Paramagnetic {[Fe(CO)2]2-µ2-η2:η2-η2:η2-(C60)2}2- Dimer Bridged by Iron Atoms and C-C Bonds: Effect of Starting Iron Carbonyls on Structures and Properties of Negatively Charged Iron-Bridged Fullerene Dimers.

The reaction between an excess of Fe(CO)5 with {Cryptand(K+)}(C60•-) produced the salt {Cryptand(K+)}2{[Fe(CO)2]2-µ2-η2:η2-η2:η2-(C60)2}2-·4C6H4Cl2 (1) containing negatively charged iron-bridged fullerene dimers. In these dimers, the C60 cages are linked via two Fe(CO)2 fragments, forming short Fe-C(C60) bonds with a length of 2.070(3) Å and via two intercage C-C bonds with a length of 1.566(3) Å. Interfullerene center-to-center distance is short, being 9.02 Å. Thus, the coordination-induced dimerization of fullerenes is observed in 1. The dimer is negatively charged, with additional negative electron density mainly localized on iron atoms and, to a lesser extent, on the C60 cages, as revealed by optical and electron paramagnetic resonance spectra. These dimers have a diamagnetic singlet ground state with a small singlet-triplet gap of 25 K; consequently, they transfer to a paramagnetic state with two S = 1/2 spins per dimer above 50 K. Previously, different dimers with isomeric structures were obtained starting from {Cryptand(K+)}(C60•-) and Fe3(CO)12. However, these dimers exhibit diamagnetic properties, owing to the formation of a Fe-Fe bond. In contrast, in dimer 1, the Fe atoms are positioned too far apart to form such a bond, preserving the spin on Fe. We assume that both dimers are formed through the same [Fe(CO)3](C60•-) intermediate, but the subsequent interaction of this intermediate with Fe3(CO)12 or its dimerization yields different dimers. Therefore, the starting carbonyls can control the structures and properties of the resulting dimers.

Magnetic behavior and ground spin states for coordination {L·[MII(Hal)2]3}3- assemblies (Hal = Cl or I) of radical trianion hexacyanohexaazatriphenylenes (L) with three coordinated high-spin FeII (S = 2) or CoII (S = 3/2) centers.

A series of trianion assemblies of hexaazatriphenylenehexacarbonitrile {HAT(CN)6} and hexaazatrinaphthylenehexacarbonitrile {HATNA(CN)6} with three Fe(II) or Co(II) ions: {cryptand(K+)}3·{HATNA(CN)6·(FeIII2)3}3-·2C6H4Cl2 (1), {cryptand(K+)}3·{HATNA(CN)6·(CoIII2)3}3-·2C6H4Cl2 (2), and (CV+)3·{HAT(CN)6·(CoIICl2)3}3-·0.5(CVCl)·2.5C6H4Cl2 (3) are synthesized (CVCl = crystal violet). Salt 1 has a χMT value of 9.80 emu K mol-1 at 300 K, indicating a contribution of three high-spin FeII (S = 2) and one S = 1/2 of HATNA(CN)6˙3-. The χMT value increases with cooling up to 12.92 emu K mol-1 at 28 K, providing a positive Weiss temperature of +20 K. Such behavior is described using a strong antiferromagnetic coupling between S = 2 and S = 1/2 with J1 = -82.1 cm-1 and a weaker FeII-FeII antiferromagnetic coupling with J2 = -7.0 cm-1. As a result, the spins of three Fe(II) ions (S = 2) align parallel to each other forming a high-spin S = 11/2 system. Density functional theory (DFT) calculations support a high-spin state of CoII (S = 3/2) for 2 and 3. However, the χMT value of 2 and 3 is 2.25 emu K mol-1 at 300 K, which is smaller than 6 emu K mol-1 calculated for the system with three independent S = 3/2 and one S = 1/2 spins. In contrast to 1, the χMT values decrease with cooling to 0.13-0.36 emu K mol-1 at 1.9 K, indicating that spins of cobalt atoms align antiparallel to each other. Data fitting using PHI software for the model consisting of three high-spin Co(II) ions and an S = 1/2 radical ligand shows very large CoII-L˙3- coupling for 2 and 3 with J1 values of -442 and -349 cm-1. The CoII-CoII coupling via the ligand (J2) is also large, being -100 and -84 cm-1, respectively, which is more than 10 times larger than that of 1. One of the reasons for the J2 increase may be the shortening of the Co-N(L) bonds in 3 and 2 to 2.02(2) and 1.993(12) Å. DFT calculations support the population of the quartet state for the Co3 system, whereas the high-spin decet (S = 9/2) state is positioned higher by 680 cm-1 and is not populated at 300 K. This is explained by the large CoII-CoII coupling. Thus, a balance between J1 and J2 couplings provides parallel or antiparallel alignment of the FeII and CoII spins, leading to high- or low-spin ground states of {L·[MII(Hal)2]3}3-.

