title: Cyanoform and Its Isomers. Relative Stabilities, Spectroscopic Features, and Rearrangements by Coupled Cluster and MCSCF-Based Methods.
abstract: Although an isolation of elusive tricyanomethane HC(CN)3was recently reported, the existence of other HC4N3species has yet to be confirmed. In this work, the relative stabilities, spectroscopic features, and rearrangements of tricyanomethane and its four isomers are examined using single- (CCSD(T), CCSD(T)-F12) and multireference (MCSCF, MRPT2) methods. Tricyanomethane and dicyanoketenimine (NC)2CCNH, which are found to be the two most stable HC4N3isomers lying within 9 kcal/mol, can be discriminated by their spectroscopic parameters. The predicted stepwise interconversion path relating HC(CN)3and (NC)2CCNH features the HC4N3species comprising the C-C-N ring moiety, with the largest barrier being associated with the initial H migration to one of the CN carbons. Adding a water molecule reduces the H migration barrier strongly and makes it possible to interconvert tricyanomethane to dicyanoketenimine in a "concerted" way.
authors.affiliation: Faculty of Chemistry, Wroclaw University , F. Joliot-Curie 14, 50-383 Wroclaw, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Szczepaniak
authors.affiliation: Faculty of Chemistry, Wroclaw University , F. Joliot-Curie 14, 50-383 Wroclaw, Poland.
authors.forename: Jerzy
authors.identifier: http://orcid.org/0000-0002-8221-1914
authors.initials: J
authors.lastname: Moc