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A new series of multicomponent compounds containing the cation [Co(NH3)6]3+ and various organic N-, N,O-, and O-donor moieties has been synthesized and crystallized. The series involves [Co(NH3)6]Cl3·2(phen)·3H2O (1), [Co(NH3)6](Hbdc)(bdc)·3H2O (2), [Co(NH3)6]Cl2(Hpht)·3H2O (3), [Co(NH3)6]Cl(Hpht)2·3H2O (4), [Co(NH3)6]Cl(2,3-pdc)·H2O (5), [Co(NH3)6]11[Co(2,5-pdc)3]8Cl·84H2O (6), [Co(NH3)6][Co(3,5-pdc)2(H2O)4]Cl·3H2O (7), [Co(NH3)6]Cl(sb)·4H2O (8), and [Co(NH3)6]2(sb)3·EtOH·2.5H2O (9) (where phen = 1,10-phenanthroline, H2bdc = diphenyl-4,4′-dicarboxylic acid, H2pht = o-phthalic acid, H2pdc = 2,3-/2,5-/3,5-pyridinedicarboxylic acid, H2sb = 4-sulfobenzoic acid). Single crystal X-ray diffraction studies have revealed that in these compounds the [Co(NH3)6]3+ cation serves as a building block for the incorporation of various anions/molecules and promotes the formation of multicomponent compounds with extended charge-supported networks between cations and anions and others such as H-bonds between charged⋯neutral and neutral⋯neutral components as well as π–π stacking interactions. In addition to the [Co(NH3)6]3+ cations, compounds 1–9 contain in changing composition Cl−, deprotonated phthalate, diphenyldicarboxylate, pyridinedicarboxylate, and sulfonate anions or complex [Co(2,5-pdc)3]4− and [Co(3,5-pdc)2(H2O)4]2− anions, as well as neutral 1,10-phenanthroline and ethanol and water molecules as components of the crystallization. Hirshfeld surface analysis was also performed to discuss the strength of hydrogen bonds and to quantify the inter-contacts. Energy decomposition analysis of the intermolecular interaction energy was performed using the SAPT method to study the non-covalent bonding interactions of [Co(NH3)6]3+ cations with mono-, dianions and neutral molecules, and it was found that the calculated bonding energy for compound 1 is minimal. Compounds 1–9 were tested in vitro against Rhizobium (Agrobacterium) vitis, an oncogenic bacterium that causes tumor formation in plants. Compound 1, comprising hexaammine cobalt(III) chloride and 1,10-phenanthroline, showed the highest inhibitory potential and is thus qualified for an application against bacterial cancer in plants.

A series of bis(triphenylamine)benzodifuran chromophores have been synthesized and fully characterised. Starting from suitably functionalized benzodifuran (BDF) precursors, two triphenylamine (TPA) moieties are symmetrically coupled to a central BDF unit either at 4,8-positions through double bonds (1) and single bonds (2) respectively, or at 2,6-positions through double bonds (3). Their electronic absorption and photoluminescence properties as well as redox behaviour have been investigated in detail, indicating that the π-extended conjugation via vinyl linkers in 1 and 3 leads to comparatively strong electronic interactions between the relevant redox moieties TPA and BDF. Due to intriguing electronic properties and structural planarity, 3a has been applied as a dopant emitter in organic light-emitting diodes. A yellowish-green OLED exhibits a high external quantum efficiency (EQE) of 6.2%, thus exceeding the theoretical upper limit most likely due to energy transfer from an interface exciplex to an emissive layer and/or favorable horizontal orientation.

In the field of molecular nanoclusters, cubane and defect-dicubane, or butterfly structures, are typical examples of tetranuclear metal core architectures. In this work, a halogenated and anionic Schiff-base ligand (L2–) is utilized as it is predisposed to chelate within a cluster core to both 3d and 4f metal ions, in different binding configurations (H2L = 4-chloro-2-(2-hydroxy-3-methoxybenzyliden amino)phenol). The phenolate oxygen atoms of the deprotonated ligand can act in μ-O and μ3-O bridging binding modes for the intramolecular assembly of metal ions. Based on that, two tetranuclear and isostructural compounds [Ni2Tb2(L)4(NO3)2(DMF)2]·2CH3CN (1) and [Ni2Er2(L)4(NO3)2(DMF)2]·0.5CH3CN (2) were synthesized and structurally characterized. Magnetic susceptibility and magnetization data indicate the occurrence of dominant intramolecular ferromagnetic interactions between the spin centers. Particular emphasis is given to the theoretical description of the magnetic behavior, taking into account the Ln–Ni and Ni–Ni coupling paths and the magnetic anisotropy of the LnIII and NiII ions. The study is distinguished for its discussion of two distinct models, whereby model A relies on the uniaxial B20 Stevens term describing the lanthanide anisotropy and model B is based on point-charge model calculations. Importantly, the physical meaning of the obtained parameters for both models was critically scrutinized.

