The synthesis, characterization, and photovoltaic performance of a series of N-annulated PDI materials is presented. Four novel N-annulated PDI compounds are reported, each of which can be synthesized in gram scale without the need for purification using column chromatography. N-Annulation of the PDI chromophore results in a decrease in electron affinity and lowering of the ionization potential, and renders the chromophore insoluble in organic solvents. Installation of an alkyl group improves the solubility. Single crystal X-ray analysis reveals a bowing of the aromatic backbone and compression of phenyl rings adjacent to the N atom. A brominated N-annulated PDI derivate represents a valuable synthon for creating novel multi-PDI chromophore materials. To demonstrate the utility of the new synthon for making electron transporting materials, a dimerization strategy was employed to create a dimeric PDI material. The PDI dimer has excellent solubility and film forming ability along with energetically deep HOMO and LUMO energy levels. X-ray crystal structure analysis reveals that, despite the isotropic nature of the molecule, only 1-D charge transport pathways are formed. Solar cells based on the new PDI dimer with the standard donor polymer PTB7 gave a high power conversion efficiency of 2.21% for this system. Through N-alkyl chain modification this PCE was increased to 3.13%. Further increases in PCE to 5.54% and 7.55% were achieved by using the more advanced donor polymers PTB7-Th and P3TEA, respectively. The simple yet high performance devices coupled with the highly modular and scalable "acceptor" synthesis make fullerene-free organic solar cells an attractive and cost-effective clean energy technology.

Experimental and synthetic details p. 2-Details of catalytic studies p. 8-Computational details p. 9-10 Basis set used in the DFT calculations p. 10-Calculated energies of the Os and Ru complexes p. 13-Optimized geometries of the Os and Ru complexes at the PBE0 level p. 14-Optimized geometries of the Os and Ru complexes at the mPW1k level p. 19-References p. 31-Crystallographic Data CCDC 820331 (complex 1), CCDC 820332 (complex 2), and CCDC 820333 (complex 7)

Catalyst tune-up: A readily available, air-stable amino-sulfide catalyst, [RuCl(2)(PPh(3)){HN(C(2)H(4)SEt)(2)}], has been developed. This complex displays outstanding efficiency for the hydrogenation of a broad range of substrates with C=X bonds (esters, ketones, imines), as well as for the acceptorless dehydrogenative coupling of ethanol to ethyl acetate.

There and back again: hydrogenation of esters and the reverse reaction of dehydrogenative coupling of alcohols are efficiently catalyzed by dimeric complexes of Ru and Os under neutral conditions. The Os dimer is an outstanding catalyst for the hydrogenation of alkenoates and triglycerides, and allows production of fatty alcohols from olive oil. This complex converts ethanol into ethyl acetate and hydrogen under reflux.

This paper presents an outstanding air-stable ruthenium catalyst that has unprecedented efficiency (TON up to 17 000) for acceptorless dehydrogenative coupling of ethanol, yielding ethyl acetate and hydrogen gas, and for hydrogenation of esters and imines at 40 °C while using as low as 50 ppm [Ru].