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.

Synthesis, X-ray Structures, and Optical and Magnetic Properties of Cu(II) Octafluoro-octakisperfluoro(isopropyl)phthalocyanine: The Effects of Electron Addition and Fluorine Accretion.

The stepwise reduction of copper(II) 1,4,8,11,15,18,22,25-octafluoro-2,3,9,10,16,17,23,24-octakisperfluoro(isopropyl) phthalocyanine (CuIIF64Pc) in o-dichlorobenzene (C6H4Cl2) by potassium graphite in the presence of cryptand(K+), abbreviated L+, results in the formation of (L+)[CuII(F64Pc•3-)]-·2C6H4Cl2 (1), (L+)2[CuII(F64Pc4-)]2-·C6H4Cl2 (2), and (L+)2[CuII(F64Pc4-)]2- (3) complexes. Single-crystal X-ray structures revealed their composition and a monotonic increase with increased phthalocyanine (Pc) negative charges of the magnitude of alternative shortening and elongation of the prior equivalent Nmeso-C bonds. The complexes are separated by bulky i-C3F7 substituents, large cryptand counterions, and solvent molecules. Weak, new bands are generated in the visible and near-infrared (NIR) domains upon reductions. The one-electron reduced complex, [CuII(F64Pc•3-)]-, is a diradical, exhibiting broad electron paramagnetic resonance (EPR) signals, with intermediate parameters between those typical to CuII and F64Pc•3-. The two-electron reduced complexes, [CuII(F64Pc4-)]2-, contain a diamagnetic F64Pc4- macrocycle and a single spin, S = 1/2, on CuII. The bulky perfluoroisopropyl groups are suppressing intermolecular π-π interactions between Pcs in the [CuII(F64Pcn-)](n-2)- (n = 3, 4) anions, 1-3, similar to the case of the nonreduced complex. However, π-π interactions between 1 and o-dichlorobenzene are observed. The d9 and Pc electrons in 1 are antiferromagnetically coupled, J = -0.56 cm-1, as revealed by superconducting quantum interference device (SQUID) magnetometry, but the coupling is at least 1 order of magnitude smaller compared with the coupling observed for CuII(F8Pc•3-) and CuII(F16Pc•3-), a testimony to the F accretion effect of rendering the Pc macrocycle progressively more electron-deficient. The data for CuII(F64Pc) provide structural, spectroscopic, and magnetochemical insights, which establish a trend of the effects of fluorine and charge variations of fluorinated Pcs within the macrocycle series CuII(FxPc), x = 8, 16, 64. Diamagnetic Pcs might be useful for photodynamic therapy (PDT) and related biomedical applications, while the solvent-processable biradicalic nature of the monoanion salts may constitute the basis for designing robust, air-stable electronic, and magnetically condensed materials.

Negatively Charged Iron-Bridged Fullerene Dimer {Fe(CO)2-µ2-η2,η2-C60}22.

