Luminescence of In(III)Cl-etioporphyrin-I.

The luminescent and photophysical properties of the etioporphyrin-I complex with indium(III) chloride, InCl-EtioP-I were experimentally studied at room and liquid nitrogen temperatures in pure and mixed toluene solutions. At 77 K, in a 1:2 mixture of toluene with diethyl ether, the quantum yield of phosphorescence reaches 10.2%, while the duration of phosphorescence is 17 ms. At these conditions, the ratio of phosphorescence-to-fluorescence integral intensities is equal to 26.1, which is the highest for complexes of this type. At 298 K, the quantum yield of the singlet oxygen generation is maximal in pure toluene (81%). Quantum-chemical calculations of absorption and fluorescence spectra at temperatures of 77 K and 298 K qualitatively coincide with the experimental data. The InCl-EtioP-I compound will further be used as a photoresponsive material in thin-film optoelectronic devices.

Phosphorescence of hexachlorosubstituted subphthalocyanine and its pyrazine analogue.

Spectral luminescence, kinetic and energetic properties of hexachlorosubphthalocyaninatoboron(III) chloride and its azaanalogue containing fused pyrazine fragments instead of benzene rings were studied at 298 and 77 K. Weak phosphorescence of complexes was detected and characterized in near-infrared region of spectrum, its parameters depend substantially on the presence of methyl iodide due to its external effect of heavy atom in solutions. Quantum yields of photosensitized formation of singlet oxygen were determined by the relative luminescence method.

An Indium Synthetic Etioporphyrin for Organic Electronics: Aggregation and Photoconductivity in Thin Films.

A new complex of indium(III)chloride with etioporphyrin-I was synthesized and characterized. As with naturally occurring extraligated etioporphyrins, the InCl-EtioP-I spectrum in solution has a very strong B-band and a more than an order of magnitude weaker Q-band, but this difference diminishes in solid films of InCl-EtioP-I obtained by thermal evaporation in vacuum. In a solid, molecules have a tight convex-convex arrangement in a 2D double layered structure with interplane distance of 3.066 Å. The conductivity of films can easily be activated by the action of temperature or light. In the cells with symmetrical lateral contacts the photocurrent exceeds the dark current by about three orders of magnitude, with the contribution of photons in the Q-band range being greater than expected from the experimental or calculated absorption spectrum. The Q-bands contribute significantly to the photovoltaic effect in the ITO/InCl-EtioP-I/Al sandwich cells. Such cells show an untypically strong signal in the photodiode regime, which yields the spectral detectivity of 10^12 Jones.

Silicon(IV) complexes of octaaryl-substituted porphyrazines and corrolazines: influence of macrocycle contraction on spectral-luminescence, acid-base, and redox properties.

The template cyclomerization of the iminoimide derivatives (obtained by the treatment of diarylfumarodinitriles with NH3 in methanol containing catalytic amounts of dissolved Na) in the presence of SiCl4 in pyridine leads to silicon(IV) octaarylporphyrazine complexes ((HO)2SiPzAr8, Ar = Ph, tBuPh) as a main reaction product. In the case of phenyl-substituted derivative, the formation of a distinctive Si(IV) complex as a byproduct was observed, which according to mass-spectroscopy measurement contains the macrocycle with five diphenylpyrrolic units. The treatment of bishydroxy complexes with tripropylchlorosilane in the presence of magnesium in pyridine leads to the formation of axially siloxylated porphyrazines (Pr3SiO)2SiPzAr8, followed by the reductive contraction of the macrocycle and formation of the corresponding corrolazine complexes (Pr3SiO)SiCzAr8. It is shown that the addition of acid (trifluoroacetic acid, TFA) facilitates the detachment of one siloxy group in (Pr3SiO)2SiPzAr8 and is essential for its Pz → Cz transformation. In the presence of TFA, only one meso-nitrogen is protonated in the porphyrazine complexes (Pr3SiO)2SiPzAr8 (stability constant of the protonated form pKs1 = -0.45 for Ar = Ph; pKs1 = 0.68 for Ar = tBuPh), while two consequent protonation stages are observed for the more basic corrolazine complex (Pr3SiO)SiCzPh8 (pKs1 = 0.93, pKs2 = 0.45). Both types of Si(IV) complexes are poorly fluorescent (ΦF < 0.07). The porphyrazine complexes have low ability to generate singlet oxygen (ΦΔ < 0.15), whereas the corrolazine derivative (Pr3SiO)SiCzPh8 is a very efficient photosensitizer (ΦΔ = 0.76).

