A permanently porous chalcogen-bonded organic framework - Nature Synthesis

A permanently porous organic framework assembled and stabilized solely by non-covalent chalcogen bonding is reported. Empirical and computational studies reveal the characteristic influence of the ope...

nature.com

Covalency of M–N Bonds in Isomorphous Lanthanide and Actinide 5-(2-Pyridyl)-1H-tetrazolate Complexes

Experimental and computational analyses of [M(pdtz)3(H2O)3]·3.5H2O (M3+ = Pu3+–Cm3+, La3+–Nd3+, and Sm3+–Ho3+, pdtz– = 5-(2-pyridyl)-1H-tetrazolate) were conducted to understand potential differences ...

pubs.acs.org

Non–linear bonding trends in maleonitrile-1,2–dithiolate complexes of the transuranium actinides - Nature Communications

Although the trivalent actinides are similar to the lanthanide series in terms of chemistry and bonding, their structures and properties can diverge significantly. Here, the authors report a series of...

nature.com

Nobelium becomes heaviest element with identified compounds

Complexes containing hydroxide, water and dinitrogen ligands detected as researchers probe chemistry on the edge of the actinide series

chemistryworld.com

Molecular complexes of low-valent f-elements from lanthanum to californium

This review outlines the structure and chemistry of divalent lanthanides and actinides in small molecule systems, focusing on the less accessible diva…

sciencedirect.com

U4+ Speciation in Acidic Aqueous Solution: Insights from UV–Vis, EXAFS, XANES, and Quantum-Statistical Simulations

This theoretical study investigates the UV–vis absorption properties of U4+-containing aqueous solutions and their relationship with the nature of aqua-complexes present at varying acidic levels. High...

doi.org

Effects of the Inverse Trans-Influence in a Berkelium(III) Phosphine Oxide Complex

An example of a 249Bk3+ phosphine oxide complex has been prepared to examine and quantify the effects of the inverse trans-influence (ITI) on a late actinide complex. This has been accomplished through a comparison of cis and trans Bk-ligand bonds in the meridional berkelium(III) complex, BkBr3(OPCy3)3 (OPCy3 = tricyclohexylphosphine oxide). A detailed bond metric analysis was completed that includes the shortest published distance for a Bk3+–O bond, attributed to the smaller coordination number of Bk3+ of six in mer-BkBr3(OPCy3)3. ITI calculations of the trans Bk3+–O bond provide an ITI value (98.5(2)%) comparable to that of mer-AmBr3(OPCy3)3 (98.2(2)%) and indicate a small 5f orbital contribution to bonding. This effect is discussed in the context of the isomorphous lanthanide(III) series where the ITI is calculated to be higher for mer-BkBr3(OPCy3)3 than in most Ln3+ analogues.

pubs.acs.org

Unveiling the covalency of versatile Pu(iii)-N bonds in a unique plutonium(iii) complex

A trivalent plutonium–pyrazinyl–tetrazolate complex Na2[Pu(Hdtp)(dtp)2(H2O)4]·9H2O (Pu_dtp, H2dtp = 2,3-di-1H-tetrazol-5-ylpyrazine) was synthesized through metathesis reaction of plutonium bromide an...

pubs.rsc.org

Praseodymium in the formal +5 oxidation state

Nature Chemistry - The most common oxidation state for lanthanide elements is +3, and, beyond cerium, examples of these elements exhibiting higher oxidation states remain scarce. Now, a molecular...

rdcu.be

Carbon–boron triple bond formed for the first time in a neutral novel molecule

Synthesis could help chemists better understand bonding

chemistryworld.com

Insights into the Complexation of Actinides by Diethylenetriaminepentaacetic Acid from Characterization of the Americium(III) Complex

Diethylenetriaminepentaacetic acid (DTPA) is a frequently used chelator in the nuclear and medical industries, especially for the complexation of trivalent actinides. However, structural data on these complexes in the solid-state have long remained elusive. Herein, a detailed structural analysis of the presented crystal structures of [C(NH2)3]4[Nd(DTPA)]2·nH2O and [C(NH2)3]4[Am(DTPA)]2·nH2O, where [C(NH2)3]+ is guanidinium, details the subtle differences in the Lewis acidity between a lanthanide/actinide pair of similar ionic sizes. Contractions in nitrogen–metal bond lengths between neodymium(III) and americium(III) were observed, while the metal–oxygen bonds remained relatively consistent, highlighting the marginal favorability for actinide complexation over the lanthanides with moderately soft N-donors. Spectroscopic analysis shows significant splitting of many transitions and relatively strong electronic interactions with traditionally low-intensity transitions in the americium complex, as is demonstrated in the 7F0→7F5 transitions. Pressure-induced spectroscopic analysis showed surprisingly little effect on the americium complex, with 5f→5f transitions either not shifting or marginally shifting from 2 to 3 nm at 11.93 ± 0.06 GPa─atypical of a soft, N-donor americium complex under pressure. Large voids occupied by water molecules in between the complexes within the crystal structure may be responsible for the lack of pressure response in the 5f→5f transitions.

