4-Azidobenzoic acid

Incorporating metal clusters within the skeleton of the organic polymers through a click reaction cannot only effectively prepare cluster-polymer composites, but also effectively avoid the cluster aggregation. Herein, an azide-containing lanthanide-titanium oxo cluster of Eu8 Ti10 -N3 (Eu8 Ti10 -N3 =[Eu8 Ti10 (μ3 -O)14 (H2 O)4 (OAc)2 (tbba)30 (paza)4 (THF)2 ]⋅4 THF⋅8 H2 O (1), Htbba=4-tert-butylbenzoic acid, Hpaza=4-azidobenzoate, HOAc=acetic acid, THF=tetrahydrofuran) through an in situ solvothermal reaction of 4-azidobenzoic acid and 4-tert-butylbenzoic acid. Reaction of 1 with PEG (PEG=methoxypoly(ethyleneglycol)alkyne, 2000 g mol-1 ) through CuI -catalyzed click chemistry generates a lanthanide-polymer composite of Eu8 Ti10 -N3 @PEG (2). Investigation with IR, 1 H NMR and ICP-OES of 2 indicates that the structural integrity of 1 is maintained in 2. Study of the luminescent properties of 1 and 2 reveals that the quantum yield of 1 itself basically remains unchanged in 2. Significantly, the formation of 2 cannot only effectively prevent the cluster 1 from aggregation, but also greatly enhance its solubility and adhesion to the substrate. Owing to the solubility and adhesion of luminescent materials being the key to their practical application, present work is thus of great significance for the development of metal cluster-polymer composite luminescent materials.

The coordination reactions of 4-Azidobenzoic Acid (ABA) molecules on different active surfaces are studied by scanning tunneling microscopy and density functional theory calculations. ABA molecules deposited on Ag(111)/Ag(100)/Cu(100) held at room temperature lead to the decomposition of azide groups and the release of a N2 molecule per ABA molecule. Two residual segments of ABA molecules can interact with one Ag/Cu adatom to form a coordination dimer through the N-Ag/Cu-N coordination bond on different substrates. Different orientations with different symmetries can result in different nanostructures based on the dimers. Interestingly, the residual segments of ABA molecules can generate four Cu adatoms as the coordination center on Cu(100) to form a novel coordination complex after annealing, which is the first report for trapping four adatoms as a coordination center. The number and the species of adatoms captured can be changed to alter coordination structures. It expounds that various regulatory effects of different substrates lead to the diversity of nanostructures dominated by coordination bonds.