Tracking the dissolution–recrystallization structural transformation (DRST) of copper(II) complexes: a combined crystallographic, mass spectrometric and DFT study

Methanol- and temperature-induced dissolution–recrystallization structural transformation (DRST) was observed among two novel CuII complexes. This is first time that the combination of X-ray crystallography, mass spectrometry and density functional theory (DFT) theoretical calculations has been used to describe the fragmentation and recombination of a mononuclear CuII complex at 60 °C in methanol to obtain a binuclear copper(II) complex. Combining time-dependent high-resolution electrospray mass spectrometry, we propose a possible mechanism for the conversion of bis(8-methoxyquinoline-κ2 N,O)bis(thiocyanato-κN)copper(II), [Cu(NCS)2(C10H9NO)2], Cu1, to di-μ-methanolato-κ4 O:O-bis[(8-methoxyquinoline-κ2 N,O)(thiocyanato-κN)copper(II)], [Cu2(CH3O)2(NCS)2(C10H9NO)2], Cu2, viz. [Cu(SCN)2(L)2] (Cu1) → [Cu(L)2] → [Cu(L)]/L → [Cu2(CH3O)2(NCS)2(L)2] (Cu2). We screened the antitumour activities of L (8-methoxyquinoline), Cu1 and Cu2 and found that the antiproliferative effect of Cu2 on some tumour cells was much greater than that of L and Cu1.

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Highly Electron-Deficient Pyridinium-Nitrones for Rapid and Tunable Inverse-Electron-Demand Strain-Promoted Alkyne-Nitrone Cycloaddition to Bicyclo[6.1.0]nonyne

10.26434/chemrxiv.8251370 ◽

2019 ◽

Author(s):

Praveen Gunawardene ◽

Wilson Luo ◽

Alexander M. Polgar ◽

John F. Corrigan ◽

Mark Workentin

Keyword(s):

Density Functional Theory ◽

Reaction Kinetics ◽

Density Functional ◽

Functional Theory ◽

X Ray ◽

Inverse Electron Demand ◽

X Ray Crystallography ◽

Electron Demand

<div> <div> <p>Highly accelerated inverse-electron-demand strain-promoted alkyne-nitrone cycloaddition (IED SPANC) between a sta- ble cyclooctyne (bicyclo[6.1.0]nonyne (BCN)) and nitrones delocalized into a Cα-pyridinium functionality is reported, with the most electron-deficient “pyridinium-nitrone” displaying among the most rapid cycloadditions to BCN that is currently reported. Density functional theory (DFT) and X-ray crystallography are explored to rationalize the effects of N- and Cα-substituent modifications at the nitrone on IED SPANC reaction kinetics and the overall rapid reactivity of pyridinium-delocalized nitrones.</p> </div> </div>

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How big is big? Separation by conventional methods, X-ray and electronic structures of positional isomers of bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato iron(II) complex

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424616500164 ◽

2016 ◽

Vol 20 (01n04) ◽

pp. 337-351 ◽

Cited By ~ 4

Author(s):

Derrick R. Anderson ◽

Pavlo V. Solntsev ◽

Hannah M. Rhoda ◽

Victor N. Nemykin

Keyword(s):

Electronic Structures ◽

Density Functional ◽

Positional Isomers ◽

Excitation Energies ◽

Functional Theory ◽

X Ray ◽

Vertical Excitation ◽

X Ray Crystallography ◽

Tddft Calculations ◽

Insight Into

A presence of bulky 2,6-di-iso-propylphenoxy groups in bis-tert-butylisocyano adduct of 2(3),9(10),16(17),23(24)-tetrachloro-3(2),10(9),17(16),24(23)-tetra(2,6-di-iso-propylphenoxy)-phthalocyaninato iron(II) complex allows separation of two individual positional isomers and a mixture of the remaining two isomers using conventional chromatography. X-ray structures of “[Formula: see text]” and “[Formula: see text]” isomers were confimed by X-ray crystallography. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations of each individual positional isomer allowed insight into their electronic structures and vertical excitation energies, which were correlated with the experimental UV-vis and MCD spectra.

