Svetlana S. Ivanova

Phosphorus(V) tetrapyrazinocorrolazines — first corrolazine derivatives with fused heterocyclic rings

Tetrapyrazinocorrolazines — first corrolazine derivatives with annulated heterocycles — have been prepared as phosphorus(V) complexes by the reaction of metal free tetrapyrazinoporphyrazines [(R8TPyzPA)H2] (R = Ph, Me) with phosphorus(III) chloride or bromide in pyridine. Oxophosphorus(V) complexes [(R8TPyzCA)P=O] were obtained when the reaction mixture was poured into water, while dilution with methanol leads to dimethoxyphosphorus(V) complexes [(R8TPyzCA)P(OMe)2]. The obtained compounds were characterized by MALDI-TOF mass-spectrometry and by IR, 1H, 31P NMR measurements. Their UV-vis spectral and basic properties in CH2Cl2–CF3COOH medium were studied in comparison to phosphorus(V) complex of octaphenylcorrolazine [(Ph8CA)P=O].

Perfluorinated porphyrazines 1: Synthesis and UV-vis spectral study of perfluorinated octaphenylporphyrazine and its indium(III) complex, [MPA(F5Ph)8](M = 2H, InIII(OH))

Novel perfluorinated porphyrazine has been prepared as indium(III) complex of octa(pentafluorophenyl)porphyrazine by cyclotetramerization of 1,2-dicyano-1,2-bis(pentafluorophenyl)-ethylene (mixture of cis- and trans-isomers) with basic indium(III) acetate in a melt. The InIII complex is stable in trifluoroacetic and sulfuric acids, but is easily demetalated with formation of the free-base in a chloroform solution containing HCl or slighly acidified with CF3COOH in the presence of tetraalkylammonium chloride as a catalyst. Perfluorination of octaphenylporphyrazine macrocycle leads to a hypsochromic shift of the Q-band maxima in the electronic absorption spectra, to drastic decrease of the basicity of meso-nitrogen atoms of porphyrazine macrocycle and to increase of the acidity of the internal NH-groups.

Indium(III) complexes of octaphenylporphyrazine: Effect of halide coordination on the basic properties and stability in acid media

Influence of halide ion coordination on the basic properties and stability of indium(III) octaphenylporphyrazine complexes in acid medium have been studied. Five-coordinated halide complexes [(Hal)InPAPh8](Hal = F, Cl, Br) are stable in dichloromethane or chloroform solutions acidified with trifluoroacetic acid up to 100%. One of four meso-nitrogen atoms is protonated in 0.1 M solution; their basicity depending of the ionic character of In–Hal bond is decreased in the order F > Cl > Br. Addition of an excess of fluoride, chloride or bromide anions leads to formation of anionic cis-dihalide complexes cis[(Hal)2InPAPh8]- which undergo very facile demetalation with formation of the free-base H2PAPh8 even in a slightly acidified solutions (0.001 M of acid). Such catalytic effect of halide anions seems to be general for demetalation reactions of indium(III) complexes with tetrapyrrolic macrocycles and was also observed for the phthalocyanine complex [(Cl)InPc]. Coordination of iodide leads to reduction of porphyrazine macrocycle assisted by meso-protonation with formation of π-anionic species, which upon demetalation and subsequent deprotonation give a mixture of free-base porphyrazine H2PAPh8 and tetraazachlorin derivatives.

Effects of solvation on the spin state of iron(III) in 2,8,12,18-tetrabutyl-3,7,13,17-tetramethyl-5,10-diazaporphyrinatoiron(III) chloride.

The chloroiron(III) complex of 2,8,12,18-tetrabutyl-3,7,13,17-tetramethyl-5,10-diazaporphyrin, [(Cl)FeMBDAP], was prepared and studied by X-ray crystallography and by solution (1)H NMR and UV-vis measurements. In the crystal structure of hemisolvate [(Cl)FeMBDAP] x 0.5CHCl(3), two nonequivalent [(Cl)FeMBDAP] units containing Fe1 and Fe2 are arranged in pi-dimers with considerable overlap on their concave sides. Axial chloride bonded to Fe2 is solvated by hydrogen bonding with CHCl(3). Parameters of the coordination pyramid have typical values for the spin-mixed (S = 3/2 / 5/2) Fe(III) complexes in the case of Fe1 and are characteristic for the pure intermediate-spin state for Fe2 (displacement from the (N(Pyr))(4) planes - 0.385 and 0.290 A and the average N(Pyr)-Fe bond lengths -1.992 and 1.954 A for Fe1 and Fe2, respectively). Effective magnetic moments in CHCl(3) and CH(2)Cl(2) capable of specific solvation of chloride by hydrogen bonding (4.5-4.6 micro(B) at 298 K) are indicative about mixed intermediate/high-spin state S = 3/2 / 5/2, with the S = 3/2 contribution increasing upon lowering of the temperature (4.02 micro(B) in CD(2)Cl(2) at 193 K). In nonsolvating CCl(4), C(6)D(6), and THF-d(8), the mu(eff) values are consistent with the predominantly high-spin state at ambient temperature (5.5-5.75 micro(B) at 298 K) and almost pure S = 5/2 state at low temperature (ca. 5.9 micro(B) in THF-d(8) below 270 K). Downfield isotropic shifts from 35 to 50 ppm are observed for alpha-alkyl protons and upfield shifts from -5 to -15 ppm for meso-CH protons, which is characteristic for the presence of the intermediate-spin state. The splitting of signals of the diastereotopic alpha-CH(2) protons is increased with growth of the S = 3/2 state contribution from 1.5 to 4 ppm in nonsolvating to 11 ppm in specifically solvating solvents at 298 K and further to 31 ppm at 193 K (in CD(2)Cl(2)). In the presence of DMSO addition and in methanol solution, the single CH(2) signal is observed at 25-28 ppm, and the meso-CH resonance is also shifted downfield to ca. 30 ppm, indicating the formation of six-coordinated complexes [(DMSO)(2)FeMBDAP](+) and [(MeOH)(2)FeMBDAP](+), the latter having the mu(eff) value of 4.92 micro(B) at 291 K is a spin-mixed species. The electron spin resonance spectra recorded at 77 K indicates that in frozen glasses in CD(2)Cl(2) and THF molecules in the high-spin state (g( perpendicular) approximately 6) and the predominantly intermediate-spin state (g( perpendicular) approximately 4.2-4.3) coexist together.