Inorganic Chemistry, Vol.51, No.15, 8545-8556, 2012
Tetrathiafulvalene-Triazine-Dipyridylamines as Multifunctional Ligands for Electroactive Complexes: Synthesis, Structures, and Theoretical Study
The electroactive ligands (2,4-bis-tetrathiafulvalene[6-(dipyridin-2'-ylamino)]-1,3,5-triazine) TTF2-tz-dpa (1) and (2-tetrathiafulvalene[4,6-bis-(dipyridin-2'-ylamino)]-1,3,5-triazine) TTF-tz-dpa(2) (2) have been synthesized by palladium cross-coupling catalysis, and the single crystal X-ray structure for 1 was determined. In the solid state the TTF and triazine units are practically coplanar and short intermolecular S center dot center dot center dot S contacts are established. Two neutral and one tetracationic Zn(II) complexes, formulated as (TTF2-tz-dpa)ZnCl2 (3), [ZnCl2(TTF-tz-dpa(2))Zn(H2O)Cl-2] (4), and ([(H2O)(2)Zn(TTF-tz-dpa(2))](ClO4)(2)}(2) (5) have been crystallized and analyzed by single crystal X-ray analysis. A peculiar feature is the evidence for anion-pi interactions, as shown by the short Cl center dot center dot center dot triazine and O(perchlorate)center dot center dot center dot triazine distances of 3.52 and 3.00 angstrom, respectively. A complex set of intermolecular pi center dot center dot center dot pi, S center dot center dot center dot S and hydrogen bonding interactions sustain the supramolecular organizations of the complexes in the solid state. Electronic absorption spectra provide evidence for the intramolecular charge transfer from TTF to triazine, also supported by time-dependent density functional theory (TD DFT) calculations.