TY - JOUR

T1 - Nucleophilicity of the Nitrile N Atom Whose Lone Pair Is Blocked by Metal Coordination. The π-Hole Interaction between an Arene Carbon and the Metal-Bound Nitrile Nitrogen

AU - Тойкка, Юлия Николаевна

AU - Рожков, Антон Викторович

AU - Burguera, Sergi

AU - Frontera, Antonio

AU - Кукушкин, Вадим Юрьевич

AU - Бокач, Надежда Арсеньевна

PY - 2024/12/23

Y1 - 2024/12/23

N2 - Cocrystallization of CuI with NCNMe2 in the presence of substituted perfluoroarenes─iodoperfluorobenzene (IFB), 4,4′-diiodoperfluorobiphenyl (4,4′-FIBP), and 4-bromoperfluorobenzonitrile (4-BrFBN)─led to the formation of three types of adducts 1·2(IFB), 1·4,4’FIBP, and 1·4-BrFBN (1 is Cu4I4(NCNMe2)4), all studied by X-ray crystallography. In these cocrystals, the coordinated nitrile N atom (whose electron pair is engaged in metal coordination) still acts as an electron donor, forming π-hole interactions, specifically, π-holearene···Nnitrile, with the perfluoroarenes. These interactions were examined in the context of their occurrence alongside other interactions involving C atoms of the electron-deficient aromatic rings and nucleophilic atoms of the copper cluster. Comprehensive theoretical calculations, including MEP, QTAIM/NCI plot analysis, EDA, ELF projections, and ETS-NOCV calculations, revealed that the nitrile ligand N atom maintains significant negative potential and that π-hole interactions are energetically more favorable than σ-hole interactions in the studied systems. This nucleophilicity is based on a noticeable contribution of the heterocumulene form, Cu-N-═C═N+Me2, in the resonance hybrid of Cu-bound NCNMe2: a phenomenon influenced by both the coordination and the conjugation between the NR2 and CN groups The discovery of π-holearene···Nnitrile contacts adds a new dimension to our understanding of coordinated push-pull nitriles, in particular dialkylcyanamides, revealing that the coordinated nitrile N atom can still function as a nucleophile in noncovalent binding.

AB - Cocrystallization of CuI with NCNMe2 in the presence of substituted perfluoroarenes─iodoperfluorobenzene (IFB), 4,4′-diiodoperfluorobiphenyl (4,4′-FIBP), and 4-bromoperfluorobenzonitrile (4-BrFBN)─led to the formation of three types of adducts 1·2(IFB), 1·4,4’FIBP, and 1·4-BrFBN (1 is Cu4I4(NCNMe2)4), all studied by X-ray crystallography. In these cocrystals, the coordinated nitrile N atom (whose electron pair is engaged in metal coordination) still acts as an electron donor, forming π-hole interactions, specifically, π-holearene···Nnitrile, with the perfluoroarenes. These interactions were examined in the context of their occurrence alongside other interactions involving C atoms of the electron-deficient aromatic rings and nucleophilic atoms of the copper cluster. Comprehensive theoretical calculations, including MEP, QTAIM/NCI plot analysis, EDA, ELF projections, and ETS-NOCV calculations, revealed that the nitrile ligand N atom maintains significant negative potential and that π-hole interactions are energetically more favorable than σ-hole interactions in the studied systems. This nucleophilicity is based on a noticeable contribution of the heterocumulene form, Cu-N-═C═N+Me2, in the resonance hybrid of Cu-bound NCNMe2: a phenomenon influenced by both the coordination and the conjugation between the NR2 and CN groups The discovery of π-holearene···Nnitrile contacts adds a new dimension to our understanding of coordinated push-pull nitriles, in particular dialkylcyanamides, revealing that the coordinated nitrile N atom can still function as a nucleophile in noncovalent binding.

UR - https://www.mendeley.com/catalogue/3209aa9c-4f9c-33c5-a672-5bd2c4ab1efa/

U2 - 10.1021/acs.inorgchem.4c03995

DO - 10.1021/acs.inorgchem.4c03995

M3 - Article

VL - 63

SP - 24210

EP - 24221

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 51

ER -