From versatile hydrogen- and halogen-bond acceptors to elastic bending of metal-containing architectures (original) (raw)
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Structural and Elastic Properties of Pd2CrPb Heusler Compound
Selçuk Üniversitesi Fen Fakültesi Fen Dergisi, 2021
Electronic, structural and elastic properties of Pd 2 CrPb compound were examined with Density Functional Theory (DFT). The lattice constant in state of balance and the total magnetic moment value were calculated and 6.454 A 0 and 3.678 µB f.u. values were obtained respectively. The lattice constant and total magnetic moment value obtained for Pd 2 CrPb compound were compared to existing values in the literature, and the results obtained were found to be consistent with the literature results. The calculation of bulk modulus in this study is non-existent in the literature. The bulk modulus of this molecule is presented in the literature in this sense. The aim of the study is to publish the results of studies on non-existent electronic, structural and elastic properties for Pd 2 CrPb compound conducted using density functional theory. The electronic band structure, total and partial density graphs for Pd 2 CrPb compound were drawn. Bulk modulus (B), Shear modulus (G), B/G ratio, Young modulus (E), Poisson ratio, C 11, C 12 and C 44 values were also calculated for this compound. Pd 2 CrPb compound meets Born stability principles and calculated elastic stabilities show that this compound is mechanically stable.
Mechanically Responsive Crystalline Coordination Polymers with Controllable Elasticity
Angewandte Chemie, 2018
Crystalline coordination polymers tend to be brittle and inelastic, however, we now describe a family of such compounds that are capable of displaying mechanical elasticity in response to external pressure. The design approach successfully targets structural features that are critical for producing the desired mechanical output. The elastic crystals all comprise 1D cadmium(II) halide polymeric chains with adjacent metal centres bridged by two halide ions resulting in the required stacking interactions and short “4 Å” crystallographic axes. These polymeric chains (structural “spines”) are further organized via hydrogen bonds and halogen bonds perpendicular to the direction of the chains. By carefully altering the strength and the geometry of these non‐covalent interactions, we have demonstrated that it is possible to control the extent of elastic bending in crystalline coordination compounds.
Crystal Growth & Design, 2006
Reaction of tris-(2-chloroethylamine) with either para-hydroxyethylbenzoate or meta-hydroxyethylbenzoate followed by hydrolysis affords the podands tris-(4-carboxy-2-phenoxy-ethyl)amine and tris-(3-carboxy-2-phenoxy-ethyl)amine, respectively. Aqueous solutions of Cd(NO 3) 2 ‚6H 2 O readily react with the podands in a 1:2 molar ratio in the presence of pyridine at room temperature to form the porous coordination polymers {[Cd(ptaH)]‚5H 2 O} n (1) and {[Cd 2 (mtaH) 2 (H 2 O) 2 ]‚14H 2 O} n (2). Compound 1 crystallizes in the triclinic space group P1 h with a) 10.223(7), b) 11.465(8), and c) 12.331(8) Å, R) 93.43(1)°,) 96.67-(1)°, γ) 95.08(1)°, V) 1426.4(2) Å 3 , Z) 2, F calcd) 1.65 g cm-3 , T) 100 K, µ) 0.839 mm-1 , R 1) 0.0741 (I > 2σ(I)), wR 2) 0.1636, and GOF) 1.322. Compound 2 crystallizes in the monoclinic space group P2 1 /c with a) 16.752(1), b) 18.568(1), and c) 21.610(2) Å,) 107.36(10)°, V) 6415.8(8) Å 3 , Z) 4, F calcd) 1.58 g cm-3 , T) 100 K, µ) 0.759 mm-1 , R 1) 0.0339 (I > 2σ(I)), wR 2) 0.0861, and GOF) 1.040. Each of the coordination polymers looks like an infinite chain of metallocycles with different void spaces. These voids are occupied by supramolecularly assembled water molecules whose structures are commensurate with the metal-organic frameworks (MOFs).
