113Cd NMR Experiments Reveal an Unusual Metal Cluster in the Solution Structure of the Yeast Splicing Protein Bud31p

Establishing the binding topology of structural zinc ions in proteins is an essential part of their structure determination by NMR spectroscopy. Using ¹¹³Cd NMR experiments with ¹¹³Cd‐substituted samples is a useful approach but has previously been limited mainly to very small protein domains. Here we used ¹¹³Cd NMR spectroscopy during structure determination of Bud31p, a 157‐residue yeast protein containing an unusual Zn₃Cys₉ cluster, demonstrating that recent hardware developments make this approach feasible for significantly larger systems.     

Design of a Heterogeneous Catalyst Based on Cellulose Nanocrystals for Cyclopropanation: Synthesis and Solid‐State NMR Characterization

Heterogeneous dirhodium(II) catalysts based on environmentally benign and biocompatible cellulose nanocrystals (CNC‐Rh₂) as support material were obtained by ligand exchange between carboxyl groups on the CNC surface and Rh₂(OOCCF₃)₄, as was confirmed by solid‐state ¹⁹F and ¹³C NMR spectroscopy. On average, two CF₃COO^? groups are replaced during ligand exchange, which is consistent with quantitative analysis by a combination of ¹⁹F NMR spectroscopy and thermogravimetry. CNC‐Rh₂ catalysts performed well in a model cyclopropanation reaction, in spite of the low dirhodium(II) content on the CNC surface (0.23 mmol g^?1). The immobilization through covalent bonding combined with the separate locations of binding positions and active sites of CNC‐Rh₂ guarantees a high stability against leaching and allows the recovery and reuse of the catalyst during the cyclopropanation reaction.     

Synthesis and solid‐state structures of t‐Bu3Ga–EPh3 Lewis acid–base adducts

Three Lewis acid–base adducts t‐Bu₃Ga–EPh₃ (E = P 1 , As 2 , Sb 3 ) were synthesized by reactions of Ph₃E and t‐Bu₃Ga and characterized by heteronuclear NMR (¹H, ¹³C (³¹P)) and IR spectroscopy, elemental analysis and single crystal X‐ray diffraction. Their structural parameters are discussed and compared to similar t‐Bu₃Ga adducts. The strength of the donor‐acceptor interactions within 1 – 3 was investigated in solution by temperature‐dependent ¹H NMR spectroscopy and by quantum chemical calculations.     

Mesoporous Core–Shell Fenton Nanocatalyst: A Mild,Operationally Simple Approach to the Synthesis of Adipic Acid

Mesoporous nanoparticles composed of γ‐Al₂O₃ cores and α‐Fe₂O₃ shells were synthesized in aqueous medium. The surface charge of γ‐Al₂O₃ helps to form the core–shell nanocrystals. The core–shell structure and formation mechanism have been investigated by wide‐angle XRD, energy‐dispersive X‐ray spectroscopy, and elemental mapping by ultrahigh‐resolution (UHR) TEM and X‐ray photoelectron spectroscopy. The N₂ adsorption–desorption isotherm of this core–shell materials, which is of type IV, is characteristic of a mesoporous material having a BET surface area of 385 m² g^?1 and an average pore size of about 3.2 nm. The SEM images revealed that the mesoporosity in this core–shell material is due to self‐aggregation of tiny spherical nanocrystals with sizes of about 15–20 nm. Diffuse‐reflectance UV/Vis spectra, elemental mapping by UHRTEM, and wide‐angle XRD patterns indicate that the materials are composed of aluminum oxide cores and iron oxide shells. These Al₂O₃@Fe₂O₃ core–shell nanoparticles act as a heterogeneous Fenton nanocatalyst in the presence of hydrogen peroxide, and show high catalytic efficiency for the one‐pot conversion of cyclohexanone to adipic acid in water. The heterogeneous nature of the catalyst was confirmed by a hot filtration test and analysis of the reaction mixture by atomic absorption spectroscopy. The kinetics of the reaction was monitored by gas chromatography and ¹H NMR spectroscopy. The new core–shell catalyst remained in a separate solid phase, which could easily be removed from the reaction mixture by simple filtration and the catalyst reused efficiently.     

