Amide Complexes Research Articles

Isoselective Ring-Opening Polymerization of rac-Lactide Catalyzed by Simple Potassium Amidate Complexes Containing Polycyclic Aryl Group

The isoselective ring-opening polymerization of rac-LA is a challenging goal. In this work, a series of potassium amidate complexes (K1–K10) were easily prepared and characterized using the 1H/13C NMR spectrum. The molecular structures of potassium complexes K2 and K10 were determined by X-ray diffraction, which showed that both were two-dimensional coordination polymers due to the adjacent π interactions of the aryl. In the presence of benzyl alcohol (BnOH), all of the potassium complexes exhibited a high catalytic activity toward the ring-opening polymerization of L-lactide and rac-LA, yielding linear polylactides capped with BnO or CH3O end groups. A significant solvent effect on the ROP of the L-LA was observed, with a superior efficiency in toluene than in THF and CH2Cl2. These complexes are iso-selective and act as active catalysts for the controlled ring-opening polymerization of rac-lactide, with a Pm from 0.54 to 0.76. This is a rare example of simple alkali metal complexes for the isoselective ROP of rac-lactide. The substituent greatly affected the monomer conversion and isoselectivities.

Elemental Magnesium as an Early Transition Metal Substitute: From Pentafulvene Coordination to Deprotonation of Amines.

The reaction of magnesium turnings and 6,6-di-para-tolylpentafulvene was investigated. Under mild conditions, the magnesium dissolves, forming the MgII complex 1 with a π-η5 : σ-κ1 coordinating ligand of the dimerized pentafulvene, analyzed by NMR and XRD investigations. As a magnesium pentafulvene complex was a possible intermediate, amines were employed as intercepting agents. Thereby, the amines were formally deprotonated by elemental magnesium, yielding the first examples of Cp'Mg(THF)2 NR2 complexes. This reaction competes with the formation of 1 and a consecutive formal [1,5]-H-shift forming an ansa-magnesocene. Employing amines with low basicity gave quantitative conversion to the amide complexes.

Vanadium Pentafulvene Complexes: Synthon for Unprecedented VanadoceneIII Derivatives.

The benzene ligand at CpV(η6-C6H6) (1) is exchanged for pentafulvenes. Using sterically demanding pentafulvenes gives a clean exchange reaction, yielding vanadium pentafulvene (2a and 2b) and benzofulvene complexes (3a and 3b). The molecular structures of the target compounds suggest a π-η5:σ-η1 coordination mode with a vanadiumIII center. With the sterically low demanding 6,6-dimethylpentafulvene, a C-H activation at the leaving ligand is observed, yielding the ring-substituted vanadoceneII4. The reactivity of the pentafulvene complexes was investigated. A series of unprecedented vanadoceneIII compounds were synthesized: Under mild conditions, E-H splitting of 4-tert-butylphenol, diphenylamine, and 2,6-diisopropylaniline yield well characterized examples of rare vanadoceneIII phenolate and amide complexes. Insertion reactions into the V-Cexo bond of the pentafulvene complexes by multiple bond containing substrates were found for acetone, 4-chlorobenzonitril and N,N'-dicyclohexylcarbodiimide.

Reactions of Low-Valent Gallium Species with Organic Azides: Formation of Imido-, Azoimido-, and Tetrazene Complexes.

