A Unique LnIII{[3.3.1]GaIII Metallacryptate} Series That Possesses Properties of Slow Magnetic Relaxation and Visible/Near‐Infrared Luminescence

A new family of [3.3.1] metallacryptates with the general composition [LnGa6(H2shi)(Hshi)(shi)7(C5H5N)] (Ln‐1; shi3−=salicylhydroximate; Ln = Pr, Nd, Sm–Yb) has been synthesized and characterized. Ln‐1 display both interesting magnetic and luminescent properties. Sm‐1 has sharp emission bands in the visible and the near‐infrared (NIR) regions with quantum yield values (QSmL) of 1.64(9) and 5.5(2).10−2 %, respectively. Tb‐1 exhibits a weak green emission (QTbL=1.89(3).10−1 %) while Pr‐1, Nd‐1, Ho‐1, Er‐1, and Yb‐1 possess emission bands in the NIR range with QPrL=3.7(2).10−3 %, QNdL=1.71(5).10−1 %, QHoL=1.1(2).10−3 %, QErL=7.1(2).10−3 % and QYbL=0.65(3) %. Nd‐1, Dy‐1, and Yb‐1 display slow magnetization relaxation in an applied field, where only Dy‐1 has been observed to follow an Orbach process (Ueff=12.7 K). The combination of NIR emission with magnetic properties makes Nd‐1 and Yb‐1 attractive candidates as smart materials addressable in two manners.A two‐for‐one scaffold: A new LnIII‐encapsulating metallamacrocyclic scaffold was synthesized and structurally determined to resemble cryptands. This metallacryptand can bind a wide variety of LnIII ions of different natures and demonstrates the ability to sensitize their characteristic emissions in the visible and/or near‐infrared. Slow magnetic relaxation was also observed for selected LnIII.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145255/1/chem201801355.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145255/2/chem201801355_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145255/3/chem201801355-sup-0001-misc_information.pd

Resetting the T Cell Compartment in Autoimmune Diseases With Autologous Hematopoietic Stem Cell Transplantation: An Update

Autologous hematopoietic stem cell transplantation (aHSCT) for autoimmune diseases has been applied for two decades as a treatment for refractory patients with progressive disease. The rationale behind aHSCT is that high-dose immunosuppression eliminates autoreactive T and B cells, thereby resetting the immune system. Post-aHSCT the cytotoxic CD8+ T cells normalize via clonal expansion due to homeostatic proliferation within a few months. CD4+ T cells recover primarily via thymopoiesis resulting in complete renewal of the T cell receptor (TCR) repertoire which requires years or never normalize completely. The increase in naïve T cells inducing immune tolerance, renewal of especially the regulatory TCR repertoire, and a less pro-inflammatory functional profile of the CD4+ T cells seem essential for successful immune reconstitution inducing long-term remission. There is currently a knowledge gap regarding the immune response in tissue sites post-aHSCT, as well as disease-specific factors that may determine remission or relapse. Future studies on lymphocyte dynamics and function may pave the way for optimized conditioning regimens with a more individualized approach

Resetting the T cell compartment in autoimmune diseases with autologous hematopoietic stem cell transplantation : An update

Autologous hematopoietic stem cell transplantation (aHSCT) for autoimmune diseases has been applied for two decades as a treatment for refractory patients with progressive disease. The rationale behind aHSCT is that high-dose immunosuppression eliminates autoreactive T and B cells, thereby resetting the immune system. Post-aHSCT the cytotoxic CD8+ T cells normalize via clonal expansion due to homeostatic proliferation within a few months. CD4+ T cells recover primarily via thymopoiesis resulting in complete renewal of the T cell receptor (TCR) repertoire which requires years or never normalize completely. The increase in naïve T cells inducing immune tolerance, renewal of especially the regulatory TCR repertoire, and a less pro-inflammatory functional profile of the CD4+ T cells seem essential for successful immune reconstitution inducing long-term remission. There is currently a knowledge gap regarding the immune response in tissue sites post-aHSCT, as well as disease-specific factors that may determine remission or relapse. Future studies on lymphocyte dynamics and function may pave the way for optimized conditioning regimens with a more individualized approach

Versatile Para‐Substituted Pyridine Lanthanide Coordination Complexes Allow Late Stage Tailoring of Complex Function

