Structures of Pd(CN)2 and Pt(CN)2: intrinsically nanocrystalline materials?

Analysis and modeling of X-ray and neutron Bragg and total diffraction data show that the compounds referred to in the literature as "Pd(CN)(2)" and "Pt(CN)(2)" are nanocrystalline materials containing small sheets of vertex-sharing square-planar M(CN)(4) units, layered in a disordered manner with an intersheet separation of ~3.44 ? at 300 K. The small size of the crystallites means that the sheets' edges form a significant fraction of each material. The Pd(CN)(2) nanocrystallites studied using total neutron diffraction are terminated by water and the Pt(CN)(2) nanocrystallites by ammonia, in place of half of the terminal cyanide groups, thus maintaining charge neutrality. The neutron samples contain sheets of approximate dimensions 30 ? × 30 ?. For sheets of the size we describe, our structural models predict compositions of Pd(CN)(2)·xH(2)O and Pt(CN)(2)·yNH(3) (x ≈ y ≈ 0.29). These values are in good agreement with those obtained from total neutron diffraction and thermal analysis, and are also supported by infrared and Raman spectroscopy measurements. It is also possible to prepare related compounds Pd(CN)(2)·pNH(3) and Pt(CN)(2)·qH(2)O, in which the terminating groups are exchanged. Additional samples showing sheet sizes in the range ~10 ? × 10 ? (y ~ 0.67) to ~80 ? × 80 ? (p = q ~ 0.12), as determined by X-ray diffraction, have been prepared. The related mixed-metal phase, Pd(1/2)Pt(1/2)(CN)(2)·qH(2)O (q ~ 0.50), is also nanocrystalline (sheet size ~15 ? × 15 ?). In all cases, the interiors of the sheets are isostructural with those found in Ni(CN)(2). Removal of the final traces of water or ammonia by heating results in decomposition of the compounds to Pd and Pt metal, or in the case of the mixed-metal cyanide, the alloy, Pd(1/2)Pt(1/2), making it impossible to prepare the simple cyanides, Pd(CN)(2), Pt(CN)(2), or Pd(1/2)Pt(1/2)(CN)(2), by this method.     

Solid state structures of the chiral heterobimetallic complexes [Cu(dach)2][Pt(CN)4] · 2H2O, [Ni(dach)3][Pt(CN)4] · 2DMF · H2O,and [Pd(dach)2][Pt(CN)4] · H2O (dach = 1 R , 2 R -diaminocyclohexane)

The chiral dinuclear heterometallic complexes [Cu(dach)₂][Pt(CN)₄]?·?2H₂O (1), [Ni(dach)₃][Pt(CN)₄]?·?2DMF?·?H₂O (2), and [Pd(dach)₄][Pt(CN)₄]?·?H₂O (3) (dach?=?1R,2R-cyclohexanediamine) have been prepared and characterized by X-ray diffraction analysis. Crystal data: 1, monoclinic, P2₁, a?=?8.108(3), b?=?15.552(6), c?=?9.914(4)?Å, β?=?110.931(6)°, V?=?1167.6(8)?ų, Z?=?2, R ₁?=?0.0420, wR ₂?=?0.1122; 2, monoclinic, P2₁, a?=?13.264(11), b?=?9.285(7), c?=?16.211(13)?Å, β?=?111.640(9)°, V?=?1856(3)?ų, Z?=?2, R ₁?=?0.0276, wR ₂?=?0.0698; 3, monoclinic, P2₁, a?=?6.887(2), b?=?12.809(4), c?=?12.975(4)?Å, β?=?94.865(4)°, V?=?1140.6(6)?ų, Z?=?2, R ₁?=?0.057, wR ₂?=?0.156. In complex 1, the Pt and Cu atoms are linked by a CN bridge that presents a very bent C=N–Cu angle [136.8(8)°].     

Evidence for hydrogen bond network formation in microsolvated clusters of Pt(CN)4(2-): collision induced dissociation studies of Pt(CN)4(2-)·(H2O)(n) n = 1-4, and Pt(CN)4(2-)·(MeCN)(m) m = 1, 2 cluster ions

Low-energy collision induced dissociation has been used to investigate the structure and stability of microsolvated clusters of the prototypical, aprotic multiply charged anion, Pt(CN)(4)(2-), i.e. Pt(CN)(4)(2-)·(H(2)O)(n) n = 1-4, Pt(CN)(4)(2-)·(MeCN)(m) m =1, 2, and Pt(CN)(4)(2-)·(H(2)O)(3)·MeCN. For all of the systems studied, the lowest energy fragmentation pathway was found to correspond to decay of the cluster with loss of the entire solvent ensemble. No sequential solvent evaporation was observed. These observations suggest that the Pt(CN)(4)(2-) solvent clusters studied here form hydrogen-bonded "surface solvated" structures. Electronic structure calculations are presented to support the experimental results. In addition, the detailed fragmentation patterns observed are interpreted with reference to the differential solvation of the ionic fragmentation and electron detachment potential energy surfaces of the core Pt(CN)(4)(2-) dianion. The results described represent some of the first experiments to probe the microsolvation of this important class of multiply charged anions.     

