Synthesis, Structures, and Properties of Crystalline Salts with Radical Anions of Metal-Containing and Metal-Free Phthalocyanines

Bimetallic neutral and anionic complexes of transition metal (Co, Mn) carbonyls with indium(III) phthalocyanine

Heterobimetallic {[Co(CO)4]-[InIII(Pc2-)]} (1) and (Cp*2Cr+){[Mn(CO)5]-[InIII(Pc˙3-)]}·2C6H4Cl2 (2) complexes based on indium(III) phthalocyanine (Pc) were obtained as crystals. The complexes were synthesized by single (1) and double (2) reduction of indium(III) phthalocyanine chloride in the presence of transition metal carbonyls. Complex 1 contains dianionic Pc2- macrocycles. Thus, the coordinated Co(CO)4 carbonyl accepts an electron in the one-electron reduction forming a diamagnetic [Co(CO)4]- anion. Complex 2 contains a heterobimetallic {[Mn(CO)5]-[InIII(Pc˙3-)]}- anion and paramagnetic Cp*2Cr+ counter cations. Therefore, in the double reduction, electrons are transferred to Mn(CO)5 forming a diamagnetic [Mn(CO)5]- anion and to the Pc2- macrocycle forming a paramagnetic radical Pc˙3- trianion. Such assignments for 1 and 2 are in line with optical spectra, crystal structures and the data of magnetic measurements. The spectrum of 1 in the UV-visible range is similar to that of the starting InIIIClPc. The formation of 2 is accompanied by an essential blue-shift of the Q-band of Pc as well as by the appearance of an intense NIR band at 1005 nm characteristic of Pc˙3-. Compound 1 is EPR silent and diamagnetic, whereas the value of the effective magnetic moment of 2 is 4.24μB at 300 K, which corresponds to the contribution of S = 1/2 (Pc˙3-) and S = 3/2 (Cp*2Cr+) spins. Both weakly coupled paramagnetic centers (J = -0.41 cm-1) are observed in the EPR spectra.

Trinuclear coordination assemblies of low-spin dicyano manganese(II) (S = 1/2) and iron(II) (S = 0) phthalocyanines with manganese(II) acetylacetonate, tris(cyclopentadienyl)gadolinium(III) and neodymium(III)

The reaction of Mn^IIPc, Fe^IIPc or Fe^IIPcCl₁₆ with KCN in the presence of cryptand[2.2.2] yielded dicyano-complexes {cryptand(K⁺)}₂{M^II(CN)₂(macrocycle^2-)}^2-·XC₆H₄Cl₂ (M = Mn and Fe, X = 1 and 2) that were used for the preparation of trinuclear assemblies of the general formula {cryptand(K⁺)}₂{M^II(CN)₂Pc·(ML)₂}^2-·nC₆H₄Cl₂ (M^II = Mn^II and Fe^II; n = 1, 4 and 5). These assemblies were formed via coordination of two manganese(II) acetylacetonate (ML = Mn^II(acac)₂, S = 5/2), tris(cyclopentadienyl)gadolinium (ML = Cp₃Gd^III, S = 7/2) or tris(cyclopentadienyl)neodymium (ML = Cp₃Nd^III, S = 3/2) units to the nitrogen atoms of bidentate cyano ligands. The N(CN)-Mn{Mn^II(acac)₂} bond is 2.129(3) Å long but the bonds are elongated to 2.43-2.49 Å for tris(cyclopentadienyl)lanthanides. {Cryptand(K⁺)}₂{Mn^II(CN)₂Pc·(Mn^II(acac)₂)₂}^2-·5C₆H₄Cl₂ (2) contains three Mn(II) ions in different spin states (S = 5/2 and 1/2). Strong antiferromagnetic coupling of spins observed between them with the exchange interaction (J) of -17.6 cm^-1 enables the formation of a high S = 9/2 spin state for {Mn^II(CN)₂Pc·(Mn^II(acac)₂)₂}^2- dianions at 2 K. The estimated exchange interaction between Mn^II (S = 1/2) and Gd^III (S = 7/2) spins in {Mn^II(CN)₂Pc·(Cp₃Gd^III)₂}^2- is only -1.1 cm^-1, and in contrast to 2, nearly independent Gd^III and Mn^II centers are formed. As a result, no transition to the high-spin state is observed in {Mn^II(CN)₂Pc·(Cp₃Gd^III)₂}^2-. The {Mn^II(CN)₂Pc·(Cp₃Nd^III)₂}^2- and{Fe^II(CN)₂Pc·(Cp₃Nd^III)₂}^2- dianions with Cp₃Nd^III show a decrease of χ_MT values in the whole studied temperature range (300-1.9 K). A similar behaviour was found previously for pristine Cp₃Nd^III and Cp₃Nd^III·L complexes (L = alkylisocyanide ligand).

