Structure of 4-(1-cyclohexenyl)-3-phenylsydnone

Oxadiazoles

“…On this basis, these compounds could be regarded as 1,3-dipolar azomethyne imines bearing a conjugative carbonyl group at C5 [29]. X-Ray structural measurements confirm that the exocyclic CÀO bond is close in length to that of a normal carbonyl group [35][36][37][38]. Therefore, according to the values of the net atomic charges on the ring, determined by semiempirical methods, the resonance structure 37 appears to be the best single representation.…”

Electrostatic properties of sydnone derivatives

“…The contributions from 2pz atomic orbitals of N2 and C4 are most important in the HOMQ. As a matter of fact, HOMOs of all 13 sydnone derivatives are similar. The four occupied x-orbitals of the sydnone ring in compound 2 are mainly allocated in the N2-N3, N3-C4, and C5-Ó6 regions, their wave functions are shown in Figure 5a-d.…”

“…30 Here we only deal with the relative values from the same calculation. Table VIII summarizes the net atomic charges of 13 sydnone derivatives computed with the MNDO method.…”