ABSTRACT
Polymer electrolyte fuel cells are an essential technology for future local emission-free mobility. One of the critical challenges for thriving commercialization is water management in the cells. We propose small- and wide-angle X-ray scattering as a suitable diagnostic tool to quantify the liquid saturation in the catalyst layer and determine the hydration of the ion-conducting membrane in real operating conditions. The challenges that may occur in operando data collection are described in detailâseparation of the anode and cathode, cell alignment to the beam, X-ray radiation damage, and the possibility of membrane swelling. A synergistic development of experimental setup, data acquisition, and data interpretation circumvents the major challenges and leads to practical and reliable insights.
ABSTRACT
Organic semiconductors containing metal binding sites within their molecular backbones are of a general interest in organic materials chemistry. In this paper, we describe a straightforward synthetic procedure, which gives access to a series of 2-(oligothienyl)-[1,10]phenanthrolines (nT-phen), 2,9-bis(oligothienyl)-[1,10]phenanthrolines (nT-phen-nT) and 2,2'-(oligothienyl)bis-[1,10]phenanthrolines (phen-nT-phen). By a Negishi-type cross coupling of 2-iodo-[1,10]phenanthroline or 2,9-diiodo-[1,10]phenanthroline with in situ generated alpha-zinc derivatives of different mono-, ter-, and quinquethiophenes we were able to synthesize the corresponding oligothienyl-phenanthrolines in medium to excellent yields. Furthermore, characterization of the optical properties of the new materials indicated that the two subunits, oligothiophene and phenanthroline, are in pi-conjugation. Characterization of the redox properties revealed additional evidence for the role of [1,10]phenanthroline as a pi-bridging unit in the nT-phen-nT series.
ABSTRACT
Ru(II)- and Os(II)-polypyridine termini are linked by a quinquethiophene bridge (the inter-metal separation is ca. 1.9 nm) wherein excitation energy flows into the luminescent Os-based unit by way of a conductive level.