scholarly journals The Synthesis of a Bis(thiosemicarbazone) Macrocyclic Ligand and the Mn(II), Co(II), Zn(II) and 68Ga(III) Complexes

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3646
Author(s):  
Melyssa L. Grieve ◽  
Patrick R. W. J. Davey ◽  
Craig M. Forsyth ◽  
Brett M. Paterson
Keyword(s):  
Density Functional ◽  
Macrocyclic Ligand ◽  
Positron Emission Tomography Imaging ◽  
Density Functional Theory Calculations ◽  
Single Species ◽  
Functional Theory ◽  
X Ray Crystallography ◽  
Positron Emission ◽  
Racemic Mixtures ◽  
Gallium 68

A 1,4,7,10-tetraazacyclododecane (cyclen) variant bearing two thiosemicarbazone pendant groups has been prepared. The ligand forms complexes with Mn2+, Co2+ and Zn2+. X-ray crystallography of the Mn2+, Co2+ and Zn2+ complexes showed that the ligand provides a six-coordinate environment for the metal ions. The Mn2+ and Zn2+ complexes exist in the solid state as racemic mixtures of the Δ(δ,δ,δ,δ)/Λ(λ,λ,λ,λ) and Δ(λ,λ,λ,λ)/Λ(δ,δ,δ,δ) diastereomers, and the Co2+ complex exists as the Δ(δ,δ,δ,δ)/Λ(λ,λ,λ,λ) and Δ(λ,λ,λ,δ)/Λ(δ,δ,δ,λ) diastereomers. Density functional theory calculations indicated that the relative energies of the diastereomers are within 10 kJ mol−1. Magnetic susceptibility of the complexes indicated that both the Mn2+ and Co2+ ions are high spin. The ligand was radiolabelled with gallium-68, in the interest of developing new positron emission tomography imaging agents, which produced a single species in high radiochemical purity (>95%) at 90 °C for 10 min.

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

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 273 ◽  
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.

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

2020 ◽  
Vol 16 ◽  
pp. 391-397 ◽  
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.

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

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.

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

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

<p>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-<b>2</b>), triple (TH-<b>2</b>), and double (DH-<b>2</b>) 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-<b>2</b> and DH-<b>2</b> 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-<b>2</b>, which comprises four [4]helicene subunits, was not resolved into enantiomers, the TH-<b>2</b> enantiomers were further separated into a pair of diastereomers at low temperature resulting from their substituted [4]helicene chirality.</p>

scholarly journals Conformational and structural diversity of iridium dimethyl sulfoxide complexes

2017 ◽  
Vol 73 (6) ◽  
pp. 1032-1042 ◽  
Author(s):  
Benjamin M. Ridgway ◽  
Ana Foi ◽  
Rodrigo S. Corrêa ◽  
Damian E. Bikiel ◽  
Javier Ellena ◽  
...  
Keyword(s):  
Dimethyl Sulfoxide ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Structural Diversity ◽  
Stable Form ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Conformational Preferences ◽  
Clinically Significant

Transition metal complexes containing dimethyl sulfoxide (DMSO) are important precursors in catalysis and metallodrugs. Understanding the solid-state supramolecular structure is crucial for predicting the properties and biological activity of the material. Several crystalline phases of DMSO-coordinated iridium anions with different cations, potassium (1a) and n-butylammonium (1b), were obtained and their structures determined by X-ray crystallography. Compound (1a) is present in two solvatomorphic forms: α and β; the β form contains disordered solvent water. In addition, the structures exhibit different rotamers of the trans-[IrCl4(DMSO)2]− anion with the trans-DMSO ligands being oriented in anti and gauche conformations. In consideration of these various conformers, the effects of the crystallized solvent and intermolecular interactions on the conformational preferences of the anion are discussed. In addition, density functional theory calculations were used to investigate the energies of the anions in the different conformations. It was found that hydrogen bonds between water and the DMSO complex stabilize the gauche conformation which is the least stable form of the trans-DMSO complex. Consequently, by controlling the number of hydrogen-bond donors and acceptors and the amount of water, it may be possible to obtain different solvatomorphs of clinically significant metallodrugs.

scholarly journals Solid-state structure of cyclic dipeptides: an X-ray and computational study of cis- and trans-diketopiperazines of N-methyl-phenylalanine with the thia-pipecolic acids and thia-prolines

2017 ◽  
Vol 73 (6) ◽  
pp. 1179-1193 ◽  
Author(s):  
Milos Budesinsky ◽  
Ivana Cisarova ◽  
Frans Borremans ◽  
Jose C. Martins ◽  
Ewald Pauwels
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Density Functional Theory Calculations ◽  
Amide Bond ◽  
Functional Theory ◽  
Torsion Angles ◽  
Molecular Conformations ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cis And Trans

Ten new crystal structures of cis and trans bicyclic diketopiperazines (DKPs) of thia-pipecolic acid (with sulfur in the β, γ or δ position) or thia-proline (with sulfur in the β or γ position) and N-methyl phenylalanine [(NMe)Phe]: cyclo[(β-S)Pip-(NMe)Phe], cyclo[(γ-S)Pip-(NMe)Phe], cyclo[(δ-S)Pip-(NMe)Phe], cyclo[(β-S)Pro-(NMe)Phe] and cyclo[(γ-S)Pro-(NMe)Phe] were determined with X-ray crystallography. Density functional theory calculations of these molecules in the gas phase succeed in reproducing the observed molecular conformations in the crystal remarkably well. This illustrates the weak to moderate impact of intermolecular packing forces in the absence of classical N—H...O hydrogen bonds. The effect of sulfur on the geometry of the DKP ring and details of amide bond non-planarity are discussed. Molecular flexibility of the DKP ring, as estimated from the calculated deformation energies of its endocyclic ring torsion angles, is not in general the decisive factor for the occurrence of multiple symmetry independent molecules in the unit cell (Z′ > 1), though in some cases a correlation is observed.

Luminescent P-Benzyl Dithienophospholes – A Joint Experimental and Theoretical Investigation

2013 ◽  
Vol 66 (10) ◽  
pp. 1171 ◽  
Author(s):  
Zisu Wang ◽  
Alva Y. Y. Woo ◽  
Thomas Baumgartner
Keyword(s):  
Density Functional Theory ◽  
Single Crystal ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Phenyl Substituent ◽  
Substitution Pattern ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sulfide Species

A series of P-benzyl functionalised dithieno[3,2-b:2′,3′-b]phospholes with different substitution pattern at the phosphorus as well as the conjugated scaffold was synthesised and characterised via optical spectroscopy. Single crystal X-ray crystallography was performed on one species. The experimentally observed data were solidified with density functional theory calculations. In contrast to related benzylated P-phenyl phospholium species, the new systems show pronounced photoluminescence in solution, with the exception of the phosphole sulfide species. The observed photophysics could be explained with dominating π→π* transitions, despite the presence of the benzyl group that had been found to quench the fluorescence in the predecessor benzyl system with P-phenyl substituent.

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