Complexes of transition metal carbonyl clusters with tin(II) phthalocyanine in neutral and radical anion states: methods of synthesis, structures and properties

Coordination of tin(II) phthalocyanine to transition metal carbonyl clusters in neutral {Sn^II(Pc^2-)}⁰ or radical anion {Sn^II(Pc˙^3-)}^- states is reported. Direct interaction of Co₄(CO)₁₂ with {Sn^II(Pc^2-)}⁰ yields a crystalline complex {Co₄(CO)₁₁·Sn^II(Pc^2-)} (1). There is no charge transfer from the cluster to phthalocyanine in 1, which preserves the diamagnetic Pc^2- macrocycle. The Ru₃(CO)₁₂ cluster forms complexes with one or two equivalents of {Sn^II(Pc˙^3-)}^- to yield crystalline {Cryptand[2.2.2](Na⁺)}{Ru₃(CO)₁₁·Sn^II(Pc˙^3-)}^- (2) or {Cryptand[2.2.2](M⁺)}₂{Ru₃(CO)₁₀·[Sn^II(Pc˙^3-)]₂}^2-·4C₆H₄Cl₂ (3) (M⁺ is K or Cs). Paramagnetic {Sn^II(Pc˙^3-)}^- species in 2 are packed in π-stacking [{Sn^II(Pc˙^3-)}^-]₂ dimers, providing strong antiferromagnetic coupling of spins with exchange interaction J/k_B = -19 K. Reduction of Ru₃(CO)₁₂, Os₃(CO)₁₂ and Ir₄(CO)₁₂ clusters by decamethylchromocene (Cp*₂Cr) and subsequent oxidation of the reduced species by {Sn^IVCl₂(Pc^2-)}⁰ yield a series of complexes with high-spin Cp*₂Cr⁺ counter cations (S = 3/2): (Cp*₂Cr⁺){Ru₃(CO)₁₁·Sn^II(Pc˙^3-)}^-·C₆H₄Cl₂ (4), (Cp*₂Cr⁺){Os₃(CO)₁₀Cl·Sn^II(Pc˙^3-)}^-·C₆H₄Cl₂ (5) and (Cp*₂Cr⁺){Ir₄(CO)₁₁·Sn^II(Pc˙^3-)}₂^- (6). It is seen that reduced clusters are oxidized by Sn^IV, which is transferred to Sn^II, whereas the Pc^2- macrocycle is reduced to Pc˙^3-. In the case of Os₃(CO)₁₂, oxidation of the metal atom in the cluster is observed to be accompanied by the formation of Os₃(CO)₁₀Cl with one Os^I center. Rather weak magnetic coupling is observed between paramagnetic Cp*₂Cr⁺ and {Sn^II(Pc˙^3-)}^- species in 4, but this exchange interaction is enhanced in 5 owing to Os₃(CO)₁₀Cl clusters with paramagnetic Os^I (S = 1/2) also being involved in antiferromagnetic coupling of spins. The formation of {Sn^II(Pc˙^3-)}^- with radical trianion Pc˙^3- macrocycles in 2-5 is supported by the appearance of new absorption bands in the NIR spectra and essential N_meso-C bond alternation in Pc (for 3-5). On the whole, this work shows that both diamagnetic {Sn^II(Pc^2-)}⁰ and paramagnetic {Sn^II(Pc˙^3-)}^- ligands substitute carbonyl ligands in the transition metal carbonyl clusters, forming well-soluble paramagnetic solids absorbing light in the visible and NIR ranges.

Macrocycle- and metal-centered reduction of metal tetraphenylporphyrins where the metal is copper(II), nickel(II) and iron(II)

The reduction of metal(II) tetraphenylporphyrins, where metal(II) is copper, nickel or iron, has been performed in toluene solution in the presence of a cryptand. Cesium anthracenide was used as a reductant. Crystalline salts {cryptand(Cs⁺)}₂{Cu^II(TPP^4-)}^2- (1) and {cryptand(Cs⁺)}{Ni^I(TPP^2-)}^-·C₆H₅CH₃ (2) have been obtained. The two-electron reduction of {Cu^II(TPP^2-)}⁰ is centered on the macrocycle allowing one to study for the first time the structure and properties of the TPP^4- tetraanions in the solid state. Tetraanions have a diamagnetic state and show essential C-C_meso bond alternation. New bands attributed to TPP^4- appear at 670, 770 and 870 nm. Unpaired S = 1/2 spin is localized on Cu^II. The one-electron reduction of {Ni^II(TPP^2-)}⁰ centered on nickel provides the formation of {Ni^I(TPP^2-)}^- with unpaired S = 1/2 spin localized on Ni^I at 100(2) K. The effective magnetic moment of 2 is 1.68μ_B at 120 K and a broad asymmetric EPR signal characteristic of Ni^I is observed for 2 and also for (Bu₃MeP⁺){Ni^I(TPP^2-)}^-·C₆H₅CH₃ (3) in the 4.2-120 K range. Since dianionic TPP^2- macrocycles are present at 100(2) K, no alternation of C-C_meso bonds is observed in 2. The excited quartet S = 3/2 state according to the calculations is positioned close to the ground S = 1/2 state. In the excited state, charge transfer from Ni^I to the macrocycle takes place resulting in the formation of Ni^II with S = 1 and TPP˙^3- with S = 1/2 in the {Ni^II(TPP˙^3-)}^- anions. Therefore, the increase in the magnetic moment of 2 above 150 K is attributed to the population of the excited quartet state with a gap of 750 K. Salt 2 is EPR silent above 150 K and manifests absorption bands characteristic of TPP˙^3- at RT. The reduction of Ni^II(TPP^2-) and Fe^II(TPP^2-) by cesium anthracenide in the presence of Bu₃MeP⁺ yields crystals of 3 and (Bu₃MeP⁺){Fe^I(TPP^2-)}^-·C₆H₅CH₃ (4) whose crystal structures and optical properties are also presented. DFT calculations have been carried out for {M^II(TPP^2-)} (M = Cu, Ni and Fe) and their anions to interpret the experimental results obtained for 1-4.

