The synthesis and characterization of a series of imidazolium diorganophosphate-based surface-active ionic liquids (SAILs) of the general formula [OMIm][(RO)2PO2] (OMIm = 1-octyl-3-methylimidazolium; R = H, Me, Et, Ph, p-MeOPh) is reported. The reaction of [OMIm][(RO)2PO2] SAILs with hydrogen peroxide is investigated via 31P-Nuclear Magnetic Resonance (NMR) spectroscopy, showing the presence of a phosphorous-peroxo product, which is corroborated by Density Functional Theory (DFT) calculations. The sizes of the SAIL micelles in aqueous hydrogen peroxide are investigated by dynamic light scattering (DLS) before and after addition of cis-cyclooctene (COE) to study the solubilization of the organic substrate in the aqueous phase. In a model case study, the SAILs are applied as micellar catalysts for the epoxidation of COE under mild conditions.

Molecular perovskites are important materials in the area of barocalorics, improper ferroelectrics and ferroelastics, where the search for principles that link composition, structure and mechanical properties is a key challenge. Herein, we report the synthesis of a new series of dicyanamide-based molecular perovskites [A]Ni(C2N3)3, where A+ is a range of alkylated piperidinium cations. We use this new family to explore how A+ cations determine their mechanical response by measuring the bulk modulus (B) – using high-pressure powder X-ray diffraction. Within the series, we find a positive correlation between the network distortions of the pseudocubic [Ni(C2N3)3]– network and B. Furthermore, we show that we can tune framework distortions, and therefore B, by synthesising A-site solid solutions. The applied methodology is a blueprint for linking framework distortions and mechanical properties in network materials and guides us toward principles for designing macroscopic properties via systematic compositional changes in molecular perovskites.

Electrocatalytic hydrogenation of 1-octene as nonactivated model substrate with neutral water as H-donor is reported, using [(tBuPCP)Ir(H)(Cl)] (1) as the catalyst, to form octane with high faradaic efficiency (FE) of 96% and a kobs of 87 s–1. Cyclic voltammetry with 1 revealed that two subsequent reductions trigger the elimination of Cl– and afford the highly reactive anionic Ir(I) hydride complex [(tBuPCP)Ir(H)]– (2), a previously merely proposed intermediate for which we now report first experimental data by mass spectrometry. In absence of alkene, the stoichiometric electrolysis of 1 in THF with water selectively affords the Ir(III) dihydride complex [(tBuPCP)Ir(H)2] (3) in 88% FE from the reaction of 2 with H2O. Complex 3 then hydrogenates the alkene in classical fashion. The presented electro-hydrogenation works with extremely high FE, because the iridium hydrides are water stable, which prevents H2 formation. Even in strongly alkaline conditions (Bu4NOH added), the electro-hydrogenation of 1-octene with 1 also proceeds cleanly (FE = 89%), suggesting a highly robust process that may rely on H2O activation, reminiscent to transfer hydrogenation pathways, instead of classical H+ reduction

In this work, we quantify the link between framework distortions and mechanical properties in molecular perovskites, showing that increasing framework distortions translates to a reduced compressibility.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Induced circular dichroism study of an asymmetric homogeneous catalyst reveals chirality transfer from ligands to the catalytically active metal centre.