The interaction of {Cryptand(K+)}(C60•-) with Fe3(CO)12 produced {Cryptand(K+)}2{Fe(CO)2-µ2-η2,η2-C60}22-·2.5C6H4Cl2 (1) as the first negatively charged iron-bridged fullerene C60 dimer. The bridged iron atoms are coordinated to two 6-6 bonds of one C60 hexagon with short and long C(C60)-Fe bonds with average lengths of 2.042(3) and 2.088(3) Å. Fullerenes are close to each other in the dimer with a center-to-center interfullerene distance of 10.02 Å. Optical spectra support the localization of negative electron density on the Fe2(CO)4 units, which causes a 50 cm-1 shift of the C≡O vibration bands to smaller wavenumbers, and the C60 cages. Dimers are diamagnetic and electron paramagnetic resonance silent and have a singlet ground state resulting from the formation of an Fe-Fe bond in the dimer with a length of 2.978(4) Å. According to density functional theory calculations, the excited triplet state is higher than the ground state by 6.5 kcal/mol. Compound 1 shows a broad near-infrared band with a maximum at 970 nm, which is attributable to the charge transfer from the orbitals localized mainly on iron atoms to the C60 ligand.

Crystalline paramagnetic supramolecular 2D-polymer of the tetra(4-pyridyl)porphyrin and terbium(III) complex.

A new promising method for the preparation of crystalline 2D polymers based on tetra(4-pyridyl)porphyrin has been developed. Radical anion {H2T(4-Py)P˙-} species are used as the starting material. A new solid-state supramolecular array [{H2T(4-Py)P}·{TbIII(TMHD)3}2]·2.84C6H14 (1) in which porphyrin units are bridged with TbIII ions to form a self-assembled 2D polymer has been obtained. The complex contains neutral porphyrin macrocycles, which is supported by optical and magnetic data. High-spin paramagnetic TbIII ions are weakly antiferromagnetically coupled in accordance with rather long distances between them.

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 MnIIPc, FeIIPc or FeIIPcCl16 with KCN in the presence of cryptand[2.2.2] yielded dicyano-complexes {cryptand(K+)}2{MII(CN)2(macrocycle2-)}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{MII(CN)2Pc·(ML)2}2-·nC6H4Cl2 (MII = MnII and FeII; n = 1, 4 and 5). These assemblies were formed via coordination of two manganese(II) acetylacetonate (ML = MnII(acac)2, S = 5/2), tris(cyclopentadienyl)gadolinium (ML = Cp3GdIII, S = 7/2) or tris(cyclopentadienyl)neodymium (ML = Cp3NdIII, S = 3/2) units to the nitrogen atoms of bidentate cyano ligands. The N(CN)-Mn{MnII(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{MnII(CN)2Pc·(MnII(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 {MnII(CN)2Pc·(MnII(acac)2)2}2- dianions at 2 K. The estimated exchange interaction between MnII (S = 1/2) and GdIII (S = 7/2) spins in {MnII(CN)2Pc·(Cp3GdIII)2}2- is only -1.1 cm-1, and in contrast to 2, nearly independent GdIII and MnII centers are formed. As a result, no transition to the high-spin state is observed in {MnII(CN)2Pc·(Cp3GdIII)2}2-. The {MnII(CN)2Pc·(Cp3NdIII)2}2- and{FeII(CN)2Pc·(Cp3NdIII)2}2- dianions with Cp3NdIII show a decrease of χMT values in the whole studied temperature range (300-1.9 K). A similar behaviour was found previously for pristine Cp3NdIII and Cp3NdIII·L complexes (L = alkylisocyanide ligand).

Strong Proton-Electron Coupling in π-Planar Metal Complex with Redox-Active Ligands.