Interaction of InIIIClPc and TlIIIClPc phthalocyanines with deprotonated porphyrin HTPP− anions. Metal-centred reduction of TlIIIClPc

Reactions of In[Formula: see text]ClPc or Tl[Formula: see text]ClPc phthalocyanines with monodeprotonated tetraphenylporphyrin HTPP[Formula: see text] anions have been studied under reduction or in the presence of [Formula: see text]-methylimidazole ([Formula: see text]-MeIm). Formation of salt {In[Formula: see text]-MeIm)2(TPP[Formula: see text]}[Formula: see text]{In[Formula: see text](Pc[Formula: see text]}[Formula: see text] ⋅ 4C6H4Cl2 (1) justifies partial abstraction of indium(III) atoms from In[Formula: see text]ClPc to form cationic {In[Formula: see text](TPP[Formula: see text]}[Formula: see text] porphyrins[Formula: see text]solvated by [Formula: see text]-MeIm and double-decker {In[Formula: see text](Pc[Formula: see text]}[Formula: see text] anions. Crystals of Tl[Formula: see text](HTPP[Formula: see text] (2) have been only obtained at the interaction of HTPP[Formula: see text] with Tl[Formula: see text]ClPc under reduction indicating that Tl[Formula: see text] is reduced to Tl[Formula: see text] and is abstracted by HTPP[Formula: see text]. To confirm the possibility of Tl[Formula: see text] formation under reduction we have studied reduction of Tl[Formula: see text]ClPc by sodium fluorenone in the presence of cryptand[2.2.2]. Crystals of {Cryptand(Na[Formula: see text]}(Tl[Formula: see text](Pc[Formula: see text]}[Formula: see text] ⋅ C6H4Cl2(3) have been isolated indicating metal-centered reduction of Tl[Formula: see text]ClPc to form Tl[Formula: see text] and preserving dianionic Pc[Formula: see text] macrocycles. Optical spectra and structures of the obtained compounds are discussed and compared with those of pristine M[Formula: see text]ClPc. It is shown that 1–3 are EPR silent due to the formation of diamagnetic components.

Dianionic States of Trithiadodecaazahexaphyrin Complexes with Homotrinuclear MII3O Clusters (M = Ni and Cu): Crystal Structures, Metal- Or Macrocycle-Centered Reduction, and Doublet-Quartet Transitions in the Dianions

Metal complexes of trithiadodecaazahexaphyrin (Hhp) that contain M^II₃O clusters inside a π-extended trianionic (Hhp^3-) macrocycle have been prepared. Studies of the magnetic properties of Ni^II₃O(Hhp) and Cu^II₃O(Hhp) reveal a diamagnetic and EPR-silent trianionic (Hhp^3-) macrocycle and diamagnetic Ni^II₃(O^2-) or paramagnetic Cu^II₃(O^2-) tetracations. The positive charge of M^II₃O(Hhp) is compensated by one acetate anion {M^II₃O(Hhp)}⁺(CH₃CO₂^-). The three-electron reduction of {M^II₃O(Hhp)}⁺ yields {cryptand(Cs⁺)}₂{Ni^II₂Ni^IO(Hhp^5-)}^2-·2C₇H₈ (1) and {cryptand(Cs⁺)}₂{Cu^II₃O(Hhp^•6-)}^2-·C₇H₈ (2) crystalline salts. The magnetic properties of 1 reveal the formation of Hhp^5- and the reduction of nickel(II) to the paramagnetic Ni^I ion (S = 1/2), which is accompanied by the formation of the {Ni^II₂Ni^IO(Hhp^5-)}^2- dianion. As a result, the magnetic moment of 1 is 1.68 μ_B in the 20-220 K range, and a broad EPR signal of Ni^I was observed. The Hhp^5- macrocycle has a singlet ground state, but the increase in the magnitude of the magnetic moment of 1 above 220 K is attributed to the population of the triplet excited state in Hhp^5-. The {Ni^II₂Ni^IO(Hhp^5-)}^2- dianion is transferred from the doublet excited state to the quartet excited state with an energy gap of 1420 ± 50 K. Salt 1 also shows an unusually strong low-energy NIR absorption, which was observed at 1000-2200 nm. In 2, a highly reduced Hhp^•6- radical hexaanion (S = 1/2) coexists with a Cu^II₃(O^2-) cluster (S = 1/2) in the {Cu^II₃O(Hhp^•6-)}^2- dianions. The dianions have a triplet ground state with antiferromagnetic exchange between two S = 1/2 spins with J = -6.4 cm^-1. The reduction of Hhp in both salts equalizes the initially alternated C-N bonds, supporting the increase in the Hhp macrocycle electron delocalization.

Structure and properties of radical anion and dianion salts of organic dye trans-perinone and its mixed salt with gallium(iii) phthalocyanine

Reduction of organic dye trans-perinone in different experimental conditions was studied. New crystallite salts containing reduced species of trans-perinone together with mixed salt with Ga^IIIClPc radical anions were obtained and characterized.