The reactivity of two α-diimine-ligated digallanes, [L2-Ga-GaL2-] (La = [(2,6-iPr2C6H3)NC(CH3)]2, dpp-dad, 1; Lb = 1,2-[(2,6-iPr2C6H3)NC]2C10H6, dpp-bian, 2), and a gallylene, [(La)2-GaNa(THF)3] (3), toward organic azides was studied. Reaction of digallane 1 or 2 with trimethylsilyl azide (Me3SiN3), 2-azido-benzonitrile (2-CNC6H4N3), or tosylazide (TosN3) results in imido-bridged complexes, [(La)·-Ga(μ-NSiMe3)2Ga(La)·-] (4) [(Lb)·-Ga(μ-NSiMe3)2Ga(Lb)·-] (5), [(Lb)·-Ga(μ-2-CNC6H4N)2Ga(Lb)·-] (6), and [(Lb)·-Ga(μ-NTos)2Ga(Lb)·-] (7), with elimination of dinitrogen. Treatment of 1 or 2 with 1-adamantyl azide (1-AdN3), on the other hand, affords the unsymmetrical dinuclear complexes [(La)·-Ga(NAd)(N3Ad)Ga(La)·-] (8) and [(Lb)·-Ga(NAd)(N3Ad)Ga(Lb)·-] (9), which contain both imido and triazene bridges. Different from the Ga(II) complexes 1 and 2, the reactions of Ga(I) species 3 with benzylazide or trimethylsilyl azide result in the tetrazene complex {Na(THF)}2[(La)2-Ga(benzyl-N4-benzyl)]2 (10) and amide complex {Na(THF)4}[(La)2-Ga(NHSiMe3)(benzyl)] (11). It is likely that these latter transformations proceed via the transient formation of the corresponding Ga═N imide complex, which undergoes either cycloaddition with a second azide (to form 10) or activation of the C-H bond of methyl in one solvent toluene molecule (to yield 11).

The Solvation Effect of C=O Group of Cyclic Anhydrides in Solution.

The paper reports the results of investigation intermolecular interactions between alanine and sarcosine anhydride in organic solvents. The absorption frequencies of cyclic dipeptide in solvents were measured by IR spectroscopy. The effect of Van der Waals interactions and the hydrogen bonding of solvents on absorption frequencies of the C=O group of anhydrides was discussed. The spectroscopic parameters for C=O∙∙∙H-O hydrogen bonding complexes of anhydride with methanol in aprotic and proton donor solvent are obtained. In multi-particle complexes of dipeptides with aliphatic alcohols, the hydrogen bond enhancement was between 10 and 16%, which is significantly lower than it is for amide complexes.

Reductive C-O Cleavage of Ethereal Solvents and 18-Crown-6 in Ln(NR2)3/KC8 Reactions (R = SiMe3).

The high reactivity accessible from the reduction of the tris(amide) complexes Ln(NR2)3 (R = SiMe3) with potassium graphite in the presence of a variety of ethers is demonstrated by crystal structures of six different types of products of C-O bond cleavage reactions with Ln = Y, Ho, Er, and Lu. Specifically, 1,2-dimethoxyethane (DME) can be cleaved in Ln(NR2)3/KC8 reactions as shown by three different types of crystals: [K (crypt)][(R2N)3Y(OCH2CH2OCH3)], 1-Y, [(R2N)2Y(μ-OCH2CH2OCH3-κO,κO')]2, 2-Y, and [K2(18-c-6)3]{[(R2N)3Lu]2[(μ-OCH2CH2O)]}, 3-Lu (18-c-6 = 18-crown-6; crypt = 2.2.2-cryptand). THF can be ring opened by the Y(NR2)3/KC8 reaction system, as shown by crystals of the butoxide, [K(crypt)][(R2N)3Y(OCH2CH2CH2CH3)], 4-Y. The cyclic ether, oxetane, OC3H6, ring opens in Ln(NR2)3/KC8 reactions to form crystals of the propoxide, [K(18-c-6)(OC3H6)][(R2N)3Ln(OCH2CH2CH3)], 5-Ln, for Ln = Ho and Er. In Et2O, the Y(NR2)3/KC8 reactions do not attack the solvent, but C-O cleavage of 18-c-6 is observed to form {[(R2N)2]Y[μ-η1:η1-O2(C10H20O4)K]}2, 6-Y. These Ln(NR2)3/KC8 C-O cleavage reactions are typically accompanied by C-H bond activation reactions, which form cyclometalates such as [K(crypt)]{(R2N)2Ln[N(SiMe3)(SiMe2CH2)-κC,κN]}, 7-Ln (Ln = Y, Ho, Er), and [K(18-c-6)]{(R2N)2Y[N(SiMe3)(SiMe2CH2)-κC,κN]}, 8-Y, which are common decomposition products of Ln(NR2)3 reactions. In addition, in this study, the hydride complex, [K(18-c-6)][(R2N)3YH], 9-Y, was isolated. NMR analysis indicates that the yttrium reactions form mixtures that consistently contain the yttrium cyclometalates 7-Y and 8-Y as major components. These results show the diversity of available reaction pathways for the Ln(NR2)3/KC8 system and highlight the inherent difficulties in isolating Ln(II) complexes containing the [Ln(NR2)3]1- anion.

