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Five-coordinate organometallic complexes RIn(TAPPh8) (R = Ph, Bu) were synthesized by the reactions of chloro(octaphenyltetraazaporphyrinato)indium(iii) ClIn(TAPPh8) with organolithium and organomagnesium compounds. The optical, IR, and 1H NMR spectra of the complexes were studied. In the presence of pyridine, the photochemical insertion of CO2 occurs at the In—C bond to form the carboxylate complexes (RCOO)In(TAPPh8). A study of the kinetics of this reaction showed a higher stability of the In—C bond in the aryl PhIn(TAPPh8) complex than that in the alkyl complex BuIn(TAPPh8). The mechanism of the reaction was proposed.

The acid-base interaction of chloro(octaphenyltetraazaporphinato)erbium(III), (acetylacetonato)(octaphenyltetraazaporphinato)erbium(III), and (acetylacetonato)(octaphenyltetraazaporphinato)dysprosium(III) in AcOH and in AcOH-benzene and AcOH-H2SO4 systems involves one meso-nitrogen atom of the complexes; the stability constants of the resulting acid forms were estimated. The solvoprotolytic dissociation of the complexes in the AcOH-H2SO4 system was studied, its kinetic parameters were determined, and some suggestions as to the dissociation mechanism were made.

A hybrid inorganic/organic heterojunction formed by p-type cuprous iodide CuI and n-type fullerene C60 was employed in the archetypal photovoltaic devices. The thickness of the p-CuI layer deposited on a molybdenum oxide (MoOx) anode buffer was optimized to achieve a higher efficiency, while the thickness of the n-C60 photoabsorber layer was fixed. In an attempt to obtain semitransparent devices, a trilayer MoOx/metal/MoOx cathode with a BCP underlayer was applied (metal = Ag or Mg, BCP = bathocuproine). The maximum photovoltage of such devices on a PET/ITO substrate was equal to 0.75 V for an average transparency of about 35% over the range of 380–1000 nm. Similar devices having a non-transparent Al cathode in conjunction with an Alq3 underlayer generate photovoltage of 0.82 V (Alq3 = tris-8-hydroxy­quinolinato-aluminum), which shows the important effect of hybrid junctions in multilayer organic-based devices.

The present report describes two series of new porphyrazine macrocycles derived from tetrakis(selenodiazole)porphyrazine, TSeDPzH 2, having the formulae [ TSeDPzM ]( CH 3 COOH )( H 2 O )x M = Mn (II), Co (II), Ni (II), Zn (II); x = 4–6) and [ TSeDPzM ( py )]( CH 3 COOH )( H 2 O )x ( M = Mn (II), Co (II), Ni (II); x = 1–5), obtained by reaction of the free ligand with the appropriate metal acetate in dimethyl (DMSO), and, respectively, pyridine. All the species isolated are stable-to-air substantially amorphous materials, almost completely insoluble in the usual organic solvents and N -donors (pyridine etc.), and only slightly soluble in CF3COOH or 96% H 2 SO 4. The complexes have been investigated by IR, Raman, and UV-vis spectra, and magnetic susceptibility measurements. Their properties in terms of electronic structure and reactivity towards N -bases are discussed in comparison with their S-containing analogs and the class of the structurally similar metal phthalocyanines.

Stability of chloro(octaphenyltetraazaporphinato)indium(III) and chloro(2,8,12,18-tetrabutyl-3,7,13,17-tetramethyl-5,15-diazaporphinato)indium(III) in 90-98 % aqueous sulfuric acid was studied. Kinetic parameters of solvoprotolytic dissociation of the complexes were determined, and a mechanism of the reaction was proposed. Diaza substitution results in more stable complexes than tetraaza substitution. The state of chloro(2,8,12,18-tetrabutyl-3,7,13,17-tetramethyl-5,15-diazaporphinato)indium(III) in a proton-donor medium was studied to show that the acid-base interaction involves one by one two meso-nitrogen atoms. Dissociation constants of the resulting acid forms were determined.

