cg201073m_si_001.pdf (430.3 kB)

Interplay between Structural and Dielectric Features of New Low k Hybrid Organic–Organometallic Supramolecular Ribbons

Download (430.3 kB)
journal contribution
posted on 22.02.2016 by Paolo Sgarbossa, Roberta Bertani, Vito Di Noto, Matteo Piga, Guinevere A. Giffin, Giancarlo Terraneo, Tullio Pilati, Pierangelo Metrangolo, Giuseppe Resnati
The synthesis and characterization of low k one-dimensional (1D) hybrid organic–organometallic supramolecular ribbons 3a,b, through halogen-bond driven co-crystallization of trans-[Pt­(PCy3)2(CC-4-py)2] (1) with 1,4-diiodotetrafluorobenzene (2a) and trans-1,2-bis-(2,3,5,6-tetrafluoro-4-iodophenyl)-ethylene (2b), are reported. The co-crystals 3a,b have been obtained by isothermal evaporation of a chloroform solution containing the corresponding starting materials at room temperature. X-ray structure determinations show that noncovalent interactions other than halogen bonds help in the construction of the crystal packing; these interactions are stronger in 3b, thus reducing the chain mobility with respect to 3a. Accordingly, the broadband dielectric spectroscopic determinations, carried out from 10–2 to 107 Hz and at a temperature ranging from 25 to 155 °C, showed that both 3a and 3b materials exhibit a real component of dielectric permittivity (ε′) significantly lower than SiO2. In particular in the case of 3b, the rigidity of the 1D chain explains the observed ε″ and tan δ values. A permittivity value that is significantly lower than that of the silica reference, tan δ values lower than 0.02 in the entire investigated temperature range, and less than 0.004 at T < 100 °C make 3b a very promising low k hybrid organic–organometallic material for application as dielectric films in next generation microelectronics.