The crystal structure of the thus far elusive orthorhombic modification of Cs[ICl 2 ] ( Pnma , Z = 4, a = 1042.2(1) pm, b = 647.35(5) pm, c = 870.38(8) pm and V = 587.21(9) Å 3 ) is reported. In contrast to the structure of the known trigonal modification ( R m ), the [ICl 2 ] − anion shows a significant I─Cl bond length asymmetry, similar to other cesium trihalides. We used quantum chemical calculations (DFT) to get further insights in the molecular electrostatic potential surfaces of the [ICl 2 ] − anion found in the new polymorph, as well as the gas‐phase optimized structure as a reference. Additionally, quantum theory of atoms in molecules and natural bond orbital analyses were performed to quantify the strength of the observed noncovalent interactions and the orbital contributions and explain the deviations found between the anion in the novel polymorph and the so far reported species. Our findings show that the orthorhombic modification most likely is a metastable modification which can be described as a transient Cl − ···I–Cl intermediate toward a symmetric [Cl–I–Cl] − anion.
Reactions of 2,9‐dichloro‐1,10‐phenanthroline and its 4,5‐substituted derivatives with the ammonia surrogate p ‐methoxybenzylamine produce the corresponding mono‐ or diamino phenanthrolines in excellent yields following deprotection. Metathesis of various 2,9‐dichloro‐1,10‐phenanthrolines with anhydrous NMe 4 F yields the respective 2,9‐difluoro‐1,10‐phenanthrolines in up to 94% yield. Condensation of 2,9‐diamino‐1,10‐phenanthroline with various 2,9‐difluoro‐1,10‐phenanthrolines affords nitrogen‐bridged bis‐phenanthroline macrocycles in 59%–80% yield. Macrocycles bearing 4,5‐(OBu) 2 substituents and their respective metal complexes exhibit high solubility in common organic solvents, enabling detailed solution‐state spectroscopic and electrochemical studies.
Protein‐bound iron–sulfur ([Fe–S]) clusters are ubiquitous and structurally diverse cofactors in biological systems, performing a wide range of biochemical functions. These [Fe–S] clusters are most commonly coordinated by cysteine residues, within defined protein scaffolds, which modulate their structural organization and redox behavior. Therefore, this review focuses on iron–sulfur cofactors ligated by four cysteine residues with variable spacing, which give rise to distinct [Fe–S] cofactors within protein scaffolds such as [1Fe] rubredoxins (Rds) and [2Fe–2S]‐/[4Fe–4S]‐ferredoxins (Fds), emphasizing the magnetic behaviors and a wide spectrum of redox potentials governed by diverse structural and environmental factors. In addition, the review highlights the structural versatility of nonclassical [Fe–S] clusters in proteins and their diverse biological roles.
The crystal structures of the low‐temperature (LT) and high‐temperature (HT) modifications of silver pyrophosphate, Ag 4 P 2 O 7 , were determined from single‐crystal X‐ray data. Thermal analysis, vibrational and 31 P‐MAS‐NMR spectroscopy studies, and density functional theory calculations complement the results. The crystal structure of HT‐Ag 4 P 2 O 7 ( T = 487 °C, , Z = 2, a = 5.5734(5) Å, c = 13.7613(18) Å) is very similar to that of the aristotype, γ ‐K 4 P 2 O 7 , whereas the crystal structure of LT‐Ag 4 P 2 O 7 ( T = 25 °C, P 3 1 21/ P 3 2 21, Z = 6, a = 5.5128(1) Å, c = 40.8723(11) Å) differs significantly from LT‐K 4 P 2 O 7 . The experimental results and those of DFT structure optimization yield bent pyrophosphate groups (bridging angle ∠(P−O b −P) ≈ 129°) for both LT‐ and HT‐Ag 4 P 2 O 7 , while their conformations change from eclipsed (HT) to staggered (LT). For one half of the Ag + cations in the HT modification, the unusual ninefold coordination in a truncated hexagonal pyramid changes to a distorted tetrahedral coordination in the LT form. Structural/dynamic instability expresses itself by formation of multinary compounds in the systems A 4 P 2 O 7 /Ag 4 P 2 O 7 ( A = Li, Na). Thus, the crystal structures of Li 3 AgP 2 O 7 and LiAg 3 P 2 O 7 show no similarity at all to that of Ag 4 P 2 O 7 , while the closely related crystal structure of Na 2 Ag 2 P 2 O 7 shows distinct ordering of Na + /Ag + despite similar ionic radii.
