New Coordination Architectures of Dithioether Ligand with Silver Salts: Effect of Anions on Complex Structures

Reactions of a flexible dithioether ligand, 2,3-bis(5-methyl-1,3,4-thiadiazole-2-thiomethyl)quinoxaline (L), with AgX (X = ClO4ˉ or PF6ˉ) lead to the formation of two new one-dimensional (1D) silver(i) complexes: {[AgL](ClO4)}∞ 1 and {[Ag2L(CH3OH)](PF6)2(CH3OH)}∞ 2, which have been characterized by elemental analysis, IR spectroscopy, and X-ray crystallography. Although 1 and 2 are synthesized under the same conditions, they take different structures due to the difference in anions in the silver salts. In 1, each ligand supplies three N-donors to bridge two silver atoms to result in a chain structure, and all silver atoms in the chain possess the same coordination geometry. In 2, each ligand gives six N-donors to coordinate to two silver atoms of different geometries, forming a 1D chain. The changes in counteranions affect the coordination mode of the ligand and the geometry of the Ag(i) centre, and consequently give rise to complexes with different structures. The coordination features of the ligand have also been primarily investigated through density functional theory calculations.

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Selective capture of carbon dioxide from hydrocarbons using a metal-organic framework

Nature Communications ◽

10.1038/s41467-020-20489-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Omid T. Qazvini ◽

Ravichandar Babarao ◽

Shane G. Telfer

Keyword(s):

Carbon Dioxide ◽

Density Functional ◽

Metal Organic Framework ◽

Density Functional Theory Calculations ◽

Time Lags ◽

X Ray Crystallography ◽

Metal Organic ◽

Adsorption Of Co ◽

Short Time ◽

Organic Framework

AbstractEfficient and sustainable methods for carbon dioxide capture are highly sought after. Mature technologies involve chemical reactions that absorb CO2, but they have many drawbacks. Energy-efficient alternatives may be realised by porous physisorbents with void spaces that are complementary in size and electrostatic potential to molecular CO2. Here, we present a robust, recyclable and inexpensive adsorbent termed MUF-16. This metal-organic framework captures CO2 with a high affinity in its one-dimensional channels, as determined by adsorption isotherms, X-ray crystallography and density-functional theory calculations. Its low affinity for other competing gases delivers high selectivity for the adsorption of CO2 over methane, acetylene, ethylene, ethane, propylene and propane. For equimolar mixtures of CO2/CH4 and CO2/C2H2, the selectivity is 6690 and 510, respectively. Breakthrough gas separations under dynamic conditions benefit from short time lags in the elution of the weakly-adsorbed component to deliver high-purity hydrocarbon products, including pure methane and acetylene.

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Synthesis of Chromium(II) Complexes with Chelating Bis(alkoxide) Ligand and Their Reactions with Organoazides and Diazoalkanes

Molecules ◽

10.3390/molecules25020273 ◽

2020 ◽

Vol 25 (2) ◽

pp. 273 ◽

Cited By ~ 1

Author(s):

