Phosphonate-substituted porphyrins as efficient, cost-effective and reusable photocatalysts.

Recent advances in visible light photocatalysis represent a significant stride towards sustainable catalytic chemistry. However, its successful implementation in fine chemical production remains challenging and requires careful optimization of available photocatalysts. Our work aims to structurally modify bioinspired porphyrin catalysts, addressing issues related to their laborious synthesis and low solubility, with the goal of increasing their efficiency and developing reusable catalytic systems. We have demonstrated the catalytic potential of readily available meso-tetrakis[4-(diethoxyphosphoryl)phenyl]porphyrins (M(TPPP)). Novel metal (Pd(II), Co(II) and In(III)) complexes with this ligand were prepared in good yields. These chromophores were characterized in solution using spectroscopic (NMR, UV-vis, fluorescence) and electrochemical methods. The introduction of phosphonate groups on the phenyl substituents of meso-tetraphenylporphyrins (M(TPP)) improves solubility in polar organic solvents without significantly altering the photophysical properties and photostability of complexes. This structural modification also leads to easier reductions and harder oxidations of the macrocycle for all investigated complexes compared to the corresponding TPP derivatives. The free base porphyrin, zinc(II), palladium(II), and indium(III) complexes were studied as photocatalysts for oxidation of sulfides to sulfoxides using molecular oxygen as a terminal oxidant. Both dialkyl and alkyl aryl sulfides were quantitatively transformed into sulfoxides under blue LED irradiation in the acetonitrile-water mixture (10 : 1 v/v) with a low loading (0.005-0.05 mol%) of porphyrin photocatalysts, where H2(TPPP) and Pd(TPPP) were found to be the most efficient. The reaction mechanism was studied using photoluminescence and EPR spectroscopies. Then, to access reusable catalysts, water-soluble derivatives bearing phosphonic acid groups, H2(TPPP-A) and Pd(TPPP-A), were prepared in high yields. These compounds were characterized using spectroscopic methods. Single-crystal X-ray diffraction analysis of Pd(TPPP-A) reveals that the complex forms a 3D hydrogen-bonded organic framework (HOF) in the solid state. Both H2(TPPP-A) and Pd(TPPP-A) were found to catalyze the photooxidation of sulfides by molecular oxygen in the acetonitrile-water mixture (1 : 1 v/v), while only Pd(TPPP-A) resulted in selective production of sulfoxides. The complex Pd(TPPP-A) was easily recovered through extraction in the aqueous phase and successfully reused in five consecutive cycles of the sulfoxidation reaction.

Structural and Electrical Properties of Novel Cr/Fe Mixed Transition-Metal Phosphates.

The phosphate KCoCr(PO4)2 and iron-substituted variants KCoCr1-xFex(PO4)2 (x = 0.25, 0.5, and 0.75) were synthesized by a solid-state reaction route, while a high substitution level of Fe was achieved. Their structures were refined using powder X-ray diffraction and indexed in a monoclinic system with a P21/n space group. A 3D framework with six-sided tunnels parallel to the [101] direction was formed in which the K atoms are located. Mössbauer spectroscopy confirms the exclusive presence of octahedral paramagnetic Fe3+ ions, with isomer shifts increasing slightly with x substitution. Electron paramagnetic resonance spectroscopy confirmed the presence of paramagnetic Cr3+ ions. The activation energy, determined by dielectric measurements, shows that the iron-containing samples present higher ionic activity. Relative to the electrochemical activity of K, these materials could be good candidates for positive and/or negative electrode materials for energy storage applications.

Synthesis of New Cobalt(III) Meso-Porphyrin Complex, Photochemical, X-ray Diffraction, and Electrical Properties for Photovoltaic Cells.