Electronic and steric effects controlling monomer-dimer self-assembly in 6H-1,4-diazepinoporphyrazines: an experimental and theoretical study.

A series of 5,7-disubstituted 1,4-diazepinoporphyrazinato magnesium(II) and nickel(II) complexes, including two novel compounds, were obtained by metal-templated macrocyclization. A combination of X-ray diffraction, 1H NMR, UV-vis, and electrochemical analyses allowed us to study their tendency towards H-type dimerization and trace the influence of structural and solvation factors on dimer stability. Based on the physicochemical and theoretical DFT calculation data, it was found that the main binding forces between 6H-1,4-diazepinoporphyrazine decks in the dimers were efficient π-π donor-acceptor interactions induced by the interdeck C-H⋯N hydrogen bonds. Furthermore, the metal-ligand (Pz2- â†’ M2+) electronic interactions have a key influence on the π-π stacking of the porphyrazine cores. It was shown that the displacement of the metal ion out of the macrocycle plane induced by coordinating agents can trigger the dissociation of the dimer, since the resulting enhancement of the donor-acceptor electronic interaction between the metal ion and the π-system of the ligand leads to a subsequent weakening of the π-π stacking of the porphyrazine cores. The TD-DFT calculations predicted the non-degeneracy of the HOMO-1 → LUMO and HOMO → LUMO+1 transitions in the 6H-1,4-diazepinoporphyrazine H-dimers, which explains the Q-band splitting in their UV-vis spectra.

DFT Study of Molecular Structure, Electronic and Vibrational Spectra of Tetrapyrazinoporphyrazine, Its Perchlorinated Derivative and Their Al, Ga and In Complexes.

Electronic and geometric structures of metal-free, Al, Ga and In complexes with tetrapyrazinoporphyrazine (TPyzPA) and octachlorotetrapyrazinoporphyrazine (TPyzPACl8) were investigated by density functional theory (DFT) calculations and compared in order to study the effect of chlorination on the structure and properties of these macrocycles. The nature of the bonds between metal atoms and nitrogen atoms was described using the NBO-analysis. Simulation and interpretation of electronic spectra were performed with the use of time-dependent density functional theory (TDDFT). A description of calculated IR spectra was carried out based on the analysis of the distribution of the potential energy of normal vibrational coordinates.

Phosphorus(V) tetrapyrazinocorrolazines bearing axial aryloxy groups as pH-sensitive fluorophores and photosensitizers.

Phosphorus(V) complexes of octaphenyltetrapyrazinocorrolazine bearing two aryloxy groups in the axial position, [TPyzCAP(OAr)2] (2a-c, Ar = phenyl (2a), 4-dimethylaminophenyl (2b), and 4-hydroxyphenyl (2c)), were prepared using a one-pot procedure by consecutive treatment of the dihydroxidophosphorus(V) derivative, [TPyzCAP(OH)2] (1), with SOCl2 and then with the corresponding phenol ArOH. Complex 2a containing axial PhO groups is fluorescent in all studied solvents (toluene, CH2Cl2, THF, and DMSO, ΦF ∼ 0.16-0.31) and is efficient to generate singlet oxygen (ΦΔ = 0.55 (THF), 0.68 (toluene)). The introduction of NMe2 and OH groups in the para-position of the axial ArO ligands strongly affects the fluorescence parameters and photosensitizing properties due to the appearance of the solvent-sensitive and pH-switchable effects of photoinduced electron transfer (PET). The PET effect of NMe2 groups completely quenches the excited state of 2b in all solvents, but it is switched-OFF upon their protonation, and in the presence of acid traces, the fluorescence of 2b becomes bright and singlet oxygen generation is strongly enhanced. The PET effect of the OH group is increased upon its deprotonation and in the presence of base 2c as well as 1 becomes non-fluorescent. Specific solvation in THF and DMSO increases the ionic character of the OH bonds, and the fluorescence and photosensitizing properties of 1 and 2c are strongly decreased in these solvents. According to the results of DFT calculations performed using the B3LYP functional with the cc-pVDZ basis set and cyclic voltammetric studies, the molecular orbitals localized on aryloxy ligands are destabilized upon the introduction of OH and especially NMe2 groups and their close position to the HOMO of corrolazine macrocycle (above HOMO in 2b and between HOMO and HOMO-1 in 2c) leads to the appearance of the PET effect.

