500893-59-4Relevant academic research and scientific papers
Formation of group 11 metal(I)-arene complexes: Bonding mode and molecule-responsive spectral variations
Xu, Feng-Bo,Li, Qing-Shan,Wu, Li-Zhu,Leng, Xue-Bing,Li, Zu-Cheng,Zeng, Xian-Shun,Chow, Yuan L.,Zhang, Zheng-Zhi
, p. 633 - 640 (2008/10/08)
Two N(n-Pr)PPh2 groups appended to the 9,10-anthracene positions through methylene spacers as a bidentate ligand coordinate with Cu+, Ag+, and Au+ ions efficiently to afford endocyclic metal complexes with metal-η6-arene bonding, rarely observed for the group 11 metal ions. The three-center metal-NP and metal-η6-arene bonding patterns in the endocyclic complexes were confirmed using ab initio and density functional calculations. The close metal-anthracene centroid distances significantly affected absorption and fluorescence properties of the complexes in solution. Among them the Cu+ complex has the shortest metal-anthracene distance and most drastic spectral abnormality. The close distances also controlled the endocyclic-exocyclic metal transition of the complexes, wherein the equilibrium heavily favored the former on account of η6 interactions. These complexes reacted with phosphines in solution to give highly fluorescent species that were proposed to possess the exocyclic configuration with the three-coordinated metal center. These exocyclic metal complexes as well as the ligand itself all form respective excimers from their singlet excited states to exhibit an additional broad fluorescence at about 455 nm. The excimers are assumed to arise from an interaction of the excited anthracene moiety with an N-P group of the ground state exocyclic molecule. The observed molecule-responsive light-switchable spectral variations have been discussed in terms of structural changes in the endocyclic-exocyclic metal transitions.