A Schiff-base ligand (L) was synthesized from the reaction of achiral precursors N 2, N 6-bis(2-aminophenpy)pyridine-2,6-dicarboximide and 4-(1H-imidazol-1-yl)benzaldehyde. Two coordination polymers (CPs), {[CdL P L MI2]& centerdot;2DMF}n (CP 1) and {[ZnL P L M(H2O)2]& centerdot;2I & centerdot;2DMF}n (CP 2) were synthesized from the reaction of L with CdI2 or ZnI2 under the same condition. The single-crystal X-ray diffraction analysis revealed that L exhibits as a racemic ligand with equal amounts of P- and M-helicity configurations. Both CPs 1 and 2 exist as 1D looped-chain polymers. In CP 1, the Cd(II) ions are six-coordinated by four imidazole nitrogen atoms and two I- anions, while the Zn(II) ions in CP 2 are six-coordinated by four imidazole nitrogen atoms and two water molecules, indicating their structural differences in coordination assembly. Moreover, the gas and vapor adsorption measurements displayed that both CPs exhibit good adsorption capacities toward methanol and ethanol vapor.
Themacrocyclic (4,4'-EtO(C=O)(2)tolaneN(3)H)(2) (1) reacts with NiCl2 center dot center dot 6H(2)O to give the complex [Ni((4,4'-EtO(C=O)(2)tolaneN(3))(2)(py)(2)]center dot py (2). The metal ion occupies the centrosymmetric position of the essentially planar macrocyclic ligand (eight-electron donor), coordinated by four N atoms of the two deprotonated diazoamine chains in a distorted octahedral coordination environment completed by two axial monodentate pyridine ligands in trans position to each other. The molecules are connected via C-H center dot center dot center dot(O)COEt contacts involving the para C-H group of the pyridine axial ligand and the carbonyl O atom of one para EtO(C=O)C6H3 substituent of the adjacent complex molecule. These chains are related by translation in the unit cell along the direction [111] through C-H center dot center dot center dot py interactions involving the methylene C-H group of one para EtO(C-O)C6H3 substituent of one [Ni((4,4'-EtO(C=O)(2)tolaneN(3))(2)(py)(2)] complex molecule, and the centroid of the crystallization solvate pyridine, and Cpy-H center dot center dot center dot py interactions involving the meta C-H group of the crystallization solvate pyridine and the centroid of the axial pyridine ligand of the adjacent complex molecule, resulting an extended supramolecular bidimensional (2-D) assembling parallel to the crystallographic plane (100). Additionally, C-H center dot center dot center dot H-C van der Waals interactions are observed along the crystallographic direction [010] involving the meta C-H group of the crystallization solvate pyridine and the methyl C-H group of one para-EtO(C-O)C6H3 substituent of the adjacent complex molecule, as well as from the para C-H group of the axial pyridine ligand and the meta C-H group of the adjacent [Ni((4,4'-EtO(C-O)(2)tolaneN(3))(2)(py)(2)] molecule unit, respectively. The analyses of the first molecular coordination sphere of 2, in addition to its intermolecular interactions analysis and computational studies are essential to understand the processes that stabilize the arrangement in the crystal packing. O ligante macrociclico reage com NiCl2 center dot center dot center dot 6H(2)O para formar o complexo [Ni((4,4'-EtO(C=O)(2)tolanoN(3))(2)(py)(2)]center dot py (2). O ion Ni2+ ocupa a posicao centrossimetrica do ligante macrociclico plano (doador de oito eletrons), coordenado por quatro atomos de nitrogenio das cadeias diazoaminicas desprotonadas. A geometria de coordenacao octaedrica distorcida do centro metalico e completada axialmente por dois ligantes piridina monodentados posicionadas trans entre si. As moleculas sao conectadas por interacoes C-H center dot center dot center dot(O)COEt envolvendo o grupamento para C-H do ligante axial piridina e o oxigenio carbonilico de um substituinte para-EtO(C-O)C6H3 da molecula do complexo adjacente. Estas cadeias relacionam-se entre si por translacao ao longo da direcao cristalografica [111] na cela elementar atraves de interacoes C-H center dot center dot center dot py envolvendo o grupamento C-H (metileno) de um substituinte para-EtO(C=O)C6H3 de uma molecula [Ni((4,4'-EtO(C-O)(2)tolanoN(3))(2)(py)(2)] e