Additional reaction and mechanism of dicyanobenzene: Formation of amidinium or amidine compounds

• Published in: Journal of molecular structure 2021-06, Vol.1234, p.130203, Article 130203
• Main Authors: Shang, Donglin, Xue, Ruide, Ling, Lixia, Han, Junping, Li, Aihong, Yang, Nan, Wang, Baojun, Guo, Jianping, Bai, Shengdi
• Format: Article
• Language: English
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2021.130203

•Two amidinium diphenylphosphinate compounds with one- or two-dimensional networks or the amidine compound were synthesized by the stoichiometric reaction or relative positions of the cyano groups of dicyanobenzene.•The structure of three compounds was determined by single crystal X-ray analysis.•The addition reaction mechanism was suggested based on the results of experiments and DFT calculations.•Fluorescence study showed that compounds 1 and 2 are available photoluminescence solid material. The interaction of LiN(SiMe3)2 with one equivalent of 1,3- or 1,4-dicyanobenzene followed by the addition of one equivalent of chlorodiphenylphosphine and oxidation by hydrogen peroxide gave amidinium diphenylphosphinate compounds of the general formula [ArC(NH2)2]+[Ph2PO2]− (Ar = 3-cyanophenyl for 1, 4-cyanophenyl for 2). These compounds, in which the polymeric networks are interconnected through a featured type of synthon, show the typical solid-state and film fluorescence. When the above reactions were carried out with half of an equivalent of 1,3-dicyanobenzene, compound 1 and ammonium diphenylphosphinate were produced; with half of an equivalent of 1,4-dicyanobenzene, compound 3 (1,4-phenylene-bis(N-diphenylphosphinato)amidine) was obtained. A mechanism for the formation of compounds 1-3 was proposed. Results of DFT calculations suggested that the nucleophilic addition reaction to the second cyano group of the dicyanobenzene is a HOMO-controlled process. The amidinium diphenylphosphinate compounds with one- or two-dimensional polymeric network which are interconnected through a featured type of synthon, show the typical solid-state and film fluorescence. [Display omitted]