Far infrared spectra of K2Pt(CN)4Br0.3·3.2H2O

Polarized far i.r. reflection spectra of K₂Pt(CN)₄Br_0.3·3.2H₂O were measured at 220, 150 and 80 K for the frequency range 15–400 cm⁻¹. The E|c and E ⊥ c spectra were analysed on the basis of the one- and four-oscillator model, respectively. Observed bands were interpreted based on the average structure (C¹_4υ, Z = 2), not taking into account Peierls distortion.     

Synthesis and Crystal Structure of the 2-D Polymer {Cu(bipy)Pt(CN)4}∞ and Its Relationship to the Tetranuclear Compound [{Cu(bipy)(H2 O)Pt(CN)4}2]·2H2O

The reaction of (NBu₄)₂[Pt(CN)₄] with Cu(NO₃)₂·2.5H₂O and bipy in stoichiometric ratio in methanol solution yields the 2-D polymer {Cu(bipy)Pt(CN)₄}. The influence of water molecules and hydrogen bonding on the formation of a 2-D polymeric structure versus a tetranuclear cluster from Cu(bipy)Pt(CN)₄ units is discussed.     

NEW THREE DIMENSIONAL [Cd(CN)2]n FRAMEWORK FORMED WITH CADMIUM CYANIDE AND Cd(CN)2·(18-CROWN-6): CRYSTAL STRUCTURE OF [Cd(CN)2]·1/2[Cd(CN)2 (18-CROWN-6)]·3/2EtOH+

Abstract

The cadmium complex Cd(CN)₂·(18-crown-6) (1) was synthesized and its structure was determined by X-ray crystallography. The cadmium ion in 1 has a hexagonal bipyramidal geometry containing six equatorial oxygen atoms from the crown ether and two axial CN ligands. The NC-Cd-CN ‘rod’ is perfectly linear with an end-to-end distance of 6.509 (12) Å. When 1 was allowed to diffuse into a cadmium cyanide solution, the infinite coordination complex [Cd(CN)₂]·1/2[(Cd(CN)₂·(18-crown-6)]·3/2EtOH (2) was obtained in which the cadmium macrocycle 1 was trapped in a 10-faced-cage formed by the [Cd(CN)₂]n framework. The terminal nitrogen atoms of 1 bind two Cd centers across the cage. The trapped Cd(CN)₂·(18-crown-6) has a significantly bent NC-Cd-CN unit and the crown ether ligand disordered over two orientations. The [Cd(CN)₂]_n framework viewed down the c axis shows two types of channels, one octagonal and one tetragonal, which are filled with Cd(CN)₂·(18-crown-6) and ethanol molecules, respectively. Crystallographic data of 1: trigonal, space group R·3 (hexagonal axis), a = 11.757 (1), c = 12.105 (1) Å, V = 1449.1 (2) ų, Z = 3, R = 0.0566, R_w = 0.0674 for 827 unique reflections (I>3σ(I)). Crystallographic data of 2: orthorhombic, Pbcn, a = 16.632 (1), b = 17.391 (3), c = 15.685 (2) Å, V = 4536.8 (9) ų, Z = 8. R = 0.0486, R_w = 0.0492 for 929 unique reflections (I>3σ(I)).     

Synthesis and Crystal Structure of a Sandwiched Trinuclear Complex [Tl2(18-Crown-6)2Pt(CN)4]·2H2O

The trinuclear complex bis(18-crown-6)thallium tetracyanoplatinate [Tl2(18-crown- 6)2Pt(CN)4]·2H2O was prepared and its structure was determined by X-ray diffraction analysis. The compound (C28H52N4O14PtTl2, Mr = 1272.57) crystallizes in monoclinic, space group P21/n with a = 10.5180(10), b = 8.6162(8), c = 21.118(2) (A), β = 92.577(2)°, V = 1911.9(3) (A)3, Z = 2, Dc = 2.211 g/cm3, F(000) = 1200, μ = 12.123 mm-1, R = 0.0181 and wR = 0.0427. The linearly arranged three metals are sandwiched by two 18-crown-6 molecules.     