Reaction of GaIIIClPc, SnIVCl2TPP and BIIIClSubPc with cyanide anions: reduction of macrocycles vs. formation of cyano-containing macrocyclic anions

The reaction of GaIIIClPc, SnIVCl2TPP and BIIIClSubPc containing phthalocyanine (Pc), tetraphenylporphyrin (TPP) and subphthalocyanine (SubPc) macrocycles with cyanide in the presence of cryptand[2.2.2] under anaerobic conditions yields crystalline salts in which cyano anions substitute chloride anions at GaIII, SnIV or BIII, as well as reducing the macrocycles or adding one or two CN- to them. The reaction of GaIIICl(Pc2-) with CN- yields {crypt(K+)}{GaIIICN(Pc˙3-)}˙-·0.5C6H4Cl2 (1) in which the Pc2- macrocycle is reduced to Pc˙3-. Such reduction could probably occur through the addition of CN- to Pc2- forming {GaIII(CN)[Pc(CN)]3-}- which can decompose further interacting with an excess of CN-. As a result, Pc˙3- and cyanogene anions are formed. The interaction of SnIVCl2(TPP2-) with CN- is accompanied by the addition of CN- to the meso-carbon atom of porphyrin forming diamagnetic TPP(CN)3- macrocycles in {crypt(K+)}{SnIV(CN)2[TPP(CN)]3-}- (2). Salt 2 shows a strong NIR absorption band with the maximum at 854 nm whose intensity is comparable with that of the Soret band. The interaction of BIIICl(SubPc2-) with three equivalents of CN- is accompanied by the addition of two CN- to carbon atoms of SubPc2- closest to meso-nitrogen atoms forming {BIII(CN)[SubPc(CN)2]4-}2-. Most probably these dianions transfer electrons to C6H4Cl2 producing the {BIII(CN)[SubPc(CN)2]˙3-}˙- radical anions which form σ-bonded diamagnetic dianions in {crypt(K+)}2{BIII(CN)[SubPc(CN)2]}22-·3C6H4Cl2 (3). The remaining carbon atom closest to the meso-nitrogen atom is involved in this dimerization. According to the calculations, the energy of the C-CN bond is minimal for {GaIII(CN)[Pc(CN)]3-}- enabling further transformation of these anions to {GaIIICN(Pc˙3-)}˙- in 1, whereas cyano-containing anions in 2 and 3 with higher energy of this bond are stable towards the elimination of CN. Optical and magnetic properties of 1-3 together with their crystal and molecular structures are presented. The possible ways of the formation of 1-3 are discussed based on DFT calculations.

Synthesis, structures and reduction chemistry of monophthalocyanine scandium hydroxides

The preparation and structural characterization of a pair of scandium(III) phthalocyanine hydroxide complexes were achieved by reaction of PcScCl with alkali metal alkoxides, likely via hydrolysis of soluble PcSc-alkoxide intermediates. A Sc[Formula: see text]Li[Formula: see text]-OH)[Formula: see text] cubane supported by two distorted Pc rings of the form (PcSc)[Formula: see text]-OH)[Formula: see text]Li[Formula: see text](THF)(DME) was isolated from the reaction of PcScCl with LiO[Formula: see text]Pr, while a simpler alkali-metal-free [Pc[Formula: see text]Sc[Formula: see text]-OH)[Formula: see text](THF)] was obtained from addition of NaO[Formula: see text]Bu; both structures are reminiscent of bent metallocenes, with dihedral angles between the two Pc rings of 50.8 and 37.7[Formula: see text]respectively. A soluble PcScOH material can also be obtained directly via hydrolysis of insoluble PcScCl in approximately 95:5 THF:water. Reduction of the Pc ring of PcScCl using KC[Formula: see text] is reversible and generates Pc[Formula: see text] and Pc[Formula: see text]-containing materials that were characterized via UV-vis spectroscopy and, where appropriate EPR and [Formula: see text]H NMR spectroscopy; analogous reductions of the PcScOH-based species were irreversible. Exposure of the air-sensitive, reduced PcScCl-based species to ambient atmosphere generated PcScOH materials analogous to the direct hydrolysis route.

Synthesis, characterization, and electrochemical properties of a first-row metal phthalocyanine series

A first-row metal phthalocyanine series is synthesized and the effects of axial metal-ligand substitution is investigated electrochemically and in the context of charge carriers for redox-flow batteries.

Effect of reduction on the molecular structure and optical and magnetic properties of fluorinated copper(ii) phthalocyanines

New salts based on reduced fluorinated copper(ii) phthalocyanines were obtained. The effect of reduction on the molecular structure and properties of the  [Cu^II(F_xPc)]ⁿ⁻ (x = 8 and 16) species in reduced states (n = 1 and 2) was studied.

Molecular structures, and optical and magnetic properties of free-base tetrapyrazinoporphyrazine in various reduction states

The synthesis, and spectral and structural characterization of the novel radical anion and dianion salts of free-base tetrapyrazinoporphyrazine (H₂TPyzPz) as well as studies of their magnetic properties have been described.

Coordination-induced metal-to-macrocycle charge transfer and effect of cations on reorientation of the CN ligand in the {SnL2Mac}2− dianions (L = CN−, OCN−, Im−; Mac = phthalo- or naphthalocyanine)

Anionic coordination {crypt(M⁺)}₂{SnL₂Mac}²⁻ complexes of tin(ii) phthalo- (Pc) and naphthalocyanines (Nc) were obtained and discussed.

