The reactivity of [Ar¹Ar²I](SCN) toward the solid-state arylation depends on the preorganization of halogen bond (XB)-bound SCN⁻: N-XB-bound thiocyanates, which, in contrast to N,S-XB-bound, undergoes the extremely rare N-arylation of SCN⁻.

Co-crystallization of dithiocarbamate complexes [M^II(S₂CNEt₂)₂] (M = Cu 1, Ni 2, Pd 3, Pt 4) and 1,3,5-triiodotrifluorobenzene (FIB) gives an isomorphic series of (1–4)·2FIB co-crystals exhibiting quadruple Cu/Ni/Pd/Pt isostructural exchange. In the structures of (1–4)·2FIB, the halogen-bonded C–I⋯M (Ni, Pd, Pt) and semicoordination M⋯I–C (Cu) metal-involving contacts were identified by X-ray diffractometry and their nature was verified theoretically. The directionality of the I_σ-hole⋯d² _zM^II and M^II⋯I_{electron belt} interactions depends on the identity of a metal center: on going from a rather electrophilic Cu^II to substantially more nucleophilic Ni^II, Pd^II, and Pt^II centers, we observed the electron belt-to-σ-hole switch of a noncovalently bound iodine(I) of FIB and, correspondingly, its shift from semicoordination to halogen bonding. The negative values of the electrostatic potentials (given in parentheses) were estimated for all metal centers and they decrease in the order Cu^II (−8.8) > Ni^II (−24.5) > Pd^II (−28.6) > Pt^II (−33.3 kcal mol⁻¹). Despite the negative potentials at all M^IIs, the semicoordinative contact Cu⋯I was established by the recognition of the LP(I) → LP*(Cu) charge transfer using natural bond orbital (NBO) analysis and the comparison of electron density (ED) and electrostatic potential (ESP) minima positions along the I⋯Cu bond paths. In the case of the rather nucleophilic (although positively charged) Pd^II and Pt^II centers, the contacts C–I⋯d² _z[Pd] and C–I⋯d² _z[Pt] can be attributed to the unconventional metal-involving halogen bonding; these contacts are among the strongest (4.30 and 5.42 kcal mol⁻¹, correspondingly) between any metal center and iodine(I)-based σ-hole donors.

Nitrosoguanidinate Ni ^II complexes were generated via a hitherto unreported reaction between nickel( ii ) salts, N , N -disubstituted cyanamides NCNR ₂ , and the amidoxime MeC(NOH)NH ₂ in MeOH.

Three types of N(H)-nucleophiles, viz. hydrazine, acetyl hydrazide, and a set of hydrazones, were used to study the nucleophilic addition to the CN group of the 2-propanenitrilium closo-decaborate cluster (Ph₃PCH₂Ph)[B₁₀H₉NCEt], giving N-closo-decaborato amidrazones. A systematic mechanistic study of the nucleophilic addition is provided and included detailed synthetic, crystallographic, computational and kinetic work. As a result, two possible mechanisms have been proposed, which consist of firstly a consecutive incorporation of two Nu(H) nucleophiles, with the second responsible for a subsequent rapid proton exchange. The second possible mechanism assumes a pre-formation of a dinuclear [Nu(H)]₂ species which subsequently proceeds with the nucleophilic attack on the boron cluster. The activation parameters for hydrazones indicate a small dependence on bond formation [ΔH^‡ = 6.8–15 kJ mol⁻¹], but significantly negative entropies of activation [ΔS^‡ ranges from −139 to −164 J K⁻¹ mol⁻¹] with the latter contributing some 70–80% of the total Gibbs free energy of activation, ΔG^‡. In the X-ray structure of (Z)-(Ph₃PCH₂Ph)[B₁₀H₉N(H)C(Et)NHNCPh₂], very rare intramolecular non-covalent B–H⋯π(Ph) interactions were detected and studied by DFT calculations (M06-2x/6-311++G** level of theory) and topological analysis of the electron density distribution within the framework of Bader's theory (QTAIM method). The estimated strength of these non-covalent interactions is 0.8–1.4 kcal mol⁻¹.

The crystal structure of the newly synthesized 4-methoxyphenyl(phenyl)iodonium thiocyanate, [PhI(4-C₆H₄OMe)](SCN), represents the first example of 16-membered cyclic heterooctamer formed by halogen bonding between the iodonium cation and SCN⁻. Results of density functional theory (DFT) calculations followed by the topological analysis of the electron density distribution within the framework of the quantum theory of atoms in molecules (QTAIM) method at the ωB97XD/DZP-DKH level of theory reveal that energies of attractive intermolecular noncovalent interactions I···S and I···N (responsible for the formation of heterooctameric supramolecular clusters {PhI(4-C₆H₄OMe)}₄·{SCN}₄ in the solid state structure of [PhI(4-C₆H₄OMe)](SCN)) vary from 0.9 to 8.5 kcal/mol.