Peripheral modification of the porphyrazine macrocycle is an important synthetic approach to β-substituted porphyrazine derivatives, especially those which cannot be obtained via direct template cyclotetramerization of maleodinitriles and other similar synthons. The paper presents the last results of the systematical investigation of the reactivity of unsubstituted porphyrazine (tetraazaporphine) in the reactions of electrophilic and radical substitution in pyrrole rings (bromination, chlorination, chloromethylation, nitration and sulfonation) and nucleophilic substitution reactions of chloro-, bromo- and sulfo-substituted porphyrazines.

The synthesis and general chemical physical characterization of the following new classes of complexes derived from tetrakis(thiadiazole)porphyrazine (TTDPzH(2)), i.e., [(TTDPz)M(DMSO)(2)] (M = Mn(II), Fe(II)), [(TTDPz)M](H(2)O)(2), and [(TTDPz)M] (M = Mn(II), Fe(II), Co(II), Ni(II), Zn(II)) are reported. The IR spectra in the region 4000-200 cm(-)(1) show for all the species typical modes of the TTDPz skeleton and specific absorptions of the thiadiazole ring. The UV-visible spectra in different media show the expected absorptions in the Soret and Q-band regions. Inspection of the IR spectra of the two six-coordinate adducts [(TTDPz)M(DMSO)(2)] and of their corresponding species containing DMSO-d(6) clearly indicate that DMSO is O-bonded to the central metal in both species (nu(SO) located at 918 and 940 cm(-)(1) for the Fe(II) and Mn(II) species, respectively), differently from the findings for DMSO (S-bonded) in the Fe(II) and Ru(II) phthalocyanine analogues. The complexes [(TTDPz)M](H(2)O)(2) and [(TTDPz)M] are all tetracoordinate species, the water molecules for the hydrated species being very likely only weakly ligated at the peripheral thiadiazole rings of the macrocycle. Some additional information on the oxidation and spin state of the complexes has been achieved by Mössbauer spectra (Fe) and room-temperature magnetic susceptibility measurements, and data at hand are compared, when allowed, with those of the parallel classes of metal phthalocyanine complexes.

A new class of porphyrazine macrocycles carrying peripheral diazepine rings, i.e. tetrakis-2,3-(5,7-diphenyl-6H-1,4-diazepino)porphyrazine [Ph2DzPzH2](H2O)4, and its metal derivatives of formula [Ph2DzPzM](H2O)x=2–7 [M = MgII(H2O), CuII, ZnII] have been prepared and characterized. Single crystal X-ray work on the monomeric precursor 5,7-diphenyl-2,3-dicyano-6H-1,4-diazepine, Ph2(CN)2Dz, and NMR spectra (CDCl3, (CD3)2SO) and UV/Vis spectra in solution of different media (basic, neutral, acid) of the monomer and its macrocyclic derivatives have provided information on the conformational flexibility of the diazepine ring as well as on the structural and electronic features of the entire porphyrazine skeleton.

Molecules of azaporphyrins combine two acidic pyrrole-type NH groups and several basic centres—two internal pyrrolenine nitrogen atoms and from one to four meso-nitrogen atoms—in one highly conjugated aromatic system. The acid–base properties of such unique multicentre ampholites have been the subject of numerous studies and discussions. Along with a short critical historical review the paper presents the latest results of a systematic investigation of the influence of successive aza substitution on the spectral properties and thermodynamic stability of the acid–base forms of azaporphyrins.

The new phthalocyanine-like macrocycle tetrakis(selenodiazole)porphyrazine, TSeDPzH 2, and its Mg ( II ) and Cu ( II ) complexes have been prepared and their general, spectroscopic (IR, UV-vis), and magnetic properties investigated. It has been observed that the peripheral selenodiazole rings of the TSeDPz skeleton can be opened by the action of H 2 S , with release of the Se atoms and formation of a new macrocycle, i.e. octaaminoporphyrazine, which is easily converted into tetrakis(pyrazino)porphyrazine derivatives.