{CpFeII(CO)2SnII(Macrocycle•3-)} Radicals with Intrinsic Charge Transfer from CpFe(CO)2 to Macrocycles (Cp: Cp or Cp*); Effective Magnetic Coupling between Radical Trianionic Macrocycles•3

Neutral {CpFe^II(CO)₂[Sn^II(Pc^•3-)]} {Cp is cyclopentadienyl (1, 2) or Cp* is pentamethylcyclopentadienyl (3); Pc: phthalocyanine}, {Cp*Fe^II(CO)₂[Sn^II(Nc^•3-)]} (4, Nc: naphthalocyanine), and {CpFe^II(CO)₂[Sn^II(TPP^•3-)]} (5, TPP: tetraphenylporphyrin) complexes in which CpFe^II(CO)₂ fragments (Cp: Cp or Cp*) are coordinated to Sn^II(macrocycle^•3-) have been obtained. The product complexes were obtained at the reaction of charge transfer from CpFe^I(CO)₂ (Cp: Cp or Cp*) to [Sn^II(macrocycle^2-)] to form the diamagnetic Fe^II and paramagnetic radical trianionic macrocycles. As a result, these formally neutral complexes contain S = 1/2 spins delocalized over the macrocycles. This provides alternation of the C-N_imine or C-C_meso bonds in the macrocycles, the appearance of new bands in the near-infrared spectra of the complexes, and blue shift of both Soret and Q-bands. The {CpFe^II(CO)₂Sn^II(macrocycle^•3-)} units (Cp: Cp or Cp*, macrocycle: Pc or Nc) form closely packed π-stacking dimers in 1 and 3 or one-dimensional chains in 2 and 4 with effective π-π interaction between the macrocycles. Such packing allows strong antiferromagnetic coupling between S = 1/2 spins. Magnetic interaction can be described well by the Heisenberg model for the isolated dimers in 1 and 3 with exchange interaction J/k _B = -78 and -85 K, respectively. Magnetic behavior of 2 and 4 is described well by the model that includes contributions from an antiferromagnetically coupled S = 1/2 dimer (J _intra) and a Heisenberg S = 1/2 chain with alternating antiferromagnetic spin exchange between the neighbors (J _inter). Compound 2 demonstrates large intradimer interaction of J _intra/k _B = -54 K and essentially weaker interdimer exchange interactions of J _inter/k _B = -6 K, whereas compound 4 shows strong magnetic coupling of spins within the dimers (J _intra/k _B = -170 K) as well as between the dimers (J _inter/k _B = -40 K). Compound {CpFe^II(CO)₂[Sn^II(TPP^•3-)]} (5) shows no π-π interactions between the porphyrin macrocycles, and magnetic coupling is weak in this case (Weiss temperature is -5 K). Preparation of a similar complex with indium(III) chloride phthalocyanine yields {CpFe(CO)₂[In(Pc^2-)]} (6). In this complex, indium(III) atoms are reduced instead of the phthalocyanine macrocycles that explains electron paramagnetic resonance silence of 6 in the 4-295 K range.

Ring-Oxidized Zinc(II) Phthalocyanine Cations: Structure, Spectroscopy, and Decomposition Behavior

A bromonium oxidizing agent was used to produce a ring-oxidized zinc phthalocyanine (PcZn), [PcZn(solvent)]^•₂[BAr^F₄]₂ (1·solvent), in good yield. This material is dimeric in the solid state with one axially coordinated solvent [tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME)] and close intradimer ring-ring distances of 3.18 and 3.136 Å (THF and DME respectively); this proximity facilitates strong antiferromagnetic coupling to yield diamagnetic dimers. 1·THF is present in solution as a monomer and a dimer. In CH₂Cl₂, the dimer is favored above 0.1 mM, and it is almost exclusively present in solvents with a high dielectric constant such as acetonitrile. The material 1·THF/DME decomposes in DME to a meso-nitrogen-protonated species, [HPcZn(DME)₂][BAr^F₄] (2), which was isolated and represents the first example of such a structurally characterized, protonated, unsubstituted PcM complex. A partially oxidized dimer or "pimer" [(PcZn(DME))₂]^•[BAr^F₄] (3) was also structurally characterized and has a intradimer ring-ring distance of 3.192 Å, similar to 1·THF/DME. Dimer 3 also represents the first isolated PcM-based pimer. Electron paramagnetic resonance analysis of a 1.0 mM solution of 1·DME in DME showed the production of 3 over hours by the combination of 1·DME and 2 in solution.

Coordination Complexes of Titanium(IV) and Indium(III) Phthalocyanines with Carbonyl-Containing Dyes: The Formation of Singly Bonded Anionic Squarylium Dimers

Reduction methods for the preparation of coordination complexes of titanium(IV) and indium(III) phthalocyanines (Pc) with organic dyes such as indigo, thioindigo, and squarylium dye III (SQ) have been developed, which allow one to obtain crystalline {cryptand(K⁺ )}{(cis-indigo-O,O)^2- Ti^IV (Pc^2- )}(Cl^- )⋅C₆ H₄ Cl₂ (1), {cryptand(K⁺ )}{(cis-thioindigo-O,O)^2- In^III (Pc^2- )}^- ⋅C₆ H₄ Cl₂ (2), and {cryptand(K⁺ )}{[(SQ)₂ -O,O]^2- In^III (Pc^2- )}^- ⋅3.5 C₆ H₄ Cl₂ (3) complexes. The formation of these complexes is accompanied by the reduction of the starting dyes to the anionic state. Transition of trans-indigo or trans-thioindigo to the cis conformation in 1 and 2 provides coordination of both carbonyl oxygen atoms of the dye to Ti^IV Pc or In^III Pc. SQ is reduced to the radical anion state and forms unusual diamagnetic singly bonded (SQ^- )₂ dimers in 3. These dimers have two closely positioned carbonyl oxygen atoms coordinated to In^III Pc. Dianionic Pc^2- macrocycles have been found in 1-3. The complexes contain two chromophore molecules at one metal center. However, their optical spectra are defined mainly by absorption bands of the metal phthalocyanines.