Synthesis of Sterically Encumbered Alkaline-Earth Metal Amides Applying the In Situ Grignard Reagent Formation.

Magnesium and calcium are too inert to deprotonate amines directly. For the synthesis of bulky amides alternative strategies are required and in the past, N-bound trialkylsilyl groups have been used to ease metalation reactions. The in situ Grignard reagent formation in stirred suspensions of magnesium or calcium with hydryl halide and imine in THF allows the synthesis of a plethora of amides with bulky silyl-free substituents. Ball milling protocols partially favor competitive side reactions such as aza-pinacol coupling reactions. Calcium is the advantageous choice for the in situ Grignard reagent formation and subsequent addition onto the imines yielding bulky calcium bis(amides) whereas the stronger reducing heavier alkaline-earth metals strontium and barium are less selective and hence, the aza-pinacol coupling reaction becomes competitive. Exemplary, the solid-state molecular structures of [(Et2 O)Mg(N(Ph)(CHPh2 )2 ] and [(Et2 O)2 Ca(N(Ph)(CHPh2 )2 ] have been determined.

Study on Preparation and Performance of a Novel Indoor Purification Material

As known to all, the quality of indoor air directly affects people’s health. Although the existence of indoor air purification products has some purification functions, there are also a variety of shortcomings. For example, activated carbon can only physically adsorb formaldehyde and cannot decompose formaldehyde, which is easy to saturate and causes secondary pollution. Based on a Japanese patent, an air purification product reacts with formaldehyde to produce N-substituted imines. Meanwhile, the products are not small molecules such as water and carbon dioxide, thus the reaction is slow and cannot meet all of the people’s needs. In this paper, a novel kind of indoor purification material is studied, which is a kind of Nanoparticle with strong oxidizing properties, showing a good function in removing formaldehyde, toluene, and other harmful gases as well as sterilization. In addition, the purification performance has been verified and compared with that of activated carbon commonly used in the market and an air purification product based on a Japanese patent, in which the main components are organic amine and amide complex. A series of experimental results show that the adsorption efficiency and capacity of the new adsorption purification material developed in this paper are much higher than those in the market. The adsorption capacity is 1.80 times that of activated carbon, and 1.13 times that of a Japanese famous brand formaldehyde removal product; The adsorption rate of the new adsorption and purification material is two times that of activated carbon, and 1.56 times that of a Japanese famous brand formaldehyde removal product. Furthermore, the new adsorption purification material has a strong inhibitory effect on common bacteria. The active substances contained in the material oxidize common bacteria in the air. The antibacterial rate of representative Escherichia coli, Staphylococcus aureus, and Klebsiella pneumonia is greater than 99%, and the antibacterial rate of Candida albicans is 96.3%. In addition, it is non-toxic, low cost, and can well meet people’s purification needs.

Efficient CO2 Capture under Humid Conditions on a Novel Amide-Functionalized Fe-soc Metal-Organic Framework.

