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The title compounds, (NH₄)₂[Mn^II(edta)(H₂O)]⋅3H₂O (H₄edta = ethylenediamine-N,N,N′,N′-tetraacetic acid), (NH₄)₂[Mn^II(cydta)(H₂O)]⋅4H₂O (H₄cydta = trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid) and K₂[Mn^II(Hdtpa)]⋅3.5H₂O (H₅dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), were prepared; their compositions and structures were determined by elemental analysis and single-crystal X-ray diffraction technique. In these three complexes, the Mn²⁺ ions are all seven-coordinated and have a pseudo-monocapped trigonal prismatic configuration. All the three complexes crystallize in triclinic system in P-1 space group. Crystal data: (NH₄)₂[Mn^II(edta)(H₂O)]⋅3H₂O complex, a = 8.774(3) Å, b = 9.007(3) Å, c = 13.483(4) Å, α = 80.095(4)°, β = 80.708(4)°, γ = 68.770(4)°, V = 972.6(5) ų, Z = 2, D_c
= 1.541 g/cm³, μ = 0.745 mm^-1, R = 0.033 and wR = 0.099 for 3406 observed reflections with I ≥ 2σ(I); (NH₄)₂[Mn^II(cydta)(H₂O)]⋅4H₂O complex, a = 8.9720(18) Å, b = 9.4380(19) Å, c = 14.931(3) Å, α = 76.99(3)°, β = 83.27(3)°, γ = 75.62(3)°, V = 1190.8(4) ų, Z = 2, D_c = 1.426 g/cm³, μ = 0.625 mm^-1, R = 0.061 and wR = 0.197 for 3240 observed reflections with I ≥ 2σ(I); K₂[Mn^II(Hdtpa)]⋅3.5H₂O complex, a = 8.672(3) Å, b = 9.059(3) Å, c = 15.074(6) Å, α = 95.813(6)°, β = 96.665(6)°, γ = 99.212(6)°, V = 1152.4(7) ų, Z = 2, D_c = 1.687 g/cm³, μ = 1.006 mm^-1, R = 0.037 and wR = 0.090 for 4654 observed reflections with I ≥ 2σ(I).

The molecular structure of 1-methyl-1-fluoroquasisilatrane (2-methyl-2-fluoro-1,3-dioxa-6-aza-2-silacyclooctane) MeFSi(OCH₂CH₂)₂NH (I) is determined by single crystal X-ray diffraction at 100 K. The coordination polyhedron of the silicon atom in this molecule is a slightly distorted trigonal bipyramid with an NH group and a strongly electron-withdrawing fluorine atom in the axial positions, and two endocyclic oxygen atoms and a СН₃ group in three vertices of the equatorial plane. The axial angle N→SiF is 171°. The length of the transannular donor-acceptor bond N→Si (2.058 Å) is as small as in 1-fluorosilatrane. The axial bond F-Si (1.660 Å) is longer than that in 1-fluorosilatrane and tetrahedral silicon compounds.

In large-scale molecular objects (nanostructures) such as dendromers, supramolecules, polymers, nanotubes, etc. external perturbations may have local character. When the perturbation is removed, atomic wave motions of a rather complex type may arise in the nanostructure. They can not only transfer signals inside the nanoobject, but also generate standing waves and antinodes and accumulate energy in other domains of the nanostructure, i.e., give rise to energy traps. These problems have not been addressed before. In this paper we propose a method to calculate the time-dependent evolution of these phenomena for large-scale molecular structures of arbitrary structure and size.