Dianionic Titanyl and Vanadyl (Cation+ )2 [MIV O(Pc4- )]2- Phthalocyanine Salts Containing Pc4- Macrocycles

In this study, the titanyl and vanadyl phthalocyanine (Pc) salts (Bu₄ N⁺ )₂ [M^IV O(Pc^4- )]^2- (M=Ti, V) and (Bu₃ MeP⁺ )₂ [M^IV O(Pc^4- )]^2- (M=Ti, V) with [M^IV O(Pc^4- )]^2- dianions were synthesized and characterized. Reduction of M^IV O(Pc^2- ) carried out with an excess of sodium fluorenone ketyl in the presence of Bu₄ N⁺ or Bu₃ MeP⁺ is exclusive to the phthalocyanine centers, forming Pc^4- species. During reduction, the metal +4 charge did not change, implying that Pc is an non-innocent ligand. The Pc negative charge increase caused the C-N(pyr) bonds to elongate and the C-N(imine) bonds to alternate, thus increasing the distortion of Pc. Jahn-Teller effects are significant in the [eg(π*)]² dianion ground state and can additionally distort the Pc macrocycles. Blueshifts of the Soret and Q-bands were observed in the UV/Vis/NIR when M^IV O(Pc^2- ) was reduced to [M^IV O(Pc^.3- )]^.- and [M^IV O(Pc^4- )]^2- . From magnetic measurements, [Ti^IV O(Pc^4- )]^2- was found to be diamagnetic and (Bu₄ N⁺ )₂ [V^IV O(Pc^4- )]^2- and (Bu₃ MeP⁺ )₂ [V^IV O(Pc^4- )]^2- were found to have magnetic moments of 1.72-1.78 μ_B corresponding to an S=1/2 spin state owing to V^IV electron spin. As a result, two latter salts show EPR signals with V^IV hyperfine coupling.

Reaction of tin(iv) phthalocyanine dichloride with decamethylmetallocenes (M = CrII and CoII). Strong magnetic coupling of spins in (Cp*2Co+){SnIVCl2(Pc˙3-)}˙-·2C6H4Cl2

The reaction of tin(iv) phthalocyanine dichloride {Sn^IVCl₂(Pc^2-)} with decamethylmetallocenes (Cp*₂M, M = Co, Cr) has been studied. Decamethylcobaltocene reduces Sn^IVCl₂(Pc^2-) to form the (Cp*₂Co⁺){Sn^IVCl₂(Pc˙^3-)}˙^-·2C₆H₄Cl₂ (1) complex. The negative charge of {Sn^IVCl₂(Pc˙^3-)}˙^- is delocalized over the Pc macrocycle providing the alternation of the C-N(imine) bonds, the appearance of new bands in the NIR range and a strong blue shift of both the Soret and Q-bands in the spectrum of 1. The magnetic moment of 1 is equal to 1.68μ_B at 300 K, indicating the contribution of one S = 1/2 spin of the Pc˙^3- macrocycles. These macrocycles form closely packed double stacks in 1 with effective π-π interactions providing strong antiferromagnetic coupling of spins at a Weiss temperature of -80 K. Decamethylchromocene initially also reduces Sn^IVCl₂(Pc^2-) to form the [(Cp*₂Cr⁺){Sn^VICl₂(Pc˙^3-)}˙^- complex but further reaction between the ions is observed. This reaction is accompanied by the substitution of one Cp* ligand of Cp*₂Cr by chloride anions originating from {Sn^IVCl₂(Pc˙^3-)}˙^- to form the complex {(Cp*CrCl₂)(Sn^IV(μ-Cl)(Pc^2-))}·C₆H₄Cl₂ (2) in which the (Cp*CrCl₂) and {Sn^IV(Pc^2-)} species are bonded through the μ-bridged Cl^- anion. According to the DFT calculations, this reaction proceeds via an intermediate [(Cp*₂CrCl)(SnClPc)] complex.

