Crystal structure of [K(18-crown-6)]+ 2[Pt(CN)4]2.
Ontology highlight
ABSTRACT:
SUBMITTER: Sellin M
PROVIDER: S-EPMC6895955 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:The title complex, poly[dodeca-μ-cyanido-diiron(III)triplat-inum(II)], [Fe(III) 2{Pt(II)(CN)4}3], has a three-dimensional polymeric structure. It is built-up from square-planar [Pt(II)(CN)4](2-) anions (point group symmetry 2/m) bridging cationic [Fe(III)Pt(II)(CN)4](+) ∞ layers extending in the bc plane. The Fe(II) atoms of the layers are located on inversion centres and exhibit an octa-hedral coordination sphere defined by six N atoms of cyanide ligands, while the Pt(II) atoms are located on twofold rotation axes and are surrounded by four C atoms of the cyanide ligands in a square-planar coordination. The geometrical preferences of the two cations for octa-hedral and square-planar coordination, respectively, lead to a corrugated organisation of the layers. The distance between neighbouring [Fe(III)Pt(II)(CN)4](+) ∞ layers corresponds to the length a/2 = 8.0070 (3) Å, and the separation between two neighbouring Pt(II) atoms of the bridging [Pt(II)(CN)4](2-) groups corresponds to the length of the c axis [7.5720 (2) Å]. The structure is porous with accessible voids of 390 Å(3) per unit cell.
| S-EPMC4331858 | biostudies-literature
Project description:The salt [K(18-crown-6)]2[Ru(CN)2(CO)3] ([K(18-crown-6)]2[1]) was generated by the reaction of Ru(C2H4)(CO)4 with [K(18-crown-6)]CN. An initial thermal reaction gives [Ru(CN)(CO)4]-, which, upon ultraviolet (UV) irradiation, reacts with a second equiv of CN-. Protonation of [1]2- gave [HRu(CN)2(CO)3]- ([H1]-), which was isolated as a single isomer with mutually trans cyanide ligands. The complex cis,cis,cis-[Ru(pdt)(CN)2(CO)2]2- ([2]2-) was prepared by the UV-induced reaction of [1]2- with propanedithiol (pdtH2). The corresponding iron complex cis,cis,cis-[Fe(pdt)(CN)2(CO)2]2- ([3]2-) was prepared similarly. The pdt complexes [2]2- and [3]2- were treated with Fe(benzylideneacetone)(CO)3 to give, respectively, [RuFe (μ-pdt)(CN)2(CO)4]2- ([5]2-) and [Fe2(μ-pdt)(CN)2(CO)4]2- ([4]2-). The pathway from [3]2- to Fe2 complex [4]2- implicates intermetallic migration of CN-. In contrast, the formation of [5]2- leaves the Ru(CN)2(CO) center intact, as confirmed by X-ray crystallography. The structure of [5]2- features a "rotated" square-pyramidal Fe(CO)2(μ-CO) site. NMR measurements indicate that the octahedral Ru site is stereochemically rigid, whereas the Fe site dynamically undergoes turnstile rotation. 57Fe Mössbauer spectral parameters are very similar for rotated [5]2- and unrotated Fe2 complex [4]2-, indicating the insensitivity of that technique to both the geometry and the oxidation state of the Fe site. According to cyclic voltammetry, [5]2- oxidizes at E1/2 ∼ -0.8 V vs Fc+/0. Electron paramagnetic resonance (EPR) measurements show that 1e- oxidation of [5]2- gives an S = 1/2 rhombic species, consistent with the formulation Ru(II)Fe(I), related to the Hox state of the [FeFe] hydrogenases. Density functional theory (DFT) studies reproduce the structure, 1H NMR shifts, and infrared (IR) spectra observed for [5]2-. Related homometallic complexes with both cyanides on a single metal are predicted to not adopt rotated structures. These data suggest that [5]2- is best described as Ru(II)Fe(0). This conclusion raises the possibility that for some reduced states of the [FeFe]-hydrogenases, the [2Fe]H site may be better described as Fe(II)Fe(0) than Fe(I)Fe(I).
