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Supertetrahedral chalcogenido (semi)metalate cluster-based frameworks possess high selectivity for alkali metal cations, matching the specific charge density of their inner surfaces, which enables their use as ion-exchange materials. Aggregates of the supertetrahedral chalcogenido metalate cluster offer even new perspectives for metal ion capture and separation. Herein, we report on ionothermal preparation of two corresponding model compounds, (C$_2$C$_1$Im)$_7$[Cs@Ge$^{II}$$_4$(Ge$^{IV}$$_4$Se$_{10}$)$_4$] (1) and (C$_2$C$_1$Im)$_{10}$[Na$_5$(CN)$_6$@Cu$_6$(Ge$_4$Se$_{10}$)$_4$(Cu)] (2). Their formation is reliant on one specific cation type each, Cs$^+$ for 1 and Na$^+$ for 2, thus providing promising separation potential during crystallization. Compound 1 is based on the largest discrete binary selenido germanate cluster reported to date and the first mixed-valent chalcogenido germanate(II/IV) supertetrahedron. Moreover, it adds to the few examples of chalcogenides capable of capturing Cs$^+$ ions. Its high selectivity for Cs$^+$ compared to that of Li$^+$, Na$^+$, K$^+$, and Rb$^+$ was confirmed by single-crystal X-ray diffraction, energy-dispersive X-ray spectroscopy, and electrospray ionization mass spectrometry. Quantum chemical studies indicate that smaller ions, K$^+$ and Rb$^+$, could also be embedded in an isolated cluster assembly, but as the cluster aggregate slightly distorts for crystallization, the selectivity for Cs$^+$ becomes exclusive in the salt. The anionic substructure of compound 2 is based on a two-dimensional network of supramolecular assemblies and exhibits an exclusive preference for Na$^+$. This work thus provides the first comprehensive insight into the selective incorporation of specific alkali metal ions into supramolecular aggregates of supertetrahedral chalcogenide clusters, as a promising basis for new ion trapping techniques─especially for heavy alkali metal ions that pose environmental challenges.

Five [PSiP]-pincer iron hydrides 1-5, [(2-Ph2PC6H4)2HSiFe(H)(PMe3)2 (1), (2-Ph2PC6H4)2MeSiFe(H)(PMe3)2 (2), (2-Ph2PC6H4)2PhSiFe(H)(PMe3)2 (3), (2-(iPr)2PC6H4)2HSiFe(H)(PMe3) (4), and (2-(iPr)2PC6H4)2MeSiFe(H)(PMe3)2 (5)], were used as catalysts to study the effects of pyridine N-oxide and the electronic properties of [PSiP]-ligands on the catalytic hydrosilylation of carbonyl compounds. It was proved for the first time that this catalytic process could be promoted with pyridine N-oxide as the initiator at 30 °C because the addition of pyridine N-oxide is beneficial for the formation of an unsaturated hydrido iron complex, which is the key intermediate in the catalytic mechanism. Complex 4 as the best catalyst shows excellent catalytic performance. Among the five complexes, complex 3 was new and the molecular structure of complex 3 was determined by single crystal X-ray diffraction. A proposed mechanism was discussed.

The conversion of tetrazolo[1,5-a]quinoxalines to 1,2,3-triazoloquinoxalines and triazoloimidazoquinoxalines under typical conditions of a CuAAC reaction has been investigated. Derivatives of the novel compound class of triazoloimidazoquinoxalines (TIQ) and rhenium(I) triazoloquinoxaline complexes as well as a new TIQ rhenium complex were synthesized. As a result, a small 1,2,3-triazoloquinoxaline library was obtained and the method could be expanded towards 4-substituted tetrazoloquinoxalines. The compatibility of various aliphatic and aromatic alkynes towards the reaction was investigated and the denitrogenative annulation towards imidazoloquinoxalines could be observed as a competing reaction depending on the alkyne concentration and the substitutions at the quinoxaline.

The optical properties of four new trinuclear chalcogenolato bridged metal complexes [Ag$_{2}$Ti(SPh)$_{6}$(PPh$_{3}$)$_{2}$], [Na(thf)$_{3}$]$_{2}$[Ti(SPh)$_{6}$], [Cu$_{2}$Ti(SePh)$_{6}$(PPh$_{3}$)$_{2}$], and [Ag$_{2}$Ti(SePh)$_{6}$(PPh$_{3}$)$_{2}$] have been investigated by absorption and photoluminescence spectroscopy as well as time-dependent density functional theory (TDDFT) calculations and compared to the results published recently for [Cu$_{2}$Ti(SPh)$_{6}$(PPh$_{3}$)$_{2}$]. All of these compounds are distinguished by efficient near-infrared luminescence at ���880���1200 nm in the solid state at low temperatures, which remains quite intense for the copper���titanium complexes at ambient temperature with PL quantum yields of 9.5 and 4.8% at ��PL = 1090 and 1240 nm for [Cu$_{2}$Ti(EPh)$_{6}$(PPh$_{3}$)$_{2}$], E = S, Se, respectively. According to the calculations, a peculiar feature of the lowest-energy electronic transitions in these complexes is their high localization on the metal and chalcogen atoms, with negligible contributions of the ���external��� ligand groups. Correspondingly, the type of atoms in the M$_{2}$TiE$_{6}$ (M = Cu, Ag, Na) core structure determines optical properties such as the absorption and emission wavelengths and PL lifetime.