Variance of Solid-state Pt···Pt Interactions in Luminescent Cyclometalated Cationic Pt(Ⅱ)-isocyanide Complexes

Polymorphic structures of cyclometalated cationic Pt(Ⅱ)-isocyanide complexes(–)-1 [Pt((-)-NNC)(Dmpi)]Cl with different packing modes can be isolated before. In this paper, a series of solid-state powders with variable colors(yellow, orange and red) have been obtained from the evaporation of complex(–)-1 in different solvents. The crystallinity, thermogravimetric properties, absorption, luminescence and excited state lifetimes have been studied. In addition, intermolecular Pt···Pt interactions in the optimized configurations of different aggregates have been explored, and calculations of frontier molecular orbitals of monomer, dimer, trimer and tetramer have been carried out.     

Crystal structure of CsLnFe(CN)6·5H2O (Ln=Ce,Pr, Nd), CsCeFe(CN)6·4H2O,and TlTmRu(CN)6·3H2O

We have investigated the crystal structures of CsLnFe(CN)₆·nH₂O (Ln=lanthanide, n=4,5), as well as TlTmRu(CN)₆·3H₂O. These phases can be thought of as derivatives of LnFe(CN)₆·4H₂O, where, simultaneously, an alkali ion (or Tl⁺) is introduced while the valence of Fe is reduced from Fe³⁺ to Fe²⁺. A new arrangement of the structural units is observed in the CsLnFe(CN)₆·5H₂O, where the coordination of the Ln-ion is changed to a bisdisphenoid. The resulting LnN₅O₃ units alternate with Fe(CN)₆ units to form an overall rocksalt-type ralted lattice that accommodates the alkali ions in interstitial sites. Due to the arrangement of the water molecules, a layer structure results.     

CRYSTAL STRUCTURE OF Na[Nd(S_2CN(C_2H_5)_2)_4]·CH_3CN

<正> Triclinic, PI, a=10.204(3), b=ll.384(2), c=18.399(4) X, a=84.19 (2), 6=106.15(2), Y=116.71(2)? V=1833.1(6)S3, Z=2, y=18.76cm, A=0.71069&, F(OOO)=809.91, room temperature, .R=0.059. In, the title compound the neodym-ium ion is coordinated by eight sulphur atoms from S2CNEt2ligands with the average distances of 2.88A and 2.<.Et2N桟桟\(:S桸Et2-Nb-\\C 桸Et2     

Vibrational Spectroscopic Investigations of M(Imidazole)2Ni(CN)4·2 Dioxane Clathrates

Four new clathrates of the formula M(Im)2Ni(CN)4·2·Dioxane (where M = Co, Ni, Cu, Cd; Im = Imidazole) have been prepared in powder form and their FT-IR and laser-Raman spectra are reported for the first time. These clathrates are analogues to the previously reported classical Hofmann type clathrates except for the copper clathrate. The Cu clathrate has different spectral features in comparison with its analogues due to the Jahn-Teller effect.     

CN在 Pt(100)表面吸附的密度泛函研究

采用密度泛函方法,以原子簇Pt14为模拟表面,对CN自由基分子在Pt(100)表面上不同吸附位的吸附情况进行了研究.结果表明,CN分子吸附在Pt(100)面上时,通过原子C垂直吸附在表面顶位是其最佳吸附方式,CN键振动频率明显发生蓝移,与实验事实相吻合;而在桥位及四方穴位吸附时CN键振动频率均发生红移.吸附前后,CN分子的σ、π电子与底物间的电荷转移的差异决定了CN键振动频率的不同变化.     

Synthesis and Crystal Structure of a Sandwiched Trinuclear Complex [Tl_2(18-Crown-6)_2Pt(CN)_4]·2H_2O

1 INTRODUCTION Tetracyanoplatinate ion often forms one-dimen- sional chain compounds, and the Pt–Pt spacings are often only 0.01~0.3 ? longer than those in Pt metal (2.78 ?). The studies of room-temperature electrical conductivities of these complexes indicate that the shorter the Pt–Pt separations in the chains are, the higher the electrical conductivity is[1~3]. Tetracyano- platinate ion may also stack with suitable planar cations into one-dimensional materials such as [Pt- (CNR)4]…     

