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1. Radical Complexes of Nickel(II)/Copper(II) and Redox Non‐innocent MB‐DIPY Ligands: Unusual Stability and Strong Near‐Infrared Absorption at λ _max ∼1300 nm

   https://doi.org/10.1002/chem.202201181  

   Zatsikha, Yuriy_V; Shamova, Liliya_I; Shepit, Michael; Berry, Steven_M; Thomas, Fabrice; Herbert, David_E; van_Lierop, Johan; Nemykin, Victor_N (June 2022, Chemistry – A European Journal)

   Abstract The preparation of radicals with intense and redox‐switchable absorption beyond 1000 nm is a long‐standing challenge in the chemistry of functional dyes. Here we report the preparation of a series of unprecedented stable neutral nickel(II) and copper(II) complexes of “Manitoba dipyrromethenes” (MB‐DIPYs) in which the organic chromophore is present in the radical‐anion state. The new stable radicals have an intense absorption atλ_max∼1300 nm and can be either oxidized to regular [M^II(MB‐DIPY)]⁺(M=Cu or Ni) or reduced to [M^II(MB‐DIPY)]⁻compounds. The radical nature of the stable [M^II(MB‐DIPY)] complexes was confirmed by EPR spectroscopy with additional insight into their electronic structure obtained by UV‐Vis spectroscopy, electro‐ and spectroelectrochemistry, magnetic measurements, and X‐ray crystallography. The electronic structures and spectroscopic properties of the radical‐based chromophores were also probed by density functional theory (DFT) and time‐dependent DFT (TDDFT) calculations. These nickel(II) and copper(II) complexes represent the first stable radical compounds with a MB‐DIPY ligand. 

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2. Introducing the Bis(mesitoyl)phosphide Ligand into Dinuclear Trivalent Rare Earth Metal Coordination Chemistry

   https://doi.org/10.1002/cplu.202400311  

   Deshapriya, Saroshan; Delano, IV, Francis; Demir, Selvan (August 2024, ChemPlusChem)

   Abstract Anionic ancillary ligands play a critical role in the construction of rare earth (RE) metal complexes due to the large influence on the stability of the molecule and engendering emergent electronic properties that are of interest in a plethora of applications. Supporting ligands comprising oxygen donor atoms are highly pursued in RE chemistry owing to the high oxophilicity innate to these ions. The scarcely employed bis(acyl)phosphide (BAP) ligands feature oxygen coordination sites and contain a phosphide backbone rendering it attractive for RE‐coordination chemistry. Here, we integrate bis(mesitoyl)phosphide (^mesBAP) as an ancillary ligand into RE^IIIchemistry to generate the first dinuclear trivalent RE complexes containing BAP ligands; [{^mesBAP}₂RE(THF)(μ‐Cl)]₂(RE=Y, (1), Gd (2), and Dy (3); THF=tetrahydrofuran). Each RE center is ligated to two monoanionic^mesBAP ligands, one THF molecule and one chloride ion. All three molecules were characterized through single‐crystal X‐ray diffraction,³¹P NMR, IR and UV‐Vis spectroscopy.³¹P,¹H and¹³C NMR on the diamagnetic yttrium congener1confirm asymmetric ligand coordination. DFT calculations conducted on2provided insight into the electronic structure. The magnetic properties of2and3were investigated via SQUID magnetometry. The Gd^IIIions exhibit weak antiferromagnetic coupling, corroborated by DFT results. 

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3. Thionitrite (SNO ⁻ ) and Perthionitrite (SSNO ⁻ ) are Simple Synthons for Nitrosylated Iron Sulfur Clusters

   https://doi.org/10.1002/anie.202204570  

   Sherbow, Tobias J.; Fu, Wen; Tao, Lizhi; Zakharov, Lev N.; Britt, R. David; Pluth, Michael D. (June 2022, Angewandte Chemie International Edition)