Proton-coupled electron transfer (PCET) of metal complexes has been widely studied, especially in biochemistry and catalytic chemistry. Although metal complexes bearing redox-active ligands play a part in these research areas, those with π-planar structure remain entirely unexplored, which are vital for future development of iono-electronics. Here, proton-electron coupling of a π-planar nickel complex bearing redox-active N,S-ligands, Ni(itsq)2 , was investigated by combining experimental and theoretical approaches. Strong proton-electron coupling was manifested in a large potential shift, which is twice greater than that of a typical PCET-type π-planar metal complex with redox-inactive ligands, [Ni(dcpdt)2 ]2- . Theoretical calculations affirmed that the stabilization of frontier orbitals by protonation is greater in Ni(itsq)2 than that in [Ni(dcpdt)2 ]2- . These results indicate that π-planar metal complexes with redox-active ligands are promising for developing novel PCET-type materials.

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 {SnII(Pc2-)}0 or radical anion {SnII(Pc˙3-)}- states is reported. Direct interaction of Co4(CO)12 with {SnII(Pc2-)}0 yields a crystalline complex {Co4(CO)11·SnII(Pc2-)} (1). There is no charge transfer from the cluster to phthalocyanine in 1, which preserves the diamagnetic Pc2- macrocycle. The Ru3(CO)12 cluster forms complexes with one or two equivalents of {SnII(Pc˙3-)}- to yield crystalline {Cryptand[2.2.2](Na+)}{Ru3(CO)11·SnII(Pc˙3-)}- (2) or {Cryptand[2.2.2](M+)}2{Ru3(CO)10·[SnII(Pc˙3-)]2}2-·4C6H4Cl2 (3) (M+ is K or Cs). Paramagnetic {SnII(Pc˙3-)}- species in 2 are packed in π-stacking [{SnII(Pc˙3-)}-]2 dimers, providing strong antiferromagnetic coupling of spins with exchange interaction J/kB = -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 {SnIVCl2(Pc2-)}0 yield a series of complexes with high-spin Cp*2Cr+ counter cations (S = 3/2): (Cp*2Cr+){Ru3(CO)11·SnII(Pc˙3-)}-·C6H4Cl2 (4), (Cp*2Cr+){Os3(CO)10Cl·SnII(Pc˙3-)}-·C6H4Cl2 (5) and (Cp*2Cr+){Ir4(CO)11·SnII(Pc˙3-)}2- (6). It is seen that reduced clusters are oxidized by SnIV, which is transferred to SnII, whereas the Pc2- 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 OsI center. Rather weak magnetic coupling is observed between paramagnetic Cp*2Cr+ and {SnII(Pc˙3-)}- species in 4, but this exchange interaction is enhanced in 5 owing to Os3(CO)10Cl clusters with paramagnetic OsI (S = 1/2) also being involved in antiferromagnetic coupling of spins. The formation of {SnII(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 Nmeso-C bond alternation in Pc (for 3-5). On the whole, this work shows that both diamagnetic {SnII(Pc2-)}0 and paramagnetic {SnII(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.

Weak Antiferromagnetic Exchange and Ferromagnetic Alignment of FeII (S=2) Spins in Differently Charged {HAT ⋠(FeII Cl2 )3 }n (n=2- and 3-) Assemblies of Hexaazatriphenylenes (HAT).

