Crystal Structure and NQR Studies of Compounds (RH)[ZnBr3(R)], (RH)2[ZnBr4] and [ZnBr2(R)2] (R = Py, n-MePy: n = 2, 3, 4); on the Dominant Stability of the Monoanionic Complexes over the Dianionic and Neutral Species

2011 ◽  
Vol 66 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Hideta Ishihara ◽  
Michio Nakashima ◽  
Hisayo Nakashima ◽  
Ryuichi Tateno ◽  
Yuki Shibamura ◽  
...  

The monoanionic complexes (C5H5NH)[ZnBr3(C5H5N)] (1) and (n-CH3C5H4NH)[ZnBr3(n- CH3C5H4N)] (n = 2 (2), 3 (3), 4 (4)) were prepared by crystallization from ethanol solutions through redistribution reactions between the corresponding dianionic complexes (C5H5NH)2[ZnBr4] (5) and (n-CH3C5H4NH)2[ZnBr4] (n = 2, 3 (6), 4 (7)) and the neutral complexes [ZnBr2(C5H5N)2] (10) and [ZnBr2(n-CH3C5H4N)2] (n = 2 (8), 3, 4 (9)). The crystal structures of 1, 4, 9, and 10 were determined; 1: triclinic, P1, a = 7.6957(5), b = 7.7975(4), c = 12.4768(8) Å , α = 90.857(5), β = 95.917(5), γ = 107.899(6)°, Z = 2, 150 K; 4: monoclinic, P21/c, a = 14.8369(6), b = 13.9504(5), c = 8.0041(3) Å , β = 96.318(4)°, Z = 4, 299 K; 9: monoclinic, P21/c, a = 14.2883(5), b = 8.0269(3), c = 13.6031(5) Å , β = 100.581(4)°, Z = 4, 150 K; 10: monoclinic, P21/c, a = 8.7388(5), b = 17.9730(10), c = 8.5452(5) Å , β = 100.024(6)°, Z = 4, 300 K. The cation and anion are paired up via bifurcated hydrogen bonds in the structure of 1 and via a normal N-H· · ·Br hydrogen bond in the structure of 4. 81Br NQR resonance lines coinciding in number with the Br atoms in the chemical formulae were observed for the compounds 1 - 5 and 7 - 9 throughout the temperature range from 77 to ca. 320 K. The comparison between the net charges on the Br atoms obtained by the Townes-Daily analysis or by the Mulliken population analysis seems to indicate that the formation of the intermolecular N-H· · ·Br hydrogen bonds and the π-π and the CH3-π interactions in the crystal structures of the monoanionic complexes are the driving forces to the redistribution reactions

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4139
Author(s):  
Barbora Vénosová ◽  
Ingrid Jelemenská ◽  
Jozef Kožíšek ◽  
Peter Rapta ◽  
Michal Zalibera ◽  
...  

Two 15-membered octaazamacrocyclic nickel(II) complexes are investigated by theoretical methods to shed light on their affinity forwards binding and reducing CO2. In the first complex 1[NiIIL]0, the octaazamacrocyclic ligand is grossly unsaturated (π-conjugated), while in the second 1[NiIILH]2+ one, the macrocycle is saturated with hydrogens. One and two-electron reductions are described using Mulliken population analysis, quantum theory of atoms in molecules, localized orbitals, and domain averaged fermi holes, including the characterization of the Ni-CCO2 bond and the oxidation state of the central Ni atom. It was found that in the [NiLH] complex, the central atom is reduced to Ni0 and/or NiI and is thus able to bind CO2 via a single σ bond. In addition, the two-electron reduced 3[NiL]2− species also shows an affinity forwards CO2.