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Local and electronic structure around Ga in CdTe: evidence of DX- and A-centers

Journal of Synchrotron Radiation ◽

10.1107/s0909049512042197 ◽

2012 ◽

Vol 20 (1) ◽

pp. 166-171

Author(s):

Vasil Koteski ◽

Jelena Belošević-Čavor ◽

Petro Fochuk ◽

Heinz-Eberhard Mahnke

Keyword(s):

Density Functional ◽

Plane Waves ◽

Lattice Relaxation ◽

Defect Structures ◽

Functional Theory ◽

Edge Structure ◽

X Ray ◽

First Time ◽

X Ray Absorption ◽

Good Agreement

The lattice relaxation around Ga in CdTe is investigated by means of extended X-ray absorption spectroscopy (EXAFS) and density functional theory (DFT) calculations using the linear augmented plane waves plus local orbitals (LAPW+lo) method. In addition to the substitutional position, the calculations are performed for DX- and A-centers of Ga in CdTe. The results of the calculations are in good agreement with the experimental data, as obtained from EXAFS and X-ray absorption near-edge structure (XANES). They allow the experimental identification of several defect structures in CdTe. In particular, direct experimental evidence for the existence of DX-centers in CdTe is provided, and for the first time the local bond lengths of this defect are measured directly.

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Exploiting superspace to clarify vacancy and Al/Si ordering in mullite

IUCrJ ◽

10.1107/s2052252518007467 ◽

2018 ◽

Vol 5 (4) ◽

pp. 497-509 ◽

Cited By ~ 2

Author(s):

Paul Benjamin Klar ◽

Iñigo Etxebarria ◽

Gotzon Madariaga

Keyword(s):

Density Functional ◽

X Ray Diffraction ◽

Intrinsic Structure ◽

Functional Theory ◽

New Approach ◽

X Ray ◽

Vacancy Ordering ◽

Harmonic Modulation ◽

First Time

Synchrotron single-crystal X-ray diffraction has revealed diffuse scattering alongside sharp satellite reflections for different samples of mullite (Al4+2xSi2−2xO10−x). Structural models have been developed in (3+1)-dimensional superspace that account for vacancy ordering and Al/Si ordering based on harmonic modulation functions. A constraint scheme is presented which explains the crystal-chemical relationships between the split sites of the average structure. The modulation amplitudes of the refinements differ significantly by a factor of ∼3, which is explained in terms of different degrees of ordering,i.e.vacancies follow the same ordering principle in all samples but to different extents. A new approach is applied for the first time to determine Al/Si ordering by combining density functional theory with the modulated volumes of the tetrahedra. The presence of Si–Si diclusters indicates that the mineral classification of mullite needs to be reviewed. A description of the crystal structure of mullite must consider both the chemical composition and the degree of ordering. This is of particular importance for applications such as advanced ceramics, because the physical properties depend on the intrinsic structure of mullite.

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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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Size Matters: New Zintl Phase Hydrides of REGa (RE = Y, La, Tm) and RESi (RE = Y, Er, Tm) with Large and Small Cations

Crystals ◽

10.3390/cryst9110600 ◽

2019 ◽

Vol 9 (11) ◽

pp. 600

Author(s):

Werwein ◽

Hansen ◽

Kohlmann

Keyword(s):

Density Functional ◽

Theoretical Calculations ◽

Structural Diversity ◽

Type Structure ◽

Zintl Phases ◽

Structure Form ◽

Functional Theory ◽

X Ray ◽

Hydrogenation Reactions ◽

Tetrahedral Voids

Many Zintl phases exhibiting a CrB type structure form hydrides. Systematic studies of AeTtHx (Ae = Ca, Sr, Ba; Tt = Si, Ge, Sn), LnTtHx (Ln = La, Nd; Tt = Si, Ge, Sn), and LnGaHx (Ln = Nd, Gd) showed the vast structural diversity of these systems. Hydrogenation reactions on REGa (RE = Y, La, Tm) and RESi (RE = Y, Er, Tm) were performed in steel autoclaves under hydrogen pressure up to 5 MPa and temperatures up to 773 K. The products were analyzed by X-ray and neutron powder diffraction. RESi (RE = Y, Er, Tm) form hydrides in the C-LaGeD type. LaGaD1.66 is isostructural to NdGaD1.66 and shows similar electronic features. Ga-D distances (1.987(13) Å and 2.396(9) Å) are considerably longer than in polyanionic hydrides and not indicative of covalent bonding. In TmGaD0.93(2) with a distorted CrB type structure deuterium atoms exclusively occupy tetrahedral voids. Theoretical calculations on density functional theory (DFT) level confirm experimental results and suggest metallic properties for the hydrides.