Hexaazatrianthracene (HATA) and hexaazatriphenylenehexacarbonitrile {HAT(CN)6 } are reduced by metallic iron in the presence of crystal violet (CV+ )(Cl- ). Anionic ligands are produced, which simultaneously coordinate three FeII Cl2 to form (CV+ )2 {HATA ⋅ (FeII Cl2 )3 }2- ⋅ 3 C6 H4 Cl2 (1) and (CV+ )3 {HAT(CN)6. (FeII Cl2 )3 }3- ⋅ 0.5CVCl ⋅ 2.5 C6 H4 Cl2 (2). High-spin (S=2) FeII atoms in both structures are arranged in equilateral triangles at a distance of 7 Å. An antiferromagnetic exchange is observed between FeII in {HATA ⋅ (FeII Cl2 )3 }2- (1) with a Weiss temperature (Θ) of -80 K, the PHI estimated exchange interaction (J) is -4.7 cm-1 . The {HAT(CN)6 ⋅ (FeII Cl2 )3 }3- assembly is obtained in 2. The formation of HAT(CN)6 .3- is supported by the appearance of an intense EPR signal with g=2.0037. The magnetic behavior of 2 is described by a strong antiferromagnetic coupling between the FeII and HAT(CN)6 .3- spins with J1 =-164 cm-1 (-2 J formalism) and by a weaker antiferromagnetic coupling between the FeII spins with J2 =-15.4 cm-1 . The stronger coupling results in the spins of the three FeII Cl2 units to be aligned parallel to each other in the assembly. As a result, an increase of the χM T values is observed with the decrease of temperature from 9.82 at 300 K up to 15.06 emu ⋅ K/mol at 6 K, and the Weiss temperature is also positive being at +23 K. Thus, a change in the charge and spin state of the HAT-type ligand to ⋅3- results in ferromagnetic alignment of the FeII spins, yielding a high-spin (S=11/2) system. DFT calculations showed that, due to the high symmetry and nearly degenerated LUMO of both HATA and HAT(CN)6 , their complexes with FeII Cl2 have a variety of closely lying excited high-spin states with multiplicity up to S=15/2.

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{CuII(TPP4-)}2- (1) and {cryptand(Cs+)}{NiI(TPP2-)}-·C6H5CH3 (2) have been obtained. The two-electron reduction of {CuII(TPP2-)}0 is centered on the macrocycle allowing one to study for the first time the structure and properties of the TPP4- tetraanions in the solid state. Tetraanions have a diamagnetic state and show essential C-Cmeso bond alternation. New bands attributed to TPP4- appear at 670, 770 and 870 nm. Unpaired S = 1/2 spin is localized on CuII. The one-electron reduction of {NiII(TPP2-)}0 centered on nickel provides the formation of {NiI(TPP2-)}- with unpaired S = 1/2 spin localized on NiI at 100(2) K. The effective magnetic moment of 2 is 1.68µB at 120 K and a broad asymmetric EPR signal characteristic of NiI is observed for 2 and also for (Bu3MeP+){NiI(TPP2-)}-·C6H5CH3 (3) in the 4.2-120 K range. Since dianionic TPP2- macrocycles are present at 100(2) K, no alternation of C-Cmeso 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 NiI to the macrocycle takes place resulting in the formation of NiII with S = 1 and TPP˙3- with S = 1/2 in the {NiII(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 NiII(TPP2-) and FeII(TPP2-) by cesium anthracenide in the presence of Bu3MeP+ yields crystals of 3 and (Bu3MeP+){FeI(TPP2-)}-·C6H5CH3 (4) whose crystal structures and optical properties are also presented. DFT calculations have been carried out for {MII(TPP2-)} (M = Cu, Ni and Fe) and their anions to interpret the experimental results obtained for 1-4.

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 MII3O clusters inside a π-extended trianionic (Hhp3-) macrocycle have been prepared. Studies of the magnetic properties of NiII3O(Hhp) and CuII3O(Hhp) reveal a diamagnetic and EPR-silent trianionic (Hhp3-) macrocycle and diamagnetic NiII3(O2-) or paramagnetic CuII3(O2-) tetracations. The positive charge of MII3O(Hhp) is compensated by one acetate anion {MII3O(Hhp)}+(CH3CO2-). The three-electron reduction of {MII3O(Hhp)}+ yields {cryptand(Cs+)}2{NiII2NiIO(Hhp5-)}2-·2C7H8 (1) and {cryptand(Cs+)}2{CuII3O(Hhp•6-)}2-·C7H8 (2) crystalline salts. The magnetic properties of 1 reveal the formation of Hhp5- and the reduction of nickel(II) to the paramagnetic NiI ion (S = 1/2), which is accompanied by the formation of the {NiII2NiIO(Hhp5-)}2- dianion. As a result, the magnetic moment of 1 is 1.68 µB in the 20-220 K range, and a broad EPR signal of NiI was observed. The Hhp5- 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 Hhp5-. The {NiII2NiIO(Hhp5-)}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 CuII3(O2-) cluster (S = 1/2) in the {CuII3O(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.