| S-EPMC10712436 | biostudies-literature
Project description:The asymmetric unit of the title compound, catena-poly[[[(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ-cyanido-κ2 N:C-[bis-(cyanido-κC)nickel(II)]-μ-cyanido-κ2 C:N] dihydrate], {[Ni2(CN)4(C10H24N4)]·2H2O] n or [{[Ni(C10H24N4)][Ni(CN)4]}·2H2O] n , consists of a pair of crystallographically non-equivalent macrocyclic cations and anions. The nickel(II) ions (all with site symmetry ) are coordinated by the four secondary N atoms of the macrocyclic ligands, which adopt the most energetically stable trans-III conformation, and the mutually trans N atoms of the tetra-cyano-nickelate anion in a slightly tetra-gonally distorted NiN6 octa-hedral coordination geometry. The [Ni(CN)4)]2- anion exhibits a bridging function, resulting in the formation of parallel polymeric chains running along the [10] direction. The water mol-ecules of crystallization play a pivotal role in the three-dimensional supra-molecular organization of the crystal. Acting as acceptors, they form N-H⋯Ow (w = water) hydrogen bonds with the secondary amino groups of the macrocycles, forming layers oriented parallel to the (001) plane. At the same time, as donors, they inter-act with the non-coordinated cyano groups of the anion via Ow-H⋯Nc (c = cyanide) hydrogen bonds, giving two-dimensional layers oriented parallel to the (100) plane and thus generating a three-dimensional network.
| S-EPMC8587981 | biostudies-literature
Project description:In our attempt to search for mixed alkaline-earth and transition metal arsenates, the title compound, barium dimanganese(II) bis-(arsenate), has been synthesized by employing a high-temperature RbCl flux. The crystal structure of BaMn2(AsO4)2 is made up of MnO6 octa-hedra and AsO4 tetra-hedra assembled by sharing corners and edges into infinite slabs with composition [Mn2(AsO4)2]2- that extend parallel to the ab plane. The barium cations reside between parallel slabs maintaining the inter-slab connectivity through coordination to eight oxygen anions. The layered anionic framework comprises weakly inter-acting [Mn4O18]28- tetra-meric units. In each tetra-mer, the manganese(II) cations are in a planar arrangement related by a center of inversion. Within the slabs, the tetra-meric units are separated from each other by 6.614 (2) Å (Mn⋯Mn distances). The title compound has isostructural analogues amongst synthetic SrM2(XO4)2 compounds with M = Ni, Co, and X = As, P.
| S-EPMC5730239 | biostudies-literature
Project description:The title compound (systematic name: cis-anti-cis-2,5,8,15,18,21-hexa-oxatri-cyclo-[20.4.0.0(9,14)]hexa-cosane aceto-nitrile disolvate), C20H36O6·2CH3CN, crystallizes from an aceto-nitrile solution of di-cyclo-hexane-18-crown-6 on evaporation. The mol-ecule is arranged around a center of symmetry with half the crown ether mol-ecule and one mol-ecule of aceto-nitrile symmetry independent. All O-C-C-O torsion angles are gauche while all C-O-C-C angles are trans. The sequence of torsion angles is [(tg(+)t)(tg(-)t)]3; the geometry of oxygen atoms is close to pseudo-D 3d with three atoms below and three atoms above the mean plane, with an average deviation of ±0.16 (1) Å from the mean plane. This geometry is identical to that observed in metal ion complexes of di-cyclo-hexane-18-crown-6 but differs significantly from the conformation of a free unsolvated mol-ecule. Each aceto-nitrile mol-ecule connects to a crown ether mol-ecule via two of its methyl group H atoms (C-H⋯O). Weaker inter-actions exist between the third H atom of the aceto-nitrile methyl group and an O atom of a neighbouring crown ether mol-ecule (C-H⋯O); and between the N atom of the aceto-nitrile mol-ecule and a H atom of another neighbouring crown ether mol-ecule. All these inter-molecular inter-actions create a three-dimensional network stabilizing the disolvate.
| S-EPMC4518961 | biostudies-literature
Project description:We report here a supercatalyst for oxygen reduction of Pt/CNx/Ni in a unique ternary heterostructure, in which the Pt and the underlying Ni nanoparticles are separated by two to three layers of nitrogen-doped carbon (CNx), which mediates the transfer of electrons from the inner Ni to the outer Pt and protects the Ni against corrosion at the same time. The well-engineered low-Pt catalyst shows ∼780% enhanced specific mass activity or 490% enhanced specific surface activity compared with a commercial Pt/C catalyst toward oxygen reduction. More importantly, the exceptionally strong tune on the Pt by the unique structure makes the catalyst superbly stable, and its mass activity of 0.72 A/mgPt at 0.90 V (well above the US Department of Energy's 2020 target of 0.44 A/mgPt at 0.90 V) after 50,000 cyclic voltammetry cycles under acidic conditions is still better than that of the fresh commercial catalyst.
