Anna Berlicka

Towards True Carbaporphyrinoids: Synthesis of 21‐Carba‐23‐thiaporphyrin

In the search for porphyrinoids with a built-in cyclopentadienyl moiety (true carbaporphyrins), a rational synthesis of carbathiaporphyrin, the synthons, has been elaborated. The donors (C,N,S,N) in the porphyrinic core of carbathiaporphyrinoids are potentially of fundamental importance for generating organometallic complexes, as exemplified through formation of the palladium(II) complex.

Intramolecular Rotation of Iron(II) Dithiaethyneporphyrin Double-Decker Complex: 1H NMR Studies

The paramagnetic six-coordinated iron(II) 3,8,13,18-tetraaryldithiaethyneporphyrin (ES(2)P)(2)Fe(II) complexes of the double-decker type have been synthesized using iron pentacarbonyl as the metal source. The complex contains two porphyrinic macrocycles coordinated to the iron(II) in the sandwich-like fashion as determined by (1)H NMR. The (1)H NMR spectra of (ES(2)P)(2)Fe(II) have been examined in detail in the 180 - 366 K temperature range. Functional group assignments based on the selective deuteration, analysis of T(1) relaxation times and the NOESY experiment have been made at 313 and 210 K. The variable temperature (1)H NMR studies allowed to elucidate the dynamic behavior of (ES(2)P)(2)Fe(II) which involves rotation of dithiaethyneporphyrin rings around the metal ion. To account for the observed conformational rearrangements a cube, a square antiprism or a distorted triangular dodecahedron structure of (ES(2)P)(2)Fe(II) defined by the mutual orientation of two macrocyclic ligands have been considered. The six vertexes of a polyhedron are occupied by two pyrrolic nitrogens and four sulfur atoms, while two remaining vertexes are filled with two ethyne moieties. The dynamic rearrangements of (ES(2)P)(2)Fe(II) involve two enantiomeric couples of four fundamental staggered rotamers. The fast dynamic process engaging rotation of two dithiaethyneporphyrin ligands has been detected at 298 K. At low temperature range two rotamers have been identified as they presented the individual spectroscopic patterns. Considering the multiplicity of resonances the fast rotational oscillation involving one enantiomeric pair has been observed at 210 K, while all other processes are slow. The exchange between diastereomers has been confirmed at 210 K as the EXSY correlations linking diastereomeric resonances have been detected at the NOESY map.

Dithiaethyneazuliporphyrin - a contracted heterocarbaporphyrin

Dithiaethyneazuliporphyrin, the first contracted carbaporphyrinoid, has been synthesized; the molecule contains an azulene moiety embedded in the [18]dithiacarbatriphyrin(4.1.1) macrocyclic framework.

Incorporation of a Phenanthrene Subunit into a Sapphyrin Framework: Synthesis of Expanded Aceneporphyrinoids.

32-Hetero-5,6-dimethoxyphenanthrisapphyrins-macrocycles that link structural features of polycylic aromatic hydrocarbons and expanded porphyrins-were obtained in a straightforward [3+1] condensation reaction of dimethoxyphenanthritripyrrane and 2,5-bis(arylhydroxymethyl)heterocyclopentadienes. The highly folded conformation of formally 4 n π-electron macrocycles causes them to manifest only limited macrocyclic π conjugation as explored by means of NMR spectroscopic and X-ray structural analyses, and supported by DFT calculations. Although protonation does not change their π-conjugation characteristics, the cleavage of ether groups at the phenanthrenylene moiety yields nonaromatic 32-hetero-5,6-dioxophenanthrisapphyrins.

10,15-di(4-pyridyl)-5,20-di(4-tolyl)-21-thiaporphyrin as a building block for porphyrin coordination arrays

10,15-di(4-pyridyl)-5,20-di(4-tolyl)-21-thiaporphyrin, (SDPyDTP)H, was prepared by condensation of 2,5-bis(4-tolylhydroxymethyl)thiophene, pyrrole and 4-pyridinecarboxaldehyde in boiling propionic acid. The synthesis introduced two pyridyl substituents at two defined (opposite to thiophene) meso positions of the porphyrin periphery. The self-assembly of the angular 10,15-dipyridyl-21-thiaporphyrin modules with cis square-planar diphosphineplatinum(II) complex leads to a cyclic rhomboid dimer [Pt(DPPP)(SDPyDTP)H]2(OTf)4. The molecule acquires butterfly geometry. The 1H NMR studies confirmed the π-π stacking of the pyridyl ring with the equatorial phenyl rings of the phosphine fragment. The conformational equilibrium, interchanging the phenyl ring positions and affording the mixture of seven conformers in solution, has been considered. 1H NMR> spectroscopy was applied to identify oligomeric species, constructed by coordination of (SDPyDTP)H to the paramagnetic nickel(II) complex 5,10,15,20-tetra(4-tolyl)-21-thiaporphyrin, (STTP)NiIICl. (SDPyDTP)H acts as a mono- or bidentate ligand coordinating by meso-pyridyl substituents. Using the paramagnetically shifted resonances as an unambiguous spectroscopic probe, 1H NMR spectroscopy readily discriminated between five- {[(STTP)NiII]((SDPyDTP)H)} and six-coordinate {[(STTP)NiII]((SDPyDTP)H)2} oligomeric subunits. The applicability of 10,15-di(4-pyridyl)-5,20-di(4-tolyl)-21-thiaporphyrin as a suitable building block in construction of larger molecules was confirmed. The new route to modify the porphyrin coordination arrays, which preserves the overall architecture but modifies intrinsic chemical properties, using heteroporphyrin was demonstrated.

A Parallel-Displaced Directly Linked 21-Carba-23-Thiaporphyrin Dimer Incorporating a Dihydrofulvalene Motif.

In the search of porphyrin arrays with a unique geometry, the efficient synthesis of a directly linked 21-carba-23-thiaporphyrin dimer with the distinctive dihydrofulvalene bridging motif has been developed. This compound acquires an uncommon parallel-displaced arrangement of two carbaporphyrin planes. The dimer undergoes an acid-triggered cleavage to create of the asymmetric carbathiaporphyrin-carbathiachlorin dyad or 2,3-dihalo-21-carba-23-thiachlorin depending on choice of acid. A formation of a reactive carbocation intermediate is postulated to account for mechanism of cleavage.