CO2 is the main source of the greenhouse gases, and its capture from flue gas under humid conditions is challenging but important for promoting carbon neutrality. Herein, we report a novel soc topology Fe-based metal-organic framework (Fe-dbai) with highly efficient postcombusion CO2 capture performance by integrating multiple specific functionalities, such as unsaturated metal sites and amide functional groups. The CO2 adsorption capacity and CO2/N2 selectivity of Fe-dbai are high up to 6.4 mmol/g and 64 (298 K, 1 bar), respectively, superior to many other reported MOFs. More importantly, the CO2 working capacity of Fe-dbai under 60% RH conditions preserves 94% of that under dry conditions in the breakthrough experiments of CO2/N2 (15:85, v/v) mixtures. The molecular simulation highlights that the electronegative amide CO- group has a good affinity for CO2 and can improve the interaction between Fe UMS and CO2. Although H2O molecules will occupy a small fraction of the adsorption sites, the confinement effect it produces can enhance the adsorption affinity of the framework for CO2, which results in Fe-dbai retaining most of the CO2 adsorption capacity under humid conditions. The excellent CO2 capture performance makes Fe-dbai a potential candidate for the practical application of CO2 capture.

Intramolecular 1,2 C−H Addition of o‐Methyl Groups to Form Unique Ruthenium Pincer Tuck‐in Complexes

AbstractNew RPNHP ligands containing 2,4‐xylyl (4mXPNHP) and mesityl (MesPNHP) groups on the phosphorus atoms were synthesized. 4mXPNHP reacts with [(cymene)RuCl2]2 followed by PMe3 to produce κ3‐4mXPNHPRu(PMe3)Cl2. MesPNHP reacts with [(cymene)RuCl2]2 to produce monomeric κ3‐MesPNHPRuCl2 that reacts with CO forming κ3‐MesPNHPRu(CO)Cl2. Surprisingly, dehydrohalogenation of these complexes results in the activation of ortho methyl groups of the pincer ligands, rather than formation of κ3‐RPNPRuLCl complexes. This results from transient κ3‐RPNPRuLCl formation followed by 1,2‐addition of an ortho C−H bond across the Ru‐amide bond. The transient amide complex of κ4‐4mXPNHPRu(PMe3)Cl was trapped with CO forming κ3‐4mXPNPRu(PMe3)(CO)Cl. In contrast, κ4‐MesPNHPRu(CO)Cl does not react with ligands to trap the expected amide complex of reverse C−H addition. Instead, CO and PMe3 displace the chloride ligand forming cationic complexes. In both cases, hemi‐lability of the pincer ligand was observed spectroscopically. The new complexes serve as precursors to moderately active catalysts for the acceptorless dehydrogenative coupling of n‐butanol.

Comparative Study on Charge–Discharge Behavior of Graphite Positive Electrode in FSA- and FTA-Based Ionic Liquid Electrolytes with Different Alkali Metal Cations

Dual-carbon batteries (DCBs), in which both the positive and negative electrodes are composed of carbon-based materials, are promising next-generation batteries owing to their limited usage of scarce metals and high operating voltages. In typical DCBs, metal cations and anions in the electrolytes are consumed simultaneously at the negative and positive electrodes, respectively, which can rapidly deplete the charge carrier ions in the electrolytes. In this study, to solve this challenge, we focused on ionic liquids (ILs) as DCB electrolytes because they are solely composed of ions and are therefore intrinsically highly concentrated electrolytes. Charge–discharge behavior of the graphite positive electrodes was investigated in several IL electrolytes containing alkali metal cations (Li+, Na+, and K+) and amide anions (FSA− and FTA−; FSA = bis(fluorosulfonyl)amide, FTA = (fluorosulfonyl)(trifluoromethylsulfonyl)amide). It was found that FTA-based ILs conferred superior cycling stability and higher capacities to graphite electrodes compared to FSA-based ILs, which was explained by the suppression of the corrosion of the aluminum current collector at high voltages. The highest reversible capacity of approximately 100 mAh g−1 was obtained for the K-ion system using FTA-based ILs at 20 mA g−1, which involved the formation of FTA–graphite intercalation compounds, as confirmed by ex situ X-ray diffraction.