Tetra-2,3-Pyrazinoporphyrazines with Externally Appended Pyridine Rings 22 Synthesis, Physicochemical and Photoactivity Studies on In(III) Mono- and Heteropentanuclear Complexes.

The basic macrocyclic octapyridinotetrapyrazinoporphyrazine InIII complex of formula [Py8TPyzPzIn(OAc)]·8H2O, prepared by reaction of the free ligand [Py8TPyzPzH2]·2H2O with In(OAc)3, is a stable-to-air species of which the structure has been studied by its X-ray powder diffraction and mass spectra and characterization operated by IR and UV-visible spectral behavior. The complex has been further examined and proven to be of potential interest for its response as an anticancer agent in the field of photodynamic therapy (PDT), the value of ΦΔ = 0.55 (in DMF) being in the range of 0.4-0.6 at the level of similar phthalocyanine and porphyrazine analogs and qualifying the species as a highly efficient anticancer agent. Planned parallel types of investigation, including their photoactive behaviour in PDT, have been extended to the mononuclear octacation [(2-Mepy)8TPyzPzIn(OAc)]8+ (salted by iodide ions) and the heteropentanuclear derivatives [(M'Cl2)4Py8TPyzPzIn(OAc)]·xH2O (M' = PdII, x = 8; PtII, x = 1)) and [{(Pd(CBT)2)4}Py8TPyzPzIn(OAc)]·19H2O (CBT = m-carborane-1-thiolate anion).

DFT Study of the Molecular and Electronic Structure of Metal-Free Tetrabenzoporphyrin and Its Metal Complexes with Zn, Cd, Al, Ga, In.

The electronic and molecular structures of metal-free tetrabenzoporphyrin (H2TBP) and its complexes with zinc, cadmium, aluminum, gallium and indium were investigated by density functional theory (DFT) calculations with a def2-TZVP basis set. A geometrical structure of ZnTBP and CdTBP was found to possess D4h symmetry; AlClTBP, GaClTBP and InClTBP were non-planar complexes with C4v symmetry. The molecular structure of H2TBP belonged to the point symmetry group of D2h. According to the results of the natural bond orbital (NBO) analysis, the M-N bonds had a substantial ionic character in the cases of the Zn(II) and Cd(II) complexes, with a noticeably increased covalent contribution for Al(III), Ga(III) and In(III) complexes with an axial -Cl ligand. The lowest excited states were computed with the use of time-dependent density functional theory (TDDFT) calculations. The model electronic absorption spectra indicated a weak influence of the nature of the metal on the Q-band position.

Water-soluble sulfonated phosphorus(V) corrolazines and porphyrazines: the effect of macrocycle contraction and pyrazine ring fusion on spectral, acid-base and photophysical properties.

Novel water-soluble dihydroxophosphorus(V) complexes of sulphophenyl substituted porphyrazine (6), corrolazine (7) and its pyrazine fused derivative (8) were prepared and their spectral, acid-base and photophysical properties in aqueous solutions were studied. Due to the presence of eight SO3H groups, the compounds were fully monomeric (7 and 8) or only slightly aggregated (6) in water. Spectrophotometric titration revealed that the two stage deprotonation of axially bonded hydroxy groups can be achieved for porphyrazine 6 (pKa1 = 5.62, pKa2 = 9.13) and pyrazine fused corrolazine 8 (pKa1 = 6.5, pKa2 = 11.7), while only the first dissociation stage could be observed for corrolazine 7 (pKa1 = 9.94). The fluorescence emission of the corrolazines 7, 8 and especially porphyrazine 6 was low in water (ΦF = 0.086, 0.18, and 0.014, respectively) and completely quenched under basic conditions due to photoinduced electron transfer. In comparison with porphyrazine 6, the contraction of the macrocycle in the corrolazines 7 and 8 induced significant improvement of singlet oxygen production in water reaching values of ΦΔ = 0.56 and 0.43, respectively, which makes the corrolazines promising photosensitizers for photodynamic therapy. The observed evolution of the electronic absorption spectra and fluorescence quenching observed in a basic medium was explained using the model DFT calculations (cc-pvtz basis set) performed for the dihydroxophosphorus(V) complexes of unsubstituted porphyrazine and corrolazine and their mono- and doubly deprotonated forms.

