Study of Electronic Effects on Normal vs. Abnormal Tetrazol-5-ylidenes at DFT

Abstract

We present electronic effects on stability (ΔES-T), nucleophilicity (N), global electrophilicity (ω), and band gaps (ΔEHOMO-LUMO) of 36 novel 1,4- and 1,3-tetrazole-5-ylidenes, 1 and 2, respectively. A union of three sets of "normal" 1W,W, 1D,D, and 1D,W are compared to another union of four sets of "abnormal" 2W,W, 2D,D, 2D,W and 2W,D NHCs, electron-withdrawing substituents (W) and electron-donating ones (D). Every 1 is more stable and shows a larger bandgap than its corresponding 2. In addition, philicities, N and ω, of every 2 appear larger than that of the corresponding 1 isomer. Carbenes with W groups increase electrophilicity while D ones increase nucleophilicity and in pull-push groups, W groups in carbene center increase electrophilicity. All our NHCs give doubly bonded head-to-head dimers except for 5 species.

Keywords

• tetrazolylidenes
• band gap
• singlet-triplet energy gap
• electronic effects