RESUMEN
[2 + 4] self-assembly of a pyrene-functionalized Pt(II)(8) tetragonal prism (2) is achieved using a newly designed star-shaped organometallic acceptor (1) in combination with an amide-based "clip" donor (L). The propensity of this prism (2) as a selective sensor for nitroaromatics (2,4-dinitrotoluene, 1,3,5-trinitrotoluene, and picric acid), which are the chemical constituents of many commercial explosives, has been examined.
RESUMEN
Coordination self-assembly of a series of tetranuclear Pt(II) macrocycles containing an organometallic backbone incorporating ethynyl functionality is presented. The 1:1 combination of a linear acceptor 1,4-bis[trans-Pt(PEt3)2(NO3)(ethynyl)]benzene (1) with three different dipyridyl donor 'clips' (LaLc) afforded three [2 + 2] self-assembled Pt(II)4 macrocycles (2a2c) in quantitative yields, respectively [La = 1,3-bis(3-pyridyl)isothalamide; Lb = 1,3-bis(3-pyridyl)ethynylbenzene; Lc = 1,8-bis(4-pyridyl)ethynylanthracene]. These macrocycles were characterized by multinuclear NMR (1H and 31P); ESI-MS spectroscopy and the molecular structures of 2a and 2b were established by single crystal X-ray diffraction analysis. These macrocycles (2a2c) are fluorescent in nature. The amide functionalized macrocycle 2a is used as a receptor to check the binding affinity of aliphatic acyclic dicarboxylic acids. Such binding affinity is examined using fluorescence and UV-Vis spectroscopic methods. A solution state fluorescence study showed that macrocycle 2a selectively binds (K(SV) = 1.4 × 10(4) M(-1)) maleic acid by subsequent enhancement in emission intensity. Other aliphatic dicarboxylic acids such as fumaric, succinic, adipic, mesaconic and itaconic acids caused no change in the emission spectra; thereby demonstrating its potential use as a macrocyclic receptor in distinction of maleic acid from other aliphatic dicarboxylic acids.