Molecular Structure, Thermodynamic and Spectral Characteristics of Metal-Free and Nickel Complex of Tetrakis(1,2,5-thiadiazolo)porphyrazine.

The Knudsen effusion method with mass spectrometric control of the vapor composition was used to study the possibility of a congruent transition to the gas phase and to estimate the enthalpy of sublimation of metal-free tetrakis(1,2,5-thiadiazolo)porphyrazine and its nickel complex (H2TTDPz and NiTTDPz, respectively). The geometrical and electronic structure of H2TTDPz and NiTTDPz in ground and low-lying excited electronic states were determined by DFT calculations. The electronic structure of NiTTDPz was studied by the complete active space (CASSCF) method, following accounting dynamic correlation by multiconfigurational quasi-degenerate second-order perturbation theory (MCQDPT2). A geometrical structure of D2h and D4h symmetry was obtained for H2TTDPz and NiTTDPz, respectively. According to data obtained by the MCQDPT2 method, the nickel complex possesses the ground state 1A1g, and the wave function of the ground state has the form of a single determinant. Electronic absorption and vibrational (IR and resonance Raman) spectra of H2TTDPz and NiTTDPz were studied experimentally and simulated theoretically.

Synthesis and characterization of heteroleptic rare earth double-decker complexes involving tetradiazepinoporphyrazine and phthalocyanine macrocycles.

Reaction of (2,3,9,10,16,17,23,24-octabutylphthalocyaninato)lanthanide(iii) acetylacetonates (BuPcLn(acac), 1a-c, Ln = Lu (a), Eu (b), La (c)) with a tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazine ligand (tBuPhDzPzH2, 2) produced sandwich compounds (tBuPhDzPz)Ln(BuPc) (3a-c), which represent the first heteroleptic double-deckers incorporating both Pc and DzPz decks. A combination of high-resolution mass spectrometry, UV-Vis/NIR, MCD, and 1H NMR spectroscopy, and square-wave voltammetry provided unambiguous characterization of target complexes 3 indicating that their spectral and electrochemical properties are generally intermediate with respect to their homoleptic relatives. Based on the data of solution-state 1H-1H NMR (COSY, NOESY) correlation spectroscopy supported by DFT calculations, a dimerization tendency of compounds 3 proportional to the Ln(iii) ion size was found. The spectroelectrochemical study of 3 and the corresponding homoleptic double-deckers revealed a pronounced tendency to aggregation of the one-electron oxidized forms of DzPz-containing double-decker complexes compared to homoleptic Pc2Ln compounds.

pH-Sensitive subphthalocyanines and subazaphthalocyanines.