DUAL BEHAVIOR OF ACETONITRILE IN A NEW CADMIUM CYANIDE CLATHRATE: CRYSTAL STRUCTURE OF Cd(CH3CN)2Cd(CN)4·2CH3CN

Abstract

We report a new crystal structure of the title clathrate containing tetrahedral and octahedral Cd atoms in a ratio of 1:1. The preparation of the compound is similar to that of the cristobalite-like clathrate Cd(CN)₂·G, where all Cd atoms are tetrahedral. The new inclusion compound crystallizes in the monoclinic space group C2/c, a = 12.337(4), b = 11.964(3), c = 13.594(3) Å, β = 108.60(2)°, Z = 4, R = 0.034 for 1631 reflections. The three-dimensional host framework is built of alternate linkages between the tetrahedral Cd atom of the tetracyanocadmate and the octahedral Cd atom similar to that of the Hofmann-Td and the en-Td types. In the new clathrate dual behavior of acetonitrile, one as a unidentate ligand in the three-dimensional host framework and the other as the guest in the cage-like cavity, has been demonstrated.     

CRYSTAL STRUCTURES OF Cd(H2O)2Cu(CN)3·2H2O,K[Cd(H2O)2Cu2(CN)5]·2H2O AND K2[Cd(H2O)Cu4(CN)8]·1.5H2O. STRUCTURES OF MULTI-DIMENSIONAL FRAMEWORKS FORMED WITH CADMIUM(II), COPPER(I) AND BRIDGING CYANO GROUPS

Abstract

In an attempt to form new multi-dimensional structures of cyano complexes including cadmium(II) and copper(I), four new complexes were obtained successively from an aqueous solution at intervals of from a few days to a few months. The complex 1 obtained first was unstable in the atmosphere. The crystal structures of the other complexes (2–4) obtained from second to fourth were determined by single crystal X-ray structure determinations. Their crystal data are as follows: 2 Cd(H₂O)₂ Cu(CN)₃·2H₂O, monoclinic, C2/m, a = 14.038(1), b = 9.944(1), c = 7.738(1) Å, β = 116.019(7)°, Z = 4; 3 K[Cd(H₂O)₂Cu₂(CN)₅]·2H₂O, triclinic, PI, a = 17.429(9), b = 16.519(7), c = 10.085(5) Å, α = 128.60(3), β = 137.44(2), γ = 45.82(2)°, Z = 4; 4 K₂[Cd(H₂O)Cu₄(CN)₈]·1.5H₂O, monoclinic, C2/c, a = 19.387(2), b = 16.056(3), c = 12.663(2)Å, β = 110.419(9)°, Z = 4. The main structural feature found in the complexes is that the whole framework consists of two networks, a Cd-Cu(I)-CN complex network that has an infinite network formed with bridging cyano groups between the metal atoms and a network formed with hydrogen bonding among water molecules. The second network is connected to Cd in the Cd-Cu(I)-CN complex network via a water ligand coordinated to Cd. In 2 a planar network of [CdCu(CN)₃] complexes are stacked along the c axis and the second network links the stacked complexes. 3 has a stacked structure of [Cd(H₂O)₂Cu(CN)₅]^2? in a bi-layered structure. The second network of 3, which includes K⁺ ions with an electrostatic interaction, spreads over the crystal, penetrating vacant spaces of the metal complex network. 4 has a double lattice structure with a pair of enantiomeric three-dimensional [Cd(H₂O)Cu₄(CN)₈]^2? complexes inter-penetrating each other. There are three structural factors for forming these framwork structures: (1) a non-planar coordination structure for Cd(II) that extends the planar structure of the Cu(I)-CN complex to a three-dimensional structure for the Cd-Cu(I)-CN complex; (2) a trigonal planar coordination structure for Cu(I) that generates vacant space in the metal complex network and makes possible hydrogen bonds to form the second network; (3) structural distortions of bridging cyano groups and a coordination structure of Cu(I) that cause variations of the metal complex network structure.     

Platinum(II) cyclo-hexamethylenedithiocarbamate complex, [Pt{S2CN(CH2)6}2] and its solvated form, [Pt{S2CN(CH2)6}2] · CHCl3: Crystal and molecular structures, 13C CP/MAS NMR data, and thermal behavior