A series of cationic and neutral p−Br and p−NO2 pyridine substituted Eu(III) and Gd(III) coordination complexes serve as versatile synthetic intermediates. Nucleophilic aromatic substitution occurs readily at the para position under mild conditions, allowing C−N and C−C bond forming reactions to take place, permitting the introduction of azide, amino and alkynyl substituents. For Eu(III) complexes, this approach allows late stage tuning of absorption and emission spectral properties, exemplified by the lowering of the energy of an LMCT transition accompanied by a reduction in the Eu−Npy bond length. Additionally, these complexes provide direct access to the corresponding Eu(II) analogues. With the Gd(III) series, the nature of the p-substituent does not significantly change the EPR properties (linewidth, relaxation times), as required for their development as EPR spin probes that can be readily conjugated to biomolecules under mild conditions

Bis(dimethylformamide)pentakis(μ-N,2-dioxidobenzene-1-carboximidato)tetrakis(1-methylimidazole)di-μ-propionato-pentamanganese(III)manganese(II)–dimethylformamide–methanol (1/0.24/1.36)

The title compound [Mn6(C7H4NO3)5(C3H5O2)2(C4H6N2)4.17(C3H7NO)1.83]·0.24C3H7NO·1.36CH3OH or Mn(II)(C3H5O2)2[15-MCMn(III)N(shi)-5](Me—Im)4.17(DMF)1.83·0.24DMF·1.36MeOH (where MC is metallacrown, shi3− is salicylhydroximate, Me—Im is 1-methylimidazole, DMF is N,N-dimethylformamide, and MeOH is methanol), contains an MnII ion in the central cavity and five MnIII ions in the MC ring. The central MnII ion is seven coordinate and has a geometry best described as distorted face-capped trigonal prismatic with Φ angles of 6.13, 10.36, and 11.73° and an estimated average s/h ratio of 1.03±0.11. Four of the ring MnIII ions are six coordinate with distorted octahedral geometries. Two of the MnIII ions have Λ absolute stereoconfiguration, while the other two MnIII ions have a planar configuration. The fifth MnIII ion is five coordinate and has a distorted square pyramidal geometry with τ = 0.20. Three of the MnIII ions bind one 1-methylimidazole ligand. Two of the ring MnIII ions have a 1-methylimidazole and a DMF disordered over a coordination site. For one of the ring MnIII ions, the occupancy ratio of the ligands refines to 0.51 (1):0.49 (1) in favor of the DMF. For the other ring MnIII ion, the occupancy ratio of the ligands refines to 0.68 (1):0.32 (1) in favor of the 1-methylimidazole. Two propionate anions serve to bridge the central MnII ion between two different MnIII ions. The methyl groups of the bridging propionate anions are disordered over two positions. The methyl group disorder also induces disorder in the H atoms of the adjacent methylene C atom to the same degree. For one of the propionate anions, the occupancy ratio refines to 0.752 (8):0.248 (8) and for the second, the occupancy ratio refines to 0.604 (6):0.396 (6). In addition, the disorder of the methyl group of the latter propionate anion is correlated with a partially occupied [0.604 (6)] methanol molecule. Furthermore, a methanol molecule and a DMF molecule are positionally disordered in the lattice. The occupancy refines to 0.757 (7):0.243 (7) in favor of the methanol molecule. Correlated to the occupancy of the methanol and DMF molecules is a disordered benzene ring of one salicylhydroximate ligand. The benzene ring is disordered over two positions with an occupancy ratio of 0.757 (7):0.243 (7). Lastly, the two lattice methanol molecules are hydrogen bonded to the 15-MC-5 molecule. For the partially occupied methanol molecule associated with the disordered propionate anion, the hydroxyl group of the methanol is hydrogen bonded to a carboxylate O atom of the propionate anion. For the partially occupied methanol molecule associated with the partially occupied lattice DMF molecule, the hydroxyl group of the methanol is hydrogen bonded to the phenolate O atom of a salicylhydroximate ligand and to the carbonyl O atom of a coordinated DMF molecule

CCDC 2096811 & 2096812: Experimental Crystal Structure Determination

Related Article: Matthieu Starck, Jack D. Fradgley, Davide F. De Rosa, Andrei S. Batsanov, Maria Papa, Michael J. Taylor, Janet E. Lovett, Jacob C. Lutter, Matthew J. Allen, David Parker|2021|Chem.-Eur.J.|27|17921|doi:10.1002/chem.20210324

The Nature of the Bridging Anion Controls the Single-Molecule Magnetic Properties of DyX₄M 12-Metallacrown‑4 Complexes