The present work describes the preparation and characterization of a new cobalt(III) porphyrin coordination compound named (chlorido)(nicotinoylchloride)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(III) dichloromethane monosolvate with the formula [CoIII(TClPP)Cl(NTC)]·CH2Cl2 (4). The single-crystal X-ray molecular structure of 4 shows very important ruffling and waving distortions of the porphyrin macrocycle. The Soret and Q absorption bands of 4 are very red-shifted as a consequence of the very distorted porphyrin core. This coordination compound was also studied by fluorescence and cyclic voltammetry. The efficiency of our four porphyrinic compounds-the H2TClPP (1) free-base porphyrin, the [CoII(TClPP)] (2) and [CoIII(TClPP)Cl] (3) starting materials, and the new Co(III) metalloporphyrin [CoIII(TClPP)Cl(NTC)]·CH2Cl2 (4)-as catalysts in the photochemical degradation was tested on malachite green (MG) dye. The current voltage of complexes 3 and 4 was also studied. Electrical parameters, including the saturation current density (Js) and barrier height (ϕb), were measured.

Chemical Composition, Antifungal and Anti-Biofilm Activities of Volatile Fractions of Convolvulus althaeoides L. Roots from Tunisia.

The antifungal drugs currently available and mostly used for the treatment of candidiasis exhibit the phenomena of toxicity and increasing resistance. In this context, plant materials might represent promising sources of antifungal agents. The aim of this study is to evaluate for the first time the chemical content of the volatile fractions (VFs) along with the antifungal and anti-biofilm of Convolvulus althaeoides L. roots. The chemical composition was determined by gas chromatography coupled to a flame ionization detector and mass spectrometry. In total, 73 and 86 chemical compounds were detected in the n-hexane (VF1) and chloroform (VF2) fractions, respectively. Analysis revealed the presence of four main compounds: n-hexadecenoic acid (29.77%), 4-vinyl guaiacol (12.2%), bis(2-ethylhexyl)-adipate (9.69%) and eicosane (3.98%) in the VF extracted by hexane (VF1). n-hexadecenoic acid (34.04%), benzyl alcohol (7.86%) and linoleic acid (7.30%) were the main compounds found in the VF extracted with chloroform (VF2). The antifungal minimum inhibitory concentrations (MICs) of the obtained fractions against Candida albicans, Candida glabrata and Candida tropicalis were determined by the micro-dilution technique and values against Candida spp. ranged from 0.87 to 3.5 mg/mL. The biofilm inhibitory concentrations (IBF) and sustained inhibition (BSI) assays on C. albicans, C. glabrata and C. tropicalis were also investigated. The VFs inhibited biofilm formation up to 0.87 mg/mL for C. albicans, up to 1.75 mg/mL against C. glabrata and up to 0.87 mg/mL against C. tropicalis. The obtained results highlighted the synergistic mechanism of the detected molecules in the prevention of candidosic biofilm formation.

Synthesis, Characterization, DFT and Photocatalytic Studies of a New Pyrazine Cadmium(II) Tetrakis(4-methoxy-phenyl)-porphyrin Compound.

This study describes the synthesis, theoretical investigations, and photocatalytic degradational properties of a new (pyrazine)(meso-tetrakis(4-tert-methoxyphenyl)-porphyrinato)-cadmium (II) ([Cd(TMPP)-Pyz]) complex (1). The new penta-coordinated CdII porphyrin complex (1) was characterized by various spectroscopic techniques, including FT-IR, NMR, UV-visible absorption, fluorescence emission, and singlet oxygen, while its molecular structure was studied using single crystal X-ray diffraction. The UV-Vis spectroscopic study highlighted the redshift of the absorption bands after the insertion of the Cd(II) metal ion into the TMPP ring. The co-coordination of the pyrazine axial ligand enhanced this effect. A fluorescence emission spectroscopic study showed a significant blueshift in the Q bands, accompanied by a decrease in the fluorescence emission intensity and quantum yields of Φf = 0.084, Φf = 0.06 and Φf = 0.03 for H2-TMPP free-base porphyrin, [Cd(TMPP)] and [Cd(TMPP)(Pyz)] (1) respectively. Singlet oxygen revealed that the H2-TMPP porphyrin produced the most efficient singlet oxygen quantum yield of (ΦΔ = 0.73) compared to [CdTMPP] (ΦΔ = 0.57) and [Cd(TMPP)(Pyz)] (1) (ΦΔ = 0.13). In the crystal lattice, the [Cd(TMPP)Pyz] was stabilized through non-covalent intermolecular interactions (NCI), such as the hydrogen bonds C-H···N and C-H···Cg. Additionally, crystal explorer software was then utilized to measure the quantitative analysis of the intermolecular interactions in the unit cell of the crystal structure and established that the C-H···π interaction dominated. The Natural bond orbital (NBO) analysis revealed that each molecule is stabilized by hyperconjugation and charge delocalization. As a photocatalyst, the coordination complex 1 showed excellent photocatalytic activity toward the degradation of Levafix Blue CA reactive dye (i.e., dye photo-degradation of 80%).

