Actinide Arene-Metalates: Ion Pairing Effects on the Electronic Structure of Unsupported Uranium-Arene Sandwich Complexes

10.26434/chemrxiv.14455983 ◽

2021 ◽

Author(s):

Jesse Murillo ◽

Rina Bhowmick ◽

Katie L. M. Harriman ◽

Alejandra Gomez-Torres ◽

Joshua Wright ◽

...

Keyword(s):

Close Contact ◽

Ion Pairing ◽

X Ray Diffraction ◽

Sandwich Complexes ◽

Metal Centers ◽

X Ray ◽

Absorption Energy ◽

Dimeric Complexes ◽

Model Complex ◽

Computational Analyses

Chatt reaction methods were employed to synthesize the first well characterized actinide-arene sandwich complexes. Namely, addition of [UI2(THF)3(μ-OMe)]2⸱THF (2⸱THF) to THF solutions containing 6 equiv. of K[C14H10] generates the dimeric complexes [K(18-crown-6)(THF)2]2[U(η6-C14H10)(η4-C14H10)(μ-OMe)]2⸱4THF (118C6⸱4THF) and {[K(THF)3][U(η6-C14H10)(η4-C14H10)(μ-OMe)]}2 (1THF) upon crystallization of the products in THF in the presence or absence of 18-crown-6, respectively. Both 118C6⸱4THF and 1THF are thermally stable in the solid-state at room temperature; however, after crystallization, they become insoluble in THF or DME solutions and instead gradually decompose upon standing. X-ray diffraction analysis reveals 118C6⸱4THF and 1THF to be structurally similar, possessing uranium centers sandwiched between anthracene ligands of mixed tetrahapto and hexahapto ligation modes. Yet, the two complexes are distinguished by the close contact potassium-arene ion pairing that is seen in 1THF but absent in 118C6⸱4THF, which is observed to have a significant effect on the electronic characteristics of the two complexes. Structural analysis, SQUID magnetometry data, XANES spectral characterization, and computational analyses are generally consistent with U(IV) formal assignments for the metal centers in both 118C6⸱4THF and 1THF, though noticeable differences are detected between the two species. For instance, the effective magnetic moment of 1THF (3.74 µB) is significantly lower than that of 118C6⸱4THF (4.40 µB) at 300 K. Furthermore, the XANES data shows the U LIII-edge absorption energy for 1THF to be 0.9 eV higher than that of 118C6⸱4THF, suggestive of more oxidized metal centers in the former. Of note, CASSCF calculations on the model complex {[U(η6-C14H10)(η4-C14H10)(μ-OMe)]2}2- (1*) shows highly polarized uranium-arene interactions defined by π-type bonds where the metal contributions are primarily comprised by the 6d-orbitals (7.3± 0.6%) with minor participation from the 5f-orbitals (1.5 ± 0.5%). These unique complexes provide new insights into actinide-arene bonding interactions and show the sensitivity of the electronic structures of the uranium atoms to coordination sphere effects.

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Inclusion compounds of plant growth regulators in cyclodextrins. V. 4-Chlorophenoxyacetic acid encapsulated in β-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768105004106 ◽

2005 ◽

Vol 61 (2) ◽

pp. 207-217 ◽

Cited By ~ 11

Author(s):

Frantzeska Tsorteki ◽

Kostas Bethanis ◽

Nikos Pinotsis ◽

Petros Giastas ◽

Dimitris Mentzafos

Keyword(s):

Guest Molecule ◽

Crystal Packing ◽

Host Molecule ◽

X Ray Diffraction ◽

Guest Molecules ◽

Space Group ◽

X Ray ◽

Dimeric Complexes ◽

The Mean ◽

Chlorophenoxyacetic Acid

The crystal structures of 4-chlorophenoxyacetic acid (4CPA) included in β-cyclodextrin (β-CD) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TMβCD) have been studied by X-ray diffraction. The 4CPA/β-CD complex crystallizes as a head-to-head dimer in the space group C2 in the Tetrad packing mode. The packing modes of some β-CD dimeric complexes, having unique stackings, are also discussed. The 4CPA/TMβCD inclusion complex crystallizes in the space group P21 and its asymmetric unit contains two crystallographically independent complexes, complex A and complex B, exhibiting different conformations. The host molecule of complex A is significantly distorted, as a glucosidic residue rotated about the O4′—C1 and C4—O4 bonds forms an aperture where the guest molecule is accommodated. The phenyl moiety of the guest molecule of complex B is nearly perpendicular to the mean plane of the O4n atoms. The conformations of the guest molecules of the two complexes are similar. The crystal packing consists of antiparallel columns as in the majority of the TMβCD complexes published so far.

