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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.

We introduce THz Stark spectroscopy by using intense single-cycle terahertz pulses as the electric field source and monitoring the induced spectral response of an isotropic molecular ensemble with a coincident femtosecond supercontinuum pulse. THz Stark spectroscopy offers several advantages over conventional Stark spectroscopy and opens previously inaccessible perspectives. Most importantly, THz pulses oscillate faster than typical molecular rotations and consequently eliminate the requirement to freeze the samples to prevent poling effects. Hence, THz Stark spectroscopy allows for time-resolved studies at arbitrary temperatures, specifically ambient conditions more relevant to physiological or operative conditions. Moreover, dynamical field effects, e.g., higher order Stark contributions or hysteresis effects (non-Markovian behavior), can be studied on the time scales of molecular vibrations or rotations. We demonstrate THz Stark spectroscopy for two judiciously selected molecular systems and compare the results to conventional Stark spectroscopy and first principle calculations.

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.

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.

An efficient synthetic approach to a symmetrically functionalized tetrathiafulvalene (TTF) derivative with two diamine moieties 2 [56 diamino 47 bis(4 pentylphenoxy) 13 benzodithiol 2 ylidene] 47 bis(4 pentylphenoxy) 13 benzodithiole 56 diamine (2) is reported. The subsequent Schiff base reactions of 2 afford large p conjugated multiple donor–acceptor (D–A) arrays for example the triad 2 [49 bis(4 pentylphenoxy) 13 dithiolo[45 g]quinoxalin 2 ylidene] 49 bis(4 pentylphenoxy) 13 dithiolo[45 g]quinoxaline (8) and the corresponding tetrabenz[bcefhiuv]ovalene fused pentad 1 in good yields and high purity. The novel redox active nanographene 1 is so far the largest known TTF functionalized polycyclic aromatic hydrocarbon (PAH) with a well resolved 1H NMR spectrum. The electrochemically highly amphoteric pentad 1 and triad 8 exhibit various electronically excited charge transfer states in different oxidation states thus leading to intense optical intramolecular charge transfer (ICT) absorbances over a wide spectral range. The chemical and electrochemical oxidations of 1 result in an unprecedented TTF·+ radical cation dimerization thereby leading to the formation of [1·+]2 at room temperature in solution due to the stabilizing effect which arises from strong p–p interactions. Moreover ICT fluorescence is observed with large solvent dependent Stokes shifts and quantum efficiencies of 0.05 for 1 and 0.035 for 8 in dichloromethane.

Magnetic measurements for the 2D coordination polymer [Mn(Pht(Pyz(H2O)2]n (1) in which metal centres are linked together by pyrazine (Pyz) and 16 bridging o phthalate ligand (Pht2 ) revealed antiferromagnetic interactions between Mn(II) ions.

Different synthetic routes have been used for the preparation of a new tetranuclear [Fe4O2(O2CCMe3)8(bpm)] cluster (1) and a one dimensional coordination polymer [Fe4O2(O2CCMe3)8(hmta)]n (2) (bpm = 22' bipyrimidine and hmta = hexamethylenetetramine). For cluster 1 two structural isomers 1a and 1b·3MeCN have been found. X ray crystallographic analysis showed that all complexes consist of a central {Fe4(m3 O)2}8+ core. In 1a metal ions in the core are additionally linked by six bridging pivalates as two other pivalates and a bpm ligand are chelated to FeIII ions whereas in cluster 1b metal ions in the {Fe4(m3 O)2}8+ core are linked by seven bridging pivalates and only one carboxylate as well as bpm are chelated to the iron centers. In coordination polymer 2 [Fe4O2(O2CCMe3)8] clusters are bridged by hmta ligands to form zigzag chains. Magnetic measurements have been carried out to characterize these complexes and revealed antiferromagnetic interactions between FeIII ions with best fit parameters of Jwb = –72.2 (1a) and –88.7 cm–1 (1b) for wing···body interactions.

Three new organic semiconductors, in which either two methoxy units are directly linked to a dibenzotetrathiafulvalene (DB-TTF) central core and a 2,1,3-chalcogendiazole is fused on the one side, or four methoxy groups are linked to the DB-TTF, have been synthesised as active materials for organic field-effect transistors (OFETs). Their electrochemical behaviour, electronic absorption and fluorescence emission as well as photoinduced intramolecular charge transfer were studied. The electron-withdrawing 2,1,3-chalcogendiazole unit significantly affects the electronic properties of these semiconductors, lowering both the HOMO and LUMO energy levels and hence increasing the stability of the semiconducting material. The solution-processed single-crystal transistors exhibit high performance with a hole mobility up to 0.04 cm2¿V-1¿s-1 as well as good ambient stability.

A new μ3-oxo trinuclear chromium(III) propionate cluster, [Cr3(μ3-O)(O2CCH2CH3)6(pyr)3]NO3·0.25(H2O) (1), has been synthesized by reaction of a μ3-oxo trinuclear chromium(III) propionate precursor [Cr3(μ3-O)(O2CCH2CH3)6(H2O)3]NO3 with a pyrazole ligand (pyr) and characterized by IR spectroscopy, single-crystal X-ray structure determination, and thermal analysis. Magnetic susceptibility and magnetization studies revealed antiferromagnetic exchange interactions within the trinuclear Cr(III) cluster (J = -11.9 cm−1) and determined the electronic ground state (S = ½) of the compound.

A new μ3-oxo trinuclear chromium(III) propionate cluster, [Cr3(μ3-O)(O2CCH2CH3)6(pyr)3]NO3·0.25(H2O) (1), has been synthesized by reaction of a μ3-oxo trinuclear chromium(III) propionate precursor [Cr3(μ3-O)(O2CCH2CH3)6(H2O)3]NO3 with a pyrazole ligand (pyr) and characterized by IR spectroscopy, single-crystal X-ray structure determination, and thermal analysis. Magnetic susceptibility and magnetization studies revealed antiferromagnetic exchange interactions within the trinuclear Cr(III) cluster (J = -11.9 cm−1) and determined the electronic ground state (S = ½) of the compound.