Sudheer S. Kurup ◽

Richard J. Staples ◽

Richard L. Lord ◽

Stanislav Groysman

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Aryl Azides ◽

Functional Theory ◽

X Ray ◽

X Ray Crystallography ◽

Chromium Vi ◽

Imido Complexes ◽

Structure And Bonding

Synthesis of new chromium(II) complexes with chelating bis(alkoxide) ligand [OO]Ph (H2[OO]Ph = [1,1′:4′,1′’-terphenyl]-2,2′’-diylbis(diphenylmethanol)) and their subsequent reactivity in the context of catalytic production of carbodiimides from azides and isocyanides are described. Two different Cr(II) complexes are obtained, as a function of the crystallization solvent: mononuclear Cr[OO]Ph(THF)2 (in toluene/THF, THF = tetrahydrofuran) and dinuclear Cr2([OO]Ph)2 (in CH2Cl2/THF). The electronic structure and bonding in Cr[OO]Ph(THF)2 were probed by density functional theory calculations. Isolated Cr2([OO]Ph)2 undergoes facile reaction with 4-MeC6H4N3, 4-MeOC6H4N3, or 3,5-Me2C6H3N3 to yield diamagnetic Cr(VI) bis(imido) complexes; a structure of Cr[OO]Ph(N(4-MeC6H4))2 was confirmed by X-ray crystallography. The reaction of Cr2([OO]Ph)2 with bulkier azides N3R (MesN3, AdN3) forms paramagnetic products, formulated as Cr[OO]Ph(NR). The attempted formation of a Cr–alkylidene complex (using N2CPh2) instead forms chromium(VI) bis(diphenylmethylenehydrazido) complex Cr[OO]Ph(NNCPh2)2. Catalytic formation of carbodiimides was investigated for the azide/isocyanide mixtures containing various aryl azides and isocyanides. The formation of carbodiimides was found to depend on the nature of organoazide: whereas bulky mesitylazide led to the formation of carbodiimides with all isocyanides, no carbodiimide formation was observed for 3,5-dimethylphenylazide or 4-methylphenylazide. Treatment of Cr2([OO]Ph)2 or H2[OO]Ph with NO+ leads to the formation of [1,2-b]-dihydroindenofluorene, likely obtained via carbocation-mediated cyclization of the ligand.

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Oxides, Silicides, and Silicates of Zirconium and Hafnium; Density Functional Theory Study

MRS Proceedings ◽

10.1557/proc-716-b6.5 ◽

2002 ◽

Vol 716 ◽

Author(s):

Maciej Gutowski ◽

John E. Jaffe ◽

Chun-Li Liu ◽

Matt Stoker ◽

Anatoli Korkin

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Gate Dielectric ◽

Density Functional Theory Calculations ◽

Heat Of Formation ◽

Density Functional Theory Study ◽

Functional Theory ◽

Exchange Correlation ◽

The Difference ◽

Constituent Elements

AbstractIt is known that the chemistries of hafnium and zirconium are more nearly identical than for any other two congeneric elements. Thus, both zirconia and hafnia, with the dielectric constant K > 20, have emerged as potential replacements for silica (K = 3.9) as a gate dielectric. We report an important difference between the zirconia/Si and hafnia/Si interfaces based on density functional theory calculations with the Perdew-Wang 91 exchange-correlation functional on the oxides, silicides, and silicates of Zr and Hf. The zirconia/Si interface has been found to be unstable with respect to formation of silicides whereas the hafnia/Si interface is stable. The difference between the two interfaces results from the fact that HfO2 is more stable than ZrO2 (i.e. has a larger heat of formation from its constituent elements) by more than 53 kJ/mol. The hafnium silicides, on the other hand, are less stable than zirconium silicides by ca. 20 kJ/mol.

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High-Pressure Structural Behavior and Equation of State of Kagome Staircase Compound, Ni3V2O8

Crystals ◽

10.3390/cryst10100910 ◽

2020 ◽

Vol 10 (10) ◽

pp. 910

Author(s):

Daniel Diaz-Anichtchenko ◽

Robin Turnbull ◽

Enrico Bandiello ◽

Simone Anzellini ◽

Daniel Errandonea

Keyword(s):

