Molecular Zeeman effect of 3-oxetanone and 3-methylene oxetane, and the comparison of the magnetic-susceptibility anisotropies, molecular quadrupole moments, and other magnetic parameters with other four-membered rings

Abstract

The molecular Zeeman effect is reported for 3-oxetanone and 3-methylene oxetane at fields near 20000 G. The results for 3-oxetanone are molecular g-values: g aa = −0.1059 ± 0.0008, g bb = −0.0581 ± 0.0004, g cc = −0.0437 ± 0.0004, magnetic susceptibility anisotropies:2 x aa - x bb - x cc = (9.6±0.5) x 10 −6 erg/G 2mole, 2 x bb - x aa - x cc = −(7.8±0.6) x 10 −6 erg/G 2mole, and molecular quadrupole moments: Q aa = −(12.8±0.8) x 10 −26 esu cm, Q bb = (7.9±0.8) x 10 −26 esu cm, and Q cc = (4.9±0.8) x 10 −26 esu cm. For 3-methylene oxetane, the results are g aa = −0.0510 ± 0.0018, g bb = −0.0435 ± 0.0010, g cc = −0.0313 ± 0.0010, 2 x aa - x bb - x cc = −(10.9±0.5) x 10 −6 erg/G 2 mole, 2 x bb - x aa - x cc = (2.3±0.9) x 10 −6 erg/G 2 mole, Q aa = -⊂5.4±1.0) x 10 −26 esu cm, Q bb = (5.1 ± 1.2) x 10 −26 esu cm, and Q cc = (0.2±1.5) x 10 −26 esu cm. The bulk magnetic susceptibility for 3-oxetanone was measured to be x = 1/2 ( x aa + x bb + x cc ) = −(30.6±1.5) x 10 −6 erg/G 2 mole. The out-of-plane minus average in-plane magnetic-susceptibility anisotropies in four-membered rings show larger paramagnetism than predicted on the basis of localized group susceptibility anisotropies. This effect is discussed and a possible explanation presented.