Phase‐ and Size‐Controllable Synthesis of Hexagonal Upconversion Rare‐Earth Fluoride Nanocrystals through an Oleic Acid/Ionic Liquid Two‐Phase System

Herein, we introduce a facile, user‐ and environmentally friendly (n‐octanol‐induced) oleic acid (OA)/ionic liquid (IL) two‐phase system for the phase‐ and size‐controllable synthesis of water‐soluble hexagonal rare earth (RE=La, Gd, and Y) fluoride nanocrystals with uniform morphologies (mainly spheres and elongated particles) and small sizes (<50 nm). The unique role of the IL 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BmimPF₆) and n‐octanol in modulating the phase structure and particle size are discussed in detail. More importantly, the mechanism of the (n‐octanol‐induced) OA/IL two‐phase system, the formation of the RE fluoride nanocrystals, and the distinctive size‐ and morphology‐controlling capacity of the system are presented. BmimPF₆ is versatile in term of crystal‐phase manipulation, size and shape maintenance, and providing water solubility in a one‐step reaction. The luminescent properties of Er³⁺‐, Ho³⁺‐, and Tm³⁺‐doped LaF₃, NaGdF₄, and NaYF₄ nanocrystals were also studied. It is worth noting that the as‐prepared products can be directly dispersed in water due to the hydrophilic property of Bmim⁺ (cationic part of the IL) as a capping agent. This advantageous feature has made the IL‐capped products favorable in facile surface modifications, such as the classic Stober method. Finally, the cytotoxicity evaluation of NaYF₄:Yb,Er nanocrystals before and after silica coating was conducted for further biological applications.     

Li47B3P14N42—A Lithium Nitridoborophosphate with [P3N9]12−, [P4N10]10−, and the Unprecedented [B3P3N13]15− Ion

Li₄₇B₃P₁₄N₄₂, the first lithium nitridoborophosphate, is synthesized by two different routes using a Li₃N flux enabling a complete structure determination by single‐crystal X‐ray diffraction data. Li₄₇B₃P₁₄N₄₂ comprises three different complex anions: a cyclic [P₃N₉]¹²⁻, an adamantane‐like [P₄N₁₀]¹⁰⁻, and the novel anion [P₃B₃N₁₃]¹⁵⁻. [P₃B₃N₁₃]¹⁵⁻ is the first species with condensed B/N and P/N substructures. Rietveld refinement, ⁶Li, ⁷Li, ¹¹B, and ³¹P solid‐state NMR spectroscopy, FTIR spectroscopy, EDX measurements, and elemental analyses correspond well with the structure model from single‐crystal XRD. To confirm the mobility of Li⁺ ions, their possible migration pathways were evaluated and the temperature‐dependent conductivity was determined by impedance spectroscopy. With the Li₃N flux route we gained access to a new class of lithium nitridoborophosphates, which could have a great potential for unprecedented anion topologies with interesting properties.     

Sonochemical Synthesis of a Novel Nanoscale Lead(II) Coordination Polymer: Synthesis,Crystal Structure,Thermal Properties,and DFT Calculations of [Pb(dmp)(μ‐N3)(μ‐NO3)]n with the Novel Pb2(μ‐N3)2(μ‐NO3)2 Unit

A new nanostructured coordination polymer of divalent lead with the ligand 2,9‐dimethyl‐1,10‐phenanthroline (dmp), [Pb(dmp)(μ‐N₃)(μ‐NO₃)]_n ( 1 ), was synthesized by sonochemical methods. The polymer was characterized by scanning electron microscopy, X‐ray powder diffraction, IR, ¹H NMR, and ¹³C NMR spectroscopy, and elemental analyses. Compound 1 was structurally characterized by single‐crystal X‐ray diffraction. The single‐crystal analysis shows that the coordination number of Pb^II ions is seven, (PbN₄O₃) has a “stereo‐chemically active” electron lone pair, and the coordination sphere is hemidirected. The chains interact with each other through π–π stacking interactions to create a 3D framework. The structure of the title complex was optimized by density functional calculations. The calculated structural parameters and the IR spectrum of the title complex are in agreement with the crystal structure.     

