Accessing cationic tetrylene-nickel(0) systems featuring donor-acceptor E-Ni triple bonds (E = Ge, Sn)

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Coordination Chemistry

Background:

• Tetrylenes (germanium and tin analogues of carbenes) are important in main group chemistry.
• Previous metal tetrylidyne complexes typically exhibit covalent or ionic bonding.
• The synthesis of cationic tetrylene metal complexes with multiple bonds remains challenging.

Purpose of the Study:

• To develop facile synthetic routes for novel linear cationic tetrylene nickel(0) complexes.
• To characterize the bonding interactions, specifically the E-Ni triple bonds, in these complexes.
• To investigate the electronic structure and bonding nature through computational analysis.

Main Methods:

• One-pot synthesis involving bulky halo-tetrylenes, nickel(0) precursors, phosphine ligands, and a non-coordinating anion.
• Isolation and characterization of the resulting cationic tetrylene nickel(0) complexes.
• Density Functional Theory (DFT) calculations to analyze the electronic structure and E-Ni bonding.

Main Results:

• Successful synthesis of linear cationic tetrylene nickel(0) complexes [^SiiPDippE·Ni(PPh₃)₃]⁺ for E = Ge (4) and Sn (5).
• Complexes 4 and 5 exhibit diamagnetism, indicating a formal zero-valent nickel center.
• Computational studies confirm significant triple bond character in the donor-acceptor E-Ni interactions.

Conclusions:

• The study presents a facile synthetic strategy for accessing unprecedented cationic tetrylene nickel(0) complexes.
• The E-Ni triple bonds in these complexes represent a unique bonding motif in organometallic chemistry.
• The findings expand the scope of bonding modes for tetrylenes and transition metals.