Theoretical studies on the inner-sphere reorganization energies for the self-exchange reactions of gas-phase diatomic molecules HA (A = Mg,Al, Si,P, S,Cl)

On the basis of the recently proposed accurate calculation scheme of the inner-sphere reorganization energies (RE ) of the reactants in gas-phase electron-transfer xprocesses, the inner-sphere RE values for the AH + AH⁺ (A = Mg, Al, Si, P, S, Cl) self-exchange systems are calculated in terms of an ab initio Hartree–Fock self-consistent-field MO method at different basis-set levels (6-31G **, 6-31 +G **, DZ , and DZP ). The structural parameters involved are also determined via the perturbation theory and the Dunham expansion of the Morse function and compared with the experimental values. Dissociation energies are corrected by electron correlation at the MP 2/6-31G * level. Results of the inner-sphere REs obtained from different models via ab initio calculations for these systems discussed here are in full agreement with the corresponding experimental data. © 1995 John Wiley & Sons, Inc.     

Theoretical study on structures and vibrational spectra of M+(H2O)Ar (M = Cu,Ag, Au)

A theoretical study on the structures and vibrational spectra of M⁺(H₂O)Ar_0‐1 (M = Cu, Ag, Au) complexes was performed using ab initio method. Geometrical structures, binding energies (BEs), OH stretching vibrational frequencies, and infrared (IR) absorption intensities are investigated in detail for various isomers with Ar atom bound to different binding sites of M⁺(H₂O). CCSD(T) calculations predict that BEs are 14.5, 7.5, and 14.4 kcal/mol for Ar atom bound to the noble metal ion in M⁺(H₂O)Ar (M = Cu, Ag, Au) complexes, respectively, and the corresponding values have been computed to be 1.5, 1.3, and 2.1 kcal/mol when Ar atom attaches to a H atom of water molecule. The former structure is predicted to be more stable than the latter structure. Moreover, when compared with the M⁺(H₂O) species, tagging Ar atom to metal cation yields a minor perturbation on the IR spectra, whereas binding Ar atom to an OH site leads to a large redshift in OH stretching vibrations. The relationships between isomers and vibrational spectra are discussed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Photodissociation spectroscopy of Zn+(H2O) and Zn+(D2O)

We report on a study of the photodissociation spectroscopy of weakly bound Zn+(H2O) and Zn+(D2O) complexes. The work is supported by ab initio electronic structure calculations of the ground and low-lying excited energy surfaces. We assign two molecular absorption bands in the near UV correlating to Zn+ (4s-4p)-based transitions, and identify vibrational progressions associated with both intermolecular and intramolecular vibrational modes of the cluster. Partially resolved rotational structure is consistent with a C(2V) equilibrium complex geometry. Experimental spectroscopic constants are in very good agreement with ab initio theoretical predictions. Results are compared with previous work on main group and transition metal ion-H2O clusters.     

K2M(H2P2O7)2·2H2O (M = Ni,Cu, Zn): ortho­rhom­bic forms and Raman spectra

The crystal structures of three isotypic ortho­rhom­bic dihydrogendiphosphates, namely dipotassium copper(II)/nickel(II)/zinc(II) bis­(dihydrogendiphosphate) dihydrate, K₂M(H₂P₂O₇)₂·2H₂O (M = Cu, Ni and Zn), have been refined from single‐crystal data. The M²⁺ and K⁺ cations are located at sites of m symmetry, and the P atoms occupy general positions. These compounds also exist in triclinic forms with very similar structural features. The structures of both forms are compared, as well as the geometry of the MO₆ octa­hedron, which is considerably elongated towards the water mol­ecules for M = Ni and Cu. Such elongation has not been observed among the other representatives of the family. A Raman study of the whole series K₂M(H₂P₂O₇)₂·2H₂O (M = Mn, Co, Ni, Cu, Zn and Mg) is reported.     

