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The effect on E-stilbazoles second order NLO response by axial interaction with M(II) 5,10,15,20-tetraphenyl porphyrinates (M=Zn, Ru, Os); a new crystalline packing with very large holes
- Source :
- Inorganica Chimica Acta. 359:3029-3041
- Publication Year :
- 2006
- Publisher :
- Elsevier BV, 2006.
-
Abstract
- The axial coordination of push–pull E-stilbazoles carrying electron donor or electron withdrawing groups with tetraphenylporphyrinates of Zn(II), Ru(II) and Os(II) does not produce any significant increase in second order NLO response, the exception being the E-stilbazole carrying the electron withdrawing CF3 group. The lack of an increase in the second order NLO response due to the polarising action on the E-stilbazole push–pull system, by the metal centres acting as Lewis acids, is attributed to the axial π backbonding of the metal atom to the E-stilbazole, such backbonding producing a screening effect that opposes σ donation. This effect becomes dominant when the E-stilbazole carries a strong electron withdrawing group. Thus, it appears that the metals in porphyrin complexes may behave in a dual way when they interact axially with soft π delocalised ligands, such as E-stilbazoles where σ acceptor or π donor properties prevail according to the nature of the E-stilbazole itself. Infrared, electronic spectra and dipole moments suggest both axial and equatorial dissipation of the electronic density located on the metal, via π backbonding processes which influence the Lewis acid behaviour of the metal centres. A particular crystal packing, with boxes formed by four porphyrinic moieties and with large empty channels within the boxes, appears to be characteristic of axially substituted tetraphenylporphyrinates, resulting in materials able to absorb gases and solvents in their void spaces.
- Subjects :
- E-stilbazoles
Materials Chemistry2506 Metals and Alloys
Transition metal complexes
Nonlinear optics
Porphyrins
Physical and Theoretical Chemistry
Inorganic Chemistry
Electron donor
Metal
chemistry.chemical_compound
Computational chemistry
Materials Chemistry
Lewis acids and bases
Porphyrin complexes
Pi backbonding
Settore CHIM/03 - Chimica Generale e Inorganica
Chemistry
Porphyrin
Acceptor
Crystallography
visual_art
visual_art.visual_art_medium
Polar effect
Electronic density
Subjects
Details
- ISSN :
- 00201693
- Volume :
- 359
- Database :
- OpenAIRE
- Journal :
- Inorganica Chimica Acta
- Accession number :
- edsair.doi.dedup.....273aee83fba91097df394ee4c29a7804