Emergence of Metallic Conduction and Cobalt(II)-Based Single-Molecule Magnetism in the Same Temperature Range.

Single-molecule magnets exhibit magnetic bistabililties at the molecular level, making them promising for molecule-based spintronics due to high magnetic densities. The incorporation of SMM behavior and electrical conductivity in one compound is rare because these two physical properties often do not operate in the same temperature range, which further hinders their use in practical applications. Here we present an organic-inorganic molecular hybrid, ß″-(BEDO-TTF)3[Co(pdms)2]·(MeCN)(H2O)2 (BO3) (BEDO-TTF = bis(ethylenedioxy)tetrathiafulvalene and H2pdms = 1,2-bis(methanesulfonamido)benzene), which manifests both metallic conduction (electrical conductivity up to 1000 S cm-1 at 12 K under 2.0 gigapascal pressure) and SMM behavior in the temperature range 12-26 K for the first time.

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

The reduction of copper(ii) octafluoro- {CuII(F8Pc)} and hexadecafluorophthalocyanines {CuII(F16Pc)} by NaCpCo(CO)2 in the presence of cryptand[2.2.2] yields new crystalline {cryptand(Na+)}[CuII(F8Pc)˙3-]-·2C6H4Cl2 (1) and {cryptand(Na+)}2[CuII(F16Pc)4-]2-·C6H14 (2) salts. Together with two previously characterized salts of CuII(FxPc) (x = 8 and 16), this allows the study of the molecular structure and optical and magnetic properties of fluorinated copper phthalocyanines in different reduction states (-1 and -2). The blue shift of the Q-band increases together with the negative charge on the macrocycle, and new weak bands of the anions appear at 820-1013 nm. Alternation of the Nmeso-C bonds manifests itself in reduced macrocycles due to a partial disruption of macrocycle aromaticity. In the case of CuII(F8Pc) this effect is nearly two times stronger for dianions than for monoanions. The alternation of the bonds is less pronounced for perfluorinated CuII(F16Pc)n- (n = 1, 2) anions most probably due to a partial delocalization of the negative charge on fluoro-substituents. The reduction also noticeably elongates the average C-F bonds in CuII(F8Pc). The first reduction centered on the macrocycle leads to the formation of [CuII(F8Pc)˙3-]- in 1 with two S = 1/2 spins positioned on CuII and the radical trianion (F8Pc)˙3- macrocycle. As a result, a broad EPR signal is observed with g = 2.1652 at RT attributable to both paramagnetic species having exchange interactions. The formation of dimerized stacks from [CuII(F8Pc)˙3-]- in 1 results in strong enough magnetic coupling of the (F8Pc)˙3- spins within the dimers (J/kB = -21.8 cm-1), and weaker intramolecular coupling is observed between CuII and (F8Pc)˙3- (J/kB = -10.8 cm-1). Coupling between (F8Pc)˙3- spins from the neighboring dimers is nearly 1.5 times weaker (-14.6 cm-1). Under reduction conditions, a second electron also comes to the macrocycle forming diamagnetic F16Pc4- tetraanions. In this case S = 1/2 spin is preserved on CuII. Magnetic coupling between these centers is weak due to the long distances between them in the [CuII(F8Pc)4-]2- chains of 2. Salt 2 shows an EPR signal with a HF splitting characteristic of CuII with g∥ = 2.1806 (A∥ = 20.11 mT), and g⊥ = 1.9597 at RT.

Solid-State Properties of Hexaazatriphenylenehexacarbonitrile HAT(CN)6 .- Radical Anions in Crystalline Salts Containing Cryptand(M+ ) and Crystal Violet Cations.