   Abstract S/N crosstalk species derived from the interconnected reactivity of H₂S and NO facilitate the transport of reactive sulfur and nitrogen species in signaling, transport, and regulatory processes. We report here that simple Fe²⁺ions, such as those that are bioavailable in the labile iron pool (LIP), react with thionitrite (SNO⁻) and perthionitrite (SSNO⁻) to yield the dinitrosyl iron complex [Fe(NO)₂(S₅)]⁻. In the reaction of FeCl₂with SNO⁻we were able to isolate the unstable intermediate hydrosulfido mononitrosyl iron complex [FeCl₂(NO)(SH)]⁻, which was characterized by X‐ray crystallography. We also show that [Fe(NO)₂(S₅)]⁻is a simple synthon for nitrosylated Fe−S clusters via its reduction with PPh₃to yield Roussin's Red Salt ([Fe₂S₂(NO)₄]²⁻), which highlights the role of S/N crosstalk species in the assembly of fundamental Fe−S motifs. 

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4. Molecular Turnstiles Featuring Bicyclic Rotators: Solution and Solid‐State Investigation of Steric and Electronic Concerns

   https://doi.org/10.1002/ejoc.202300716  

   Rammer, Megan_L; Gonnering, Emily_R; Driscoll, Zakarias_L; Vang, Herh_G; Bosch, Eric; Bowling, Nathan_P (August 2023, European Journal of Organic Chemistry)

   Abstract A molecular rotor is created when a 2,1,3‐benzothiadiazole rotator is incorporated into a rigid arylene ethynylene framework supported by pyridine coordination to a metal (Ag⁺or PdCl₂) guest. Comparisons to a similarly sized naphthyl rotator via¹H NMR spectroscopy provide insights into the movement of these bicyclic rotators relative to the rigid stator framework. Chemical shift increases of 0.3 ppm, or more, upon metal complexation are consistent with through‐space interaction of the central arene with a bound PdCl₂guest. Further study via X‐ray crystallography illustrates that rotation of the 2,1,3‐benzothiadiazole unit in the solid state is likely hampered by relatively strong chalcogen bonding (N⋅⋅⋅S distance of 2.93 Å), forming 2S‐2N squares between benzothiadiazoles of neighboring complexes. Strong π–π interactions (3.29–3.36 Å) between neighboring complexes likewise restrict solid‐state rotation of the potential benzothiadiazole rotator. Modest changes to UV–vis spectra upon metal coordination suggest that electronic properties are mostly independent of stator configuration. 

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5. Interaction of Pb ²⁺ ions in water with two-dimensional molybdenum disulfide

   https://doi.org/10.1088/2515-7639/ab7ab3  

   Li, Duo O.; Gilliam, Matthew S.; Debnath, Abhishek; Chu, Ximo S.; Yousaf, Ahmed; Green, Alexander A.; Wang, Qing Hua (March 2020, Journal of Physics: Materials)

   Abstract The removal of heavy metal contaminants from water is important for public health, and recently many two-dimensional (2D) materials with high specific surface areas are being studied as promising new active components in water purification. In particular, 2D MoS₂nanosheets have been used for the removal of various heavy metals, but usually in either in complex geometries and composites, or in the chemically exfoliated metallic 1T-MoS₂phase. However, the interaction of heavy metals dissolved in water with unmodified semiconducting 2H-MoS₂is not well studied. In this paper, we report a detailed fundamental investigation of how Pb²⁺ions interact with 2H-MoS₂. We observe small solid clusters that form on the MoS₂surfaces after exposing them to Pb(NO₃)₂aqueous solutions as shown by atomic force microscopy and transmission electron microscopy, and for liquid phase exfoliated MoS₂we observe the nanosheets precipitating out of dispersion along with insoluble solid granules. We use a combination of x-ray photoelectron spectroscopy and x-ray diffraction to identify these solid clusters and granules as primarily PbSO₄with some PbMoO₄. We put forth an interaction mechanism that involves MoS₂defects acting as initiation sites for the partial dissolution in aqueous oxygenated conditions which produces MoO₄²⁻and SO₄²⁻ions to form the solids with Pb²⁺. These results are an important contribution to our fundamental understanding of how MoS₂interacts with metal ions and will influence further efforts to exploit MoS₂for water remediation applications. 

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