High Pressure ◽

Equation Of State ◽

Density Functional ◽

Room Temperature ◽

Ambient Pressure ◽

Density Functional Theory Calculations ◽

X Ray Diffraction ◽

X Ray ◽

Cell Parameters ◽

A Chain

We report on high-pressure synchrotron X-ray diffraction measurements on Ni3V2O8 at room-temperature up to 23 GPa. According to this study, the ambient-pressure orthorhombic structure remains stable up to the highest pressure reached in the experiments. We have also obtained the pressure dependence of the unit-cell parameters, which reveals an anisotropic compression behavior. In addition, a room-temperature pressure–volume third-order Birch–Murnaghan equation of state has been obtained with parameters: V0 = 555.7(2) Å3, K0 = 139(3) GPa, and K0′ = 4.4(3). According to this result, Ni3V2O8 is the least compressible kagome-type vanadate. The changes of the crystal structure under compression have been related to the presence of a chain of edge-sharing NiO6 octahedral units forming kagome staircases interconnected by VO4 rigid tetrahedral units. The reported results are discussed in comparison with high-pressure X-ray diffraction results from isostructural Zn3V2O8 and density-functional theory calculations on several isostructural vanadates.

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Six-fold C–H borylation of hexa-peri-hexabenzocoronene

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.16.37 ◽

2020 ◽

Vol 16 ◽

pp. 391-397 ◽

Cited By ~ 1

Author(s):

Mai Nagase ◽

Kenta Kato ◽

Akiko Yagi ◽

Yasutomo Segawa ◽

Kenichiro Itami

Keyword(s):

Density Functional ◽

Bathochromic Shift ◽

Density Functional Theory Calculations ◽

Absorption Bands ◽

Functional Theory ◽

X Ray ◽

X Ray Crystallography ◽

Polycyclic Aromatic ◽

Direct Functionalization ◽

Poorly Soluble

Hexa-peri-hexabenzocoronene (HBC) is known to be a poorly soluble polycyclic aromatic hydrocarbon for which direct functionalization methods have been very limited. Herein, the synthesis of hexaborylated HBC from unsubstituted HBC is described. Iridium-catalyzed six-fold C–H borylation of HBC was successfully achieved by screening solvents. The crystal structure of hexaborylated HBC was confirmed via X-ray crystallography. Optoelectronic properties of the thus-obtained hexaborylated HBC were analyzed with the support of density functional theory calculations. The spectra revealed a bathochromic shift of absorption bands compared with unsubstituted HBC under the effect of the σ-donation of boryl groups.

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Synthesis, Structure, and Visible Phosphorescence Emission of Novel CuI Coordination Polymers Based on 4,4′-Bis(3-pyridyl)-2,2′-bis(hydroxylmethyl) Biphenyl

Australian Journal of Chemistry ◽

10.1071/ch14153 ◽

2015 ◽

Vol 68 (2) ◽

pp. 307 ◽

Cited By ~ 2

Author(s):

Guo-Xia Jin ◽

Jian-Ping Ma ◽

Chuan-Zhi Sun ◽

Yu-Bin Dong

Keyword(s):

Coordination Polymers ◽

Density Functional ◽

Room Temperature ◽

Emission Spectra ◽

Density Functional Theory Calculations ◽

X Ray Diffraction ◽

Ligand Charge Transfer ◽

Yellow Orange ◽

The Difference ◽

1D Chains

Four new CuI coordination polymers, [(CuCl)L]n (1), {[(CuCl)2L2]·(H2O)}n (2), [(CuBr)L]n (3), and {[(CuBr)2L2]·(H2O)}n (4), were obtained from a new ligand 4,4′-bis(3-pyridyl)-2,2′-bis(hydroxylmethyl) biphenyl (L) and characterized by single-crystal X-ray diffraction. In 1 and 3, the rhombic [Cu2(μ-X)2] units are connected to each other by the bidentate linkers to form an infinite 1D double chain (X = Cl, Br). Such 1D chains are arranged into a 2D sheet through inter-chain π···π interactions. In 2 and 4, there are similar 1D double chains, but different inter-chain arrangement. Such 1D chains are connected into a 2D layer and further arranged in an ABAB fashion through O–H···X hydrogen bonds. The emission spectra and lifetimes in the microsecond range were measured at room temperature and at 77 K. Complexes 1 and 3 exhibit strong orange and yellow–orange emission in the solid state at room temperature, and were assigned to X-and M-to-ligand charge transfer excited states based on density functional theory calculations. The emission property of 2 and 4 was distinctly different from that of 1 and 3, probably due to the difference in coordination environments of the CuI centres as well as the dissimilar intermolecular arrangement.