@Attempt to obtain imidazoporphyrazine by treatment of formic acid on “diaminoporph yrazine” formed in situ by deselenation of hexaphenyl substituted (1,2,5-selenadiazolo)porphyrazine in the presence of H 2S and pyridine unexpectedly led to diformamidoporphyrazine. It is suggested that formation of imidazoporphyrazine is hindered by steric strain appearing in the case when two 5-membered heterocycles – pyrrole and imidazole are fused together.

Iron(II) complexes of hexaphenyl(1,2,5-thia/selenadiazolo)porphyrazines have been prepared as bis(pyridine) adducts [Py 2 Fe(XN 2 )PAPh 6 ] (X = S, Se) from the corresponding Mg II complexes obtained by template co-cyclotetramerization of diphenylfumarodinitrile with 1,2,5-thia/selenadiazolo-3,4-dicarbonitriles, and the unusual direct replacement of Se by S in the reaction of [Py 2 Fe(SeN 2 )PAPh 6 ] with H 2 S has been observed.

The new macrocycle tetrakis(thiadiazole)porphyrazine, TTDPzH2, has been prepared, in CF3COOH, from its corresponding Mg(II) derivative, [TTDPzMg(H2O)]·CH3COOH, which, in turn, is obtained by the reaction of magnesium(II) propylate and 3,4-dicyano-1,2,5-thiadiazole. The Mg(II) complex is also used for the preparation of the Cu(II) derivative, TTDPzCu, by reaction with copper acetate in CF3COOH. An alternative preparation allows the Cu(II) complex to be obtained from the metal-free macrocycle and Cu(OCOCH3)2 in pyridine. Like the Mg(II) complex, TTDPzH2 and TTDPzCu are obtained as solvated species (carboxylic acid, water). Practically complete elimination of the solvent molecules can be achieved by heating the species under vacuum (10-2 mmHg) at 300−310 °C, only the Mg(II) complex retaining water. TTDPzH2 and TTDPzCu can also be obtained by sublimation under vacuum (10-2 mmHg, 400−450 °C) from the parent solvated complexes. IR spectra in the range 4000−200 cm-1 allow easy identification of the different spe...

This chapter describes the synthesis of phthalocyanines, subphthalocyanines and porphyrazines bearing fluorine atoms and/or perfluorinated alkyl or aryl groups. Influence of fluorination of macrocycle on its physico-chemical properties and perspectives of application is also briefly considered.

The proton NMR spectra of unsubstituted porphyrazine (tetraazaporphine) and of its Zn complex in pyridine-D5 and in CF3COOD have been obtained for the first time. The observed strong deshielding of the pyrrole hydrogen atoms of these compounds compared with porphyrins indicates the existence of strong intramolecular hydrogen bonds with neighboring pyrrolenic nitrogen atoms. An unsymmetrical bridge structure is proposed for the reaction center of unsubstituted porphyrazine with significantly ionized N−H bonds. It is suggested that a symmetrical bridge structure almost completely ionized, may exist only in the presence of such strong electron-accepting substituents as halogen in the pyrrole rings of the porphyrazine macrocycle.

Cross cyclotetramerization of bis(4-tert-butylphenyl)fumaronitrile with 1,2,5-selenadiazole-3,4-dicarbonitrile in the presence of magnesium butoxide as template afforded a mixture of magnesium(II) porphyrazine complexes, from which magnesium complex of 5,6,8,9,11,12-hexakis(4-tert-butylphenyl)[1,2,5]selenadiazolo[3,4-b]porphyrazine was isolated by column chromatography and was subjected to demetalation on treatment with trifluoroacetic acid. The free ligand was found to undergo protonation at one meso-nitrogen atom in acid medium and deprotonation of one pyrrole ring to form monoanion by the action of bases. Reductive deselenation of the title compound with formation of vicinal diamino porphyrazine was studied by spectral and kinetic methods, and a mechanism involving two hydrosulfide ions was proposed.