pubs.acs.org

Measuring the elusive half-life of samarium-146

The isotope is critical for understanding Earth’s origins. An accurate half-life is key—and researchers may have finally measured it

cen.acs.org

High-Pressure Effects on an Octa-Hydrated Curium Complex: An Experimental and Theoretical Investigation

An octa-hydrated curium compound [Cm(H2O)8](Hdtp)(dtp)·H2O (Cm1, H2dtp = 2,3-di(tetrazol-5-yl)pyrazine) along with its lanthanide analogues [Ln(H2O)8](Hdtp)(dtp)·H2O (Ln1, Ln3+ = La3+–Nd3+, Sm3+–Lu3+)...

pubs.acs.org

Superheavy element half-life measurements push back the limits of stability

Experimental observations of the half life of rutherfordium-252 demonstrate that its stability lies well within the limits required for full atoms to form

chemistryworld.com

Coordination Chemistry and Photoluminescence of Sm(II) Dibenzo-24-crown-8 Complexes

Three Sm(II) dibenzo-24-crown-8 (db24c8) complexes were synthesized in anhydrous, air-free conditions via the reaction of SmI2 with db24c8 and tetrabutylammonium tetraphenylborate ([TBA][BPh4]; where ...

pubs.acs.org

Unraveling the interplay of 4fn+1 and 4fn5d1 configurations in Ln2+ complexes - SCM

scm.com

High‐Valent Cobalt‐Difluoride in Oxidative Fluorination of Saturated Hydrocarbons

Polyamine-supported CoII complexes catalyzed the oxidative fluorination of saturated hydrocarbons, in some instances selectively, when combined with Selectfluor and CsF, producing fluorinated product...

onlinelibrary.wiley.com

Isolation of Inner-Sphere Aquo Complexes of Samarium(II)

The cis-anti-cis and cis-syn-cis isomers of [Sm(dicyclohexano-18-crown-6)(H2O)2]I2 exhibiting trans water molecules bound to the Sm2+ ion have been isolated and characterized. Sm2+ possesses an electrochemical potential sufficient for water reduction, and thus these complexes add to the recent body of evidence that the oxidation of Sm2+ by water can operate by a mechanism that is not straightforward. These complexes are obtained by the direct addition of stoichiometric amounts of water to solutions of the respective Sm(dicyclohexano-18-crown-6)I2 isomers under an inert atmosphere. The parent complex, Sm(dicyclohexano-18-crown-6)I2, lacking coordinating water molecules can be obtained through rigorous exclusion of water. It was determined that the bulky cyclohexano-substituents deter intramolecular interactions between [Sm(dicyclohexano-18-crown-6)(H2O)2]I2 complexes and slow the oxidization of the metal centers. The extent of the stability of these complexes to the presence of water has been further probed through cyclic voltammetry, where it was found that the redox potential of both isomers of [Sm(dicyclohexano-18-crown-6)(H2O)2]I2 maintains quasi-reversible behavior with a 50,000-fold excess of water to Sm2+ in solution with the cis-syn-cis complex being quasi-reversible at even higher concentrations of water. Solution-phase spectroscopy of these complexes in acetonitrile shows a corresponding hypsochromic shift of the Sm2+ 4f → 5d transition typically observed in the visible region from Sm2+ complexes. The crystalline compounds obtained in this study support solid-state spectroscopic trends observed from other Sm2+ crown-ether complexes containing iodide counterions, wherein the proximity of the iodide ions to the metal center determines whether the complex can exhibit 4f → 4f photoluminescence.

pubs.acs.org

A comprehensive approach for elucidating the interplay between 4fn+1 and 4fn5d1 configurations in Ln2+ complexes

Lanthanides (Ln) are typically found in the +3 oxidation state. However, in recent decades, their chemistry has been expanded to include the less stable +2 oxidation state across the entire series exc...

pubs.rsc.org