With the aim to design new water-soluble organometallic Ru(II) complexes acting as anticancer agents catalysing transfer hydrogenation (TH) reactions with biomolecules, we have synthesized four Ru(II) monocarbonyl complexes (1-4) featuring the 1,4-bis(diphenylphosphino)butane (dppb) ligand and different bidentate nitrogen (N^N) ligands, of general formula [Ru(OAc)CO(dppb)(N^N)]n (n = +1, 0; OAc = acetate). The compounds have been characterised by different methods, including 1H and 31P NMR spectroscopy, electrochemistry as well as single crystals X-ray diffraction in the case of 1 and 4. The compounds have also been studied for their hydrolysis in aqueous environment, and for the catalytic regioselective reduction of NAD+ to 1,4-NADH in aqueous solution with sodium formate as hydride source. Moreover, the stoichiometric and catalytic oxidation of 1,4-NADH have also been investigated by UV-Visible spectrophotometry and NMR spectroscopy. Overall, initial structure-activity relationships could be inferred which point towards the influence of the extension of the aromatic N^N ligand in the cationic complexes 1-3 on the TH in both reduction/oxidation processes. The neutral complex 4, featuring a picolinamidate N^N ligand, stands out as the most active catalyst for the reduction of NAD+, while being completely inactive towards NADH oxidation. The compound can also convert pyruvate into lactate in the presence of formate, albeit with scarce efficiency. In any case, for all compounds, Ru(II) hydride intermediates could be observed and even isolated in the case of complexes 1-3. Together, insight from the kinetic and electrochemical characterization suggests that, in the case of Ru(II) complexes 1-3, catalytic NADH oxidation sees the H-transfer from 1,4-NADH as the rate limiting step, whereas for NAD+ hydrogenation with formate as the H-donor, the rate limiting step is the transfer of the ruthenium hydride to the NAD+ substrate. The latter is further modulated by the presence of di-cationic aquo- or mono-cationic hydroxo-species of complexes 1-3. Instead, compound 4, stable with respect to hydrolysis in aqueous solution, appears to operate via a different mechanism. Finally, the anticancer activity and ability to form reactive oxygen species (ROS) of complexes 1-3 have been studied in cancerous and non-tumorigenic cells in vitro. Noteworthy, the conversion of aldehydes to alcohols could be achieved by the three Ru(II) catalysts in living cells, as assessed by fluorescence microscopy. Furthermore, the formation of Ru(II) hydride intermediate upon treatment of cancer cell extracts with complex 3 has been detected by 1H NMR spectroscopy. Overall, this study paves the way to the application of non-arene based organometallic complexes as TH catalysts in biological environment.

For network forming materials, the wine-rack structure motif is known to facilitate anisotropic structural responses to temperature and pressure variation. Here we propose that linear negative thermal expansion in Pd(acac)(2) can be rationalised through intermolecular interactions that can be mapped on a wine-rack network. By comparison with isomorphous Cu(acac)(2), the decisive role of intermolecular interactions in Pd(acac)(2) for the emergence of collective responsive structural properties is shown. Our results suggest that concepts that have previously been used to understand the responsive behaviour of framework forming materials such as metal-organic frameworks can be transferred to coordination compounds and molecular crystals, underlining that the challenge of enforcing collective structural responsiveness is coupled to the control of distinct, directional chemical interactions.

We present the activation of hydrogen peroxide by micellar imidazolium nitrates via H-bond formation in water, as shown by vibrational spectroscopy and supported by DFT calculations. Mechanistic insight into the interactions of the surfactant cation, the nitrate anion and H2O2 is given. The micelles solubilise and epoxidise cyclooctene in the aqueous phase.

In order to explain the different catalytic activity in hydrogenation of two new intermetallic Ni/Ga clusters, [Ga-7](NiCp*)(6) (1A) and [NiGa6](NiCp*)(6) (1B) (Cp* = C5Me5), investigations of structure-function relationship have been performed based on Raman and infrared (IR) spectroscopy and theoretical (density functional theory [DFT] and normal coordinate) calculations. Full interpretation of the Raman, far-IR, and mid-IR spectra of these dark colored solids has been proposed. Based on the overview of metal-Cp* complexes, all the 14 characteristic Cp*(-) skeletal fundamental modes have been identified. By comparison of the Ni-Cp* stretching and tilting external modes (350-380 cm(-1)), their force constants, and bond lengths, cluster 1B exhibited slightly stronger metal-ligand bonding. Vibrations of Ga-7 and NiGa6 cluster cores showed that the stretching wavenumbers and force constants of Ni-Ga (100-350 cm(-1)) and Ga-Ga (60-250 cm(-1)) bonds are higher for cluster 1B, in agreement with the shorter averaged experimental and calculated bond lengths of Ga-Ga bonds (2.873 and 2823 angstrom for clusters 1A and 1B, respectively). Cluster hydrogenation experiments with H-2 and D-2 showed strong Ni-H and N-D stretching features (at 1750 and 1260 cm(-1), respectively), and at the same time, characteristic bands of self-hydrogenated Cp*H and remained nondegraded clusters have been detected. The extent of H-D exchange in cluster deuteration was obtained about 1.5 times more effective with cluster 1B than cluster 1A. The stronger hydrogen or deuterium uptake by cluster 1B and the more intensive self-hydrogenation of Cp* clearly support the higher hydrogenation activity of cluster 1B compared with that of 1A.