Crystalline {Cryptand[2.2.2](Na+ )}{HAT(CN)6 .- }⋅0.5C6 H4 Cl2 (1), {Cryptand[2.2.2](K+ )}{HAT(CN)6 .- } (2), (CV+ ){HAT(CN)6 .- } (3), and (CV+ ){HAT(CN)6 .- }⋅2C6 H4 Cl2 (4) salts (where CV+ is the crystal violet cation) containing hexaazatriphenylenehexacarbonitrile radical anions have been obtained. The solid-state molecular structure as well as the optical and magnetic properties of HAT(CN)6 .- are studied. The formation of HAT(CN)6 .- in 1-4 leads to the appearance of new bands in the visible range, at 694 and 740 nm. The HAT(CN)6 .- radical anions have spin state S=1/2 and are packed in one-dimensional stacks containing the {HAT(CN)6 .- }2 dimers alternated with weaker interacting pairs of HAT(CN)6 .- in 1 and nearly isolated {HAT(CN)6 .- }2 dimers in 2. The {HAT(CN)6 .- }2 dimers are diamagnetic in 1 but they effectively mediate one-dimensional antiferromagnetic coupling of spins within the stacks with moderate exchange interaction of J/kB = -80 K. The behaviour of salt 2 is described by a singlet-triplet model for the {HAT(CN)6 .- }2 dimers with an energy gap of 434(±7) K. Magnetic behaviour of both salts agree well with the data of extended Hückel calculations. Salts 3 and 4 contain isolated stacks of alternated HAT(CN)6 .- and CV+ ions, and in this case, nearly paramagnetic behaviour is observed with Weiss temperatures of -1 and -7 K, respectively. Narrow Lorentzian EPR signals with g = 2.0033-2.0039 were found for the HAT(CN)6 .- radical anions in 1 and 4 but in solution g-factor shifts to 1.9964. The electronic structure of HAT(CN)6 .- is analysed based on X-ray diffraction data for 2, showing a Jahn-Teller distortion of the radical anion that reduces the symmetry from D3h to Cs and splits the initially degenerated LUMOs.

Decacyclene Radical Anions Showing Strong Low-energy Intramolecular Absorption and Magnetic Coupling of Spins in a Hexagonal Network.

Two salts of the aromatic hydrocarbon decacyclene, {cryptand[2.2.2](Cs+ )} (decacyclene.- ) (1) and {Bu3 MeP+ }(decacyclene.- ) (2), were obtained. In both salts, decacyclene.- radical anions formed channels occupied by cations. However, corrugated hexagonal decacyclene.- layers could be outlined in the crystal structure of 1 with several side-by-side C⋅⋅⋅C approaches. The decacyclene.- radical anions showed strong distortion in both salts, deviating from the C3 symmetry owing to the repulsion of closely arranged hydrogen atoms and the Jahn-Teller effect. Radical anions showed intense unusually low energy absorption in the IR-range, with maxima at 4800 and 6000 cm-1 . According to the carculations, these bands can originate from the SOMO-LUMO+1 and SOMO-LUMO+2 transitions, respectively. Radical anions exhibited a S=1/2 spin state, with an effective magnetic moment of 1.72 µB at 300 K. The decacyclene.- spin antiferromagnetically coupled with a Weiss temperature of -11 K. Spin ordering was not observed down to 1.9 K owing to spin frustration in the hexagonal decacyclene.- layers.

Strong magnetic coupling of spins in Fe(ii) dimers with differently charged thioindigo ligands.

A first coordination {[2.2.2]cryptand(K+)}2{FeII(TI˙-)(TI2-)}2·2C6H4Cl2 (1) complex of iron(ii) containing radical anions and dianions of thioindigo (TI) was obtained. The complex has two high-spin FeII centers bound by two oxygen atoms, and the TI˙- radical anions are coordinated to each FeII. As a result, the 4-spin system consisting of TI˙- (S = 1/2)-FeII (S = 2)-FeII (S = 2)-TI˙- (S = 1/2) coupled spins is formed within a dimer with strong FeII-FeII (J = -51.1 cm-1) and weaker FeII-TI˙- interactions of (J = -35.4 cm-1).