CO2 to CO Electroreduction, Electrocatalytic H2 Evolution, and Catalytic Degradation of Organic Dyes Using a Co(II) meso-Tetraarylporphyrin.

The meso-tetrakis(4-(trifluoromethyl)phenyl)porphyrinato cobalt(II) complex [Co(TMFPP)] was synthesised in 93% yield. The compound was studied by 1H NMR, UV-visible absorption, and photoluminescence spectroscopy. The optical band gap Eg was calculated to 2.15 eV using the Tauc plot method and a semiconducting character is suggested. Cyclic voltammetry showed two fully reversible reduction waves at E1/2 = -0.91 V and E1/2 = -2.05 V vs. SCE and reversible oxidations at 0.30 V and 0.98 V representing both metal-centred (Co(0)/Co(I)/Co(II)/Co(III)) and porphyrin-centred (Por2-/Por-) processes. [Co(TMFPP)] is a very active catalyst for the electrochemical formation of H2 from DMF/acetic acid, with a Faradaic Efficiency (FE) of 85%, and also catalysed the reduction of CO2 to CO with a FE of 90%. Moreover, the two triarylmethane dyes crystal violet and malachite green were decomposed using H2O2 and [Co(TMFPP)] as catalyst with an efficiency of more than 85% in one batch.

Effect of the coordination of π-acceptor 4-cyanopyridine ligand on the structural and electronic properties of meso-tetra(para-methoxy) and meso-tetra(para-chlorophenyl) porphyrin cobalt(ii) coordination compounds. Application in the catalytic degradation of methylene blue dye.

To examine the influence of both the important π-acceptor character of the 4-cyanopyridine ligand and the nature of the para-substituted phenyls of meso-porphyrins on the electronic, electrochemical and structural properties of cobaltous metalloporphyrins, we prepared and fully characterized two coordination compounds: the (4-cyanopyridine)[meso-tetra(para-methoxyphenyl)porphyrinato]cobalt(ii) and the (4-cyanopyridine)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(ii) with the [CoII(TMPP)(4-CNpy)] and [CoII(TClPP)(4-CNpy)] formulas (complexes 1-2). The solution structures of compounds 1-2 were confirmed by 1H NMR spectroscopy and mass spectrometry methods. They were further characterized by cyclic voltammetry and photoluminescence studies. The X-ray molecular structure data show that the Co-TClPP-4-NCpy derivative (2) exhibits high ruffling deformation compared to that of the Co-TMPP-4-CNpy species (1). Notably, the crystal packing of complex 1 shows the formation of Co⋯Co supramolecular dimers with a distance of 5.663 Å. As an application of our two cobaltous compounds, an investigation involving complexes 1-2 in the degradation of the methylene blue dye in the presence and absence of H2O2 in aqueous solutions was carried out. These promising results show that 1-2 can be used as catalysts in the degradation processes of dyes.

Zinc(ii) triazole meso-arylsubstituted porphyrins for UV-visible chloride and bromide detection. Adsorption and catalytic degradation of malachite green dye.