X-ray, spectral (UV-visible, nuclear magnetic resonance and photoelectron spectroscopy) data and quantum-chemical calculation results for porphyrins, phthalocyanines and azaporphyrins are compared and conclusions about the influence of aza substitution on the geometry of CN skeleton and on the state of NH bonds in porphyrin-type ligands are made. The studies of kinetics of metal ion incorporation in azaporphyrins are reviewed and the effect of the ligand structure, nature of metal salt and solvent on the complex formation reaction is discussed.

Tetraphenyltetraazaporphyrin was reacted with bromine in trifluoroacetic acid to obtain tetrakis(4-bromophenyl)tetraazaporphyrin. The latter forms with pyridine and dimethyl sulfoxide proton-transfer complexes which differ from each other by the degree of proton transfer from the NH acid to base.

Five-coordinate complexes of iron with octaphenyltetraazaporphine (H2OPTAP) containing halide or hydrosulfate as an axial acido-ligand (XFeIIIOPTAP; X=F, Cl, Br, I, HSO4) have been synthesized by treatment of the μ-oxo dimer, O(FeIIIOPTAP)2, or of the anionic dihydroxo complex [(HO)2FeIIIOPTAP]− with the corresponding acid HX. UV-Vis, IR, 1H NMR and Mossbauer spectroscopy methods and magnetic susceptibility measurements have been used for the characterization of these complexes. Magnetic moment (μeff=3.44 for chloro and 2.98 for bromo complex at r.t.), Mossbauer parameters (δFe=0.24−0.29 mm s−1 and ΔEQ=2.8-3.6 mm s−1 at 82 K) and the character of the paramagnetic shifts of the phenyl proton resonances (o-Ph 5.4–6.1 ppm, m-Ph 10.6–11.6 ppm and p-Ph 3.1–3.5 ppm in CHCl3 at r.t.) are consistent with an intermediate spin state ( S= 3 2 ) of iron in these complexes. The origin of the absorption bands in the UV-Vis and IR spectra is discussed and their assignment is proposed. A comparison with the corresponding five-coordinate complexes of porphyrins and phthalocyanine is made.

Monoribbed-substituted mono- and dicyano-functionalized iron(II) macrobicycles were obtained for the first time by the reaction of iron(II) diiodoclathrochelate precursor with copper(I) cyanide-triphenylphosphine complex under mild conditions. The target dinitrile clathrochelate is a minor product of this reaction, whereas the major product contains only one cyano group. The clathrochelates obtained were characterized using elemental analysis, (1)H and (13)C{(1)H} NMR, IR and UV-vis spectroscopy, MALDI-TOF spectrometry and X-ray diffraction crystallography. The geometry of their FeN(6)-coordination polyhedra is intermediate between a trigonal prism (TP) and a trigonal antiprism (TAP); the distortion angles, φ, are 22.6-24.7°. In the molecule of the precursor, the Fe-N distances are close, whereas in the mononitrile macrobicycles those for their functionalized chelate fragments are substantially smaller than the corresponding distances in the α-benzyldioximate moieties. The heights, h, of the TP-TAP coordination polyhedra and the average bite angles, α, (2.33 Å and 39°, respectively) are the same for the X-rayed clathrochelates. The UV-vis spectra indicate a dramatic redistribution of the electron density in the π-conjugated clathrochelate framework caused by functionalization with inherent nitrile substituents. The proposed mechanism of the dehalogenation-reduction reaction of iron(II) diiodoclathrochelate resulting in substitution of their iodine atoms by a cyano group and hydrogen atom includes the anion-radical hydrodehalogenation of this precursor with acetonitrile as a source of hydrogen atom. Then, the monomethinemonoiodine macrobicyclic product underwent a substitution with a cyano group only. The copper(I) cyanide-triphenylphosphine-acetonitrile system is proposed as a tool for the synthesis of nitrile derivatives of electron-withdrawing heterocycles starting from their halogen-containing precursors.

