No abstract

No abstract

No abstract

A system has been designed for the NMR observation (at 60 M H z ) of unstable intermediates, with half-lives of 100 ms, at concentration levels above lo-* M. Rapid mixing can be achieved in less than 40 ms and a series of eight spectra acquired in less than 1.08s. Low temperature operation is straightforward. Reactive intermediates involved in the reaction of methylamine with 2,4,6,-trinitroanisole and the acid-catalysed hydrolysis of l,l-diethoxy-2,3-diphenylcycloprop-2-ene were identified, and in a kinetic application, the rate of hydrolysis of ttimethyloxonium tetrafluoroborate was measured.

Table II. Calculated Orbital Energies of 1, 3, and 4 compd -e(ZDO) -e(MINDO/3) 1 (7.14 (n)) 7.81 (a2, x) 7.39 (x) 8.01 (bi, n_) 8.17 (x) 8.54 (b2, x) 8.57 (x) 8.75 (a2, x) (9.34 (n)) 8.88 (ai, n+) 9.60 (x) 9.73 (b2, x) 3 7.42 (x) 7.83 (x) 8.09 (x) 8.43 (x) 8.63 (n) 8.86 (x) 9.41 (x) 9.03 (n) 9.88 (x) 9.76 (x) 4 7.62 (x) 7.71 (x) 8.41 (x) 8.43 (x) 8.92 (x) 8.92 (x) 9.78 (x) 9.72 (x) 11.36 (x) 9.86 (x)and for the amino group -10.6 eV.6 Assuming a rotation of 40°around the CN bond in 3 and 0°in 4, we obtain the values shown in Table II. The agreement between experiment and ZDO calculation is fairly good. Our assignment given in Table I is based on the ZDO results.