Three new triazole meso-arylporphyrins (4a-c) were synthesized by the copper(i)-catalyzed azide alkyne cycloaddition (CuAAC) "click" reaction in high yield. The corresponding zinc(ii) coordination compounds (5a-c) have also been prepared. All 4a-c and 5a-c porphyrin species were fully characterized by elemental analysis, electrospray ionization and MALDI-TOF mass spectrometry, infrared spectroscopy, proton nuclear magnetic resonance, UV-visible, fluorescence and cyclic voltammetry. The zinc(ii) 5a-c complexes have been tested as detectors for Cl- and Br- anions. UV-visible titrations reveal that these host systems exhibit strong anion binding affinities. The efficiency of the adsorption of the malachite green dye (MG) dye on the 4a-c free base porphyrins and the corresponding zinc(ii) complexes 5a-c was investigated by a kinetic study using these synthetic porphyrin derivatives as adsorbents. The use of our triazole Zn(ii) complexes in the catalytic degradation of the MG dye is the first example where a metalloporphyrin is involved in the MG dye decolorization reaction. The degradation reactions were carried out using an ecological oxidant (H2O2), where the efficiency of the decolorization has been characterized by UV-visible spectroscopic analysis. Several factors affecting the degradation phenomenon have been studied. The energetic parameters concerning the degradation process have also been determined.

A new cobalt(ii) meso-porphyrin: synthesis, characterization, electric properties and application in the catalytic degradation of dyes.

In this work, a new porphyrin, 5,10,15,20-tetrakis{4-[((4-methoxyphenyl)acetyl)oxy]phenyl}porphyrin (H2TMAPP) (1), and its cobalt complex [CoII(TMAPP)] (2) were synthesized in good and quantitative yields, respectively. The chemical structures of these synthesized compounds were confirmed by FT-IR, 1H NMR, MS, UV-visible, and fluorescence spectroscopy. Their photophysical properties, namely their molar extinction coefficients (∑), fluorescence quantum yields (Φ f) and lifetimes (τ f), were determined and compared with those of meso-tetraphenylporphyrin. Furthermore, their electrochemical behaviours were examined using cyclic voltammetry (CV). Dielectric properties such as the conductivity (σ) and the real (M') and imaginary (M'') parts of the dielectric modulus were investigated as a function of temperature and frequency. The impedance analysis was carried out using Cole-Cole plots to elucidate the electrical conduction mechanism. The catalytic power and the adsorption properties of the prepared compounds were studied for methylene blue (MB) and crystal violet (CV) degradation. The results reveal that the studied compound [CoII(TMAPP)] can be used as a catalyst for the decolourisation of dyes in the presence of H2O2.

Development of a new bisphenol A electrochemical sensor based on a cadmium(ii) porphyrin modified carbon paste electrode.

In this study, the (5,10,15,20-tetrakis[(4-methoxyphenyl)]porphyrinato)cadmium(ii) complex ([Cd(TMPP)]) was successfully used as a modifier in a carbon paste electrode (CPE) and exploited for bisphenol A (BPA) detection. Analytical performance revealed two linear ranges from 0.0015-15 µM and 0.015-1.5 mM with a detection limit of 13.5 pM. The proposed method was implemented in water samples, which resulted in quantitative signals over the range 6.5-1000 µM with recoveries between 92.6 and 107.7% for tap water and between 96.6 to 106.0% for mineral water.

Synthesis and SPAR exploration of new semicarbazone-triazole hybrids in search of potent antioxidant, antibacterial and antifungal agents.

A new series of semicarbazone-triazole hybrid derivatives have been synthesized by condensation between heterocyclic aldehydes and the commercial semicarbazide hydrochloride. The in vitro antioxidant activity of these species was tested using 1,1-diphenyl-2-picrylhydrazyl radical, 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and Ferric reducing antioxidant power assays and their antimicrobial activity against different microbial strains was carried out. Furthermore, molecular properties prediction and drug likeness were also determinated using Molinspiration. Among such derivatives, compounds (E)-2-(4-((1-(2,6-dimethylphenyl)-1H-1,2,3-triazol-4-yl)methoxy)benzylidene)hydrazine carboxamide (4c), and (E)-2-(4-((1-(2-methoxyphenyl)-1-H-1,2,3-triazol-4-yl)methoxy)benzylidene)hydrazine-carboxamide (4e) exhibit excellent scavenging ability, especially with IC50 = 1.57 ± 1.66 mg/mL (4c) and IC50 = 1.82 ± 0.15 mg/mL (4e) with 1,1-diphenyl-2-picrylhydrazyl radical and IC50 = 1.90 ± 1.33 mg/mL (4c) with 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) as compared to the standards butylhydroxytoluene (IC50 = 1.60 ± 1.98 mg/mL) and Trolox (IC50 = 1.45 ± 1.33 mg/mL), respectively. The antimicrobial assay results, show that compounds 4c and 4e highlighted the most interesting profile with the potent activity was obtained against S. enteritidis (1.56-fold) and then M. luteus (1.45-fold) which are significantly higher than the positive control, chloramphenicol. By the other hand, the synthesized semicarbazone derivatives met the Lipinski's rule criteria by presenting good drug likeness and bioactivity scores. The structure-property-activity relationships have been carried out in order to determine the effect of various substituents on the molecular and the biological properties. All these investigations confirm that our synthetic semicarbazone can be explored for generating new potential drug with good oral bioavailability.