o ponto centroide do solvato de cristalizacao piridina, e interacoes Cpy-H center dot center dot center dot py envolvendo o grupamento meta C-H do solvato de cristalizacao piridina e o ponto centroide do ligante piridina axial da molecula do complexo adjacente, resultando um arranjo cristalino supramolecular (2-D) estendido e paralelo ao plano cristalografico (100). Adicionalmente, sao observadas interacoes de van der Waals C-H center dot center dot center dot H-C ao longo da direcao cristalografica [010] a partir do solvato de cristalizacao piridina envolvendo o grupamento meta' C-H da piridina e o grupamento C-H (metila) de um substituinte para-EtO(C=O)C6H3 da molecula do complexo adjacente, e a partir do grupamento para C-H do ligante axial piridina e o grupamento meta C-H de um fragmento fenila da unidade molecular [Ni((4,4'0-EtO(C=O)(2)tolaneN(3))(2)(py)(2)] adjacente. Essas analises da primeira esfera de coordenacao molecular representam, juntamente com o estudo das interacoes intermoleculare e analises computacionais, uma informacao essencial para a compreensao sobre os processos envolvidos no empacotamento cristalino.
The crystal structures of [Na([2.2.2]crypt)]2Na2[(eta 4-Pb4)Mo(CO)3] & centerdot; 8.7NH3 and Na6[Pb4{Mo(CO)3}3] & centerdot; 22NH3 are reported. They contain the novel transition metal-functionalized Zintl ions [(eta 4-Pb4)Mo(CO)3]4- and [Pb4{Mo(CO)3}3]6- that can be related to previously reported lead clusters via the isolobal principle. Nudged elastic band calculations are employed to propose a possible formation mechanism for [(eta 4-Pb4)Mo(CO)3]4-.
Mayenite Ca12Al14O33 (C12A7) is known for its unique properties, resulting from a crystal structure, which consists of a positively charged 'antizeolite-like' framework [Ca12Al14O32]2+ forming cages with 'trapped' oxide ions. Depending on the synthesis route, different transport properties and particle morphologies can be achieved. Due to its potential applications in catalysis, hydrothermally synthesised mayenite with a high specific surface is of special interest. In this work, a new approach for the synthesis of the mayenite precursor hydrogarnet via a microwave-assisted hydrothermal route is introduced. Various synthesis parameters were optimised to shorten the hydrothermal reaction time down to 5 min at a temperature of 80 degrees C. The final formation of C12A7 can be achieved at a moderate temperature of 800 degrees C. An increase of the surface area up to 70 m2/g was obtained. In situ X-ray diffraction and TG-MS measurements were performed to gain insight in the reaction mechanism. This new microwave approach offers a fast and efficient route to mayenite with advantageous properties for catalytic applications.
Applying the three different solutions [Cu(dien)] 2+ in DMSO/H 2 O, acetonitrile, and [Ta 6 O 19 ] 6‐ /H 2 O in a layering approach, the two new polyxotantalates [Cu(dien)] 5 {(Cu(dien)(H 2 O) 2 )Cu(Ta 6 O 19 ) 2 }·DMSO·32 H 2 O ( I ) and K 2 [(Cu(dien)) 6 {Cu(Ta 6 O 19 ) 2 }]·26H 2 O ( II ) (dien = diethylenetriamine) could be synthesized at room temperature within a short time. In the structures of I and II , a Cu 2+ cation and two [Cu(dien)] 2+ complexes connect two {T 6 O 19 } clusters, forming a {(Cu(dien)) 2 Cu(Ta 6 O 19 ) 2 } unit. In the structure of I , two such units are present, which are crystallographically independent but structurally nearly identical. One of the {(Cu(dien)) 2 Cu(Ta 6 O 19 ) 2 } units is expanded by six Cu 2+ ‐centered complexes, while the second group has TaOCuOTa bridges to eight complexes and forms nearly straight chains. These chains are connected by the former {(Cu(dien)) 2 Cu(Ta 6 O 19 ) 2 } moiety, thus generating layers that contain pores. In the structure of II , the {(Cu(dien)) 2 Cu(Ta 6 O 19 ) 2 } unit is structurally very similar to those of I . The building block is expanded by eight Cu 2+ ‐centered complexes, of which two are terminally coordinated. Each {(Cu(dien)) 2 Cu(Ta 6 O 19 ) 2 } unit is connected to four other units via TaOCuOTa bonds to form a puckered layered structure containing pores. The K + ion is coordinated by nine O atoms in a strongly distorted tricapped trigonal prism.