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Tb2(bpdc)3 and Eu2(bpdc)3 Nanoparticles (bpdc: 2,2ʹ-Bipyridine-4,4ʹ- dicarboxylate) and Their Luminescence

Zeitschrift für Naturforschung B ◽

10.5560/znb.2014-3293 ◽

2014 ◽

Vol 69 (2) ◽

pp. 248-254 ◽

Cited By ~ 1

Author(s):

Ana Kuzmanoski ◽

Claus Feldmann

Keyword(s):

Colloidal Stability ◽

Aqueous Suspension ◽

Earth Metal ◽

Quantum Yields ◽

X Ray Diffraction ◽

Antenna Effect ◽

Metal Centers ◽

X Ray ◽

Suspension Particle ◽

Absolute Quantum

Tb2(bpdc)3 and Eu2(bpdc)3 nanoparticles (bpdc: 2,2ʹ-bipyridine-4,4ʹ-dicarboxylate) have been prepared via straightforward precipitation from aqueous solution. The nanoparticles exhibit mean diameters of 41(5) nm (Tb2(bpdc)3) and 56(4) nm (Eu2(bpdc)3) and show a very good colloidal stability in aqueous suspension. Particle size and chemical composition have been characterized based on electron microscopy, X-ray diffraction, infrared spectroscopy and thermogravimetry. Photoluminescence validates an efficient excitation of Tb3+/Eu3+ via the bpdc ligand as an antenna that leads to intense characteristic green and red emissions. The absolute quantum yields of Tb2(bpdc)3 and Eu2(bpdc)3 have been determined at 28 and 12%, respectively. Although rare-earth metal-based photoluminescence is typically quenched in water due to vibronic loss processes (v(O-H)), here, the antenna effect and the shielding of the metal centers via the bpdc ligand are very efficient, allowing for an intense green and red emission of the Tb2(bpdc)3 and Eu2(bpdc)3 nanoparticles even in aqueous suspension.

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Tuning the Linear and Nonlinear Optical Properties of Pyrene-Pyridine Chromophores by Protonation and Complexation to d10 Metal Centers †

Inorganics ◽

10.3390/inorganics7030038 ◽

2019 ◽

Vol 7 (3) ◽

pp. 38 ◽

Cited By ~ 2

Author(s):

Elena Lucenti ◽

Alessandra Forni ◽

Daniele Marinotto ◽

Andrea Previtali ◽

Stefania Righetto ◽

...

Keyword(s):

Nonlinear Optical ◽

Second Harmonic ◽

Protonated Form ◽

Lewis Acidity ◽

X Ray Diffraction ◽

Metal Centers ◽

X Ray ◽

Nlo Response ◽

D10 Metal ◽

Simple Exposure

The linear and second-order nonlinear optical (NLO) properties of two pyrene-pyridine chromophores, namely, 4-(pyren-1-yl)pyridine (L1) and 4-(2-(pyren-1-yl)ethyl)pyridine (L2), were investigated and modulated by performing protonation/deprotonation cycles or by complexation to d10 metal centers such as Zn(II) and Cu(I) to form the monomeric [Zn(CH3CO2)2(L1)2] complex and the [CuI(L2)]n coordination polymer, respectively. The structures of L1, L2, [Zn(CH3CO2)2(L1)2] and [CuI(L2)]n were determined by means of single-crystal X-ray diffraction studies. The NLO response, measured by the electric-field-induced second harmonic generation (EFISH) technique, was positive for both chromophores and showed an inversion of the sign after exposure to HCl vapors. This process was completely reversible and the original values were restored by simple exposure to NH3 vapors. Coordination of L1 to Zn(II) also resulted in a negative NLO response, although smaller in magnitude compared to the protonated form, due to the weak Lewis acidity of the “Zn(CH3CO2)2” fragment. The results were also interpreted on the basis of DFT/TDDFT calculations.