Tetrakis(ethyl-4(4-butyryl)oxyphenyl)porphyrinato zinc complexes with 4,4'-bpyridin: synthesis, characterization, and its catalytic degradation of Calmagite.

This work reports on the synthesis and characterization of a new porphyrins complex:[Zn(TEBOP)(4,4'-bpy)](4,4'-bipyridine)(5,10,15,20-(tetraethyl-4(4-butyryl)oxyphenyl)porphyrinato)zinc(ii) (3). Single crystal X-ray diffraction, photophysical and electrochemical characteristics were studied. The prepared complex, penta-coordinated zinc(ii) porphyrin derivatives shows moderate ruffling distortion and the zinc atom is nearly planar with the porphyrin core. Tolyl and ethyl-4(4-butyryl)oxyphenyl) moieties at the meso positions present a bathochromic shift of the absorption bands, and a notable increase in the absorption coefficient of the Q(0,0) and Q(0,1) bands was observed with a higher fluorescence quantum yield and lifetime compared with the free base porphyrin. The electrochemical investigation shows a reversible reduction of the synthesized complexes. The catalytic power and the adsorption properties of the prepared complexes were studied for Calmagite degradation, an azoic organic dye. The results reveal that the studied compounds could be used as catalysts for the decolourisation of dyes in the presence of H2O2.

Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato-κ(4) N}zinc.

The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin-ation geometry about the central Zn(II) atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro-gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn-N(pyrrole) bond length is 2.078 (7) Šand the Zn- N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Šfrom the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra-molecular structure is made by parallel pairs of layers along (100), with an inter-layer distance of 4.100 Šwhile the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol-ecules. The given chemical formula and other crystal data do not take into account these solvent mol-ecules.

Synthesis, FT-IR characterization and crystal structure of aqua-(5,10,15,20-tetra-phenyl-porphyrinato-κ(4) N)manganese(III) tri-fluoro-methane-sulfonate.

In the title salt, [Mn(C44H28N4)(H2O)](CF3SO3) or [Mn(III)(TPP)(H2O)](CF3SO3) (where TPP is the dianion of 5,10,15,20-tetra-phenyl-porphyrin), the Mn(III) cation is chelated by the four pyrrole N atoms of the porphyrinate anion and additionally coordinated by an aqua ligand in an apical site, completing the distorted square-pyramidal coordination environment. The average Mn-N(pyrrole) bond length is 1.998 (9) Šand the Mn-O(aqua) bond length is 2.1057 (15) Å. The central Mn(III) ion is displaced by 0.1575 (5) Šfrom the N4C20 mean plane of the porphyrinate anion towards the apical aqua ligand. The porphyrinate macrocycle exhibits a moderate ruffling and strong saddle deformations. In the crystal lattice, the [Mn(III)(TPP)(H2O)](+) cation and the tri-fluoro-methane-sulfonate counter-ions are arranged in alternating planes packed along [001]. The components are linked together through O-H⋯O hydrogen bonds and much weaker C-H⋯O and C-H⋯F inter-actions. The crystal packing is further stabilized by weak C-H⋯π inter-actions involving the pyrrole and phenyl rings of the porphyrin moieties.