Materials with low dimensionality have been identified as potential candidates for electronic and optoelectronic applications. Semiconducting polyphosphides with one‐dimensional (1D) substructures, such as materials adopting the HgPbP 14 ‐structure type or Pb 5 I 2 P 28 , are examples of this class. Herein, we report on (PbBr 2 )[Pb 2 P 14 ] 2 that crystallizes monoclinically, in space group P 2 1 / n (No. 14), with the cell parameters a = 9.8175(7) Å, b = 17.5841(11) Å, c = 18.9568(15) Å, and β = 97.612(6)°. The title compound consists of formal charge‐neutral PbBr 2 units that interlink entities, resulting in a more descriptive formula (PbBr 2 )[Pb 2 P 14 ] 2 rather than the sum formula Pb 5 Br 2 P 28 . Raman spectroscopy was used to support this adduct description, indicating that the title compound exhibits a bonding situation within the Pb substructure similar to PbBr 2 . First‐principle density functional theory (DFT) calculations on (PbBr 2 )[Pb 2 P 14 ] 2 and isostructural (PbI 2 )[Pb 2 P 14 ] 2 (Pb 5 I 2 P 28 ) illustrate typical semiconductor behavior for these two polyphosphides. Photoluminescence spectroscopy shows two band gaps at 1.90 and 1.79 eV in both (PbBr 2 )[Pb 2 P 14 ] 2 and (PbI 2 )[Pb 2 P 14 ] 2 , which align with the calculated values found from DFT calculations.
Nanomaterials are considered as pioneering and indispensable in the discipline of biological technology for wide range of implementations in biotechnology, pharmaceutical industries, and biomedical fields. Metallic nanoparticles are worthy biological contenders with fascinating physiochemical properties. Among these, the platinum nanoparticles are explored as more valuable due to their unique features. Different strategies are employed to synthesize platinum nanoparticles including chemical, physical, and biological methods. Biological methods are deliberated as the best methods to fabricate Pt nanoparticles as these are convenient, economical, and environment friendly. This review provides an insightful discussion on the properties, harmful impacts, and biomedical applications of platinum nanoparticles that are strongly reliant on their size, elemental composition, morphology, and structure which is controlled by the fabrication technique used. The cytotoxic behavior of platinum nanoparticles is influenced by the size, surface functionalization, and dose quantity which make the ejection of platinum ions within cells more markedly. They possess diverse applications in multiple fields such as nanomedication, nanodiagnostics, bioimaging, and drug delivery carriers owing to their inimitable physiochemical properties. PtNPs have crucial part to radiotherapy, because of their capabilities to persuade cell injury in discriminating part, subsequent to radioactivity contact and have potential to combat tumors. Interestingly, numerous intelligences reveal the advanced capabilities of PtNPs in contrast to other nanozymes such as wound healing, tissue regeneration, and the treatment of some biological ailments related to oxidative stress. In the future, there will be immense variety of applications of platinum nanoparticles in nanomedicine field.
The vacancy‐ordered quadruple perovskites Rb 4 CuSb 2 X 12 ( X = Cl, Br) were synthesized from acidic solutions and by solid‐state reaction. Although both crystal structures are described as new distortion variants of vacancy‐ordered quadruple perovskites, the coordination of the Sb atoms differs depending on the halides (X = Br: CN = 2 + 2 + 2; X = Cl: CN = 4 + 1 + 2). The similarities and differences of the two compounds to each other as well as to the perovskite structure are discussed on the basis of group‐subgroup relationships. In addition, the optical properties (bandgap of approx. 0.63/0.82 eV, Br/Cl) and the electronic structure of Rb 4 CuSb 2 Br 12 are discussed. This also addresses the difficulties in accurately determining the electronic structure of compounds containing Cu 2+ ions using DFT‐based methods.