Isolation and Characterization of Four Phosphorus Cluster Anions P73–, P144–, P162– and P264– from the Nucleophilic Functionalization of White Phosphorus with 1,4‐Dilithio‐1,3‐butadienes

Studies on the aggregation degrees of negatively charged phosphides derived from the nucleophilic P₄ functionalization could help understand the pathway of phosphorus atoms degradation or aggregation. In this report, we have isolated and characterized four phosphorus cluster anions (P₇^3–, P₁₄^4–, P₁₆^2–, and P₂₆^4–) from the nucleophilic functionalization of P₄ with 1,4‐dilithio‐1,3‐butadienes. These phosphorus clusters could be rationalized as the P‐atom‐containing products besides the main phospholyl lithium. Their structural features and ³¹P NMR behaviors are discussed based on single crystal X‐ray diffraction analysis and ³¹P{¹H} COSY NMR analysis.     

[Am(C5Me4H)3]: An Organometallic Americium Complex

We report the small‐scale synthesis, isolated yield, single‐crystal X‐ray structure, ¹H NMR solution spectroscopy /solid‐state UV/Vis‐nIR spectroscopy, and density functional theory (DFT)/ab initio wave function theory calculations on an Am³⁺ organometallic complex, [Am(C₅Me₄H)₃] ( 1 ). This constitutes the first quantitative data on Am?C bonding in a molecular species.     

Reaktion von Kupferarylen mit Imidazol‐2‐ylidenen oder Triphenylphosphan ‐ Bildung von 1:1‐Addukten mit zweifach koordinierten Kupferatomen

Reaction of Copper Aryls with Imidazol‐2‐ylidenes or Triphenylphosphane — Formation of 1:1‐Adducts with Two‐coordinate Copper Atoms The reaction of the copper aryls CuDmp (Dmp = 2, 6‐Mes₂C₆H₃; Mes = 2, 4, 6‐Me₃C₆H₂) and CuMes with the σ‐donors triphenylphosphane and 1, 3‐Di‐iso‐propyl‐4, 5‐dimethylimidazol2‐ylidene affords the adducts DmpCu←PPh₃ ( 1 ), DmpCu←C{N(iPr)CMe}₂ ( 2 ) and MesCu←C{N(iPr)CMe}₂ ( 3 ) in yields between 65 and 84 %. The colorless compounds were characterized by ¹H and ¹³C‐NMR‐spectroscopy, single crystal structure analysis as well as by ³¹P NMR‐spectroscopy ( 1 ), elemental analysis ( 2 ), mass spectrometry ( 2 , 3 ), IR‐spectroscopy ( 2 ) and melting point ( 2 , 3 ). In the solid state structures the two‐coordinate copper atoms possess relatively short Cu—P and Cu—C(carbene) distances of 218, 91(11) ( 1 ), 190, 2(3) ( 2 ) and 191, 1(4) pm ( 3 ).     

Halogen‐ and Hydrogen‐Bonding Catenanes for Halide‐Anion Recognition

Halogen‐bonding (XB) interactions were exploited in the solution‐phase assembly of anion‐templated pseudorotaxanes between an isophthalamide‐containing macrocycle and bromo‐ or iodo‐functionalised pyridinium threading components. ¹H NMR spectroscopic titration investigations demonstrated that such XB interpenetrated assemblies are more stable than analogous hydrogen bonding (HB) pseudorotaxanes. The stability of the anion‐templated halogen‐bonded pseudorotaxane architectures was exploited in the preparation of new halogen‐bonding interlocked catenane species through a Grubbs’ ring‐closing metathesis (RCM) clipping methodology. The catenanes’ anion recognition properties in the competitive CDCl₃/CD₃OD 1:1 solvent mixture revealed selectivity for the heavier halides iodide and bromide over chloride and acetate.     