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A New Binuclear Lutetium(III) Dimethyl-N-trichloroacetylamidophosphate Complex with a γ, γ'-Dipyridyl Bridge, {Lu[CCl3C(O)NP(O)(OCH3)2]3}2-μ(γ,γ'-dipy)

Zeitschrift für Naturforschung B ◽

10.1515/znb-2001-0306 ◽

2001 ◽

Vol 56 (3) ◽

pp. 249-254 ◽

Cited By ~ 8

Author(s):

Victor A. Trush ◽

Jolanta Swiatek-Kozlowska ◽

Victor V. Skopenko ◽

Vladimir M. Amyrkhanov

Keyword(s):

Crystal And Molecular Structure ◽

Carbonyl Oxygen ◽

Carbonyl Groups ◽

X Ray Diffraction ◽

Triclinic Space Group ◽

Metal Centers ◽

X Ray ◽

Heterocyclic Ligand ◽

New Type ◽

Ir Spectroscopic

Abstract A new type of binuclear coordination compound of lutetium, {Lu2L6 · μ-(γ,γ '-dipy)} (where L = dimethyl-N-trichloroacetylamidophosphate anion and γ,γ '-dipy = 4,4'-dipyridyl), has been obtained. The IR spectroscopic data reveal that the ambidentate phosphoryl ligand is coordinated to the metal center in a bidentate manner via the phosphoryl and carbonyl oxygen atoms. The crystal and molecular structure of {Ln2L6-μ-(γ ,γ '-dipy)} has been determined by means of X-ray diffraction (triclinic, space group P i with parameters: a = 9.259(2), b = 12.530(3), c = 16.548(3) Å, α = 85.44(3)°, β = 75.64(3)°, γ = 70.56(3)°, Z = 1). The structure is made up of centrosymmetric binuclear molecules, in which the neutral heterocyclic ligand is coordinated to the metal centers in a bidentate bridging manner via its nitrogen atoms. The coordination number of each Lu(III) atom is 7 [60(L-) + N((γ ,γ '-dipy)]. Phosphoryl and carbonyl groups of the L- ligands are disposed in syn-position and are included in the six-membered chelate metallocycles. The coordination polyhedron of lutetium can be described as distorted mono-capped octahedron.

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Syntheses, Structures, Thermal and Photoluminescence Properties of Two Zn(II) and Cd(II) Coordination Polymers Constructed from Taurine-derived Schiff Base and 4,4’-Bipyridine Ligands

Zeitschrift für Naturforschung B ◽

10.5560/znb.2012-0170 ◽

2012 ◽

Vol 67 (8) ◽

pp. 774-782 ◽

Cited By ~ 2

Author(s):

Wei-Ting Guo ◽

Zhi-Min Miao ◽

Yun-Long Wang

Keyword(s):

Schiff Base ◽

Coordination Polymers ◽

Tridentate Ligand ◽

Supramolecular Architecture ◽

Photoluminescence Properties ◽

X Ray Diffraction ◽

Monodentate Ligand ◽

Metal Centers ◽

X Ray ◽

Ethanesulfonic Acid

Two chain-like coordination polymers, namely, {[Zn(saes)(4,4'-bipy)(H2O)]·H2O}n (1) and {[Cd (Hsaes)2(4,4'-bipy)(H2O)2]·2H2O}n (2), where H2saes=2-(2-hydroxybenzylideneamino)ethanesulfonic acid and 4,4'-bipy=4,4'-bipyridine, have been synthesized and characterized by singlecrystal X-ray diffraction, IR spectroscopy, elemental, thermogravimetric and photoluminescence analysis. X-Ray diffraction analyses indicate that 1and 2display octahedral metal centers with N3O3 and N2O4 donor sets, respectively. The Schiff base serves as a common N,O'-tridentate ligand in 1, and as a unique O-monodentate ligand in 2. In the crystal, both 1and 2form a 3D supramolecular architecture by O-H···O, C-H···O interactions or π···π stacking. The thermal and solid-state photoluminescence properties of both complexes have been investigated

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One ligand fits all: lanthanide and actinide sandwich complexes comprising the 1,4-bis(trimethylsilyl)cyclooctatetraenyl (=COT′′) ligand

New Journal of Chemistry ◽

10.1039/c5nj00991j ◽

2015 ◽

Vol 39 (10) ◽

pp. 7656-7666 ◽

Cited By ~ 22

Author(s):

Janek Rausch ◽

Christos Apostolidis ◽

Olaf Walter ◽

Volker Lorenz ◽

Cristian G. Hrib ◽

...