Crystal structure of (4-cyano-pyridine-κN){5,10,15,20-tetrakis[4-(benzoyloxy)phenyl]porphyrinato-κ(4) N}zinc-4-cyano-pyridine (1/1).

In the title compound, [Zn(C72H44N4O8)(C6H4N2)]·C6H4N2 or [Zn(TPBP)(4-CNpy]·(4-CNpy) [where TPBP and 4-CNpy are 5,10,15,20-(tetra-phenyl-benzoate)porphyrinate and 4-cyano-pyridine, respectively], the Zn(II) cation is chelated by four pyrrole-N atoms of the porphyrinate anion and coordinated by a pyridyl-N atom of the 4-CNpy axial ligand in a distorted square-pyramidal geometry. The average Zn-N(pyrrole) bond length is 2.060 (6) Šand the Zn-N(4-CNpy) bond length is 2.159 (2) Å. The zinc cation is displaced by 0.319 (1) Šfrom the N4C20 mean plane of the porphyrinate anion toward the 4-cyano-pyridine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling and doming deformations. In the crystal, the [Zn(TPBP)(4-CNpy)] complex mol-ecules are linked together via weak C-H⋯N, C-H⋯O and C-H⋯π inter-actions, forming supra-molecular channels parallel to the c axis. The non-coordinating 4-cyano-pyridine mol-ecules are located in the channels and linked with the complex mol-ecules, via weak C-H⋯N inter-actions and π-π stacking or via weak C-H⋯O and C-H⋯π inter-actions. The non-coordinating 4-cyano-pyridine mol-ecule is disordered over two positions with an occupancy ratio of 0.666 (4):0.334 (4).

Crystal structure of bis-(benzyl-amine-κN)[5,10,15,20-tetra-kis-(4-chloro-phen-yl)porphyrinato-κ(4) N]iron(II) n-hexane monosolvate.

In the title compound, [Fe(II)(C44H24Cl4N4)(C6H5CH2NH2)2]·C6H14 or [Fe(II)(TPP-Cl)(BzNH2)2]·n-hexane [where TPP-Cl and BzNH2 are 5,10,15,20-tetra-kis-(4-chloro-phen-yl)porphyrinate and benzyl-amine ligands, respectively], the Fe(II) cation lies on an inversion centre and is octa-hedrally coordinated by the four pyrrole N atoms of the porphyrin ligand in the equatorial plane and by two amine N atoms of the benzyl-amine ligand in the axial sites. The crystal structure also contains one inversion-symmetric n-hexane solvent mol-ecule per complex mol-ecule. The average Fe-Npyrrole bond length [1.994 (3) Å] indicates a low-spin complex. The crystal packing is sustained by N-H⋯Cl and C-H⋯Cl hydrogen-bonding inter-actions and by C-H⋯π inter-molecular inter-actions, leading to a three-dimensional network structure.

Crystal structure of chlorido-(5,10,15,20-tetra-phenyl-porphyrinato-κ(4) N)manganese(III) 2-amino-pyridine disolvate.

In the title compound, [Mn(C44H28N4)Cl]·2C5H6N2, the Mn(III) centre is coordinated by four pyrrole N atoms [averaged Mn-N = 2.012 (4) Å] of the tetra-phenyl-porphyrin mol-ecule and one chloride axial ligand [Mn-Cl = 2.4315 (7) Å] in a square-pyramidal geometry. The porphyrin macrocycle exhibits a non-planar conformation with major ruffling and saddling distortions. In the crystal, two independent solvent mol-ecules form dimers through N-H⋯N hydrogen bonding. In these dimers, one amino N atom has a short Mn⋯N contact of 2.642 (1) Šthus completing the Mn environment in the form of a distorted octa-hedron, and another amino atom generates weak N-H⋯Cl hydrogen bonds, which link further all mol-ecules into chains along the a axis.

Crystal structure of di-aqua-[5,10,15,20-tetra-kis-(4-bromo-phen-yl)porphyrinato-κ(4) N]magnesium.

