H sc in dimethylcarbomoyl group

1482/1459

C-H w in dimethylcarbomoyl group

1513/1466

C-H s

1519/1448

CH3 w/sc in dimethylcarbomoyl group

1548/1500

CH3 w/sc in dimethylcarbomoyl group

1616/1549

1616/1553

C=C s in pyrrolidine ring

1751/1749, 1604

C=O s in trans-hydroxyethyl group

1818/1749, 1651

1818/1749

C=O s in carboxyl group

1887/1749

C=O s in pyrrolidine ring

3020/2939

C-H s in dimethylcarbomoyl group

3027/2947

C-H s in dimethylcarbomoyl group

3052/2961

C-H s in trans-hydroxyethyl group group

3137/2997

C-H s in methyl group