Graphene films have attracted a lot attention due to their potential application in nanoelectronic devices. Noncovalent functionalization of graphene does not disrupt the extended π-conjugation. Incorporation of intercalators in the form of redox- and/or photoactive building blocks enables the usage of electron donor-acceptor (D–A) interactions. Accordingly, the noncovalent functionalization of nanographene (NG) or graphene sheets with either aromatic electron donors or acceptors, as demonstrated in the case of carbon nanotubes, is widely exploited in contemporary research. Herein, we report the exfoliation of graphite via intercalation and immobilization of planar pi-conjugates tetrathiafulvalene–perylenediimide (TTF–PDI). The resultant nanohybrids have been characterized by complementary spectroscopic and microscopic techniques.

The cubane-type structure is a typical representative of tetranuclear coordination compounds. In this work, two anionic Schiff-base ligands, (L1)2&minus, and (L2)2&minus, each offering an O^N^O coordination pocket, ligate four NiII ions into a [Ni4O4] cubane core. The ligands are H2L1 = 2&minus, [[(3-ethoxy-2&minus, hydroxyphenyl) methylene]amino]benzenemethanol and H2L2 = 2&minus, [[(5-fluoro-2&minus, hydroxyphenyl)methylene]amino]benzenemethanol. In both compounds, [Ni4(L1)4(EtOH)4] (1) and [Ni4(L2)4(MeOH)4] (2), alkoxy oxygens of the ligands act in a bridging &mu, 3-O binding mode. Magnetic susceptibility and magnetization data for compounds 1 and 2 are presented. The Ni&ndash, O&ndash, Ni bond angles of the cubane core determined from single crystal X-ray diffraction data play a key role for a magneto-structural correlation. Dominant intracube ferromagnetic behavior is observed, and the coupling parameters were determined for both compounds, leading to nonzero spin ground states in accordance with the broadly accepted bond angle guideline.

Tetrathiafulvalene(TTF)-fused donor-acceptor (D–A) ensembles are of high interest due to their unique (opto)electronic properties and potential applications in organic conductors, photovoltaics, sensors, switches and molecular electronics. A direct annulation of a TTF with a variety of electron-acceptors has been achieved for studying photo-induced intramolecular charge transfer (ICT) as well as the photogeneration of long-lived charge separated states in resultant D-A systems. Herein, we describe redox and optical properties of a new D–A ensemble (Chart 1) which was prepared by complexation of BF2 with a TTF-fused 2,3-di(1H-2-pyrrolyl)quinoxaline ligand. A detailed experimental and theoretical study of an ICT process in TTF-QB is presented.

Dispersions of preexfoliated nanographene (NG) and fused electron donor–acceptor tetrathiafulvalene–perylenediimide (TTF–PDI) enable multifunctional, noncovalently functionalized NG. They were characterized by complementary spectroscopic and microscopic techniques. The design strategy of the chromophoric and electroactive molecular conjugate renders a large and planar π-extended system with a distinct localization of electron-rich and electron-poor parts at either end of the molecular conjugate. Within the in-situ formed nanohybrid, the conjugate was found to couple electronically with NG preferentially through the electron accepting PDI rather than the electron donating TTF and to lead to p-doping of graphene.

Luminescence and energy transfer in [Zn1-xRux(bpy)3][NaAl1-yCry(ox)3] (x ≈ 0.01, y = 0.006 − 0.22; bpy = 2,2‘-bipyridine, ox = C2O42-) and [Zn1-x-yRuxOsy(bpy)3][NaAl(ox)3] (x ≈ 0.01, y = 0.012) are presented and discussed. Surprisingly, the luminescence of the isolated luminophores [Ru(bpy)3]2+ and [Os(bpy)3]2+ in [Zn(bpy)3][NaAl(ox)3] is hardly quenched at room temperature. Steady-state luminescence spectra and decay curves show that energy transfer occurs between [Ru(bpy)3]2+ and [Cr(ox)3]3- and between [Ru(bpy)3]2+ and [Os(bpy)3]2+ in [Zn1-xRux(bpy)3][NaAl1-yCry(ox)3] and [Zn1-x-yRuxOsy(bpy)3] [NaAl(ox)3], respectively. For a quantitative investigation of the energy transfer, a shell type model is developed, using a Monte Carlo procedure and the structural parameters of the systems. A good description of the experimental data is obtained assuming electric dipole−electric dipole interaction between donors and acceptors, with a critical distance Rc for [Ru(bpy)3]2+ to [Cr(ox)3]3- energy transfer of 15 Å and for [Ru(bpy)3]2+ to [Os(bpy)3]2+ energy transfer of 33 Å. These values are in good agreement with those derived using the Förster−Dexter theory.

