The aromatic character of thienopyrrole-modified 20π-electron porphyrinoids.

نویسندگان

  • Rashid R Valiev
  • Heike Fliegl
  • Dage Sundholm
چکیده

Magnetically induced current densities and current pathways have been calculated for six tautomers of substituted and nonsubstituted core-modified porphyrinoids with one of the pyrrole rings replaced by a thienopyrrole moiety. The calculations show that the aromatic properties of the porpyrinoid macrocycle are strongly influenced by the ethyl-formate substituent at the pyrrole ring of the thienopyrrole moiety, whereas the alkyl substituents at the β positions of the ordinary pyrrole rings have a much smaller effect on the ring-current strength. The ethyl-formate substitution decreases the strength of the paratropic ring current of the macrocycle rendering the energetically lowest tautomer nonaromatic. The substituted tautomers with both porphyrinoid hydrogens inside the macroring are antiaromatic according to the ring current criterion, whereas the three tautomers with one hydrogen at the outer nitrogen of the thienopyrrole moiety are nonaromatic. Current calculations on the nonsubstituted core-modified porphyrinoids show that they are all antiaromatic. The antiaromatic thienopyrrole-modified porphyrinoids are dominated by paratropic ring currents inside the macroring and a weaker diatropic current along the periphery of the macroring. The nonaromatic porphyrinoid tautomers sustain significant ring currents around the thienopyrrole moiety, whereas the other pyrrole rings are practically nonaromatic.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Synthesis and switching the aromatic character of oxatriphyrins(2.1.1).

Triangularly shaped, contracted porphyrinoids belong to a group of molecules where the geometry significantly modifies the observed electronic properties. The need for a controllable, effective, and widely applicable approach to triphyrins drives extensive research towards macrocyclic materials that act as potential controlling motifs by switching their aromaticity. Two isomeric thiophene-fused...

متن کامل

Deciphering aromaticity in porphyrinoids via adaptive natural density partitioning.

The adaptive natural density partitioning (AdNDP) method has been applied for the first time to porphyrinoids in order to describe their aromaticity. The analysis of π-electron system reveals that aromaticity of annulene originates from 6-π-electron delocalization, while aromaticity of porphyrin can be better described in terms of local aromaticities of the appended 6-π-electron pyrrolic hetero...

متن کامل

CdS nanoparticles: An efficient, clean and reusable heterogeneous catalyst for one-pot procedure for synthesis of 3,4-Dihydropyrimidin-2(1H)-ones in solvent-free conditions

3,4-Dihydropyrimidinones and their derivatives are synthesized via Biginelli routes involving an aromatic aldehydes, ethylacetoacetates and urea in one-pot procedure by using CdS nanoparticles as efficient heterogeneous catalyst in solvent-free conditions. Compared with classical Biginelli reaction reported in 1893, this new method provides much improved modification in terms of simplicity. The...

متن کامل

CdS nanoparticles: An efficient, clean and reusable heterogeneous catalyst for one-pot procedure for synthesis of 3,4-Dihydropyrimidin-2(1H)-ones in solvent-free conditions

3,4-Dihydropyrimidinones and their derivatives are synthesized via Biginelli routes involving an aromatic aldehydes, ethylacetoacetates and urea in one-pot procedure by using CdS nanoparticles as efficient heterogeneous catalyst in solvent-free conditions. Compared with classical Biginelli reaction reported in 1893, this new method provides much improved modification in terms of simplicity. The...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Physical chemistry chemical physics : PCCP

دوره 16 22  شماره 

صفحات  -

تاریخ انتشار 2014