Ladder photophysics

Photophysics of Methyl-Substituted PPP-Type Ladder Polymers... 

Hybrid Orbitals. Orbitals, as one-electron energy levels, and corresponding wavefunctions are mathematical concepts only states are physically observable. Nevertheless, the simple picture of orbitals as the rungs of an energy ladder is very helpful, and is in many cases sufficient to account for the photophysical and photochemical properties of molecules. In more accurate pictures of orbitals it is necessary to consider their interactions, as they are not really totally independent. In this respect the concept of hydrid orbitals is important such hybrid orbitals are formed from a combination of elementary orbitals defined by their quantum numbers n, /, and m. The best... 

Figure 2.27 ORTEP diagram of [Na(DB18C6)H20][Tb(L )2] with the thermal ellipsoids drawn at the 30% probability level and the hydrogen atoms removed for clarity [59]. (Reprinted with penmssion from P.N. Remya, S. Bijn, M.L.P. Reddy, A.H. Cowley and M. Findlater, ID Molecnlar ladder of the ionic complex of terbinm-4-sebacoylbis( 1 -phenyl-3-methyl-5-pyrazolonate) and sodium dibenzo-18-crown-6 synthesis, crystal structure, and photophysical properties, Inorganic Chemistry, 47, 7396-7404, 2008. 2008 American Chemical Society.)...

Measuring the steady state optical absorption and emission properties of any luminescent polymer is the most basic but fundamental photophysical measurement we can make. Figure 1 depicts both the absorption and emission spectra for a series of polyfluorene oligomers and poly[9,9-di- -(2-ethylhexyljfluorene] (PF2/6), along with the fully rigid ladder type MeLPPP. 

Fig. 5 Absorption and emission spectra of hydrogen- (HLPPP, dashed line) and methyl-substituted (MLPPP, solid line) ladder-type polyparaphenylenes. Again, full alkylation leads to more stable materials with regard to the photophysical properties (modified from [43])...

Leising, U. Scherf, K. Mullen, Photophysics of Methyl-Substituted Poly(para-Phenyl-ene)-1ype Ladder Polymers, in G. Hadziio-annou, P.F. van Hutten (eds ), Semiconducting Polymers, Wiley-VCH, Weinheim (2000), p. 235. 

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