Glasovac, Zoran; Vazdar, Mario; Margetić, Davor
Proton Affinities of Didehydroporphyrin and Subporphyrin in Ground and Excited States Obtained by Quantum Chemical Calculations.
Croatica Chemica Acta, 82
Quantum-chemical calculations were used to investigate molecular and electronic properties of porphyrin and subporphyrin. Their basicities were estimated in ground and excited states. It was found that multiple proton - nitrogen lone-pair coordination plays an important role in acid/base properties of the studied molecules. Lone pair-lone pair interactions in didehydroporphyrin and energetic stabilization of its protonated form lead to the increase of a proton affinity compared to porphyrin by 18 kcal mol(-1). A planarization of the protonated (dehydroporphyrin) structure leads to the complete reversal of the pi-electron ring currents indicating aromaticity of the protonated form. On the other hand, calculations indicate that subporphyrin is slightly (by 5 kcal mol(-1)) more basic than porphyrin, which was explained by non-planar geometry, imposed by smaller ring size.
||DFT calculations; NICS; TDDFT; proton affinity; basicity; density-functional theory; molecular-orbital calculations; neutral organic-bases; gas-phase; ab-initio; electronic-structure; conjugated systems; hydrogen-bonds; subphthalocyanines; aromaticity
||NATURAL SCIENCES > Chemistry
||Division of Organic Chemistry and Biochemistry
|Project title||Project leader||Project code||Project type|
|Host-guest međudjelovanja u policikličkim sustavima|| Davor Margetić||098-0982933-3218||MZOS|
|Organski i bioorganski procesi u osnovnom i elektronski pobuđenim stanjima|| Mirjana Maksić||098-0982933-2920||MZOS|
||18 Oct 2013 07:54
||10 Feb 2014 09:53
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