Theoretical study of the desorption of neutral and ionic alkali metal atoms from the excited Li+(H2O)n = 1-4 and Na+(H2O)n = 1-4 cluster models: Electronic excitation charge transfer

In this work, the potential energy curves of several low-lying excited states of M⁺(H₂O)_{n = 1-4} (M = Li and Na) clusters with one M─O bond, related to the stretching of their M─O bond, were calculated in the gas phase. The time-dependent density functional theory and direct-symmetry-adapted cluster-configuration interaction were used in this study separately. Theoretical calculations showed that the charge transfer occurred between M⁺ and (H₂O)_n in the excited clusters so that the neutral metal atom was obtained at the dissociation limit of the potential curves. The excited potential curves of clusters were also calculated in the presence of the electrostatic field of water (EFW), and it was found that the charge transfer was blocked in the presence of EFW. The effect of the size of the (H₂O)_n cluster on the shape of the excited potential curves was investigated to observe how the M─O bond was affected in the excited states depending on the (H₂O)_n size. It was found that the increase in the size of the (H₂O)_n cluster increased the number of bonding excited potential curves. The difference between the electron density of the excited and ground electronic states was calculated to see how the charge transfer was affected by the size of the (H₂O)_n cluster.     

Dimethylhydroxyoxosulfonium(VI) Hexafluoridometallates, [(CH3)2SO(OX)]+[MF6]–(X = H,D; M = As,Sb)

Dimethylsulfone reacts in the binary superacidic systems XF/MF₅ (X = H, D; M = As, Sb) under the formation of the corresponding salts of the type [(CH₃)₂SO(OX)]⁺[MF₆]^–. The salts are characterized by low temperature vibrational spectroscopy. In case of [(CH₃)₂SO(OH)]⁺[SbF₆]^– a single‐crystal X‐ray structure analysis is reported. The salt crystallizes in the orthorhombic space group Pbca with eight formula units per unit cell [a = 10.3281(3) Å, b = 12.2111(4) Å, c = 13.9593(4) Å]. The experimental results are discussed together with quantum chemical calculations on the PBE1PBE/6‐311G++(3pd,3df) level of theory.     

Examination of the structures,energetics, and vibrational frequencies of small sulfur-containing prototypical dimers, (H2S)2 and H2O/H2S

The optimized geometries, vibrational frequencies, and dissociation energies from MP2 and CCSD(T) computations with large correlation consistent basis sets are reported for (H₂S)₂ and H₂O/H₂S. Anharmonic vibrational frequencies have also been computed with second-order vibrational perturbation theory (VPT2). As such, the fundamental frequencies, overtones, and combination bands reported in this study should also provide a useful road map for future spectroscopic studies of the simple but important heterogeneous H₂O/H₂S dimer in which the hydrogen bond donor and acceptor can interchange, leading to two unique minima with very similar energies. Near the CCSD(T) complete basis set limit, the HOH⋯SH₂ configuration (H₂O donor) lies only 0.2 kcal mol⁻¹ below the HSH⋯OH₂ structure (H₂S donor). When the zero-point vibrational energy is included, however, the latter configuration becomes slightly lower in energy than the former by <0.1 kcal mol⁻¹. © 2018 Wiley Periodicals, Inc.     

Fully Delocalized Mixed-Valent Cu1.5Cu1.5 Complex: Strong Cu-Cu interaction and Fast Electron Self-Exchange Rate Despite Large Structural Changes**

A flexible macrocyclic ligand with two tridentate {CNC} compartments can host two Cu ions in reversibly interconvertible states, Cu^ICu^I ( 1 ) and mixed-valent Cu^1.5Cu^1.5 ( 2 ). They were characterized by XRD and multiple spectroscopic methods, including EPR, UV/Vis absorption and MCD, in combination with TD-DFT and CASSCF calculations. 2 features a short Cu⋅⋅⋅Cu distance (≈2.5 Å; compared to ≈4.0 Å in 1 ) and a very high delocalization energy of 13 000 cm⁻¹, comparable to the mixed-valent state of the biological Cu_A site. Electron self-exchange between 1 and 2 is rapid despite large structural reorganization, and is proposed to proceed via a sequential mechanism involving an active conformer of 1 , viz. 1′ ; the latter has been characterized by XRD. Such electron transfer (ET) process is reminiscent of the conformationally gated ET proposed for biological systems. This redox couple is a unique pair of flexible dicopper complexes, achieving fast electron self-exchange closely related to the function of the Cu_A site.     