Facile Conversion of Red Phosphorus into Soluble Polyphosphide Anions by Reaction with Potassium Ethoxide

Soluble polyphosphide anions were successfully generated in a number of organic solvents by the reaction between shelf‐stable red phosphorus and potassium ethoxide. The species were identified by ³¹P NMR spectroscopy in solution and by X‐ray crystal‐structure determination of (Bu₄N)₂P₁₆ in the solid state. The reaction was scaled up to gram quantities by using a flow‐chemistry process.     

Robust Cluster Building Unit: Icosanuclear Heteropolyoxocopperate Templated by Carbonate

The encapsulation of carbonate derived from atmospheric CO₂ has resulted in an icosanuclear heteropolyoxocopperate, isolated as a metal–organic 1D chain, 2D sheet, or 3D framework, in which the Cu₂₀ nanocluster represents the first eight‐capped α‐Keggin polyoxometalate with the late‐transition‐metal Cu^II as the polyatom, CO₃^2? as the heteroanion, and OH^? and suc^2? or glu^2? (H₂suc=succinic acid; H₂glu=glutaric acid) as the terminal ligands, which suggests a conceptual similarity to classical polyoxometalates. Even in the presence of competitive SO₄^2? in the assembly system, the CO₃^2? anion is still captured as a template to direct the formation of the Cu₂₀ nanocluster, which indicates the stronger templation ability of CO₃^2? compared with SO₄^2?. When other aliphatic dicarboxylates, such as glutaric acid, were used as ligands, the CO₃^2?‐templated Cu₂₀ nanocluster was maintained and acted as a cluster building unit (CBU) to be linked by two glutarate bridges to generate a distinct 1D metal–organic chain. This report presents not only a rare example of a huge anion‐templated transition‐metal cluster, but also its use as a robust CBU to construct novel coordination architectures. Variable‐temperature magnetic susceptibility studies revealed that an antiferromagnetic interaction exists within the Cu₂₀ nanocluster. The correlation between the coordination structure and the electron paramagnetic resonance spectra recorded of both powder and single‐crystal samples are discussed in detail.     

[(HBNPEt3)4NPEt3]3+ – ein bicyclisches Penta(phosphorano)boraziniumTrikation

[(HBNPEt₃)₄NPEt₃]³⁺ – a Bicyclic Penta(phosphorano)borazinium Trication [(HBNPEt₃)₄NPEt₃]Br₃ ( 1 ) has been prepared by the reaction of Me₃SiNPEt₃ with [HBBr₂(SMe₂)] in dichloromethane solution at 20°C. According to ¹¹B‐NMR and ³¹P‐NMR spectroscopy and to a crystal structure determination the cation of 1 has the structure of a bicyclic penta(phosphorano)borazinium‐trication. 1 _.3CH₂Cl₂: Space group P2₁2₁2₁, Z = 8, lattice dimensions at –83°C: a = 2124.8(1), b = 2307.6(1), c = 2323,1(1) pm, R₁ = 0.0733.     

Monoxidised Sulfur and Selenium Derivatives of 1,8‐Bis(diphenylphosphino)naphthalene: Synthesis and Coordination Chemistry