Structural characterization of the 1-metallo-2-t-butyl-1,2-dihydropyridyl rubidium and caesium complexes

With recent reports of alkali metal amides used in homogeneous catalytic chemistry where the reactivity down group one is dependent on the metal identity, esoteric rubidium and caesium amides are finding new admirers amongst chemists who usually study lithium, sodium, and potassium utility amides. Here, as a forerunner to their exploitation in catalysis, we report the X-ray crystallographic and NMR solution structures of the 1-metallo-2-t-butyl-1,2-dihydropyridyl (DHP) complexes of rubidium and caesium, thereby completing the homologous alkali metal series. Crystallized as monosolvated {[Rb(tBuDHP)·THF]2}∞ and hemisolvated {[Cs(tBuDHP)]2·THF}∞, both form spectacular supramolecular structures. While each shares a plethora of metallo-π-contacts with the DHP anion, their subunits differ. The former dimerizes in a ‘slipped’ fashion via interactions between the symmetrically-equivalent Rb centres and the π-system of the adjacent DHP ring, but the latter has distinct Cs centres within its dinuclear subunit, with one Cs engaging in σ-bonding to two tBuDHP anions, whereas the other Cs binds in a more side-on fashion to the π-system of the ring.

Vanadium-Catalyzed Dinitrogen Reduction to Ammonia via a [V]═NNH2 Intermediate.

The catalytic transformation of N2 to NH3 by transition metal complexes is of great interest and importance but has remained a challenge to date. Despite the essential role of vanadium in biological N2 fixation, well-defined vanadium complexes that can catalyze the conversion of N2 to NH3 are scarce. In particular, a V(NxHy) intermediate derived from proton/electron transfer reactions of coordinated N2 remains unknown. Here, we report a dinitrogen-bridged divanadium complex bearing POCOP (2,6-(tBu2PO)2-C6H3) pincer and aryloxy ligands, which can serve as a catalyst for the reduction of N2 to NH3 and N2H4. Low-temperature protonation and reduction of the dinitrogen complex afforded the first structurally characterized neutral metal hydrazido(2-) species ([V]═NNH2), which mediated 15N2 conversion to 15NH3, indicating that it is a plausible intermediate of the catalysis. DFT calculations showed that the vanadium hydrazido complex [V]═NNH2 possessed a N-H bond dissociation free energy (BDFEN-H) of as high as 59.1 kcal/mol. The protonation of a vanadium amide complex ([V]-NH2) with [Ph2NH2][OTf] resulted in the release of NH3 and the formation of a vanadium triflate complex, which upon reduction under N2 afforded the vanadium dinitrogen complex. These transformations model the final steps of a vanadium-catalyzed N2 reduction cycle. Both experimental and theoretical studies suggest that the catalytic reaction may proceed via a distal pathway to liberate NH3. These findings provide unprecedented insights into the mechanism of N2 reduction related to FeV nitrogenase.

A rare isocyanide derived from an unprecedented neutral yttrium(ii) bis(amide) complex.

A room temperature stable complex formulated as Y(NHAr*)2 has been prepared, where Ar* = 2,6-(2,4,6-(iPr)3C6H2)C6H3, by KC8 reduction of ClY(NHAr*)2. Based on EPR evidence, Y(NHAr*)2 is an example of a d1 Y(ii) complex with significant delocalization of the unpaired electron density from the metal to the ligand. The isolation of molecular divalent metal complexes is challenging for rare earth elements such as yttrium. In fact, stabilization of the divalent state requires judicious ligand design that allows the metal center to be coordinatively saturated. Divalent rare earth elements tend to be reactive towards various substrates. Interestingly, Y(NHAr*)2 reacts as a radical donor towards t BuNC to generate an unusual yttrium isocyanide complex, CNY(NHAr*)2, based on spectroscopic evidence and single-crystal X-ray diffraction data.

Light emission mechanism in dimers of carbene-metal-amide complexes.