Role of interlayer M k atoms and H2O molecules in the structure formation of M k (VUO6) k · nH2O uranovanadates

M ^k (VUO₆) _k · nH₂O uranovanadates of alkali (Li, Na, K, Rb, Cs), alkaline-earth (Mg, Ca, Sr, Ba), 3d transition (Mn, Fe, Co, Ni, Cu, Zn), and rare-earth (Y, La, Ln) elements were prepared by precipitation from solutions under hydrothermal conditions and in solid-phase reactions. The composition and structure of these compounds and the role of M ^k atoms and H₂O molecules in the formation of their structure were studied by X-ray diffraction, IR-spectroscopy, thermal analysis, and chemical analysis.     

Two Hexagonal Series of Lanthanoid(III) Oxide Fluoride Selenides: M6O2F8Se3 (M = La – Nd) and M2OF2Se (M = Nd,Sm, Gd – Ho)

Two hexagonal series of lanthanoid(III) oxide fluoride selenides with similar structure types can be obtained by the reaction of the components MF₃, M₂O₃, M, and Se in sealed niobium tubes at 850 °C using CsI as fluxing agent. The compounds with the lighter and larger representatives (M = La – Nd) occur with the formula M₆O₂F₈Se₃, whereas with the heavier and smaller ones (M = Nd, Sm, Gd – Ho) their composition is M₂OF₂Se. For both systems single‐crystal determinations were used in all cases. The compounds crystallize in the hexagonal crystal system (space group: P6₃/m) with lattice parameters of a = 1394–1331 pm and c = 403–372 pm (Z = 2 for M₆O₂F₈Se₃ and Z = 6 for M₂OF₂Se). The (M1)³⁺ cations show different square antiprismatic coordination spheres with or without an extra capping fluoride anion. All (M2)³⁺ cations exhibit a ninefold coordination environment shaped as tricapped trigonal prism. In both structure types the Se^2– anions are sixfold coordinated as trigonal prisms of M³⁺ cations, being first condensed by edges to generate trimeric units and then via faces to form strands running along [001]. The light anions reside either in threefold triangular or in fourfold tetrahedral cationic coordination. For charge compensation, both structures have to contain a certain amount of oxide besides fluoride anions. Since F^– and O^2– can not be distinguished by X‐ray diffraction, bond‐valence calculations were used to address the problem of their adjunction to the available crystallographic sites.     

Degradation thermique et etude vibrationnelle de MII(NH4)4(P3O9)2x4H2O(M II=Cu2+, Ni2+, Co2+)

We have studied the thermal behaviour under atmospheric pressure of isotypic tetrahydrate cyclotriphosphates M^II(NH₄)₄(P₃O₉)₂x4H₂O (M ^II=Cu, Ni and Co), between 25 and 1400°C, by X-ray diffraction, thermal analyses (TG and DTA) and infrared spectrometry. This study shows that the series of the compounds M^II(NH₄)₄(P₃O₉)₂x4H₂O (M ^II=Cu, Ni and Co) after elimination of water, in two different stages, and ammonia leads, at 400°C to cyclotetraphosphate M₂ ^IIP₄O₁₂ crystallized and to a thermal residue with a formula H₄P₄O₁₂ which undergoes under a thermal degradation by evolving water and pentoxide phosphorus. The kinetic characteristics of the dehydration and elimination of ammonia have been determinated. The vibrational spectra of Cu(NH₄)₄(P₃O₉)₂x4H₂O were examined and interpreted, in the domain of the valency frequencies, on the basis of the crystalline structure of its isotypic compound Co(NH₄)₄(P₃O₉)₂x4H₂O whose cycle has the site symmetry C₁, of our results of the calculation of the IR frequencies and the successive isotopic substitutions of the equivalent atoms (3P, 3Oi and 6Oe belonging to the P₃Oi₃Oe₆ ring) of the P₃O₉ ³⁻ cycle with high symmetry D_3h. This revised version was published online in August 2006 with corrections to the Cover Date.     

