화학공학소재연구정보센터
Inorganic Chemistry, Vol.48, No.24, 11847-11852, 2009
Evidence of Disruption of Conjugation Involving Delta Bonds in Intramolecular Electronic Coupling
A dimer of dimers containing two quadruply bonded [Mo-2(DAniF)(3)](+) units (DAniF = N,N'-di(p-anisyl)formamidinate) linked by the S-donor linker, dimethyldithiooxamidate was synthesized, structurally characterized, and electronic communication was probed. The core of [Mo-2(DAniF)(3)](2)(C2S2N2Me2), 1, formed by the Mo2NSC2SNMo2 atoms shows two fused but non planar six-membered rings, which differs from that of the beta form of dimethyloxamidate analogue that has a heteronaphthalene-type structure (Cotton, F. A.; Liu, C. Y.; Murillo, C. A.; Villagran, D.; Wang, X. J. Am. Chem. Soc. 2004, 126,14822). For these two analogous compounds electronic coupling between the two [Mo-2] units, as determined by electrochemical measurements, diminishes considerably upon replacement of O-donor by S-donor atoms (Delta E-1/2 = 531 mV and 440 mV, respectively) This suggests that the non planar conformation of the linker in 1 hampers a pathway leading to pi conjugation. Density functional theory (DFT) calculations show that the highest occupied molecular orbitals HOMO-HOMO-1 energy gap of 0.12 eV for 1 is much smaller than that of 0 61 eV for the O-donor analogue, which is consistent with the electrochemical data.