SnPhPc phthalocyanines with dianion Pc(2-) and radical trianion Pc˙(3-) macrocycles: syntheses, structures, and properties

The interaction of Sn(IV)Cl2Pc with an excess of NaBPh4 in the presence of fullerenes C60 and C70 provides complete dissolution of Sn(IV)Cl2Pc and the formation of blue solutions from which the crystals of [SnPhPc(2-)](+)(BPh4)(-)·C6H14 () or [SnPhPc˙(3-)]·C6H4Cl2 () were selectively isolated. According to the optical spectra, salt contains dianionic Pc(2-) macrocycles, whereas macrocycles are reduced to form the Pc˙(3-) radical trianions in . As a result, the phthalocyanine macrocycle is dianionic in , and the positive charge of Sn(IV) is compensated by the Ph(-), Pc(2-), and BPh4(-) anions in this compound. The formally neutral compound contains two anionic species of Ph(-) and Pc˙(3-) and the Sn(IV) ion as the counter cation. Phenyl substituents are linked to the Sn(IV) atoms by the Sn-C(Ph) bonds of 2.098(2) () and 2.105(2) Å () length. The dianionic Pc(2-) macrocycle significantly deviates from planarity in while Pc˙(3-) is planar in . Salt manifests only a weak impurity EPR signal. Compound manifests an intense EPR signal with g = 2.0046 and a linewidth of 0.5 mT at 298 K due to the presence of Pc˙(3-). Spins are weakly antiferromagnetically coupled in the π-stacking [SnPhPc˙(3-)]2 dimers of with a Weiss temperature of -3 K and the estimated magnetic exchange interaction J/kB = -0.23 K.

Interligand Charge Transfer in a Complex of Deprotonated cis-Indigo Dianions and Tin(II) Phthalocyanine Radical Anions with Cp*IrIII

A diamagnetic complex, {(cis-indigo-N,N)^2-(Cp*Ir^III)} (1), in which deprotonated cis-indigo dianions coordinate an iridium center through two nitrogen atoms was obtained. By employment of the ability of the iridium center in 1 to coordinate an additional ligand, the complex [(Bu₄N⁺)₂{[Sn^II(Pc^•3-)](cis-indigo-N,N)^2-Cp*Ir^III}^•-₂·0.5(H₂Indigo)·2.5C₆H₄C_l2 (2), which has two functional ligands coordinating an Ir^III center, was obtained. This complex has a magnetic moment of 1.71 μ_B at 300 K, in accordance with an S = 1/2 spin state. The spin density is mainly delocalized over the Pc^•3- macrocycle and partially on (cis-indigo-N,N)^2-. Due to an effective π-π interaction, a thermally activated charge transfer from [Sn^II(Pc^•3-)]^•- to (cis-indigo-N,N)^2- is observed, with an estimated Gibbs energy (-ΔG°) of 9.27 ± 0.18 kJ/mol. The deprotonation of indigo associated with the coordination of Ir^III by the indigo releases H⁺ ions, which protonate noncoordinating indigo molecules to produce leuco cis-indigo (H₂Indigo). One H₂indigo links two (cis-indigo-N,N)^2- dianions in 2 to produce strong N-H···O═C and O-H···O═C hydrogen-bonding interactions.

Synthesis and properties of N-methylimidazole solvates of vanadium(ii), chromium(ii) and iron(ii) phthalocyanines. Strong NIR absorption in VII(MeIm)2(Pc2−)

Crystal structures and optical and magnetic properties of N-methylimidazole (MeIm) solvates of vanadium(ii), chromium(ii) and iron(ii) phthalocyanines have been studied.

Salts with titanyl and vanadyl phthalocyanine radical anions. Molecular design and effect of cations on the structure and magnetic and optical properties

Our recent data on radical anion salts of titanyl (Ti^IVOPc) and vanadyl (V^IVOPc) phthalocyanines as well as additional new data are summarized.

Tetrabutylammonium Salts of Aluminum(III) and Gallium(III) Phthalocyanine Radical Anions Bonded with Fluoren-9-olato- Anions and Indium(III) Phthalocyanine Bromide Radical Anions

Reduction of aluminum(III), gallium(III), and indium(III) phthalocyanine chlorides by sodium fluorenone ketyl in the presence of tetrabutylammonium cations yielded crystalline salts of the type (Bu₄ N⁺ )₂ [M^III (HFl-O^- )(Pc^.3- )]^.- (Br^- )⋅1.5 C₆ H₄ Cl₂ [M=Al (1), Ga (2); HFl-O^- =fluoren-9-olato^- anion; Pc=phthalocyanine] and (Bu₄ N⁺ ) [In^III Br(Pc^.3- )]^.- ⋅0.875 C₆ H₄ Cl₂ ⋅0.125 C₆ H₁₄ (3). The salts were found to contain Pc^.3- radical anions with negatively charged phthalocyanine macrocycles, as evidenced by the presence of intense bands of Pc^.3- in the near-IR region and a noticeable blueshift in both the Q and Soret bands of phthalocyanine. The metal(III) atoms coordinate HFl-O^- anions in 1 and 2 with short Al-O and Ga-O bond lengths of 1.749(2) and 1.836(6) Å, respectively. The C-O bonds [1.402(3) and 1.391(11) Å in 1 and 2, respectively] in the HFl-O^- anions are longer than the same bond in the fluorenone ketyl (1.27-1.31 Å). Salts 1-3 show effective magnetic moments of 1.72, 1.66, and 1.79 μ_B at 300 K, respectively, owing to the presence of unpaired S=1/2 spins on Pc^.3- . These spins are coupled antiferromagnetically with Weiss temperatures of -22, -14, and -30 K for 1-3, respectively. Coupling can occur in the corrugated two-dimensional phthalocyanine layers of 1 and 2 with an exchange interaction of J/k_B =-0.9 and -1.1 K, respectively, and in the π-stacking {[In^III Br(Pc^.3- )]^.- }₂ dimers of 3 with an exchange interaction of J/k_B =-10.8 K. The salts show intense electron paramagnetic resonance (EPR) signals attributed to Pc^.3- . It was found that increasing the size of the central metal atom strongly broadened these EPR signals.