Treatment of 1,8‐bis(diphenylphosphino)naphthalene (dppn, 1 ) with stoichiometric amounts of sulfur or selenium in toluene at 80 °C selectively afforded the diphosphine monochalcogenides 1‐Ph₂P(C₁₀H₆)‐8‐P(:S)Ph₂ (dppnS, 2 a ) and 1‐Ph₂P(C₁₀H₆)‐8‐P(:Se)Ph₂ (dppnSe, 2 b ). The ³¹P{¹H} NMR spectrum of 2 b showed an unusually large ⁵J(P–Se) value, which indicates a significant through‐space coupling component. The monosulfide acted as a bidentate P,S‐ligand towards platinum(II) ( 3 a ), whereas the corresponding monoselenide complex ( 3 b ′) lost elemental selenium with formation of the previously reported complex [PtCl₂(dppn)‐P,P′] ( 3 ). Treatment of dppnSe with [(nor)Mo(CO)₄] (nor = norbornadiene) led to formation of [(dppnSe)Mo(CO)₄‐P,Se] ( 3 b ). Solutions of the latter slowly deposited Se with formation of [(dppn)Mo(CO)₄‐P,P′] ( 4 ) which was also obtained by independent synthesis from 1 and [(nor)Mo(CO)₄]. All isolated new compounds were characterised by a combination of ³¹P, ¹H, ¹³C and ⁷⁷Se ( 2 b ) NMR spectroscopy, IR spectroscopy, mass spectrometry and elemental analysis. Single‐crystal X‐ray structure determinations were performed for dppnSe ( 2 b ), [PtCl₂(dppnS)‐P,S] ( 3 a ), [(dppnSe)Mo(CO)₄‐P,Se] ( 3 b ) and [(dppn)Mo(CO)₄‐P,P′] ( 4 ). In 2 b steric effects cause the naphthalene ring to be distorted and force the phosphorus atoms by 65 and 59 pm to opposite sides of the best naphthalene plane. In the metal complexes 3 a , 3 b and 4 the phosphino‐phosphinochalcogenyl systems act as bidentate ligands through the P and the chalcogen atoms. The naphthalene systems are again distorted. The two independent molecules of 4 differ in their conformations.     

The Hydrothermal Synthesis of Sulfate Cancrinite (SO4‐CAN): Relations between Si‐Al Sources and Crystal Quality

Sulfate cancrinite (SO₄‐CAN) Na₈[AlSiO₄]₆(SO₄)(H₂O)_n (2.6 < n < 3.2) was synthesized under hydrothermal conditions at 200 °C and 48 hours. Three different Si‐Al sources were inserted: (a) kaolinite (K), (b) a gel of sodium‐waterglass and sodium aluminate (G), and (c) an oxide mixture of cristobalite and corundum (CK). The products were characterized by X‐ray powder diffraction (XRD), ²⁹Si and ²⁷Al MAS NMR spectroscopy, scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDXS) and BET surface area analysis as well as simultaneous thermoanalysis (TG‐DTA). Mostly nanocrystals of platelet habit and dimensions smaller than 100 nm (beside a very few larger crystals) were observed from K. In contrast the gel (G) yielded to cancrinites with typical rod‐like morphology and dimensions of 100 × 500 nm. Large prismatic cancrinites up to 5 μm width and 10 μm length were observed from the oxide mixture CK. Furthermore the transition kinetics of the cancrinites into nosean was investigated at a temperature of 1000 °C under open conditions. This process was already complete after 1 hour for the nanocrystals from K but needed 10 hours for the nanocrystals from G and the microcrystals from CK. The relations between the individual Si‐Al source and the crystal properties like size, habit, and thermal transition kinetics were discussed.     

Towards a New Family of Photoluminescent Organozinc 8‐Hydroxyquinolinates with a High Propensity to Form Noncovalent Porous Materials

We report on investigations of reactions of tBu₂Zn with 8‐hydroxyquinoline (q‐H) and the influence of water on the composition and structure of the final product. A new synthetic approach to photoluminescent zinc complexes with quinolinate ligands was developed that allowed the isolation of a series of structurally diverse and novel alkylzinc 8‐hydroxyquinolate complexes: the trinuclear alkylzinc aggregate [tBuZn(q)]₃ ( 1₃ ), the pentanuclear oxo cluster [(tBu)₃Zn₅(μ₄‐O)(q)₅] ( 2 ), and the tetranuclear hydroxo cluster [Zn(q)₂]₂[tBuZn(OH)]₂ ( 3 ). All compounds were characterized in solution by ¹H NMR, IR, UV/Vis, and photoluminescence (PL) spectroscopy, and in the solid state by X‐ray diffraction, TGA, and PL studies. Density functional theory calculations were also carried out for these new Zn^II complexes to rationalize their luminescence behavior. A detailed analysis of the supramolecular structures of 2 and 3 shows that the unique shape of the corresponding single molecules leads to the formation of extended 3D networks with 1D open channels. Varying the stoichiometry, shape, and supramolecular structure of the resulting complexes leads to changes in their spectroscopic properties. The close‐packed crystal structure of 1₃ shows a redshifted emission maximum in comparison to the porous crystal structure of 2 and the THF‐solvated structure of 3 .     