Recently an efficient dual electroluminescence from monomers and dimers was observed among the structural examples of the emerging emitter class of carbene-metal-amides (CMAs), allowing the preparation of simple design white organic light emitting diodes (wOLEDs). Here we investigate in detail the light emission mechanism in the dimeric species of CMA emitters on the basis of a copper(I) complex TCP bearing thiazoline carbene and 10H-phenothiazine 5,5-dioxide (Ptz) ligands. The X-ray structure for crystals with dimer-only emission was obtained, revealing that emissive aggregates consist of face-to-face stacked molecular pairs with an intermolecular distance of 3.673 Å. The close packing is aided by reduced sterical bulk at the carbene ligand, as well as by a torsional twist between the carbene and amide fragments. Experimental and computational data show that the emission mechanism in aggregates is related to the formation of a persistent dimer, not the excimer. Radiative relaxation proceeds through an intermolecular charge transfer process between the carbene and amide ligands of the neighbouring molecules. In comparison to the monomer, the thermally activated delayed fluorescence (TADF) process in the dimer is characterized with significantly higher energy gaps (ΔEST) between the lowest singlet (S1) and triplet (T1) excited states. At the same time the aggregated species exhibit a significantly increased phosphorescence rate (τ = 12 μs at 10 K temperature) due to the presence of two metal atoms, resulting in a sixfold increase in the spin-orbit coupling (SOC) matrix element in comparison to the monomer.

Potential precursors for terminal ytterbium(II) imide complexes bearing the hydrotris(3-tert-butyl-5-methylpyrazolyl)borato ligand.

Monomeric, divalent ytterbium primary amides TptBu,MeYb(NHR)(thf)x (R = C6H3iPr2-2,6 = AriPr = Dipp, C6H3(CF3)2-3,5 = ArCF3, SiPh3) supported by the bulky hydrotris(3-tBu-5-Me-pyrazolyl)borato scorpionate ligand are synthesized acccording to salt metathesis and protonolysis protocols, respectively. Yb(II) precursors comprise YbI2(thf)2, Yb[N(SiMe3)2]2(thf)2 and TptBu,MeYb[N(SiMe3)2]. Complexes TptBu,MeYb(NHR)(thf)x readily engage in donor (thf) exchange with nitrogen donors like DMAP (4-dimethylaminopyridine) and pyridine. Treatment of TptBu,MeYb(NHArCF3)(thf)2 with the Lewis acids AlMe3 and GaMe3 results in the heterobimetallic complexes TptBu,MeYb(NHArCF3)(MMe3) (M = Al, Ga). Reactions of TptBu,MeYb(NHR)(thf)x (R = AriPr, ArCF3) with the halogenating agents C2Cl6 and TeBr4 give access to trivalent complexes [TptBu,MeYb(NHR)(X)] (X = Cl, Br). The ytterbium(II) complexes under study display 171Yb NMR chemical shifts in the range 582 ppm for TptBu,MeYb(NHArCF3)(GaMe3) to 954 ppm for TptBu,MeYb(NHSiPh3)(dmap). The salt-metathesis route is also applicable for the synthesis of complexes TptBu,MeLn(NHAriPr)(thf) (Ln = Sm, Eu) and TptBu,MeYb(NHArMe) (ArMe = C6H3Me2-2,6).

STATISTICAL STUDY OF THE DYNAMICS OF SUNFLOWER PRODUCTION: NEW REALITIES AND CHALLENGES OF THE TIME

This article delves into a meticulous examination of the sunflower production dynamics in Ukraine, scrutinizing the evolving landscape and confronting challenges in the contemporary era. The analysis encompasses a broad spectrum, including shifts in production practices, market trends, economic ramifications, environmental considerations, and the influence of global factors. With a focus on the new realities and challenges faced by the Ukrainian sunflower industry, the article aims to provide nuanced insights into the opportunities and obstacles within the context of a dynamically changing agricultural and geopolitical backdrop. Sunflower, a pivotal crop in Ukraine, holds significance both domestically and internationally, serving as a lucrative avenue for agricultural enterprises. Internationally, Ukraine emerges as a leading contributor to sunflower oil production, with profound implications for global vegetable oil markets. The article navigates through these intricacies, shedding light on the industry's role, challenges posed by geopolitical events like the Russia-Ukraine conflict, and the consequential economic impacts. As Ukraine grapples with damages to its agricultural sector, particularly in sunflower production, the article outlines the extensive recovery and reconstruction needs, providing a comprehensive strategy for revitalizing the industry. This research contributes to a deeper understanding of the Ukrainian sunflower industry's current state and its resilience amid complex challenges.