The title compound, [Mg(C44H24Br4N4)(H2O)2] or [Mg(TBrPP)(H2O)2], where TBrPP is the 5,10,15,20-tetra-kis-(4-bromo-phen-yl)porphyrinato ligand, was obtained unintentionally as a by-product of the reaction of the [Mg(TBrPP)] complex with an excess of di-methyl-glyoxime in di-chloro-methane. The entire mol-ecule exhibits point group symmetry 4/m. In the asymmetric unit, except for two C atoms of the phenyl ring, all other atoms lie on special positions. The Mg(II) atom is situated at a site with symmetry 4/m, while the N and the C atoms of the porphyrin macrocycle, as well as two C atoms of the phenyl ring and the Br atom lie in the mirror plane containing the porphyrin core. The H atoms of the axially bonded water mol-ecule are incompatible with the fourfold rotation axis and are disordered over two sites. In the crystal, mol-ecules are packed in rows along [001]. Weak inter-molecular C-H⋯π and C-H⋯Br inter-actions, as well as O-H⋯Br hydrogen bonds, stabilize the crystal packing.

Crystal structure of di-aqua-[5,10,15,20-tetra-kis-(4-meth-oxy-phen-yl)porphyrinato-κ(4) N]iron(III) di-aqua-(18-crown-6)potassium bis-(tri-fluoro-methane-sulfonate)-18-crown-6 (1/2).

In the title compound, [Fe(III)(C48H36N4O2)(H2O)2][K(C12H24O6)(H2O)2](SO3CF3)2·2C12H24O6, the Fe(III) atom is situated on an inversion centre and is octa-hedrally coordin-ated by four pyrrole N atoms of the deprotenated 5,10,15,20-tetra-kis-(4-meth-oxy-phen-yl)porphyrinate ligand and two water mol-ecules. The average equatorial Fe-N(pyrrole) bond length [2.043 (6) Å] is consistent with a high-spin (S = 5/2) iron(III) metalloporphyrin derivative. The K(+) cation, which also lies on an inversion centre, is chelated by the six O atoms of one 18-crown-6 mol-ecule and is additionally coordinated by two water mol-ecules in a distorted hexa-gonal-bipyramidal geometry. In the crystal, the cations, anions and one non-coordinating 18-crown-6 mol-ecule are linked by classical O-H⋯O hydrogen bonds and non-conventional C-H⋯O hydrogen bonds, leading to a one-dimensional supra-molecular architecture along [10-1]. The crystal packing is further stabilized by weak C-H⋯π inter-actions involving pyrrole and phenyl rings of the porphyrins, as well as weak C-H⋯F contacts involving the (SO3CF3)(-) counter-ion and the 18-crown-6 mol-ecules.

Crystal structure of bis-(4-nitro-aniline-κN (1))(5,10,15,20-tetra-phenyl-por-phy-rin-ato-κ(4) N)cobalt(III) chloride di-chloro-methane monosolvate.

The reaction of [Co(III)(TPP)Cl] (TPP is the dianion of 5,10,15,20-tetra-phenyl-porphyrin) with an excess of 4-nitro-aniline in di-chloro-methane leads to the title compound, [Co(III)(C44H28N4)(C6H6N2O2)2]Cl·CH2Cl2. The Co(III) ion lies on an inversion centre and is octa-hedrally coordinated by two N atoms of the NH2 groups of the two 4-nitro-aniline trans-axial ligands and four pyrrole N atoms of the porphyrin. The asymmetric unit contains one half of the [Co(III)(TPP)(4-nitro-aniline)2](+) ion complex, one chloride counter-ion (lying on a twofold rotation axis) and one half di-chloro-methane solvent mol-ecule, where the C atom lies on a twofold rotation axis. The average equatorial Co-N(pyrrole) distance (Co-Np) is 1.982 (2) Šand the axial Co-N(4-nitro-aniline) bond length is 2.006 (2) Å. The crystal packing is stabilized by an N-H⋯Cl hydrogen bond between the N atom of the amino group of the 4-nitro-aniline axial ligand and the chloride counter-ion. The supra-molecular architecture is further stabilized by weak C-H⋯π inter-actions.