Nanostructured discotic Pd(II) metallomesogens as one-dimensional proton conductors

作者:Cuerva Cristian; Campo Jose A; Cano Mercedes; Schmidt Rainer
来源:Dalton Transactions, 2017, 46(1): 96-105.
DOI:10.1039/c6dt03521c

摘要

A novel family of square-planar Pd(II) complexes based on isoquinoline-functionalised pyrazolate ligands [Pd(pz(R(n,n)iq)) (2)] (R(n, n) = C6H3(OCnH2n+1) 2, n = 4, 6, 8, 10, 12, 14, 16, 18) has been synthesised and characterised. The new complexes show mesomorphic properties and exhibit columnar mesophases that are highly-stable in exceptionally wide temperature ranges of up to 345 degrees C. The formation of nanochannels in the fluid liquid crystal phases generates continuous pathways for one-dimensional proton conduction on the basis of C-H center dot center dot center dot N proton transfer. The complex with an intermediate chain length (n = 12) shows the highest proton conductivity of 1.34 x 10(-4) S m(-1) at 269 degrees C in the hexagonal columnar mesophase, and an activation energy of 0.84 eV. The influence of both the terminal alkyl chain length and the mesophase columnar organisation on the proton conduction mechanism is demonstrated. The series of Pd(II) complexes investigated in this work constitutes one of the first examples of proton-conducting metallomesogens with potential applications in PEM fuel cells.

  • 出版日期2017-1-7