Keyword(s):

X Ray Diffraction ◽

Sandwich Complexes ◽

X Ray

Twelve new lanthanide and actinide sandwich complexes containing the 1,4-bis(trimethylsilyl)cyclooctatetraenyl ligand (COT′′) have been prepared and structurally characterized by X-ray diffraction.

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Digold(I) Complexes Derived from 5,5′-Bibenzimidazolin-2-ylidene Ligands

Zeitschrift für Naturforschung B ◽

10.5560/znb.2014-4194 ◽

2014 ◽

Vol 69 (11-12) ◽

pp. 1248-1252 ◽

Cited By ~ 1

Author(s):

Mareike C. Jahnke ◽

Christian Schulte to Brinke ◽

F. Ekkehardt Hahn

Keyword(s):

Molecular Structure ◽

Silver Oxide ◽

Silver Complexes ◽

X Ray Diffraction ◽

Gold Complexes ◽

Metal Centers ◽

X Ray ◽

Steric Crowding ◽

Aurophilic Interactions

Abstract The 5,5′-bibenzimidazolium dibromide salts 2 and 3 have been prepared by fourfold N-alkylation of 5,5′-bibenzimidazole (2: R=Pr; 3: R=Bu). The diazolium salts were treated with silver oxide, and the in situ-formed silver complexes were subsequently reacted with [AuCl(SMe2)] to give the dinuclear gold complexes 4 and 5. The molecular structure of complex 5 has been determined by X-ray diffraction showing linearly coordinated gold(I) centers and, most likely due to steric crowding around the metal centers, no aurophilic interactions.

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[(Ln)Ru{η3-(tpdt)}] Complexes as Dithiolate Donors to Group 10 Metal Centers: Synthetic, Single-Crystal X-ray Diffraction and Electrochemical Studies {Ln= η6-C6Me6(HMB) and η5-C5Me5(Cp*); tpdt = S(CH2CH2S)2}

Organometallics ◽

10.1021/om049407t ◽

2004 ◽

Vol 23 (26) ◽

pp. 6108-6115 ◽

Cited By ~ 7

Author(s):

Richard Y. C. Shin ◽

Geok Kheng Tan ◽

Lip Lin Koh ◽

Lai Yoong Goh ◽

Richard D. Webster

Keyword(s):

Single Crystal ◽

Electrochemical Studies ◽

X Ray Diffraction ◽

Metal Centers ◽

X Ray ◽

Group 10

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In Situ EXAFS Characterization of Nanoparticulate Catalysts

MRS Bulletin ◽

10.1557/mrs2007.213 ◽

2007 ◽

Vol 32 (12) ◽

pp. 1038-1043 ◽

Cited By ~ 23

Author(s):

John Evans ◽

Anna Puig-Molina ◽

Moniek Tromp

Keyword(s):

Platinum Group Metal ◽

Metal Catalysts ◽

X Ray Diffraction ◽

Reaction Conditions ◽

Metal Centers ◽

X Ray ◽

Xafs Spectroscopy ◽

Vibrational Spectroscopies ◽

Complementary Techniques

AbstractX-ray absorption fine structure (XAFS) spectroscopy probes the structure and electronic properties of metal centers. Because it can be applied to noncrystalline materials, it is a key technique for probing nanoparticulate materials, such as colloidal and heterogeneous metal catalysts. The high brilliance of modern synchrotron radiation x-ray sources facilitates in situ studies, which provide direct structure–function relationships with both spatial and time resolution; this is especially effective when applied in combination with complementary techniques such as x-ray diffraction, mass spectrometry, and optical or vibrational spectroscopies. Tracking the particle formation of platinum-group metal catalysts, their behavior under reaction conditions, and the distribution of sites within a catalyst bed shows that this approach is essential for understanding the chemistry of these nanoparticles. Rather than behave as monolithic entities, nanoparticulate catalysts undergo rapid structural transformations induced by the gas environment and reaction conditions, and their lifetimes as catalysts depend on the reversibility of these changes.

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