In analogy to the [M(II)(bpy)(3)](2+) cations, where M(II) is a divalent transition-metal and bpy is 2,2'-bipyridine, the tris-chelated [M(III)(bpy)(3)](3+) cations, where M(III) is Cr(III) or Co(III), induce the crystallization of chiral, anionic three-dimensional (3D) coordination polymers of oxalate-bridged (&mgr;-ox) metal complexes with stoichiometries [M(II)(2)(ox)(3)](n)()(2)(n)()(-) or [M(I)M(III)(ox)(3)](n)()(2)(n)()(-). The tripositive charge is partially compensated by inclusion of additional complex anions like ClO(4)(-), BF(4)(-), or PF(6)(-) which are encapsulated in cubic shaped cavities formed by the bipyridine ligands of the cations. Thus, an elaborate structure of cationic and anionic species within a polymeric anionic network is realized. The compounds isolated and structurally characterized include [Cr(III)(bpy)(3)][ClO(4)] [NaCr(III)(ox)(3)] (1), [Cr(III)(bpy)(3)][ClO(4)][Mn(II)(2)(ox)(3)] (2), [Cr(III)(bpy)(3)][BF(4)] [Mn(II)(2)(ox)(3)] (3), [Co(III)(bpy)(3)][PF(6)][NaCr(III)(ox)(3)] (4). Crystal data: 1, cubic, P2(1)3, a = 15.523(4) Å, Z = 4; 2, cubic, P4(1)32, a = 15.564(3) Å, Z = 4; 3, cubic, P4(1)32, a = 15.553(3) Å, Z = 4; 4, cubic, P2(1)3, a = 15.515(3) Å, Z = 4. Furthermore, it seemed likely that 1,2-dithiooxalate (dto) could act as an alternative to the oxalate bridging ligand, and as a result the compound [Ni(II)(phen)(3)][NaCo(III)(dto)(3)].C(3)H(6)O (5) has successfully been isolated and structurally characterized. Crystal data: 5, orthorhombic, P2(1)2(1)2(1), a = 16.238(4) Å, b = 16.225(4) Å, c = 18.371(5) Å, Z = 4. In addition, the photophysical properties of compound 1 have been investigated in detail. In single crystal absorption spectra of [Cr(III)(bpy)(3)][ClO(4)][NaCr(III)(ox)(3)] (1), the spin-flip transitions of both the [Cr(bpy)(3)](3+) and the [Cr(ox)(3)](3)(-) chromophores are observed and can be clearly distinguished. Irradiating into the spin-allowed (4)A(2) --> (4)T(2) absorption band of [Cr(ox)(3)](3)(-) results in intense luminescence from the (2)E state of [Cr(bpy)(3)](3+) as a result of rapid energy transfer processes.

A tetrathiafulvalene (TTF)-fused piazselenole as a novel redox-active probe for highly sensitive determination of physiological thiols by electrochemical detection has been synthesised and successfully tested in intracellular non-protein thiol detection, reaching a detection limit of 10−10 M.

A mononuclear Fe(II) complex involving a tetrathiafulvalene-based ligand exhibits thermal spin-crossover (around 143 K) with pronounced hysteresis behaviour (48 K). The chromophoric and π-extended ligand allows Near-Infrared (NIR) sensitization for the light-induced excited spin-state trapping (LIESST) with T(LIESST) = 90 K.

Four new tetrathiafulvalene (TTF)-based dyes featured with a donor–bridge–acceptor (D–π–A) structure were synthesized and characterized. All of them undergo two reversible oxidations to form stable radical cation and dication species. The electronic interactions between the TTF donor and the cyanoacrylic acid acceptor through the different π-linkers have been demonstrated by the presence of a photo-induced intramolecular charge-transfer (ICT) absorption band in the visible region. A red shift of the ICT state can be finely tuned by the degree of aromaticity and extended conjugation of π-bridges. To some extent, the oxidation potentials of these dyes are affected by the nature of π-bridges. They have been applied in organic dye-sensitized solar cells, showing relatively low power conversion efficiencies of up to 0.87% due to substantial charge recombination losses.