Four different [PSiP]-pincer ligands L1-L4 ((2-Ph2PC6H4)2SiHR (R = H (L1) and Ph (L2)) and (2-iPr2PC6H4)2SiHR' (R' = Ph (L3) and H (L4)) were used to investigate the effect of substituents at P and/or Si atom of the [PSiP] pincer ligands on the formation of silyl cobalt(I) complexes by the reactions with CoMe(PMe3)4 via Si-H cleavage. Two penta-coordinated silyl cobalt(I) complexes, (2-Ph2PC6H4)2HSiCo(PMe3)2 (1) and (2-Ph2PC6H4)2PhSiCo(PMe3)2 (2), were obtained from the reactions of L1 and L2 with CoMe(PMe3)4, respectively. Under similar reaction conditions, a tetra-coordinated cobalt(I) complex (2-iPr2PC6H4)2PhSiCo(PMe3) (3) was isolated from the interaction of L3 with CoMe(PMe3)4. It was found that, only in the case of ligand L4, silyl dinitrogen cobalt(I) complex 4, [(2-iPr2PC6H4)2HSiCo(N2)(PMe3)], was formed. Our results indicate that the increasing of electron cloud density at the Co center is beneficial for the formation of a dinitrogen cobalt complex because the large electron density at Co center leads to the enhancement of the π-backbonding from cobalt to the coordinated N2. It was found that silyl dinitrogen cobalt(I) complex 4 is an effective catalyst for catalytic transformation of dinitrogen into silylamine. Among these four silyl cobalt(I) complexes, complex 1 is the best catalyst for hydrosilylation of alkenes with excellent regioselectivity. For aromatic alkenes, catalyst 1 provided Markovnikov products, while for aliphatic alkenes, anti-Markovnikov products could be obtained. Both catalytic reaction mechanisms were proposed and discussed. The molecular structures of complexes 1-4 were confirmed by single-crystal X-ray diffraction.

The goal of this study was to design a ligand system which can accommodate single lanthanide(III)-ions and investigate the properties of the resulting complexes. The complexes of all the accesible lanthanides and yttrium with the new ligand LH6 = N,N′-dimethyl-N,N′-ethylene-bis(5-bromo-3-(1H-benzimidazol-2-yl)hydrazineylidene)-2-hydroxybenzylamine) were obtained in high yield at room temperature under aerobic reaction conditions. The corresponding compounds were characterised using X-ray diffraction, FT-IR, elemental analysis and the optical properties of all complexes were investigated using UV-vis and fluorescence spectroscopy. The air stable complexes efficiently transform biomass furfural to trans-4,5-cyclopentenones in high yield.

Different metal phosphinates and phosphonates were obtained containing zinc, calcium and magnesium as cations by means of a salt metathesis reaction with sodium salts of DOPO and DOPO‐OH. The synthesized complexes [Zn(DOPO)2]n, [Zn(DOPO‐OH)2]n and [Ca(DOPO)2(H2O)]n are featured a polymeric structure. The open‐ring metal phosphinate coordination compound [Zn(DOPO)2]n is able to undergo a non‐reversible thermally induced oxidative cyclisation to the corresponding metal phosphonate [Zn(DOPO‐OH)2]n. The magnesium and calcium phosphinates cannot be oxidized to their corresponding metal phosphonate complexes. All organophosphorus compounds were analyzed by means of X‐ray crystallography, NMR, TGA and TDMS. The oxidative cyclisation reaction of [Zn(DOPO)2]n was investigated by DSC. Additionally, the coordination polymer [Zn(DOPO)2]n can be transformed into a molecular complex by adding nitrogen ligands such as N‐methylimidazole, whereby the phosphonate ligand changes from a bridging to a monodentate ligand. The synthesized coordination compounds exhibit very high thermostabilities of up to 520 °C.

The reactions of unsymmetrical N-heterocyclic carbene (NHC) [CNC]-pincer preligands with CoMe(PMe3)4 gave rise to NHC [CNC]-pincer cobalt(III) hydrides, [(CcarbeneNaminoCnaphthyl)Co(H)(PMe3)2] (3a)...