Electrophilic-Nucleophilic Dualism of Nickel(II) toward Ni···I Noncovalent Interactions: Semicoordination of Iodine Centers via Electron Belt and Halogen Bonding via σ-Hole.

The nitrosoguanidinate complex [Ni{NH═C(NMe)NN(O)}] (1) was cocrystallized with I and sym-trifluorotriiodobenzene (FIB) to give associates 1·2I and 1·2FIB. Structures of these solid species were studied by XRD followed by topological analysis of the electron density distribution within the framework of Bader's approach (QTAIM) at the M06/DZP-DKH level of theory and Hirshfeld surface analysis. Our results along with inspection of XRD (CCDC) data, accompanied by the theoretical calculations, allowed the identification of three types of Ni···I contacts.

Metal-mediated reactions between dialkylcyanamides and acetamidoxime generate unusual (nitrosoguanidinate)nickel(ii) complexes.

The nitrosoguanidinate complexes [Ni{NH[double bond, length as m-dash]C(NR)NN(O)}] (R = Me1, (CH)O 2, (CH)3, (CH)4, (Me)Ph 5, Ph6, (p-MeCH)7) were obtained in low-to-moderate (12-26%) yields but reproducible yields in an unexpected metal-mediated reaction in MeOH between the nickel salt NiCl·2HO, N,N-disubstituted cyanamides NCNR, and the amidoxime MeC([double bond, length as m-dash]NOH)NH. These complexes were formed along with a spectrum of cyanamide-oxime coupling products. The IR and X-ray data indicate the delocalization within the NNO and NCN systems of the nitrosoguanidinate ligand.