2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Christoph Ludwig Teske ◽  
Huayna Terraschke ◽  
Sebastian Mangelsen ◽  
Wolfgang Bensch

Abstract The title compounds were prepared by precipitation from acidic solutions of the reactants in acetone/water. Bi(S2CNH2)2Cl (1) crystallizes in the non-centrosymmetric trigonal space group P32 with a = 8.6121(3) and c = 11.1554(4) Å, Z = 3; Bi(S2NH2)2SCN (2) in P21/c (monoclinic) with a = 5.5600(2), b = 14.3679(5), c = 12.8665(4) Å, and β = 90.37(3)°. In the crystal structure of 1 Bi3+ is in a sevenfold coordination of two bidentate and one monodentate S2CHNH2 − anions with an asymmetric coordination pattern of five Bi–S and two Bi–Cl− bonds. The linkage of these polyhedra via common Cl–S edges leads to a 1D polymeric structure with undulated chains propagating in the direction [001]. These chains are linked by strong and medium strong hydrogen bonds forming the 3D crystal structure. In the crystal structure of 2 the Bi3+ cation is in an eightfold coordination. The polyhedron can be described as a significantly distorted tetragonal anti-prism, capped by an additional S atom. Two of these prisms share a common quadrilateral face to form a “prism-double” (Bi2S10N2). These building units are linked by common edges, and the resulting 1D infinite angulated chains propagate along [100]. By contrast to organo-dithiocarbamate compounds, where C–H···X bridges are dominant, the interchain connections in the crystal structures of 1 and 2 are formed exclusively via N–H···S, N–H···Cl, and N–H···N interactions, generating the 3D networks. A significant eccentricity of the Bi3+ cation in the crystal structures of both complexes is observed. Both compounds emit light in the orange range of the electromagnetic spectrum.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Chunhong Zhang ◽  
Zhongzheng Zhang ◽  
Wanjun Yan ◽  
Xinmao Qin

Borophene is a new type of two-dimensional material with a series of unique and diversified properties. However, most of the research is still in its infancy and has not been studied in depth. Especially in the field of semiconductor optoelectronics, there is no related research on the modulation of photoelectric properties of borophene. In this work, we focus on the effect of doping on the photoelectric properties of borophene by using the first-principles pseudopotential plane wave method. We calculate the geometric structure, electronic structure, Mulliken population analysis, and optical properties of impurity (X = Al, Ga) doped α-sheet borophene. The results show that α-sheet borophene is an indirect band gap semiconductor with 1.396 eV. The band gap becomes wider after Al and Ga doping, and the band gap values are 1.437 eV and 1.422 eV, respectively. Due to the orbital hybridization between a small number of Al-3p electrons and Ga-4p state electrons and a large number of B 2p state electrons near the Fermi level, the band gap of borophene changes and the peak value of the electron density of states reduces after doping. Mulliken population analysis shows that the B0-B bond is mainly covalent bond, but there is also a small amount of ionic bond. However, when the impurity X is doped, the charge transfer between X and B atoms increases significantly, and the population of the corresponding X-B bonds decreases, indicating that the covalent bond strength of the chemical bonds in the doped system is weakened, and the chemical bonds have significant directionality. The calculation of optical properties shows that the static dielectric constant of the borophene material increases, and the appearance of a new dielectric peak indicates that the doping of Al and Ga can enhance the ability of borophene to store electromagnetic energy. After doping, the peak reflectivity decreases and the static refractive index n0 increases, which also fills the gap in the absorption of red light and infrared light by borophene materials. The research results provide a basis for the development of borophene materials in the field of infrared detection devices. The above results indicate that doping can modulate the photoelectric properties of α-sheet borophene.


1989 ◽  
Vol 44 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Jutta Hartmann ◽  
Shi-Qi Dou ◽  
Alarich Weiss

Abstract The 79Br and 127I NQR spectra were investigated for 1,2-diammoniumethane dibromide, -diiodide, 1,3-diammoniumpropane dibromide, -diiodide, piperazinium dibromide monohydrate, and piperazinium monoiodide in the temperature range 77 ≦ T/K ≦ 420. Phase transitions could be observed for the three iodides. The temperatures for the phase transitions are: 400 K and 404 K for 1,2-diammoniumethane diiodide, 366 K for 1,3-diammoniumpropane diiodide, and 196 K for piperazinium monoiodide.The crystal structures were determined for the piperazinium compounds. Piperazinium dibromide monohydrate crystallizes monoclinic, space group C2/c, with a= 1148.7 pm, 0 = 590.5 pm, c= 1501.6pm, β = 118.18°, and Z = 4. For piperazinium monoiodide the orthorhombic space group Pmn 21 was found with a = 958.1 pm, b = 776.9 pm, c = 989.3 pm, Z = 4. Hydrogen bonds N - H ... X with X = Br, I were compared with literature data.