Cyclotetramerization of a mixture of 3,4-dicyano-1,2,5-thiadiazole or 3,4-dicyano-1,2,5-selenodiazole with 3,6-diamyloxyphthalo-dinitrile gives new unsymmetrical porphyrazines with annulated 1,2,5-thia(seleno)diazole and 3,6-diamyloxybenzene rings; the structures of the 1:3 products H2{XN2}{3,6-(OAm)2Bz}3Pz (X = S, Se) has been elucidated by single-crystal X-ray diffraction.

New styryl-substituted tetrapyrazinoporphyrazines [St8PyzPzM] (M = 2NaI , MgII(H2O) and ZnII ; St = -CH=CHAr , where Ar = phenyl or cumyl) were prepared by template cyclotetramerization of 5,6-distyrylpyrazine-2,3-dicarbonitriles available from condensation of diaminomaleodinitrile with the substituted cinnamils (StCO)2 obtained from biacetyl and arylaldehydes ArCHO . The new porphyrazine macrocycles were characterized by electronic absorption and emission spectra, which provide evidence of efficient π-interaction of the peripheral styryl moieties with the central pyrazinoporphyrazine framework. The electronic excitation of the stylbenoid chromophore in the near UV-region (400 nm) leads to strong emission of the porphyrazine chromophore near 700 nm, allowing to consider the styryl-substituted porphyrazines as efficient light-harvesting species. Their spectral properties and electrochemical behavior are compared with those of stylbenoid phthalocyanines and peripherally substituted tetrapyrazinoporphyrazines.

Cross cyclotetramerization of trans-2,3-diphenylbutanedinitrile with 1,2,5-thia(selena)diazole-3,4-dicarbonitriles or phthalodinitrile in the presence of magnesium butoxide gave mixtures of Mg(II) porphyrazine complexes which were treated with trifluoroacetic acid to isolate unsymmetrical hexaphenyl-substituted 1,2,5-thia(selena)diazolo-and benzo-fused porphyrazines together with diphenyltribenzoporphyrazine. Their 1H NMR and electronic absorption spectra (in the UV and visible regions) were recorded. The effect of benzene and heteroring fusion on the electronic and steric structure and spectral properties of porphyrazine derivatives was studied in terms of the molecular orbital perturbation theory and semiempirical quantum-chemical calculations (AM1, PM3, ZINDO/S, CNDO/S).

Template co-condensation of 2,3-dicyano-5,7-diphenyl-6H-1,4-diazepine 1 with 10-fold molar excess of phthalodinitrile 2 in the presence of MgII propoxide or butoxide in the corresponding alcohol leads to a mixture of MgII-diazepinoporphyrazines 3–6 from which the low symmetry 3:1 species 3, which contains three annulated benzene and one 1,4-diazepine rings, is separated by column chromatography as the aquo complex, [2,4-diphenyltribenzo[b,g,l][1,4]diazepino[2,3-q]porphyrazinato(aquo)magnesium(ii)], [Bz3DzPzMg(H2O)]. The complex 3 can be demetalated in acetic or trifluoroacetic acids under mild conditions with formation of the corresponding free-base [Bz3DzPzH2] 3a. This latter is also formed by co-cyclotetramerization of the same precursors 1 and 2 in the presence of sodium ethoxide in ethanol or lithium butoxide in butanol followed by demetalation of the intermediate disodium or dilithium salts in acid medium. The constitution and structure of the obtained compounds were established on the basis of elemental analysis, mass spectrometry, and 1H NMR spectra. The variable temperature 1H NMR measurements provide evidence that in porphyrazines 3 and 3a the 1,4-diazepine ring exists predominantly in the 6H-form over a wide temperature range. The free energy of activation for the inversion of the 1,4-diazepine ring determined for 3 is 45.6 ± 1.7 kJ mol–1. Solution UV-visible spectra measurements in acidic media (CH2Cl2/CF3COOH) provide evidence that the MgII complex 3 is easily protonated on the meso-N atom of the porphyrazine macrocycle followed by slow demetallation with formation of the free base 3a in its neutral form or as a species protonated on the diazepine ring.

