Gas-phase synthesis and deposition of metal-bipyridine complex [M-bpy] (M = Ag, Cu)

• Published in: Physical chemistry chemical physics : PCCP Vol. 23; no. 3; pp. 16334 - 1634
• Main Authors: Guo, Mengdi, Huang, Benben, Yi, Qiuhao, Luo, Zhixun
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 04.08.2021
• Subjects: Charge distribution; Charge transfer; Clusters; Coordination compounds; Copper; Energy levels; Glass substrates; Magnetron sputtering; Mathematical analysis; Molecular orbitals; Nanoparticles; Nitrogen atoms; Quantum chemistry; Raman spectra; Silver; Synthesis; Vapor phases
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d1cp02399c

Controllable synthesis of organometallic clusters in the gas phase is a topic of reasonable interest with precisely tunable properties depending on sizes, compositions, and intra-cluster charge-transfer interactions. Here, we have prepared small Ag n + and Cu n + clusters by using a customized magnetron sputtering (MagS) source and observed the gas-phase reactions with 2,2′-bipyridine. It is found that the small silver and copper clusters readily react with bipyridine and form products of [M-bpy 1-2 ] + (M = Ag, Cu). Quantum chemistry calculations reveal that the bipyridine in both [Ag-bpy 1-2 ] + and [Cu-bpy 1-2 ] + takes on cis -conformation with altered N-C-C-N dihedral angles, which is in contrast to the trans -conformation of a free 2,2′-bipyridine molecule itself. In order to unveil the principle of conformational transition, we have fully studied the interactions between the nitrogen atoms of bipyridine and the cationic Ag + and Cu + , calculated the donor-acceptor orbital overlaps, and analyzed the correlation of their frontier molecular orbital energy levels. Furthermore, by using a soft-landing strategy, we have managed to deposit the [Cu-bpy 2 ] + complex onto the glass substrates coated with Ag nanoparticles, and recorded the surface-enhanced Raman scattering spectra. Small Ag n + and Cu n + clusters react with 2,2′-bipyridine in the gas-phase giving rise to the production of [M-bpy 1-2 ] + (M = Ag, Cu).