M(H2O)2(4,4′‐bipy)[C6H4(COO)2]·2H2O (M = Mn2+, Co2+) – Zwei isotype Koordinationspolymere mit Schichtstruktur

M(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O (M = Mn²⁺, Co²⁺) – Two Isotypic Coordination Polymers with Layered Structure Monoclinic single crystals of Mn(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]·2H₂O ( 1 ) and Co(H₂O)₂(4,4′‐bipy)[C₆H₄(COO)₂]· 2H₂O ( 2 ) have been prepared in aqueous solution at 80 °C. Space group P2/n (no. 13), Z = 2; 1 : a = 769.20(10), b = 1158.80(10), c = 1075.00(10) pm, β = 92.67(2)°, V = 0.9572(2) nm³; 2 : a = 761.18(9), b = 1135.69(9), c = 1080.89(9) pm, β = 92.276(7)°, V = 0.9337(2) nm³. M²⁺ (M = Mn, Co), which is situated on a twofold crystallographic axis, is coordinated in a moderately distorted octahedral fashion by two water molecules, two oxygen atoms of the phthalate anions and two nitrogen atoms of 4,4′‐biypyridine ( 1 : M–O 219.5(2), 220.1(2) pm, M–N 225.3(2), 227.2(2) pm; 2 : Co–O 212.7(2), 213.7(2) pm, Co–N 213.5(3), 214.9(3) pm). M²⁺ and [C₆H₄(COO)₂)]^2? build up chains, which are linked by 4,4′‐biyridine molecules to yield a two‐dimensional coordination polymer with layers parallel to (001).Thermogravimetric analysis in air of 1 indicated a loss of water of crystallization between 154 and 212 °C and in 2 between 169 and 222 °C.     

The double salts M3RE(SO4)3 (M=K,Rb) with framework structures

The crystal structures of K₃Er(SO₄)₃ [space group Pc, a=9.222(2), b=14.688(1), c=9.008(1) Å, =110.72(2)^o, Z=4, R=0.59] and of Rb₃Tm(SO₄)₃ [space group Cc, a=10.649(2), b=15.149(3), c=9.320(2) Å, =124.49(1)^o, Z=4, R=0.043] have been studied (CAD-4 diffractometer, Mo radiation). It has been shown that the compounds K₃RE(SO₄)₃ (RE=Nd–Er) and Rb₃RE(SO₄)₃ (RE=Tm–Lu), which crystallize in accordance with these structural types, form a family of framework structures with a single basis. The relationship between their structure and the structure of the rhombohedral compounds M₃M^III(SO₄)₃ (M^III=Al, Ga, In) and Cs₃Yb(SO₄)₃ has been examined.Scientific-Research Institute of Chemical Reagents and Ultrapure Chemical Substances. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 2, pp. 110–115, March–April, 1991.     

Infrared and Raman spectra and external mode calculations for M2Cu2O5 semiconductors (M = In,Sc, Y and lanthanides from Tb to Lu)

The room temperature FTIR transmission and Raman scattering spectra of M₂Cu₂O₅ (M = In, Sc, Y, TbLu) semiconductors in the 30–700 cm⁻¹ range are examined. A factor group analysis and normal coordinate calculations have been performed to identify the external modes. The Urey—Bradley Force Field model and potential energy distribution were applied in the phonon calculations. The Y/Er and Y/Gd exchange effects were studied and analysed in terms of M³⁺ ion translation energy.     