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Twisted Push - Pull Ethylenes

Australian Journal of Chemistry ◽

10.1071/ch08277 ◽

2008 ◽

Vol 61 (10) ◽

pp. 805 ◽

Cited By ~ 8

Author(s):

Rakesh Naduvile Veedu ◽

Paul V. Bernhardt ◽

Rainer Koch ◽

Curt Wentrup

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Room Temperature ◽

Dihedral Angles ◽

Functional Theory ◽

Activation Barriers ◽

Rapid Rotation ◽

X Ray ◽

X Ray Crystallography ◽

Calculated Activation

As determined by X-ray crystallography, Meldrum’s acid derivatives 5, 6, and 8 feature dihedral angles around the central C5=C7 double bond of 14–35°, whereas for the anion 9 this angle is 90°. Density functional theory and MP2 calculations are in agreement with the experimental X-ray data for compounds 5–8, but for anion 9 an angle of only ~65° is predicted. It is concluded that a part of the torsion is due to packing forces in the crystal. It is further concluded that these molecules undergo rapid rotation about the central CC bonds at room temperature (calculated activation barriers 5–14 kcal mol–1).

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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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An amino–imino resonance study of 2-amino-4-methylpyridinium nitrate and 2-amino-5-methylpyridinium nitrate

Acta Crystallographica Section C Crystal Structure Communications ◽

10.1107/s0108270112047877 ◽

2012 ◽

Vol 69 (1) ◽

pp. 61-65 ◽

Cited By ~ 2

Author(s):

Xing-Chen Yan ◽

Yu-Hua Fan ◽

Cai-Feng Bi ◽

Xia Zhang ◽

Zhong-Yu Zhang

Keyword(s):

Density Functional Theory ◽

Ir Spectroscopy ◽

Ground State ◽

Density Functional ◽

Acta Cryst ◽

Functional Theory ◽

X Ray ◽

X Ray Crystallography ◽

Ground State Structures

The contributions of the amino and imino resonance forms to the ground-state structures of 2-amino-4-methylpyridinium nitrate, C6H9N2+·NO3−, and the previously reported 2-amino-5-methylpyridinium nitrate [Yan, Fan, Bi, Zuo & Zhang (2012).Acta Cryst.E68, o2084], were studied using a combination of IR spectroscopy, X-ray crystallography and density functional theory (DFT). The results show that the structures of 2-amino-4-methylpyridine and 2-amino-5-methylpyridine obtained upon protonation are best described as existing largely in the imino resonance forms.

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1,4,8,11-Tetra[2-aryl-1-diazenyl]-1,4,8,11-tetraazacyclotetradecanes — Synthesis, characterization, and X-ray crystallography of the first tetrakistriazenes to be reported

Canadian Journal of Chemistry ◽

10.1139/v06-090 ◽

2006 ◽

Vol 84 (10) ◽

pp. 1280-1289 ◽

Cited By ~ 1

Author(s):

Jeffery D Clarke ◽

Keith Vaughan ◽

Valerio Bertolasi

Keyword(s):

Mass Spectrometry ◽

High Resolution ◽

Electrospray Mass Spectrometry ◽

Diazonium Salt ◽

Diazonium Salts ◽

The Novel ◽

Analogous Reaction ◽

X Ray ◽

X Ray Crystallography ◽

The Mean

The reactions of a series of arene diazonium salts with 1,4,8,11-tetraazacyclotetradecane (cyclam) afford the novel compounds, the 1,4,8,11-tetra[2-aryl-1-diazenyl]-1,4,8,11-tetraazacyclotetradecanes (1a–1f), which are the first examples of tetrakistriazenes to be reported. The tetrakistriazenes were characterized by IR spectroscopy, proton and carbon NMR, elemental analysis, high resolution electrospray mass spectrometry, and X-ray crystallography. The analogous reaction of a diazonium salt with 1,4,7-triazacyclononane or 1,5,9-triazacyclododecane yields the tristriazenes 2, 3a, and 3b. The structures of compounds 1c and 1e were solved by X-ray crystallography at low temperature (150 K). Both molecules display a conformation where the four phenyltriazenyl groups point alternately upwards and downwards with respect to the mean macrocyclic plane.Key words: triazene, tetrakistriazene, cyclam, tetraazacyclotetradecane, X-ray, NMR, cyclic polyamines.

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