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Structural Effects of meso-Halogenation on Porphyrins: meso-Xn-ABCD Macrocycles

10.3762/bxiv.2021.21.v1 ◽

2021 ◽

Author(s):

Keith J Flanagan ◽

Maximilian Paradiz Dominguez ◽

Zoi Melissari ◽

Hans-Georg Eckhardt ◽

René M Williams ◽

...

Keyword(s):

Conformational Analysis ◽

Crystal Engineering ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Normal Coordinate ◽

Functional Theory ◽

X Ray ◽

X Ray Crystallography ◽

The Past ◽

Meso Position

The use of halogens in the crystal engineering of porphyrin scaffolds has been a topic of strong interest over the past decades. Previously, this was focused on the introduction of a variety of halogens on the meso-phenyl groups of the porphyrin. However, investigations into the effects of direct halogenation of porphyrins at the meso-position on their crystalline architectures have not been conducted to date. Herein we have characterized a series of direct meso-halogenated porphyrins using single crystal X-ray crystallography. This is accompanied by a detailed conformational analysis of all deposited meso-halogenated porphyrins in the CCDC. In this study we have used the Hirshfeld fingerprint plots together with normal-coordinate structural decomposition and determined crystal structures to elucidate the conformation, present intermolecular interactions, and compare respective contacts within the crystalline architectures. Additionally, we have used density functional theory calculations to determine the structure of several halogenated porphyrins. This contrasts conformational analysis with existing X-ray structures and gives a method to characterize samples that are difficult to crystallize.

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Kupfer- und Goldkomplexe von Dithiocarbaminsäureestern. Strukturen von [CuCI(L1)3] · CH2Cl2, [AuCl(L1)2], [CuI(L1)(PPh3)]2 und [Cu2ICuIICl4(L2)2]n (L1 = N-Phenyl-S-methyldithiocarbaminsäureester, L2 = N,N-Dimethyl-S-methyldithiocarbaminsäureester) / Copper and Gold Complexes of Dithiocarbamate Esters. X-Ray Structures of [CuCl(L1)3] · CH2Cl2, [AuCl(L1)2], [CuI(L1)(PPh3)]2 and [Cu2ICuIICl4(L2)2]n (L1 = N-Phenyl-S-methyldithiocarbamate, L2 = N,N-Dimethyl-S-methyldithiocarbamate)

Zeitschrift für Naturforschung B ◽

10.1515/znb-1993-0911 ◽

1993 ◽

Vol 48 (9) ◽

pp. 1227-1233 ◽

Cited By ~ 5

Author(s):

Klaus Schulbert ◽

Rainer Mattes

Keyword(s):

Mixed Valence ◽

Chain Structure ◽

Metal Centers ◽

X Ray ◽

X Ray Crystallography ◽

Square Planar ◽

Coordination Spheres ◽

A Chain ◽

Identity Period ◽

Mixed Valence Complex

Reactions of N-phenyl-S-methyldithiocarbamate (L1) and N,N-dimethyl-S-methyldithio-carbamate (L2) with CuCl2, [Cu2I2(PPh3)3] and HAuCl4 yield the complexes [CuCl(L1)3] • CH2Cl2 (1), [AuCl(L1)2] (2), [CuI(L1)(PPh3)]2 (3) and [Cu2ICuIICl4(L2)2]n (4). Their structures have been determined by single crystal X-ray crystallography. 1 and 2 are monomeric, with Cu(I) tetrahedrally four-coordinate and Au(I) two-coordinate with an S-Au-S angle of 158.2(1)°. 3 is dimeric with a central CuI2Cu core, the Cu•••Cu distance of which [314.9(1) pm] is rather large. The mixed valence complex 4 has a chain structure with the identity period CuII(μ-Cl)2CuI(μ-S)2CuI(μ-Cl)2. CuI is in a tetrahedral, CuII in a square planar environment. The (μ-S)2 bridged CuI ••• CuI distance is only 259.1(1) pm. The structures of the CuX2Cu cores of 3 and 4 are mainly determined by steric interactions of the donor atoms within the coordination spheres of the metal centers.

