Synthesis and Structural Studies of Donor-Bridge-Acceptor Complexes Based on Co(III)(cyclam) Acetylides

Obtaining a greater understanding of photo-induced electron-transfer (PET) processes is key to synthesizing photovoltaic materials with enhanced efficiency. Gaining knowledge about the structure property relationship in photo-active donor-bridge-acceptor (D-B-A) dyads will help to optimize electronic and photoelectronic materials. Metal acetylide complexes have attracted increasing interest for their potential applications as building blocks for electronic and photoelectronic materials. Their unique υ(C≡C) (2000-2100 cm^-1) allows for selective excitation, making them an appealing target for attenuating PET processes across a metal acetylide backbone. The following topics will be discussed: i.) an overview of M(cyclam′) alkynyl chemistry, where M = Cr, Fe, Co, or Ni, with a focus on reactivity and spectroscopy, ii.) selective synthesis of dissymmetric species, utilizing a Co^III(cyclam) (1,4,8,11-tetraazacyclotetradecane) alkynyl bridge, iii) synthesis and characterization of metal alkynyl D-B-A dyads trans- [R'₂N-4-C₆H₄C₂-Co^III(cyclam)-C_n-NAP^R]⁺ (n = 2 or 4), where the chromophore acceptor is NAP^iPr (N-isopropyl-1,8-napthalimide) and the putative donor is -C₆H₄-4-NR'₂ (R' = Me or Ph-4-OMe), iv.) design and synthesis of D-B-A derivatives, alter NAP^R (R = mesityl, methyl, 1-ethylpropyl, 2-ethylhexyl, or octyl) to tune reactivity and crystallinity, v.) electronic and spectroscopic influence the bridging center on A, and vi.) effect of η² coordination of MX₂ (MX₂ = CuCl₂ or Ag(NO₃)₂) to the alkyne bridge on electron transfer.