173166-63-7Relevant academic research and scientific papers
Observation of proton-coupled electron transfer by transient absorption spectroscopy in a hydrogen-bonded, porphyrin donor - Acceptor assembly
Damrauer, Niels H.,Hodgkiss, Justin M.,Rosenthal, Joel,Nocera, Daniel G.
, p. 6315 - 6321 (2004)
Proton-coupled electron transfer (PCET) kinetics of a Zn(II) porphyrin donor noncovalently bound to a naphthalene-diimide acceptor through an amidinium-carboxylate interface have been investigated by time-resolved spectroscopy. The S1 singlet excited-state of a Zn(II) 2-amidinium-5,10,15,20-tetramesitylporphyrin chloride (ZnP-?2-AmH +) donor is sufficiently energetic (2.04 eV) to reduce a carboxylate-diimide acceptor (??G?° = -460 mV, THF). Static quenching of the porphyrin fluorescence is observed and time-resolved measurements reveal more than a 3-fold reduction in the S1 lifetime of the porphyrin upon amidinium-carboxylate formation (THF, 298 K). Picosecond transient absorption spectra of the free ZnP-?2-AmH+ in THF reveal the existence of an excited-state isosbestic point between the S1 and T1 states at ??probe = 650 nm, providing an effective 'zero-kinetics' background on which to observe the formation of PCET photoproducts. Distinct rise and decay kinetics are attributed to the build-up and subsequent loss of intermediates resulting from a forward and reverse PCET reaction, respectively (kPCET(fwd) = 9 ?? 108 s -1 and kPCET(rev) = 14 ?? 108 s -1). The forward rate constant is nearly 2 orders of magnitude slower than that measured for covalently linked Zn(II) porphyrin-acceptor dyads of comparable driving force and D-A distance, establishing the importance of a proximal proton network in controlling charge transport.
Naphthalene amidine imide dyes by transamination of naphthalene bisimides
Langhals, Heinz,Jaschke, Harald
, p. 2815 - 2824 (2008/02/03)
Derivatives of naphthalene-1,4,5,8-tetracarboxylic acid with amidine structures have been prepared. The light absorption of the bisimide derivatives in the UV region is shifted to the visible for the amidine imides, which also fluoresce with a large Stoke