Benzene-1,3,5-tri(dithiocarboxylate) (BTDTC3-), the sulfur-donor analogue of trimesate (BTC3-, benzene-1,3,5-tricarboxylate), is introduced, and its potential as a multidentate, electronically bridging ligand in coordination chemistry is evaluated. For this, the sodium salt Na3BTDTC has been synthesized, characterized, and compared with the sodium salt of the related ditopic benzene-1,4-di(dithiocarboxylate) (Na2BDDTC). Single-crystal X-ray diffraction of the respective tetrahydrofuran (THF) solvates reveals that such multitopic aromatic dithiocarboxylate linkers can form both discrete metal complexes (Na3BTDTC·9THF) and (two-dimensional) coordination polymers (Na2BDDTC·4THF). Additionally, the versatile coordination behavior of the novel BTDTC3- ligand is demonstrated by successful synthesis and characterization of trinuclear Cu(I) and hexanuclear Mo(II)2 paddlewheel complexes. The electronic structure and molecular orbitals of both dithiocarboxylate ligands as well as their carboxylate counterparts are investigated by density functional theory computational methods. Electrochemical investigations suggest that BTDTC3- enables electronic communication between the coordinated metal ions, rendering it a promising tritopic linker for functional coordination polymers.

A methodology is introduced for controlled postsynthetic thermal defect engineering (TDE) of precious group metal-organic frameworks (PGM-MOFs). The case study is based on the Ru/Rh analogues of the archetypical structure [Cu3(BTC)2] (HKUST-1; BTC = 1,3,5-benzenetricarboxylate). Quantitative monitoring of the TDE process and extensive characterization of the samples employing a complementary set of analytical and spectroscopic techniques reveal that the compositionally very complex TDE-MOF materials result from the elimination and/or fragmentation of ancillary ligands and/or linkers. TDE involves the preferential secession of acetate ligands, intrinsically introduced via coordination modulation during synthesis, and the gradual decarboxylation of ligator sites of the framework linker BTC. Both processes lead to modified Ru/Rh paddlewheel nodes. These nodes exhibit a lowered average oxidation state and more accessible open metal centers, as deduced from surface-ligand IR spectroscopy using CO as a probe and supported by density functional theory (DFT)-based computations. The monometallic and the mixed-metal PGM-MOFs systematically differ in their TDE properties and, in particular in the hydride generation ability (HGA). This latter property is an important indicator for the catalytic activity of PGM-MOFs, as demonstrated by the ethylene dimerization reaction to 1-butene.

Vibrational spectroscopic study of crystalline copper hexacyanoferrate complexes of composition K4Cu6II [Fe-II(CN)(6)](4)nH(2)O (1) and Cu-6(II)[Fe-III(CN)(6)](4)nH(2)O (2) with -Cu-N equivalent to C-Fe- bridging structures have been performed. The cubic Fmm (O-h(5)) unit-cells contain ideally 4 Fe and 4 Cu ions which were calculated by periodic density functional theory (DFT) (using the Gaussian09 C.01 software package) for ideal lattice compositions of K8Cu4II[Fe-II(CN)(6)](4) (1a), K4Cu4II[Fe-III(CN)(6)](4) (2a) and with lattice water molecules KCu4II[Fe-III(CN)(6)](3)6H(2)O (3a). Systematically, non-linear Cu-N equivalent to C structure was fitted with Cu-N equivalent to C bond angles about 155 degrees for complexes 1a, 2a, and 3a. Practically, all optically active internal modes of Fe(CN6)(n-) moieties resulted from factor group analysis as 4A(1g) + 6E(g) + 4F(1g) + 10F(1u) were experimentally observed and assigned. Some low-frequency translatory and librational modes were also interpreted. Vibrational bands were assigned to cis- and trans-Cu(NC)(4)(OH2) complexes which are formed in the lattice holes of both complexes. Vibrational spectra and force constants of a great number of transition metal hexacyano complexes of compositions K-4[M-II(CN)(6)], K-3[M-III(CN)(6)], CsLi2[M-III(CN)(6)] and Prussian blue analogues have been reexamined and recalculated. Internal and external modes of 6 different lattice water species (coordinated, hydrogen bonded, or zeolitic type) have been interpreted for complex 2 using results of periodic DFT calculation of model complex 3a.

