Characterization of Excited-State Electronic Structure in Diblock π-Conjugated Oligomers with Adjustable Linker Electronic Coupling.

Diblock conjugated oligomers are π-conjugated molecules that contain two segments having distinct frontier orbital energies and HOMO-LUMO gap offsets. These oligomers are of fundamental interest to understand how the distinct π-conjugated segments interact and modify their excited state properties. The current paper reports a study of two series of diblock oligomers that contain oligothiophene (T) and 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (TBT) segments that are coupled by either ethynyl (-C≡C-) or -(-C≡C-)Pt(II)(PBu) acetylide linkers.

Excitation-Wavelength-Dependent Charge Injection and Hole Localization in Diblock Oligomers Anchored to TiO.

A series of diblock oligomers containing oligothiophene (T, = 4, 5) and 4,7-di(thiophen-2-yl)benzo[][1,2,5]thiadizole (TBT) segments, functionalized with carboxylic acid anchoring groups, were prepared and anchored to mesoporous TiO films to study wavelength-dependent interfacial electron transfer mechanisms. Thin films of the surface-anchored diblock oligomers contained two absorption bands centered at 400 and 500 nm, corresponding to the T and TBT blocks, respectively. Pulsed-laser excitation of the oligomer-sensitized films yielded local excited-states that promoted electron injection into TiO.

Synthesis, Electrochemistry, and Spectroscopy of Blue Platinum(II) Polyynes and Diynes.

The smallest band gap observed so far (1.77 eV) for an organometallic polymer is exhibited by the blue, rigid-rod polymer 2, which is prepared by the reaction of trans-[PtCl (PnBu ) ] with one equivalent of 1.