Journal of Molecular Structure, 2018
Three new coordination polymers of {[Cd(bib) 3 ](ClO 4) 2 } n (1), [Cd(µ 2-bip) 2 (N 3) 2 ] n (2) and [Cd(µ-bib Me)Cl 2 ] n (3) were prepared by using the neutral N-donor ligands 1,4bis(imidazolyl)butane (bib), 1,3-bis(imidazolyl)propane (bip) and 1,4-bis(2methylimidazolyl)butane (bib Me) and CdX 2 (X=ClO 4-, N 3 and Cl-). The results of the X-ray measurements demonstrate that in the crystal structure of 1 and 2 the cadmium(II) ion adopts CdN 6 octahedral geometry while, in the structure of 3, the metal ion forms CdN 2 Cl 2 tetrahedral geometry. In compound 1, six bib ligands are coordinated to one central cadmium(II) to form an open 3D 2-fold interpenetrating framework of the α-polonium (pcu) type topology, while in compound 2 and 3 the N 3 or Clgroups are terminally bonded to the metal center and each linker compound (bip or bib Me) acts as bridging ligand connecting two metal ions to form a one-dimensional zigzag chain. The adjacent 1D chains of complex 2 and 3 are further extended into a non-covalent 2D network structure by C-H•••N and C-H•••Cl intermolecular hydrogen bonds, respectively. The complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction.
Electronic spectroscopy of the A1A" - X1A' system of CDBr
We report fluorescence excitation and single vibronic level emission spectra of jet-cooled CDBr in the 450-750 nm region. A total of 32 cold bands involving the pure bending levels 2 0 n with n =3-10 and combination bands 2 0 n 3 0 1 ͑n =2-10͒, 2 0 n 3 0 2 ͑n =2-9͒, 1 0 1 2 0 n ͑n =7-10͒, and 1 0 1 2 0 n 3 0 1 ͑n =6,8-9͒ in the à 1 AЉ ← X 1 AЈ system of this carbene were observed; most of these are reported and/or rotationally analyzed here for the first time. Rotational analysis yielded band origins and effective ͑B ͒ rotational constants for both bromine isotopomers ͑CD 79 Br and CD 81 Br͒. The derived à 1 AЉ vibrational intervals are combined with results of Yu et al. ͓J. Chem. Phys. 115, 5433 ͑2001͔͒
Inorganic Chemistry, 1992
Compounds of formula Cd(dmpd)2X2 (dmpd = 2,2-dimethylpropane-1,3-diamine; X = Cl, Br, I) were prepared and investigated by means of structural and spectroscopic (IR and Raman) measurements. The Cd(dmpd)& compound cr s t a k e s in the monoclinic R l / c space group, with two formula units in a cell of dimensions a = 6.235 (5) A, b = 18.462 (9) 1, c = 8.294 (5) A, and j3 = 93.37 (6)O, with R = 0.039 and R, = 0.044. The structure consists of discrete [Cd(dmpd),I,] monomeric units, where the Cd atom is surrounded by four nitrogen atoms of two in-plane chelating dmpd molecules and by two iodine atoms asymmetrically coordinated in axial positions. The Cd(dmpd),Br2 compound crystallizes in the triclinic Pi space group, with Z = 3 and a cell of dimensions a = 12.713 (2) A, b = 16.592 (2) A, c = 6.281 (3) A, a = 91.22 (2)", j3 = 96.67 (2)O, and y = 78.72 (3)O, with R = 0.031 and R, = 0.036. The structure consists of 1:l molecular packing of Cd(dmpd)2Br2 monomeric and [Cd(dmpd),Br212 dimeric units. In the monomer the Cd atom is octahedrally coordinated by four in-plane nitrogen atoms of two chelating dmpd molecules and by two bromine atoms in axial positions. The dimer consists of a pair of octahedrally coordinated Cd atoms, related by an inversion center, connected in a 12-membered metallacycle by two ambidentate dmpd molecules. The octahedral arrangement of each Cd atom in the dimer is completed by an in-plane chelating dmpd and by two bromine atoms, axially coordinated. The Cd(dmpd)2Clz compound is isomorphous with the bromine derivative, with unit cell dimensions a = 12.714 (3) A, b = 16.228 (3) A, c = 6.087 (5) A, a = 91.61 (3)O, j3 = 96.02 (3)O, and y = 77.76 (4)". The CdN stretching vibrations are discussed and assigned in the light of the known structures.
Thermo-elastic and bonding features of the CdMgS 2 crystal: an ab initio study
Physica Scripta, 2012
An investigation of the chalcopyrite and rock-salt phase of the CdMgS 2 compound was carried out in terms of fp-lapw calculations. We found that the electron density of crystals contains important information required for studying the phase transition in this compound. By means of the atoms-in-molecules (aim) and electron localization function (elf) formalisms, we found that the chalcopyrite semiconductor phase of the investigated compound undergoes a phase transition to a metallic rock salt. The closure of the band gap is reflected in an increasing electronic delocalization across a change in the nature of the bonding. Thermal effects were included via a quasi-harmonic non-empirical Debye model in order to study their linear expansion parameters. Calculations of the elastic constants of this crystal are possible in both phases, but, obviously, this does not imply that the rock-salt phase is the thermodynamically stable one for this crystal.