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One-Step Simultaneous Synthesis of Circularly Polarized Luminescent Multiple Helicenes Using a Chrysene Framework

10.26434/chemrxiv.13480431.v1 ◽

2020 ◽

Author(s):

Tomoyuki Ikai ◽

Shoya Yamakawa ◽

Nozomu Suzuki ◽

Eiji Yashima

Keyword(s):

Density Functional ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

Circularly Polarized ◽

X Ray Crystallography ◽

Circularly Polarized Luminescence ◽

Polarized Luminescence ◽

One Step ◽

Acidic Conditions ◽

Simultaneous Synthesis

A series of multiple helicenes was simultaneously synthesized in one step by intramolecular cyclization of a single chrysene derivative containing two 2-[(4-alkoxyphenyl)ethynyl]phenyl units accompanied by rearrangements of the aryl pendants. The electrophile-induced double cyclization with or without aryl migrations proceeded efficiently under acidic conditions to afford annulative p-extension of the chrysene units and produced quadruple (QH-2), triple (TH-2), and double (DH-2) helicenes containing [4]- and/or [5]helicene frameworks with dynamic and/or static helicene chirality in one step. Three multiple helicenes’ structures were determined by X-ray crystallography and/or density functional theory calculations. The multiple TH-2 and DH-2 helicenes were separated into enantiomers because of the stable one and two [5]helicene moieties, respectively, and showed intense circular dichroism and circularly polarized luminescence. Although QH-2, which comprises four [4]helicene subunits, was not resolved into enantiomers, the TH-2 enantiomers were further separated into a pair of diastereomers at low temperature resulting from their substituted [4]helicene chirality.

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Structure of Electronically Reduced N-Donor Bidentate Ligands and Their Heteroleptic Four-Coordinate Zinc Complexes: A Survey of DFT Results

10.26434/chemrxiv.7491455.v1 ◽

2018 ◽

Author(s):

Madanakrishna Katari ◽

Duncan Carmichael ◽

Denis Jacquemin ◽

Gilles Frison

Keyword(s):

Density Functional ◽

Structural Changes ◽

Density Functional Theory Calculations ◽

Small Degree ◽

Zinc Complexes ◽

Hartree Fock ◽

Exact Exchange ◽

The Difference ◽

Geometric Changes

The role of Hartree-Fock exchange in describing the structural changes occurring upon reduction of bipyridine-based ligands and their complexes is investigated in the framework of density functional theory calculations. A set of 4 free ligands in their neutral and radical anionic forms, and 2 of their zinc complexes in their dicationic and monocationic radical forms, is used to compare a large panel of pure, conventional, and long-range corrected hybrid DFT functionals; coupled cluster single and double calculations are used alongside experimental results as benchmarks. Particular attention has been devoted to the magnitude of the change, upon reduction, of the D-parameter, which measures the difference between the Cpy-Cpy and the C-N bond lengths in bipyridine ligand and is known to experimentally correlate with the charge of the ligands. Our results indicate that the structural changes significantly depend on the amount of exact exchange included in the functional. A progressive evolution is observed for the free ligands, whereas two distinct sets of results are obtained for the complexes. Functionals with a small degree of HF exchange, e.g., B3LYP, do not adequately describe geometric changes for the considered species and, quite surprisingly, the same holds for the CC2 method. The best agreement to experimental and CCSD values is obtained with functionals including a significant but not excessive part of exact exchange, e.g., CAM-B3LYP, M06-2X, and wB97X-D. The location of the added electron upon reduction, which depends on the self-interaction error, is used to rationalize these outcomes.

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