Two new layered chalcogenide–chloridoaluminate compounds, Cu(Sb 2 Se 3 )[AlCl 4 ] and Cu 5 (Bi 2 Se 3 ) 6 [AlCl 4 ] 5 , were obtained by ionothermal synthesis from Lewis‐acidic [BMIm]Cl/AlCl 3 melts at 200°C. Single‐crystal X‐ray diffraction shows that Cu(Sb 2 Se 3 )[AlCl 4 ] contains corrugated Cu(Sb 2 Se 3 )] + layers in which an intrinsically two‐dimensional Sb 2 Se 3 net built from 12‐membered rings is cross‐linked by copper(I) atoms; [AlCl 4 ] − anions separate the cationic sheets and provide a weak CuCl coordination. Cu 5 (Bi 2 Se 3 ) 6 [AlCl 4 ] 5 features terraced Cu 3 (Bi 2 Se 3 ) 6 ] 3+ layers composed of Bi 2 Se 3 ] ribbons that are connected by copper(I) atoms. The interlayer region comprises [AlCl 4 ] − anions and [CuSeCl 3 ] tetrahedra. Density functional theory‐based bonding analyses indicate highly polar AlCl and CuCl interactions, more covalent CuSe bonding, and predominantly covalent SbSe and BiSe bonds. Electronic‐structure calculations yield indirect band gaps of about 1.35 eV for Cu(Sb 2 Se 3 )[AlCl 4 ] and 0.40 eV for Cu 5 (Bi 2 Se 3 ) 6 [AlCl 4 ] 5 . Optically allowed direct transitions at slightly higher energies account for the broad absorption observed in the UV/Vis spectra. Treatment with dilute HCl partially extracts the chloridoaluminate components and promotes splitting along the layers, producing flake‐like products, albeit with substantial loss of long‐range order.
Green, moisture-sensitive Ca9N4Te3 was obtained from Ca/Na flux at 1173 K as a by-product of reddish-brown Ca6N2Te3 and crystallizes in the trigonal space group R (No. 148, Z = 3). The crystal structure is characterized by layers of edge-sharing trigonal prisms NCa6, face-sharing with octahedra NCa6, which sandwich the layers of prisms. One telluride ion resides in the center of a cuboctahedron formed by 12 calcium cations, while a second crystallographic distinct telluride ion is surrounded by nine calcium ions and another telluride ion. According to electronic structure calculations, the title compound represents a semiconductor. The bonding is predominantly ionic in character. The average ICOBI value of 0.004 for Te(2)-Te(2) reflects that the attractive interaction between two Te(2) atoms is merely of van der Waals type.
A high‐temperature solid‐state synthesis in weld‐shut tantalum ampoules yielded a new alkaline‐earth silicate fluoride, LiBa 2 SiO 4 F. The compound crystallizes isotypically to LiSr 2 SiO 4 F in the monoclinic space group P 2 1 / m (no. 11) with cell parameters of a = 6.8840(3) Å, b = 5.5998(2) Å, c = 7.2670(2) Å, β = 112.60(1)°, and a cell volume of V = 258.62(2) Å 3 . When Eu 2+ as an activator is provided in the synthesis, the resulting product exhibits strong photoluminescence in the blue spectral region with λ max = 465 nm (2.67 eV, 21 505 cm −1 ) and a bandwidth of FWHM = 95 nm (0.54 eV, 4336 cm −1 ) under irradiation with UV‐light. The single‐crystal and powder X‐ray diffraction data as well as the photoluminescence spectroscopy measurements are complemented with scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), and experiments to determine the thermal quenching resistance of the luminescence intensity. Structure and luminescence properties are compared to those of the isotypic strontium compound.
The rocksalt‐type double nitride Ca 2 TaN 3 was synthesized via hot isostatic pressing (HIP) at 1400°C and 150 MPa static dinitrogen pressure from Ca 3 N 2 and Ta 3 N 5 . The bright yellow microcrystalline powder crystallizes in the cubic space group with a lattice parameter of a = 4.7473(1) Å. Structure solution by Rietveld refinement reveals that Ca and Ta statistically share a common crystallographic position. Magnetization measurements confirm a diamagnetic compound with tantalum in the oxidation state +V, while UV–Vis spectroscopy reveals a direct bandgap of E gap = 2.46 eV responsible for the yellow body color. Temperature‐dependent X‐ray diffraction demonstrates excellent thermal stability up to 1000°C with a linear thermal expansion coefficient of α a = 9.95(7) × 10 −6 K −1 . This work demonstrates the potential of HIP for the synthesis of alkaline earth transition metal nitrides.