Although subphthalocyanines (SubPcs) possess advantageous fluorescence properties and serve as an amazing tool to attach a recognition sensor moiety to the axial position, a limited number of switchable SubPcs have been described so far. Isosteric aza-replacement is known to improve sensing properties in closely related phthalocyanine families; however, pyrazino[2,3-b,g,l]subporphyrazines (SubPyzPzs) have not yet been investigated for use in sensing applications. Therefore, this project focuses on the synthesis and sensing abilities of pH-sensitive SubPcs and SubPyzPzs on the principle of photoinduced electron transfer (PET). 4-Dimethylaminophenoxy (for acidic pH) or 4-hydroxyphenoxy (for basic pH) groups were employed as pH-sensitive axial ligands. Electrochemical studies revealed improvements in the electron-accepting properties of SubPyzPzs (Ered-0.56 V vs. SCE) in comparison to those of SubPcs (Ered-1.0 V vs. SCE). Hydroxy groups on the axial phenoxy ligands of SybPyzPzs and SubPcs have been found to act as donors for PET. The sensing properties under basic conditions could not be studied, since all the SubPcs and SubPyzPzs decomposed under basic conditions, SubPyzPzs were more susceptible to this process. On the other hand, compounds with 4-dimethylaminophenoxy groups as axial ligands showed great potential for sensing applications. These compounds were nonfluorescent (ΦF < 0.01) in acetone due to efficient PET, while their fluorescence steeply increased by two orders of magnitude upon the addition of trifluoroacetic acid, reaching a ΦF value of up to 0.17 (λem range of 563-590 nm). These compounds maintained their sensing properties in aqueous medium after incorporation into microemulsions. The most basic derivative showed pKA = 2.95 with ΦF = 0.10 in the ON state (fluorescence enhancement factor = 46, λem = 577 nm).

DFT Study of Molecular and Electronic Structure of Ca(II) and Zn(II) Complexes with Porphyrazine and tetrakis(1,2,5-thiadiazole)porphyrazine.

Electronic and geometric structures of Ca(II) and Zn(II) complexes with porphyrazine (Pz) and tetrakis(1,2,5-thiadiazole)porphyrazine (TTDPz) were investigated by density functional theory (DFT) calculations and compared. The perimeter of the coordination cavity was found to be practically independent on the nature of a metal and a ligand. According to the results of the natural bond orbital (NBO) analysis and quantum theory of atoms in molecules (QTAIM) calculations, Ca-N bonds possess larger ionic contributions as compared to Zn-N. The model electronic absorption spectra obtained with the use of time-dependent density functional theory (TDDFT) calculations indicate a strong bathochromic shift (~70 nm) of the Q-band with a change of Pz ligand by TTDPz for both Ca and Zn complexes. Additionally, CaTTDPz was synthesized and its electronic absorption spectrum was recorded in pyridine and acetone.

DFT Study of Molecular and Electronic Structure of Y, La and Lu Complexes with Porphyrazine and Tetrakis(1,2,5-thiadiazole)porphyrazine.

Electronic and geometric structures of Y, La and Lu complexes with porphyrazine (Pz) and tetrakis(1,2,5-thiadiazole)porphyrazine (TTDPz) were investigated by density functional theory (DFT) calculations and compared. The nature of the bonds between metal atoms and nitrogen atoms has been described using the analysis of the electron density distribution in the frame of Bader's quantum theory of atoms in molecule (QTAIM). Simulation and interpretation of electronic spectra were performed with use of time-dependent density functional theory (TDDFT) calculations. Description of calculated IR spectra was carried out based on the analysis of the distribution of the potential energy of normal vibrations by natural vibrational coordinates.

Tetra-2,3-pyrazinoporphyrazines with Peripherally Appended Pyridine Rings. 20. Mono- and Pentanuclear AlIII and GaIII Complexes: Synthesis and Physicochemical and Photoactivity Studies.

The autocyclotetramerization of the precursor 2,3-dicyano-5,6-di(2'-pyridyl)pyrazine [(CN)2Py2Pyz] in the presence of MCl3 compounds (M = AlIII, GaIII) leads to the formation of the new mononuclear porphyrazine complexes [Py8TPyzPzMCl]·xH2O (Py8TPyzPz = tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazinato anion). From these species, the hydroxide analogues [Py8TPyzPzMOH]·xH2O were obtained by contact with hot water, and their corresponding pentanuclear species [(PdCl2)4Py8TPyzPzMCl]·xH2O could be easily formed by the reaction with PdCl2. Physicochemical characterization of the mono- and pentanuclear macrocycles was based on elemental analysis, and mass, powder X-ray, and IR spectra. UV-vis spectral studies of the mononuclear species in solutions of DMF, DMSO, or pyridine (c ≈ 10-5-10-6 M) indicate (mainly in DMF and DMSO) the initial presence of aggregation, in some cases accompanied by the concomitant occurrence for the complex of a one-electron reduction. While disaggregation into a single species evolves spontaneously over time, the -1 charged species, eventually also found present, can be brought back to its neutral form by addition of a slight amount of HCl, the final spectrum showing the presence of the starting neutral species in its pure monomeric form. Similar aspects were faced also for the parent pentanuclear complexes. Cyclic voltammetry experiments, conducted for the mono-/pentanuclear complexes in DMF and DMSO (c ≈ 10-4 M), exhibit progressive one-electron reductions (1 → 4) characterized by E1/2 values (V vs SCE) positioned to significantly less negative values than those known for the phthalocyanine (Pc) analogues, these data confirming the previously already proven higher electron-deficient character of the MII derivatives of the Py8TPyzPz macrocycle with respect to Pc. The role of the present new series of AlIII and GaIII macrocyclic species to act as photosensitizers for the generation of singlet oxygen, 1O2, the cytotoxic agent in the anticancer treatment known as photodynamic therapy (PDT), has been explored in DMF/HCl. Among the quantum yields ΦΔ, the value found for the GaIII complex [Py8TPyzPzGaCl] (0.68), practically coincident with that observed for the TTDPz analogue (0.69), is well above those of most porphyrazines analogues (ΦΔ = 0.4-0.6), a result encouraging further research work for potential applications in the biochemical field.