Platinum(II) cyclo-hexamethylenedithiocarbamate (HmDtc) complex, [Pt{S₂CN(CH₂)₆}₂] (I), and its solvated form, Pt{S₂CN(CH₂)₆}₂] · CHCl₃ (II), are synthesized and characterized by the ¹³C MAS NMR data. The HmDtc ligands in structure I are not equivalent, whereas the solvation of the complex is accompanied by the structural unification of the initially nonequivalent HmDtc ligands. In addition, the spectra are characterized by the ¹³C-¹⁹⁵Pt spin-spin coupling. The noncentrosymmetric molecular structure of compound I determined by X-ray diffraction analysis includes two nonequivalent dithiocarbamate ligands coordinated by the metal in the S,S′-bidentate mode. The central atom forming the [PtS₄] chromophore (intraorbital dsp ²-hybrid state of platinum) shifts from the plane of four sulfur atoms by 0.07 Å in the vertex of the flattened tetragonal pyramid. The seven-membered heterocycles ?N(CH₂)₆ of the HmDtc ligands are oppositely directed in space relative to the [S₄] plane (trans orientation). The thermal behavior of compounds I and II are studied by simultaneous thermal analysis. In both cases, the final product of the multistage thermal destruction of the complexes is reduced metallic platinum.     

Synthesis and Structure of Acetonitrile Solvates of Copper(II) Monofluoroacetate and Silver(I) Trifluoroacetate, [Cu2(CH2FCOO)4· 2CH3CN](CH3CN) and Ag3(CF3COO)3(CH3CN)2

Compounds [Cu₂(CH₂FCOO)₄· 2CH₃CN](CH₃CN) (I) and Ag₃(CF₃COO)₃(CH₃CN)₂(II) were synthesized and studied by X-ray structural analysis. Crystals Iare monoclinic, space group C2/c, a= 27.854(6), b= 8.286(2), c= 19.428(4) Å, = 106.82(3)°, V= 4292(2) ų, Z= 8, R ₁= 0.0426; crystals IIare triclinic, space group , a= 8.676(2), b= 9.819(2), c= 11.961(2) Å, = 95.27(3), = 109.59(3)°, = 104.60(3)°, V= 911.4(3) ų, Z= 2, R ₁= 0.0252. Structure Iis composed of the structural units (lanterns) typical of copper(II) carboxylates. The presence of an additional acetonitrile molecule noncoordinated by the copper atoms makes it possible to consider compound Ias a lattice clathrate. Structure IIhas no analogs among the silver carboxylates. It simultaneously contains silver atoms with coordination numbers varying from 2 to 4.     

Oxidation of coordinated ethylenediamine in platinum(IV) complexes with bromine. Crystal structures of [Pt(en)Py2Br2]Br2 · H2O, [Pt(HN-C(O)-C(O)-NH)Py2Br2] · H2O, and [Pt(en)PyBr3]NO3

Heating of an aqueous solution of [Pt(en)Py₂Cl₂]Cl₂ · 2H₂O (I) with KBr excess leads to the formation of [Pt(en)Py₂Br₂]Br₂ · H₂O (II). The interaction of a solution of II with bromine water results in the precipitation of polybromide ([Pt(en)Py₂Br₂]Br₂ · Br₂), which within a few days in the reaction solution partly transforms into oximide platinum(IV) complex, [Pt(HN-C(O)-C(O)-NH)Py₂Br₂] · H₂O (III). Complex [Pt(en)PyBr₃]Br · H₂O (IV) with an impurity of II was prepared by reacting KBr excess and the product of [Pt(en)Py₂]Cl₂ oxidation with chlorine in 0.05 N HCl. The action of HNO₃ on the solution of IV produced a nitrate derivative ([Pt(en)PyBr₃]NO₃, V). Complex IV, unlike II, does not react with bromine. The IR spectra of all the obtained compounds were recorded. Complexes II, III, and V were studied by X-ray crystallography. The crystals of II are monoclinic, space group P2₁/c, a = 15.640(2) Å, b = 9.345(1) Å, c = 14.167(2) Å, β = 102.63(1)°, V = 2020.5(5) ų, Z = 4, R _hkl = 0.033. The crystals of III are triclinic, space group P $\bar 1$ , a = 7.108(1) Å, b = 10.946(1) Å, c = 11.020(2) Å, α = 83.63(1)°, β = 80.31(1)°, γ = 75.02(1)°, V = 814.4(2) ų, Z = 2, R _hkl = 0.033. In the near-planar five-membered chelate ring (torsion angle NCCN is 7°), the C-O distances (1.23(1) Å) correspond to double bonds; the C-C (1.53(1) Å) and C-N (1.31(1) Å), distances correspond to ordinary bonds. The crystals of V are monoclinic, space group P2₁/c, a = 8.306(2) Å, b = 8.995(2) Å, c = 20.231(4) Å, β = 97.48(2)°, V = 1498.6(6) ų, Z = 4, R _hkl = 0.037.