Realization Of An Al Equivalent To Al Triple Bond In The Gas-Phase Na3al2- Cluster Via Double Electronic Transmutation

The discovery of homodinuclear multiple bonds composed of Group13 elements represents one of the most challenging frontiers in modern chemistry. A classical triple bond such as NN and HCCH contains one sigma bond and two bonds constructed from the porbitals perpendicular to the sigma bond. However, the traditional textbook triple bond between two Al atoms has remained elusive. Here we report an AlAl triple bond in the designer Na3Al2- cluster predicted insilico, which was subsequently generated by pulsed arc discharge followed by mass spectrometry and photoelectron spectroscopy characterizations. Being effectively Al2- due to the electron donation from Na, the Al atoms in Na3Al2- undergo a double electronic transmutation into Group15 elements, thus the Al2-Al2- kernel mimics the PP and NN molecules. We anticipate this work will stimulate more endeavors in discovering materials using Al2-Al2- as a building block in the gas phase and in the solid state.