Polarized Absorption Spectra of 1,10-Phenanthroline and Phenanthrene in Stretched PVA Sheets

Abstract

Polarized absorption spectra of naphthalene and acenaphthene were measured in stretched PVA (polyvinyl alcohol) sheets below 46.5 kK, and the polarization directions of the electronic transitions of the compounds were determined experimentally: It has been confirmed that naphthalene has four electronic transitions in the near ultraviolet region at 31.3 kK, 34.7 kK, 44.6 kK and 45.5 kK, and these transitions are polarized along the x‐ (the long axis of the molecule), y‐ (the short axis), x‐ and y‐axis, respectively. In the case of acenaphthene, an additional y‐axis polarized electronic transition, corresponding to the forbidden transition (1 Ag ‐1Ag) of naphthalene, was found apparently at 41 kK.

Characterization and photocatalytic behavior of 2,9-di(aryl)-1,10-phenanthroline copper(i) complexes

“…62 The shift is even more pronounced when electrondonating groups are present on the phenyl substituents, as is the case with ligands 1-4. This is consistent with emission that arises from a π-π* state that is polarized along the transverse axis (as is the case with the 1 L B excited state 56,57 ). Similar effects have been observed with 3,8-disubstituted phenanthroline ligands.…”

“…56 This transition is polarized along the long axis (perpendicular to the symmetry axis in each case). 56,57 The bands between 340 and 350 nm correspond to the lowest-energy 1 π-π* transition of the substituted 1,10-phenanthroline ligands (most likely the 1 L b transition 54,55 ), with a possible admixture of states from the 1 π-π* transition of the phenyl substituent. A bathochromic shift of the low-energy absorption bands is typically observed in substituted 1,10-phenanthroline ligands.…”

A critical comparison of methods for analysis of linear dichroism of solutes in stretched polymers

“…Sometimes, the authors do not comment on this deviation or conclude that it can be attributed to experimental errors: 93°in acridine,58 87.2°in phenazine,58 and 87°in 1,10-phenanthroline. 59 At other times, it is concluded from such a deviation that the molecule is nonplanar or otherwise nonsymmetrical: 94°or larger in protonated l-7f-l,3-diazaazulene-2-one60 of presumed61 structure 3 (structure 4 appears more likely to us in spite of arguments to the contrary in ref 61).…”