Noble Gas Chemistry and Coordination Complexes

Noble gases, long regarded as chemically inert, have emerged as participants in diverse bonding scenarios ranging from weak non-covalent assemblies to fully covalent frameworks. Advances in experimental techniques and high-level computations have revealed that under suitable conditions—such as cryogenic matrices, high pressures or in the presence of highly polarising Lewis acids—noble gases can engage in coordination complexes with main-group and transition-metal centres. These interactions span a continuum from van der Waals–type attractions and aerogen bonds to donor–acceptor adducts and genuine covalent bonds. The ability to trap noble gases within molecular cages or to stabilise them via superelectrophilic anions has led to the discovery of novel cationic, anionic and neutral species, expanding the boundaries of inorganic and organometallic chemistry. Beyond fundamental interest, noble-gas coordination complexes offer insights into catalysis, high-pressure materials and the design of reactive species under extreme conditions.

Research from Nature Portfolio

Recent foundational work includes the identification of an aromatic noble-gas hydride formed in a xenon matrix, demonstrating that aromatic substrates can host covalent xenon–carbon and xenon–hydrogen bonds under cryogenic conditions. Infrared spectroscopy combined with quantum-chemical calculations confirmed the structure and stability of this species, marking the first aromatic noble-gas hydride and illustrating the potential for π-conjugated systems to incorporate noble gases. This achievement has broadened the scope of organonoble-gas chemistry and provided a template for designing covalent noble-gas frameworks.

Noble Gas Chemistry and Coordination Complexes publication trend

The graph below shows the total number of articles in noble gas chemistry and coordination complexes across all publications each year (not limited to Nature Index journals).

Technical terms

Coordination complex: A compound in which a central metal or main-group atom is bonded to surrounding ligands via coordinate (dative) bonds.

Matrix isolation: An experimental technique that traps reactive species in an inert, cryogenic solid (often noble-gas matrices) to enable spectroscopic characterisation.

Superelectrophile: A highly electron-deficient species, often multiply charged, that exhibits enhanced Lewis acidity and binds inert gases strongly.

π-hole interaction: A non-covalent attraction between an electron-rich site (Lewis base) and an electron-deficient region above or below a π-system.

References

1. On the Nature of the Partial Covalent Bond between Noble Gas Elements and Noble Metal Atoms. Molecules (2023).
2. Chemical Aristocracy: He3 Dication and Analogous Noble-Gas-Exclusive Covalent Compounds. The Journal of Physical Chemistry Letters (2024).
3. New Perspectives in the Noble Gas Chemistry Opened by Electrophilic Anions. Frontiers in Chemistry (2020).
4. An aromatic noble-gas hydride: C6H5CCXeH. Scientific Reports (2017).