Cleavage of the C-H Bond in Bu3MeP+ by Zinc Porphyrin Dianions: Formation of {ZnII(CH2PBu3)(TPyPH)}- Containing Zn-C(ylide) Bond and the (TPyPH)3- Macrocycle Showing Strong NIR Absorption.

Reduction of {ZnII(TPyP)} to the {ZnII(TPyP)}2- dianions (TPyP: tetra(4-pyridyl)porphyrin) in the presence of Bu3MeP+ allows one to observe the C-H bond cleavage in the methyl group of Bu3MeP+ to form (Bu3MeP+){ZnII(CH2PBu3)(TPyPH)}-·0.337C6H5CH3 (1). Salt 1 is the first coordination complex of neutral CH2PBu3 ylide and metalloporphyrin. The released hydrogen atom attacks the meso-carbon atom of TPyP4- forming a TPyPH3- macrocycle related to phlorins. Decreased symmetry of the TPyPH3- allows the observation of a strong NIR absorption. We discuss the molecular structure, optical, and magnetic properties of 1 together with its formation pathways.

Simultaneous manifestation of metallic conductivity and single-molecule magnetism in a layered molecule-based compound.

Single-molecule magnets (SMMs) show superparamagnetic behaviour below blocking temperature at the molecular scale, so they exhibit large magnetic density compared to the conventional magnets. Combining SMMs and molecular conductors in one compound will bring about new physical phenomena, however, the synergetic effects between them still remain unexplored. Here we present a layered molecule-based compound, ß''-(BEDO-TTF)4 [Co(pdms)2]·3H2O (BO4), (BEDO-TTF (BO) and H2pdms are bis(ethylenedioxy)tetrathiafulvalene and 1,2-bis(methanesulfonamido)benzene, respectively), which was synthesized by using an electrochemical approach and studied by using crystal X-ray diffraction. This compound simultaneously exhibited metallic conductivity and SMM behaviour up to 11 K for the first time. The highest electrical conductivity was 400-650 S cm-1 at 6.5 K, which is the highest among those reported so far for conducting SMM materials. Furthermore, antiferromagnetic ordering occurred below 6.5 K, along with a decrease in conductivity, and the angle-independent negative magnetoresistance suggested an effective electron correlation between the conducting BO and Co(pdms)2 SMM layers (d-π interactions). The strong magnetic anisotropy and two-dimensional conducting plane play key roles in the low-temperature antiferromagnetic semiconducting state. BO4 is the first compound exhibiting antiferromagnetic ordering among SMMs mediated by π-electrons, demonstrating the synergetic effects between SMMs and molecular conductors.

Double-Decker Paramagnetic {(K)(H3 Hhp)2 }⋠2- Radical Dianions Comprising Two [30]Trithia-2,3,5,10,12,13,15,20,22,23,25,30-Dodecaazahexaphyrins and a Potassium Ion.

Reduction of free-base [30]trithia-2,3,5,10,12,13,15,20,22,23,25,30-dodecaazahexaphyrin (H3 Hhp) yields {cryptand[2.2.2](K)}2 {(K)(H3 Hhp)2 }⋅4C6 H4 Cl2 (1) containing double-decker {(K)(H3 Hhp)2 }⋅2- radical dianions, whose structure was elucidated using X-ray diffraction. Potassium ion forms 12 short (K+ )⋅⋅⋅N(H3 Hhp) contacts with two H3 Hhp macrocycles in the 3.048-3.157 Šrange. Dianions have S=1/2 spin state manifesting an effective magnetic moment of 1.64 µB at 300 K and a narrow Lorentzian electron paramagnetic resonance signal. Quantum chemical calculations support the ionic nature of the (K+ )-N(H3 Hhp) interactions and the nearly equal distribution of the -1.5 charge over each macrocycle. H3 Hhp takes the role of an aza-crown ether in free-base reduced state and forms a new type of double-decker complex.