Two New Lead(II) Coordination Polymers with (Substituted) Bipyridine and Auxiliary Nitrate Ligands

The reaction of lead(II) nitrate with 4,4′‐bipyridine (4,4′‐bpy) and 4,4′‐dimethyl‐2,2′‐bipyridine (4,4′‐dm‐2,2′‐bpy) or 5,5′‐dimethyl‐2,2′‐bipyridine (5,5′‐dm‐2,2′‐bpy) resulted in the fomation of single crystals of [Pb₂(4,4′‐bpy)(5,5′‐dm‐2,2′‐bpy)₂(NO₃)₄] ( 1 ) and [Pb₃(4,4′‐bpy)₂(4,4′‐dm‐2,2′‐bpy)₂(NO₃)₆] ( 2 ). The new compounds have been characterized by single‐crystal X‐ray diffraction structure analysis as well as through elemental analysis, IR, ¹H‐NMR and ¹³C‐NMR spectroscopy and their stability has been studied by thermal analysis. In the crystal structure of ( 1 ) formula‐like dimers are further connected to a 2‐D network through the auxiliary nitrate ligands. The crystal structure of ( 2 ) exhibits two crystallographically independent Pb^II central atoms (in a ratio of 1:2). With the aid of the 4,4′‐bpy and the nitrate ions, a 3‐D polymeric structure is achieved.     

[(Me3Si)Si]3EtGe9Pd(PPh3), a Pentafunctionalized Deltahedral Zintl Cluster: Synthesis,Structure, and Solution Dynamics

The title compound, which has a ten‐atom deltahedral cluster core of Ge₉Pd, was synthesized through insertion of Pd(PPh₃) into the tetrasubstituted nona‐germanium cluster [(Me₃Si)Si]₃EtGe₉ through a reaction of the latter with Pd(PPh₃)₄. This first reaction of neutral tetrasubstituted nine‐atom clusters shows that they retain reactivity despite their neutral charge. The Ge₉Pd core is the first that incorporates a 5‐connected transition metal other than from Group VI, a noble metal in this case. Single‐crystal X‐ray diffraction shows that the ten‐atom core is a closo‐cluster with the expected shape of a bicapped square antiprism. ¹H and ¹³C NMR spectroscopy show that, in contrast to the parent tetra‐substituted [(Me₃Si)Si]₃EtGe₉, the new compound does not exhibit dynamics. Relativistic DFT calculations are used to explain the differences.     

Hydride Migration from a Triangular Face to a Tetrahedral Cavity in Tetranuclear Iron Carbonyl Clusters upon Coordination of [AuPPh3]+ Fragments

Metal hydrides are of fundamental importance in chemistry, both as solid‐state materials and molecular compounds. The first low‐valent molecular metal cluster containing an interstitial four‐coordinate hydride in a tetrahedral site is decribed, which undergoes hydride migration from the surface to the tetrahedral cavity of the cluster upon coordination of a [AuPPh₃]⁺ fragment. The [HFe₄(CO)₁₂(AuPPh₃)₂]^? mono‐anion, which contains a surface μ₃‐H, was obtained from the reaction of [HFe₄(CO)₁₂]^3? with two equivalents of [Au(PPh₃)Cl]. This is, in turn, transformed into the neutral [HFe₄(CO)₁₂(AuPPh₃)₃] upon addition of a third [AuPPh₃]⁺ fragment, with concomitant migration of the unique hydride from the surface of the cluster to its tetrahedral cavity. All of these species have been fully characterized in solution by means of IR and multinuclear NMR spectroscopy, and in the solid state by single‐crystal X‐ray diffractometry.