X-ray diffraction analysis of four perfluorinated homophthalic (2-carboxymethylbenzoic) acids is carried out. In the crystals of 2-carboxymethyl-3,4,5,6-tetrafluorobenzoic acid (1) the chains (1D architecture) form with the usual dimeric carboxylic C(O)OH:::O(HO)C synthon. The aromatic carboxylic group is disordered in the ratio 0.58:0.42 over two positions. In the crystals of 2-(carboxydifluoromethyl)-3,4,5,6-tetrafluorobenzoic (2) and 2-(1-carboxy-2,2,2-trifluoroethyl)-3,4,5,6-tetrafluorobenzoic acids (3) the layers (2D architecture) with dimeric and chain-like synthons C(O)OH…O(HO)C are found. In the crystals of 2-[methoxycarbonyl(difluoromethyl)]-3,4,5,6-tetrafluorobenzoic acid (4) only dimers (0D architecture) form with the chain synthon that incorporates both an ester and a carboxylic group. In the crystals of 1 and 2 intermolecular Н-O…π interactions, in the crystals of 4 C-F…π interactions, and in 3 both types of interactions are observed.

By the reaction of [Mo₃S₄(C₂O₄)₃(H₂O)₃]^2- with PdCl₂ and NH₄H₂PO₂ as a reducing agent, followed by the addition of PPh₃, a new oxalate cuboidal cluster complex [Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]^2- is obtained. It was isolated and structurally characterized as K₂[Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]⋅0.5H₂O.

By the high-temperature reaction of Nb₂S₄Br₄ and TlBr a thallium salt of the anionic cluster complex [Nb₂S₄Br₈]^4- is obtained. Its crystal structure is determined by X-ray structural analysis. The complex is also characterized by Raman spectroscopy and electrospray-mass-spectrometry.

By means of X-ray diffraction the chain structure of [Cu(l-Arg)₂]Hg₂Cl₆ (monoclinic, a = 10.2348(9) Å, b = 9.1386(7) Å, c = 14.8521(14) Å, β = 97.455(11)°, space group P2₁) is established. The chains are formed by square-planar [Cu(l-Arg)₂]²⁺ cations of the type trans-[Cu(N)₂(О)₂] (l-Аrg is the zwitter-ion of arginine; Cu-N 1.992 Å and 1.938(6) Å, Cu-O 1.953 Å and 1.967(4) Å) that are bonded to two adjacent binuclear [Cl₂Hg(μ-Cl)₂HgCl₂]^2- ions through its clorine atoms Cl (Hg-Cl bonds are within 2.34-2.78 Å). With these two additional Cu…Cl contacts Cu adopts the geometry of an elongated octahedron with two apical Cl (Cu-Cl 2.961 Å and 3.064(3) Å).

The X-ray analysis of a single crystal of Mg(C₁₂H₁₃N₄O₄S)₂⋅11H₂O, where (C₁₂H₁₃N₄O₄S)^- is the anion of 4-p-aminobenzenesulfamido-2,6-dimethoxypyrimidine (sulfadimethoxine) is carried out. Unit cell parameters are: а = 19.753(4) Å, b = 34.031(7) Å, c = 13.859(3) Å; β = 125.37(3)°, C2/c, Z = 8, R(F) = 0.042. The structure is built of [Mg(OH₂)₆]²⁺, (C₁₂H₁₃N₄O₄S)^-, and water molecules and corresponds to the formula [Mg(OH₂)₆](C₁₂H₁₃N₄O₄S)₂⋅5H₂O. The IR bands of ν_asymSO₂ and ν_symSO₂ are bathochromically shifted as a result of their participation in hydrogen bonding, and not because of any direct coordination of sulfadimethoxinate anion to the complexing atom through oxygen.

The structure of the syn-isomer of 2-N,N′-dimethylamino-5-methylbenzophenone oxime is studied by X-ray diffraction and mass-spectrometry. This molecular compound crystallizes in the triclinic system. Unit cell parameters are: a = 19.5318(10) Å, с = 19.5439(17) Å, V = 6456.9(7) ų, Z = 18, space group The molecules are linked into centrosymmetric pseudo dimers by hydrogen bonds О-H…N formed by the oxime groups. The pathway of the electron-impact induced decomposition of the compound is discussed.

An X-ray diffraction analysis and quantum chemical calculations of hydrated 2-thenoyltrifluoroacetone show that the planar diketone, form of ТТА found in its metal complexes, does not occur in the free ligand. Hydrated ТТА with two geminal hydroxo groups has a non-planar structure stabilized by an intramolecular hydrogen bond.