| S-EPMC6348290 | biostudies-literature
Project description:The compression behavior of [Rb(18-crown-6)][SbCl6] crystal under pressure up to 2.16 (3) GPa was investigated in a diamond anvil cell (DAC) using a mixture of pentane-isopentane (1:4) as the pressure-transmitting fluid. The compound crystallizes in trigonal space group R3 and no phase transition was observed in the indicated pressure range. The low value of pressure bulk modulus [9.1 (5) GPa] found in this crystal is a characteristic of soft materials with predominant dispersive and electrostatic interaction forces. The nonlinear relationship between unit-cell parameters under high pressure is attributed to the influence of reduced intermolecular H...Cl contacts under pressure over 0.73 GPa. It also explains the high compression efficiency of [Rb(18-crown-6)][SbCl6] crystals at relatively low pressures, resulting in a significant shift of the Rb atom to the center of the crown ether cavity. At pressures above 0.9 GPa, steric repulsion forces begin to play a remarkable role, since an increasing number of interatomic H...Cl and H...H contacts become shorter than the sum of their van der Waals (vdW) radii. Below 0.9 GPa, both unit-cell parameter dependences (P-a and P-c) exhibit hysteresis upon pressure release, demonstrating their influence on the disordered model of Rb atoms. The void reduction under pressure also demonstrates two linear sections with the inflection point at 0.9 GPa. Compression of the crystal is accompanied by a significant decrease in the volume of the voids, leading to the rapid approach of Rb atoms to the center of the crown ether cavity. For the Rb atom to penetrate into the center of the crown ether cavity in [Rb(18-crown-6)][SbCl6], it is necessary to apply a pressure of about 2.5 GPa to disrupt the balance of atomic forces in the crystal. This sample serves as a compression model demonstrating the influence of both attractive and repulsive forces on the change in unit-cell parameters under pressure.
| S-EPMC10994168 | biostudies-literature
Project description:The first synthesis of BePh2 was accomplished almost a century ago. However, its structure has remained unknown so far, while the corresponding aryls of the elements adjacent to beryllium in the periodic table are well investigated. Herein, we present an improved synthesis for diphenylberyllium and show by X-ray diffraction that it forms a trinuclear complex in the solid state. NMR spectroscopy revealed that this structure is also retained in solution but exhibits dynamic behavior. Its stability against heat and coordinating solvents is discussed and the possible obstacles to the synthesis of BePh2 from BeCl2 are examined. In the process of this study two ether adducts, BePh2 ⋅Et2 O and Be2 Ph4 ⋅Et2 O, have been characterized as well as the previously unknown triphenylberyllate anion. From the latter several single-crystal structures were obtained under various conditions, in which [BePh3 ]- is either isolated or acts as a ligand for Li+ . Furthermore, the crown ether induced selfionization of BePh2 is described and the resulting [(12-crown-4)BePh]+ cation was isolated, which shows an unusual 4+1 coordination around the Be atom.
| S-EPMC7496417 | biostudies-literature
Project description:The structure of the title compound, poly[triaquatetra-?-cyanido-tetracyanidobis-(1,4,10,13-tetra-oxa-7,16-diaza-cyclo-octa-deca-ne)di-barium(II)tetra-gold(I)], [Au(4)Ba(2)(CN)(8)(C(12)H(26)N(2)O(4))(2)(H(2)O)(3)](n), displays O-H?N hydrogen bonding between water molecules and cyano ligands and an unusual pattern of aurophilic inter-actions that yields a monomer, dimer, and trimer of [Au(CN)(2)](-) within the same crystal structure. In two of the five Au positions, the atom resides on a center of inversion. The overall arrangement is that of a coordination polymer assisted by aurophilic and hydrogen-bonded inter-actions.
| S-EPMC2968470 | biostudies-literature
Project description:Density functional theory computational investigation was performed to study the electronic structures, muon sites, and the associated hyperfine interactions in [Au25(SR)18]0 and [Au25(SeR)18]0 where R is phenylethane. The calculated electronic structures show inhomogeneous spin density distribution and are also affected by different ligands. The two most stable muon sites near Au atoms in the thiolated system are MAu11 and MAu6. When the thiolate ligands were replaced by selenolate ligands, the lowest energy positions of muons moved to MAu6 and MAu5. Muons prefer to stop inside the Au12 icosahedral shell, away from the central Au and the staple motifs region. Muonium states at phenyl ring and S/Se atoms in the ligand were found to be stable and the Fermi contact fields are much larger as compared to the field experienced by muons near Au atoms.
| S-EPMC7774246 | biostudies-literature