1990 ◽  
Vol 209 ◽  
Author(s):  
J. A. Cogordan ◽  
L. E. Sansores ◽  
A. A. Valladares

ABSTRACTMolecular ab initio SCF calculations on a cluster formed by Y, Cu(2)-O(2)-O(3) plane, Ba-O(1) plane and Cu(1)-O(4) chains are reported. The computations were performed for five different sets of lattice parameters of YBACu2O6+δ Each of these sets correspond to a values of the oxygen stoichiometry. Mulliken population analysis results show a charge transfer to the Cu(2)-O(2)-O(3) plane when the oxygen stoichiometry is increased from six to seven.


1990 ◽  
Vol 68 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Pascal Dufour ◽  
Yves Dartiguenave ◽  
Michèle Dartiguenave ◽  
Nathalie Dufour ◽  
Anne-Marie Lebuis ◽  
...  

Crystals of 7-azaindole ([Formula: see text], a = 11.312(4), b = 14.960(6), c = 15.509(5) Å, α = 102.86(3), β = 108.78(3), γ = 90.71(3)°, Z = 16, R = 0.052) contain tetrameric units of approximate S4 symmetry, in which the molecules are associated by means of four complementary N—H … N hydrogen bonds. [CH3Hg(7-azaindole)]NO3 ([Formula: see text], a = 7.818(3), b = 7.884(3), c = 9.135(4) Å, α = 97.89(3), β = 109.13(3), γ = 103.28(3)°, Z = 2, R = 0.039) contains well-separated nitrate ions and complex cations in which the methylmercury group is linearly bonded to the pyridine nitrogen atom, whereas the five-membered ring remains protonated. In the neutral [CH3Hg(azaindolate)] complex ([Formula: see text], a = 10.926(10), b = 11.333(8), c = 11.647(10) Å, α = 92.13(8), β = 104.83(9), γ = 111.86(7)°, Z = 6, R = 0.048), methylmercury groups have substituted the N—H proton in the five-membered ring for the three symmetry-independent molecules. Intermolecular secondary Hg … N bonds are found with pyridine nitrogens. Keywords: azaindole, methylmercury, crystal structure.


2007 ◽  
Vol 62 (7-8) ◽  
pp. 417-424
Author(s):  
Basavalinganadoddy Thimme Gowda ◽  
Sabine Foro ◽  
Jozef Kožíšek ◽  
Hartmut Fuess ◽  

The effect of ring substitution and N-chlorination on the molecular geometry of arylsulphonamides and N-chloro-arylsulphonamides have been studied by determining the crystal structures of 2-methyl- 4-chloro-benzenesulphonamide (2M4CBSA) and the sodium salt of N-chloro-2-methyl-4-chlorobenzenesulphonamide (NaNC2M4CBSA). The results are analyzed along with the crystal structures of benzenesulphonamide, 4-methyl-benzenesulphonamide and 4-chloro-benzenesulphonamide. The crystal structure of NaNC2M4CBSA has also been compared and correlated with the crystal structures of the above compounds and those of the sodium salts of N-chloro-benzenesulphonamide, Nchloro- 4-methyl-benzenesulphonamide, N-chloro-4-chloro-benzenesulphonamide and N-chloro-2,4- dichloro-benzenesulphonamide. The crystal system, space group, formula units and lattice constants in Å of the new structures are: 2M4CBSA: triclinic, P1, Z = 4, a = 7.9030(10), b = 8.6890(10), c = 13.272(2), α = 100.680(10)°, β = 98.500(10)°, γ = 90.050(10)°; NaNC2M4CBSA: monoclinic, C2/c, Z =4, a = 10.9690(10), b = 6.7384(6), c = 30.438(2), β = 98.442(7)°. The structure of 2M4CBSA is quite complex with four molecules in its asymmetric unit. The S-N bond length slightly decreases with substitution of electron-withdrawing groups, while the effect is more pronounced with disubstitution. The structure of NaNC2M4CBSA confirms that there is no interaction between nitrogen and sodium, and Na+ is attached to one of the sulphonyl oxygen atoms. The Na+ coordination sphere involves oxygen atoms from water moleculess of crystallization and neighbouring molecules. The S-N distance of 1.586 Å for the compound is consistent with a S-N double bond. The molecules are held together by hydrogen bonds with distances varying from 2.12 to 2.85 Å.


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