The reaction of 3,7,13,17-tetramethyl-2,8,12,18-tetrabutyl-5,15-diazaporphine [H2DAPMB] 1 with indium(III) acetate in acetic acid leads to the formation of acetatoindium(III) complex [In(OAc)DAPMB] 2, which is easily converted to chloroindium(III) complex [In(Cl)DAPMB] 3.

The redox properties of the phthalocyanine-like tetrakis(thiadiazole)porphyrazines, [TTDPzM] (M = MgII(H2O), ZnII, CuII, 2HI), were investigated by cyclic voltammetry, and their ground- and excited-state electronic properties were studied in detail by density functional theory (DFT) and time-dependent DFT (TDDFT) methods. Bulk and specific (axial ligation) solvent effects on the molecular and electronic structure were also taken into account. The title compounds show stepwise reversible ligand-centered one-electron reductions in the range 0 to -2.0 V vs SCE, with E1/2 values being systematically less negative than corresponding reduction potentials for the same processes of the phthalocyanine (Pc) analogues. No electroxidations were observed at positive potentials. The observed redox behavior is rationalized on the basis of the ground-state electronic structures which reveal that replacement of the benzo rings of the Pc macrocycle by electron-withdrawing thiadiazole rings induces a large stabilization of both the HOMO and LUMOs in the investigated macrocycles. An excellent correlation is found between the first one-electron reduction potentials and the gas-phase LUMO energies along the series. The same sequence in the first reduction potentials is theoretically reproduced in pyridine, even if the ZnII and MgII complexes are assumed to be in the axially ligated form, [TTDPzM(py)]. TDDFT calculations of the lowest excited states of the ZnII, MgII, and CuII complexes in pyridine provide an accurate description of their UV-visible spectra. The calculated optical spectra for the free-base macrocycle in chlorobenzene and pyridine confirm previous data in that the thiadiazoleporphyrazine [TTDPzH2] is mostly present in pyridine in its deprotonated form [TTDPz]2-. DFT results, in keeping with electrochemical data, indicate, however, that in pyridine it is the neutral species [TTDPzH2] being reduced instead of its deprotonated form [TTDPz]2-.

Chloro(octaphenyltetraazaporphyrinato)iron(III) [(Cl)FeIIIOPTAP] reacts with aryl Grignard reagents (ArMgBr; Ar = phenyl or p-tolyl) forming stable low-spin δ-aryliron(III) complexes [(Ar)FeIIIOPTAP].

Cross cyclotetramerization of 1,2,5-thiadiazole-3,4-dicarbonitrile and 4-tert-butylphthalodinitrile in the presence of magnesium butoxide gave a mixture of symmetric and asymmetric porphyrazine magnesium(II) complexes. One of these, (22(3),72(3),122(3)-tri-tert-butyltribenzo[b,g,l][1,2,5]thiadiazolo[3,4-q]-5,10,15,20-tetraazaporphyrinato)magnesium(II) (MgSBBB), was isolated by column chromatography and was treated with trifluoroacetic acid to obtain the corresponding free ligand (H2SBBB). The effect of the mode of heteroring fusion on the electronic absorption spectra of tribenzoporphyrazines was studied.

Nitrido(octaphenyltetraazaporphyrinato)manganese(V) (NMnOPTAP) obtained by treatment of chlorine on acido(octaphenyl-tetraazaporphyrinato)manganese(III) [(X)MnOPTAP; X = Cl, AcO, HSO4] in chloroform solution saturated with ammonia, reacts with acido(octaphenyltetraazaporphyrinato)iron(III) [(X)FeOPTAP; X = Cl, Br, AcO] forming the heterometallic µ-nitrido complex µ-(MnNFe)(OPTAP)2; µ-nitrido complexes with a dissimilar porphyrin ligand on each metal have also been prepared.

AM1 calculations gave the proton affinities of different types of donor sites in tetrakis-3,4-(1,2,5-thiadiazolo)porphyrazine, H2{[SN2)4PA}, and protonation of the meso-nitrogen atoms was found to be favored. A spectrometric study showed that the basicity of the meso-nitrogen atoms of the porphyrazine macrocycle is strongly diminished and these atoms in CF3CO2H are involved in an incomplete acid-base interaction (ABI) to give acid solvates, while a complete ABI (protonation) is found only in the presence of sulfuric acid. The basicity constants of the meso-nitrogen atoms were determined spectrophotometrically in CF3CO2H-H2SO4. The kinetics of decomposition of the macrocyclic chromophore in concentrated sulfuric acid was studied and a possible mechanism for this process was proposed.

