Synthesis and characterisation of heterometallic molecular triangles using ambidentate linker: self-selection of a single linkage isomer.
The coordination driven self-assembly of discrete molecular triangles from a non-symmetric ambidentate linker 5-pyrimidinecarboxylate (5-pmc) and Pd(II)/Pt(II) based 90 degrees acceptors is presented. Despite the possibility of formation of a mixture of isomeric macrocycles (linkage isomers) due to different connectivity of the ambidentate linker, formation of a single and symmetrical linkage isomer in both the cases is an interesting observation. Moreover, the reported macrocycles represent the first example of discrete metallamacrocycles of bridging 5-pmc. While solution composition in both the cases was characterised by multinuclear NMR study and electrospray ionization mass spectrometry (ESI-MS), the identity of the assemblies in the solid state was established by X-ray single crystals structure analysis. Variable temperature NMR study clearly ruled out the formation of any other macrocycles by [4 + 4] or [2 + 2] self-assembly of the reacting components.
Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India.
Arun Kumar
AK
Bar
Rajesh
R
Chakrabarty
Ki-Whan
KW
Chi
Stuart R
SR
Batten
Partha Sarathi
PS
Mukherjee