Tetrakis(1,2,5-thiadiazolo)porphyrazines. 9. Synthesis and spectral and theoretical studies of the lithium(i) complex and its unusual behaviour in aprotic solvents in the presence of acids.

The template cyclotetramerization of 1,2,5-thiadiazolo-3,4-dicarbonitrile in the presence of lithium n-butoxide in n-butanol leads to the Li(i) complex of tetrakis(1,2,5-thiadiazolo)porphyrazine. Various possible structures of dilithium and monolithium complexes have been considered by DFT/B3LYP molecular modelling using the cc-pvtz basis set, and their theoretical IR and UV-VIS spectra have been calculated. The experimental 7Li NMR, IR and UV-VIS spectra measurements show that the complex contains two inequivalent lithium atoms - one is coordinated to the macrocyclic dianion to form the anionic lithate complex [TTDPaLi]-, while the other forms the solvated countercation [Li(Solv)4]+. The lithate complex is stable in protic solvents, such as methanol, and is soluble in water to give aggregated solutions. Its demetallation occurs in the presence of acids (CH3COOH, CF3COOH, H2SO4). In aprotic solvents (DMF, DMSO), the acid-catalyzed formation of the [TTDPa]2- dianion is observed which is followed by the formation of the meso-protonated form {H[TTDPa]}- at higher acid concentrations. Both processes can be reversed by the addition of a lithium salt excess or neutralization of the acid. The fluorescence quantum yield for the lithate complex [TTDPaLi]- is much higher than that for the [TTDPa]2- dianion (0.34 and 0.01 in DMSO), and this can be used for detecting low concentrations of acids and Li+ in aprotic solvents (10-6-10-5 M). The first reversible reduction of the macrocycle in the anionic lithate complex (-0.94 V vs. SCE in DMSO) is ∼0.5 V more difficult than that in the complexes with divalent metals [TTDPaM] (M = MgII, ZnII, CuII).

Optical readout of controlled monomer-dimer self-assembly.

5,7-Substituted 1,4-diazepinoporphyrazine magnesium(ii) complexes were synthesized via Mg(ii)-alkoxide templated macrocyclization. A single crystal growth synchrotron diffraction analysis permitted what is to our knowledge the first structural characterization of a 1,4-diazepinoporphyrazine. It exists as a dimer in the solid state. In silico calculations supported by solution phase spectral studies involving a series of representative derivatives, provided insights into the factors governing dimerization of 1,4-diazepinoporphyrazines. The present 1,4-diazepinoporphyrazines serve as useful probes for understanding the determinants that guide dimer-monomer equilibria and the self-assembly of phthalocyanine derivatives.

First tellurium-containing phthalocyanine analogues: strong effect of tellurium on spectral, redox and conductivity properties of porphyrazines with annulated chalcogenodiazole ring(s).

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.

Synthesis and structure of the first clathrochelate iron(II) tris-dioximates with inherent nitrile substituent(s) and new dehalogenation--reduction reaction at a quasi-aromatic macrobicyclic framework.

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.