Investigation of new ferrocenyl-artesunate derivatives as antiparasitics.

Artesunate (Ars) is a semisynthetic antimalarial drug and is a part of the artemisinin-based combination therapy arsenal employed for malaria treatment. The drug functions mainly by activation of its endoperoxide bridge leading to increased oxidative stress in malaria parasites. The purpose of this study was to ascertain the antiparasitic effects of combining ferrocene and Arsvia short or long chain ester or amide linkages (C1-C4). The compounds were evaluated for growth inhibition activity on the apicomplexan parasites, Plasmodium falciparum (P. falciparum) and Toxoplasma gondii (T. gondii). All the complexes demonstrated good activity against T. gondii with IC50 values in the low micromolar range (0.28-1.2 μM) and good to excellent antimalarial activity against a chloroquine sensitive strain of P. falciparum (NF54). Further investigations on T. gondii revealed that the likely mode of action (MoA) is through the generation of reactive oxygen species. Additionally, immunofluorescence microscopy suggested a novel change in the morphology of the parasite by complex C3, an artesunate-ferrocenyl ethyl amide complex. The complexes were not cytotoxic or showed low cytotoxicity to two normal cell lines tested.

Na7RbTl4 – A New Ternary Zintl Phase Containing [Tl4]8− Tetrahedra

AbstractNa7RbTl4 has been prepared by solid state reaction from the elements. Single crystal X‐ray structure analysis suggested the presence of pseudo‐merohedral twinning. The final model could be derived in space group Pbam (a=16.3584(4) Å, b=16.3581(4) Å, c=11.3345(3) Å, V=3033.04(14) Å3, R1/wR2 0.0282/0.0402) and proved the presence of isolated [Tl4]8− anions, which are only known from two other solid state thallide phases so far. The structure of Na7RbTl4 is compared to the long‐known Na2Tl and the similarities and differences in the three‐dimensional arrangement within the crystal structures are reported on. DOS calculations revealed a pseudo‐band gap at EF. Dissolution experiments in the style of the chemistry of group 14 and group 15 Zintl anions in liquid ammonia yielded degradation of the thallides. Subsequent characterization of the reaction products by powder X‐ray diffraction allowed for the determination of alkali metal amide and elemental thallium as products.

Development of a Library of Extremely Bulky Amide Ligands, and their use for the Stabilization of Germanium(I) and Germanium(II) Compounds

AbstractEleven new extremely bulky aryl/silyl substituted secondary amines, L1–11H, have been prepared. These incorporate a combination of one of the bulky aryl groups, C6H2{C(H)Ph2}2R‐2,6,4; R=Me (Ar*), Pri (Ar†); C6H2{C(H)(C6H3But2‐3,5)2}2Me‐2,6,4) (Ar#); or C6H2{C(H)(2‐naphthyl)2}2Me‐2,6,4 (Ar¥), and one of the silyl fragments, SiMe3, SiCy3 (Cy=cyclohexyl), SiPri3, Si(p‐C6H4But)3, or Si(OBor)3 (OBor=[(1S)‐endo]‐(−)‐borneoxy). Amines including the latter silyl group represent the first enantiopure examples of this ligand class. All amines are readily deprotonated with n‐butyllithium or KH. Reactions of five alkali metal amide complexes with GeCl2⋅dioxane have given monomeric amido‐germanium(II) chloride complexes, LxGeCl (x=1–4, 7). Treatment of two of these with KOBut afforded monomeric amido‐germanium(II) tert‐butoxide species, LxGeOBut (x=1 or 3). Reductions of two amido‐germanium(II) chloride systems with a dimagnesium(I) compound afforded amido‐digermyne species, LxGeGeLx (x=3 or 4), the X‐ray crystal structures of which show them to possess very short Ge−Ge bonds, with considerable implied multiple bond character.