VIBRATIONAL SATELLITES IN THE ROTATIONAL SPECTRA OF eCAPROLACTAM

VIBRATIONAL SATELLITES IN THE ROTATIONAL SPECTRA OF e-CAPROLACTAM AND CYCLOHEXANONE OXIME NOBUHIKO KUZE, EMI SATO, NORIKO INOUE, TAKESHI SAKAIZUMI AND OSAMU OHASHI Department of Chemistry Sophia University Tokyo 102 -8554, Japan

e-CAPROLACTAM AND CYCLOHEXANONE OXIME e-CAPROLACTAM BECKMANN REARRANGEMENT e-CAPROLACTAM CYCLOHEXANONE OXIME Chemical Week, Sep. 15, 2005 (Yamabe et al. , 2005)

THIS WORK • The rotational spectra of the normal and deuterated species of e -caprolactam and cyclohexanone oxime have been studied e -caprolactam-d cyclohexanone oxime-d cyclohexanone oxime-2, 2, 6, 6 -d 4 • The rotational spectra were observed in the range of 26 -40 GHz by using a 100 k. Hz square-wave Stark modulation spectrometer. • Determination of the molecular conformation • Analyses of the excited vibrational satellites

THREE POSSIBLE CONFORMERS OF e-CAPROLACTAM chair boat Crystal structure (Winkler and Dunitz, 1975) e-caprolactam adopts a chair conformation twist

e-CAPROLACTAM IN THE GAS PHASE: chair CONFORMER ONLY b c a N H(D)

VIBRATIONAL SATELLITES FOR e-CAPROLACTAM: THREE VIBRATIONAL STATES WERE FOUND ν 1 v=0 ν 2 v=1 I 0 ν 3 v=1 35050 J=13 0 13← 12 0 12 v=1 v=2 Estimation of the vibrational wavenumbers Iv 35100 35150 35200 35250 MHz

SIX POSSIBLE CONFORMERS OF CYCLOHEXANONE OXIME N O NOH cis-isomer NOH H NOH trans-isomer N O H chair Crystal structure (Olivato et al. , 2001) (Lutz et al. , 2004) cis-isomer chair conformation boat twist-boat

CYCLOHEXANONE OXIME : chair CONFORMER ONLY normal species 80, 73 and 39 spectral lines were fitted in the least-square analyses for normal, d 1 and d 4 species, respectively. d 1 species d 4 -species chair twist-boat

r 0 STRUCTURE OF CYCLOHEXANONE OXIME C(ipso) C(para) Torsion angles for cyclohexyl ring Deviations (Å) of C(ipso) and C(para) atoms from the central plane

VIBRATIONAL SATELLITES FOR CYCLOHEXANONE OXIME: TWO VIBRATIONAL STATES WERE FOUND v=0 J=13 0 13← 12 0 12 vt = 1 31050 MHz vb = 1 31100 MHz a) Ohara (1983). b) ( ): 1σ c) κ=(2 B-A-C)/(A-C) vb = 2 31150 MHz d) ΔI=Ic-Ia-Ib vb = 3 31200 MHz e) MP 2/6 -31 G(d, p)

z MODES ASSIGNMENT OF THE VIBRATIONAL e-CAPROLACTAM Ring-bending 58(15) cm-1 (observed) 70 cm-1 (B 3 LYP/6 -31 G(d, p)) 78 cm-1 (B 3 LYP/6 -31++G(d, p)) Ring-twisting 105(25) cm-1 166 cm-1 Ring-twisting 237(29) cm-1 237 cm-1 238 cm-1 CYCLOHEXANONE OXIME Out-of-plane-bending 97(28) cm-1 78 cm-1 (MP 2/6 -31 G(d, p)) 81 cm-1 (B 3 LYP/6 -31 G(d, p)) Ring-twisting 198(35) cm-1 182 cm-1 178 cm-1