Molecular titanium nitrides: nucleophiles unleashed

In this contribution we present reactivity studies of a rare example of a titanium salt, in the form of [μ2-K(OEt2)]2[(PN)2Ti[triple bond, length as m-dash]N]2 (1) (PN- = N-(2-(diisopropylphosphino)-4-methylphenyl)-2,4,6-trimethylanilide) to produce a series of imide moieties including rare examples such as methylimido, borylimido, phosphonylimido, and a parent imido. For the latter, using various weak acids allowed us to narrow the pK a range of the NH group in (PN)2Ti[triple bond, length as m-dash]NH to be between 26-36. Complex 1 could be produced by a reductively promoted elimination of N2 from the azide precursor (PN)2TiN3, whereas reductive splitting of N2 could not be achieved using the complex (PN)2Ti[double bond, length as m-dash]N[double bond, length as m-dash]N[double bond, length as m-dash]Ti(PN)2 (2) and a strong reductant. Complete N-atom transfer reactions could also be observed when 1 was treated with ClC(O)tBu and OCCPh2 to form NCtBu and KNCCPh2, respectively, along with the terminal oxo complex (PN)2Ti[triple bond, length as m-dash]O, which was also characterized. A combination of solid state 15N NMR (MAS) and theoretical studies allowed us to understand the shielding effect of the counter cation in dimer 1, the monomer [K(18-crown-6)][(PN)2Ti[triple bond, length as m-dash]N], and the discrete salt [K(2,2,2-Kryptofix)][(PN)2Ti[triple bond, length as m-dash]N] as well as the origin of the highly downfield 15N NMR resonance when shifting from dimer to monomer to a terminal nitride (discrete salt). The upfield shift of 15Nnitride resonance in the 15N NMR spectrum was found to be linked to the K+ induced electronic structural change of the titanium-nitride functionality by using a combination of MO analysis and quantum chemical analysis of the corresponding shielding tensors.

Solid state structures and properties of free-base 5,10,15-triphenylcorrole (TPCor) anions obtained by deprotonation and reduction. Effective magnetic coupling of spins in (Cp*2Cr+)(H+)(H2TPCor˙2−)·C6H4Cl2

The structures and properties of free-base triphenylcorrole radical H2TPCor˙²⁻ dianions and diamagnetic deprotonated H2TPCor⁻ anions have been studied. In both cases, deprotonation provides a planar shape of the corrole macrocycle. High-spin Cp*₂Cr⁺ (S = 3/2) and H2TPCor˙²⁻ with the S = 1/2 spin state alternate in the π-stacks providing effective antiferromagnetic coupling of spins.

Crystalline salts of metal phthalocyanine radical anions [M(Pc˙3−)]˙− (M = CuII, PbII, VIVO, SnIVCl2) with cryptand(Na+) cations: structure, optical and magnetic properties

Radical anion salts of metal phthalocyanines (M = Cu^II, Pb^II, V^IVO and Sn^IVCl₂) with the {cryptand(Na⁺)} cations have been obtained and studied.

Azaporphyrin phosphorus(v) complexes: synthesis, structure, and modification of optical properties

Azaporphyrinoids, such as phthalocyanines (Pcs), tetraazaporphyrins (TAPs), and tetrabenzotriazacorroles (TBCs), are some of the most well-known and successful artificial dyes and pigments in modern material chemistry.

Charge transfer complexes of metal-free phthalocyanine radical anions with decamethylmetallocenium cations: (Cp*2Co+)(H2Pc˙−)·solvent and (Cp*2Cr+)(H2Pc˙−)·4C6H4Cl2

Complexes of metal-free phthalocyanine (H₂Pc) and decamethylmetallocenium cations were obtained and studied.

Radical anion and dianion salts of titanyl macrocycles with acceptor substituents or an extended π-system

Crystalline anionic salts of titanyl macrocycles: (PPN⁺)₂{OTi^IV(PcCl₈⁴⁻)}²⁻ (1), (PPN⁺){OTi^IV(Nc˙³⁻)}˙⁻·solv (2) and (PPN⁺)₂{OTi^IV(AceTPrzPz⁴⁻)}²⁻·solv (see figure, 3) have been obtained and their optical and magnetic properties are studied.

Valence tautomerism in synthetic models of cytochrome P450

CytP450s have a cysteine-bound heme cofactor that, in its as-isolated resting (oxidized) form, can be conclusively described as a ferric thiolate species. Unlike the native enzyme, most synthetic thiolate-bound ferric porphyrins are unstable in air unless the axial thiolate ligand is sterically protected. Spectroscopic investigations on a series of synthetic mimics of cytP450 indicate that a thiolate-bound ferric porphyrin coexists in organic solutions at room temperature (RT) with a thiyl-radical bound ferrous porphyrin, i.e., its valence tautomer. The ferric thiolate state is favored by greater enthalpy and is air stable. The ferrous thiyl state is favored by entropy, populates at RT, and degrades in air. These ground states can be reversibly interchanged at RT by the addition or removal of water to the apolar medium. It is concluded that hydrogen bonding and local electrostatics protect the resting oxidized cytP450 active site from degradation in air by stabilizing the ferric thiolate ground state in contrast to its synthetic analogs.