Crystal structure of (C2H7N4O)2[(UO2)2)(OH)2(C2O4)(CHO2)2]

An X-ray diffraction study of the single crystals of (C₂H₇N₄O)₂[(UO₂)₂(OH)₂(C₂O₄)(CHO₂)₂] was carried out. The compound crystallizes in the triclinic system, space group $P\bar 1$ , Z = 2, a = 5.5621(8) Å, b = 8.1489(10) Å, c = 11.8757(16) Å, α = 88.866(7)°, β = 82.204(6)°, γ = 87.378(6)°, V = 532.7(1) ų, ρ_calcd = 2.988 g/cm³. The main structural units in the crystal are the [(UO₂)₂(OH)₂(C₂O₄)(CHO₂)₂)]^2? chains corresponding to the crystal chemical group A₂M ₂ ² K⁰²M ₂ ¹ (A = UO ₂ ²⁺ , M² = OH^?, K⁰² = C₂O ₄ ^2? , M¹ = CHO ₂ ^? ) of uranyl complexes. The chains are united into a three-dimensional framework through the electrostatic interaction and hydrogen bonds involving uranyl, oxalate, and hydroxyl groups, formate ions, and 1-carbamoylguanidinium cations.     

Über die Struktur vonM(BF4)2·6H2O fürM=Mg2+, Zn2+, Cd2+

The IR and Raman spectra ofM(BF₄)₂·6H₂O forM=Mg²⁺, Zn²⁺ and Cd²⁺ in the range 4000–140 cm^?1 were recorded, as were theirDTA andTG curves up to 500°C. The data obtained confirm the presence of the water complex [M(H₂O)₆]²⁺ and of the complex anion BF₄ ^? in these compounds. It was also established that the six water molecules in Mg(BF₄)₂·6H₂O and in Zn(BF₄)₂·6H₂O are not crystallographically equivalent, and that hydrogen bonds of the type H₂O...H₂O...F₄B and H₂O...H₂O...H₂O participate in the structure. The energy of the hydrogen bonds H₂O...F₄B for the three crystal hydrates was also calculated. The thermal and thermogravimetric data are in agreement with and confirm the spectroscopic data.     

Zur Chemie in Schmelzlösungen. IV. Darstellung von kristallinen Boraten M2+M4+(BO3)2

Borates of the compositions formulated above are prepared in crystalline form by cooling their molten solutions in the corresponding borate M²⁺O · xB₂O₃. Some properties of the compounds are reported.     

K3Na5(H2NCH2CH2NH3)2{(VO)12O6[B3O6(OH)]6}(H2O)•12H2O的合成与晶体结构

利用水热合成技术成功制备出一种新型多钒硼氧化合物， 用X射线单晶衍射分析技术对其晶体结构和分子结构进行了确定。结果表明在该化合物中多钒硼氧阴离子具有一个新颖的三明治结构。上下两个结构单元都是由六个VO₅四角锥交替地通过顺式和反式共边的方式连接起来构成的一个钒氧三角形结构。中间的结构单元是由BO₃平面三角形和BO₄四面体以共角的方式相互连接形成的一个折叠型的B₁₈O₃₆(OH)₆环。三明治结构中层与层之间通过桥氧相连。一个水分子处于它的核心位置上，与每个VO₅四角锥中的钒原子都保持几乎相等的距离。该化合物及其晶体中存在着丰富的化学结构和成键信息，同时也有作为氧化还原反应催化剂的潜能。     

Expansion of Germanato‐Polyoxovanadate Cluster Cores: Solvothermal Syntheses and Selected Properties of (trenH2)2[{M(tren)}4V15Ge6O48(H2O)] (M = Co and Zn)

Two germanato‐polyoxovanadates with the {V₁₅Ge₆O₄₈} cluster core are extended by covalent bonds to four transition metal amine complexes [M(tren)]²⁺ (M = Co and Zn, tren = tris(2‐aminoethyl)amine). The complexes have bonds to terminal atoms of the Ge₂O₇ units and such expansion of a germanato‐polyxovanadate was never observed before. The characterization of these compounds revealed the presence of two protonated tren molecules charge balancing the negative charges of the [{M(tren)}₄V₁₅Ge₆O₄₈(H₂O)]^4– anion.