title: Coordination self-assembly of tetranuclear Pt(II) macrocycles with an organometallic backbone for sensing of acyclic dicarboxylic acids.
abstract: 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’ (La–Lc) afforded three [2 + 2] self-assembled Pt(II)4 macrocycles (2a–2c) 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 (2a–2c) 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.
authors.affiliation: Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Sankarasekaran
authors.initials: S
authors.lastname: Shanmugaraju
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Bar
authors.forename: Harshal
authors.initials: H
authors.lastname: Jadhav
authors.forename: Dohyun
authors.initials: D
authors.lastname: Moon
authors.forename: Partha Sarathi
authors.initials: PS
authors.lastname: Mukherjee
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D003998:Dicarboxylic Acids / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D010984:Platinum / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D003998:Dicarboxylic Acids; D047028:Macrocyclic Compounds; D010984:Platinum