The aim of this study is the investigation of the optical limiting behavior of some azaporphyrins and related RSA mechanism, since all mechanisms have additive character. The optical limiting by RSA mechanisms depends on the structure of the coordination center in azaporphyrin complexes, solvent, initial transparency, energy of photon and intensity of radiation. Complexes octaphenyltetraazaporphyrine with the group III metals bearing halides as axial ligands, were chosen as objects in this study

Following a previous report on the synthesis and physicochemical characterization of a novel class of porphyrazines carrying peripherally annulated seven-membered rings, i.e., tetrakis-2,3-(5,7-diphenyl-1,4-diazepino)porphyrazine [Ph(8)DzPzH(2)].4H(2)O and its metal derivatives [Ph(8)DzPzM].xH(2)O (x = 2-7, M = Mg(II)(H(2)O), Cu(II), and Zn(II)), a new more convenient procedure is reported here, allowing the preparation in high yields of the Li(I) and Na(I) derivatives of formulas [Ph(8)DzPzLi(2)].5H(2)O and [Ph(8)DzPzNa(2)].6H(2)O, which can be directly converted into other metal derivatives under mild conditions (room temperature) and in good yields. The series studied has been extended to include the Mn(II) and Co(II) complexes also reported here for the first time. Physicochemical characterization of the new "diazepinoporphyrazines" was based on fast atom bombardment (FAB) mass spectrometry and X-ray powder patterns, infrared (IR), electron paramagnetic resonance (EPR), and room-temperature magnetic susceptibility measurements. A detailed discussion of the UV-vis spectra emphasizes the role played by the external diazepine rings in electron delocalization through their tautomeric or protonated forms present in neutral, basic, and acidic media. The nonlinear optical effect of optical limiting for the different species [M = 2H, Mg(II)(H(2)O), Mn(II), Co(II), Cu(II), and Zn(II)] has also been measured. It has been observed that the extent of the optical limiting depends on the specific M center. The observed nonlinear optical features are analyzed and discussed in terms of the electronic and magnetic properties exhibited by some of the metal ions and taking into account the model of the excited-state absorption in which the nature of M determines the kinetics of formation of the highly absorbing state of the specific complex examined. As evidenced by the detailed electrochemical and spectroelectrochemical study carried out on this new class of macrocycles, one of the most important aspects is the facilitated electron delocalization for the oxidized and reduced species allowed by a 1H-6Htautomerism taking place on the peripheral diazepine rings.

Co-cyclization of 1,2,5-thiadiazole-3,4-dicarbonitrile and 3,6-diamyloxyphthalodinitrile in the presence of magnesium or lithium amylate in amyl alcohol leads to mixtures containing the Mg derivatives of the symmetrical species tetrakis(1,2,5-thiadiazolo)porphyrazine, (S(4))PzH(2), and tetrakis(1,4-diamyloxybenzo)porphyrazine, (A(4))PzH(2), and the low-symmetry macrocycles bearing peripheral 1,2,5-thiadiazole and 1,4-diamyloxybenzene rings in the ratio 1:3, 2:2 (cis and trans), and 3:1, that is, (SA(3))PzH(2), (S(2)A(2))PzH(2), (SASA)PzH(2), and (S(3)A)PzH(2), respectively. The basic Mg materials were converted to the corresponding free-base macrocycles by treatment with CF(3)COOH. The species were separated from the mixtures by chromatography, either as Mg complexes or demetalated materials. With results on (S(4))PzH(2) and (SA(3))PzH(2) in hand, including crystallographic work on the latter, a general chemical physical investigation has been carried out of all the symmetrical and unsymmetrical free-base macrocycles. The structures of the species (S(2)A(2))PzH(2) and (A(4))PzH(2). were elucidated by single-crystal X-ray crystallography. The effect of the progressive variation of the macrocyclic structure along the series, from the symmetrical (S(4))PzH(2) to its symmetrical partner (A(4))PzH(2) via the low-symmetry 3:1, 2:2 (cis and trans), and 1:3 macrocycles, was studied by IR, (1)H NMR, and UV/Vis linear and nonlinear (optical limiting) measurements. The results are interpreted on the basis of intra- and intermolecular interactions between the electron-deficient 1,2,5-thiadiazole and the electron-donating 1,4-diamyloxybenzene moieties.