Despite its sensitivity, ethyltrioxorhenium (ETO) is applicable as catalyst in the epoxidation of olefins using either tert-butylhydroperoxide (TBHP) or hydrogen peroxide as oxidants. Conversions of approximately 80% with only epoxide being formed and a turnover frequency (TOF) of up to 1200 h−1 can be achieved with TBHP in 1,1,1,3,3,3-hexafluroroisopropanol (HFI). As proven for its more stable congener MTO, the active species is highly likely an alkyl peroxo species, as shown by 17O-NMR experiments. Experimental and theoretical studies on the decomposition mechanism of ETO in diluted polar solvents reveal that the degradation pathway proceeds equally via β-hydrogen elimination and radical decomposition.

This work presents the first full series of mixed precious-group metal-organic frameworks (MPG-MOFs) using ruthenium and rhodium. The obtained crystalline, highly porous and thermally robust materials were characterized by means of powder X-ray diffraction, N2/CO2 sorption isotherms, thermogravimetry, spectroscopy methods (IR, Raman, UV/VIS-, NMR and XPS) and as well by high resolution transmission electron microscopy (HR-TEM) with elemental mapping (HAADF-EDS). Additionally, the assignment of spectroscopic data is supported by computational (time dependent)-density functional theory methods. The materials turned out to consist of homogeneously dispersed Ru2 and Rh2 paddlewheel units being linked by benzenetricarboxylate (BTC) to yield a framework that is isoreticular to [Cu3(BTC)2] (HKUST-1, Hong Kong University of Science and Technology). However, acetate (OAc) is incorporated as an intrinsic component which compensates for missing BTC-linker defects and some Cl is coordinated to the Ru centre at an apical position. The exact empirical formula of the MPG-MOFs is derived as [RuxRh3-x(BTC)2-a(OAc)b(Cl)c].

In this work, cluster expansion of nine-atomic germanium clusters with nickel and platinum atoms is reported. The compounds [(Me3Si)(3)Si](3)Et[Ge9Ni](PPh3) and [(Me3Si)(3)Si](3)Et[Ge9Pt](PPh3) are characterized by NMR spectroscopy, elemental analysis, and single crystal X-ray structure analysis. The latter represents the first intermetalloid Ge-Pt cluster with a platinum atom as part of a deltahedron. So far, only one compound of this type has been reported for the homologous Pd. Hence, with these new compounds, metal-coordinated deltahedral Ge-9 clusters are now known for the whole triad of group 10 elements. The cluster compounds are accessible by treating [(Me3Si)(3)Si](3)EtGe9 with eta(2)-ethylene-bis-(triphenylphosphine)-nickel(0) and eta(2)-ethylene-bis-(triphenylphosphine)-platinum(0), respectively, in toluene. The crystal structure determination reveals ten-vertex-closo-[Ge9M]-cluster cores (M = Ni, Pt) bearing five exo-bonded ligands. Unlike the nine-vertex-cluster [(Me3Si)(3)Si](3)EtGe9, the penta-functionalized platinum containing cluster compound [(Me3Si)(3)Si](3)Et[Ge9Pt](PPh3) does not show fluctuating behavior in solution over a wide temperature range on the NMR time scale, whereas the [(Me3Si)(3)Si](3)Et[Ge9Ni](PPh3) shows highly dynamic processes in solution at ambient temperature.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

In contrast to Nature that accomplishes polyene cyclizations seemingly with ease, such transformations are difficult to conduct in the lab. In our program dealing with the development of selective halogenations of alkenes, we now asserted that standard X+ reagents are perfectly suited for the biomimetic cation-π cyclization of both electron rich and poor linear polyenes in the presence of the Lewis base morpholine and the Lewis acid HFIP. The method stands out due to its broad substrate scope and practicability together with high chemical yields and excellent selectivities, even for highly challenging chloriranium-induced polyene cyclizations.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.