The synthesis of novel bisaxially coordinated ruthenium(II) complexes of octaphenyltetraazaporphine (L(2)Ru(OPTAP); L = NH(3), pyridine (py), pyrazine (pyz), s-tetrazine (tz), tert-butyl isocyanide (t-BuNC), and p-diisocyanodurole (did)) is reported. Template condensation of diphenylfumaronitrile with pentaammine(dinitrogen)ruthenium(II) dichloride gives the crude compound "Ru(OPTAP)" containing mainly the bis(ammine) derivative (NH(3))(2)Ru(OPTAP). Heating of "Ru(OPTAP)" with excess of L (L = py, pyz, tz, t-BuNC, did) gives L(2)Ru(OPTAP) which are readily soluble in organic solvents and can be purified chromatographically. In the case of the bidentate ligands (L = pyz, tz, did) refluxing of the solutions of monomers L(2)Ru(OPTAP) results in formation of oligomers with the bridgedmgr;-L coordination. For L = pyz and tz, the sparingly soluble oligomers contain predominantly dimers [(L){Ru(OPTAP)}(mgr;-L){Ru(OPTAP)}(L)], and, for L = did, the insolublemgr;-bridged polymer [(did){Ru(OPTAP)}((mgr;-did){Ru(OPTAP)})(x)()(10)(did)] is formed. UV-visible, IR, and (1)H NMR spectroscopy and mass spectrometry were used for characterization of the obtained compounds. Cyclic voltammetry study has shown one reduction (OPTAP(2)(-)/OPTAP(3)(-)) and one oxidation (Ru(II)/Ru(III)) process (for (py)(2)Ru(OPTAP) observed at -1.15 and 0.68 V, respectively). Comparison with the data on the corresponding phthalocyanine complexes (L(2)Ru(Pc)) reveals the stronger pi-back-bonding properties, the higher oxidation potential, and lower aromaticity of the porphyrazine macrocycle present in L(2)Ru(OPTAP). These factors along with the lesser extent of oligomerization are responsible for the lower electrical conductivity (sigma(RT)10(-)(11) S/cm) of themgr;-bridged Ru(OPTAP) complexes as compared with that of themgr;-bridged RuPc polymers.

The first tellurium-containing phthalocyanine analogues have been prepared and spectroscopically characterised: the Mg(II) complex of tetra(1,2,5-telluradiazolo)porphyrazine and a low-symmetry tert-butyl substituted Mg(II) tribenzoporphyrazine with one fused 1,2,5-telluradiazole ring. It was observed that the introduction of Te atom(s) reduces the energy of the Q-transition, facilitates the reduction of the macrocycle and strongly increases the conductivity of thin films.

A nitrido-bridged iron phthalocyanine has recently been shown to catalyze hydrocarbon activation, displaying in this respect distinctly different reactivity than the monomeric phthalocyanine or the oxo-bridged dimer. Here, DFT calculations are shown on models of this catalyst, indicating a distinct difference in electronic structures between the μ-oxo and μ-nitrido-bridged dimers, with the nitride acting as a remarkable charge reservoir and acquiring S = 1 N-character while the oxo bridge remains redox-inert; this difference in charge localization appears to be mirrored by a tendency towards higher symmetry in the Fe–N/O bonds with the nitrido bridge compared to the oxo one, and by a tendency of the nitride to favour lower-spin states more efficiently than the oxide.