A family of <b>DyX</b>_<b>4</b><b>M­(12-MC</b>_{<b>Mn</b>^<b>III</b><b>(N)shi</b>}<b>-4)</b> compounds were synthesized and magnetically characterized (X = salicylate, acetate, benzoate, trimethylacetate, M = Na^I or K^I). The bridging ligands were systematically varied while keeping the remainder of the MC-geometry constant. The type of monovalent cation, necessary for charge balance, was also altered. The dc magnetization and susceptibility of all compounds were similar across the series. Regardless of the identity of the countercation, the <b>Dy­(Hsal)</b>_<b>4</b><b>M 12-MC-4</b> compounds were the only compounds to show frequency-dependent ac magnetic susceptibility, a hallmark of single-molecule magnetism. This indicates that the nature of the bridging ligand in the 12-MC_Mn^III(N)shi-4 compounds strongly affects the out-of-phase magnetic properties. The SMM behavior appears to correlate with the p<i>K</i>_a of the bridging ligand

The Nature of the Bridging Anion Controls the Single-Molecule Magnetic Properties of DyX₄M 12-Metallacrown‑4 Complexes

A family of <b>DyX</b>_<b>4</b><b>M­(12-MC</b>_{<b>Mn</b>^<b>III</b><b>(N)shi</b>}<b>-4)</b> compounds were synthesized and magnetically characterized (X = salicylate, acetate, benzoate, trimethylacetate, M = Na^I or K^I). The bridging ligands were systematically varied while keeping the remainder of the MC-geometry constant. The type of monovalent cation, necessary for charge balance, was also altered. The dc magnetization and susceptibility of all compounds were similar across the series. Regardless of the identity of the countercation, the <b>Dy­(Hsal)</b>_<b>4</b><b>M 12-MC-4</b> compounds were the only compounds to show frequency-dependent ac magnetic susceptibility, a hallmark of single-molecule magnetism. This indicates that the nature of the bridging ligand in the 12-MC_Mn^III(N)shi-4 compounds strongly affects the out-of-phase magnetic properties. The SMM behavior appears to correlate with the p<i>K</i>_a of the bridging ligand

Controllable Formation of Heterotrimetallic Coordination Compounds: Systematically Incorporating Lanthanide and Alkali Metal Ions into the Manganese 12-Metallacrown‑4 Framework

The inclusion of Ln^III ions into the 12-MC-4 framework generates the first heterotrimetallic complexes of this molecular class. The controllable and deliberate preparations of these compounds are demonstrated through 12 crystal structures of the Ln^IIIM^I(OAc)₄[12-MC_Mn^III_(N)shi-4]­(H₂O)₄·6DMF complex, where OAc^– is acetate, shi^3‑ is salicylhydroximate, and DMF is <i>N,N</i>-dimethylformamide. Compounds <b>1</b>–<b>12</b> have M^I as Na^I, and Ln^III can be Pr^III (<b>1</b>), Nd^III (<b>2</b>), Sm^III (<b>3</b>), Eu^III (<b>4</b>), Gd^III (<b>5</b>), Tb^III (<b>6</b>), Dy^III (<b>7</b>), Ho^III (<b>8</b>), Er^III (<b>9</b>), Tm^III (<b>10</b>), Yb^III (<b>11</b>), and Y^III (<b>12</b>). An example with M^I = K^I and Ln^III = Dy^III is also reported (Dy^IIIK­(OAc)₄[12-MC_Mn^III_(N)shi-4]­(DMF)₄·DMF (<b>14</b>)). When La^III, Ce^III, or Lu^III is used as the Ln^III ions to prepare the Ln^IIINa^I(OAc)₄[12-MC_Mn^III_(N)shi-4] complex, the compound Na₂(OAc)₂[12-MC_Mn^III_(N)shi-4]­(DMF)₆·2DMF·1.60H₂O (<b>13</b>) results. For compounds <b>1</b>–<b>12</b>, the identity of the Ln^III ion affects the 12-MC_Mn^III_(N)shi-4 framework as the largest Ln^III, Pr^III, causes an expansion of the 12-MC_Mn^III_(N)shi-4 framework as demonstrated by the largest metallacrown cavity radius (0.58 Å for <b>1</b> to 0.54 Å for <b>11</b>), and the Pr^III causes the 12-MC_Mn^III_(N)shi-4 framework to be the most domed structure as evident in the largest average angle about the axial coordination of the ring Mn^III ions (103.95° for <b>1</b> to 101.69° for <b>11</b>). For <b>14</b>, the substitution of K^I for Na^I does not significantly affect the 12-MC_Mn^III_(N)shi-4 framework as many of the structural parameters such as the metallacrown cavity radius (0.56 Å) fall within the range of compounds <b>1</b>–<b>12</b>. However, the use of the larger K^I ion does cause the 12-MC_Mn^III_(N)shi-4 framework to become more planar as evident in a smaller average angle about the axial coordination of the ring Mn^III ions (101.35°) compared to the analogous Dy^III/Na^I (<b>7</b>) complex (102.40°). In addition to broadening the range of structures available through the metallacrown analogy, these complexes allow for the mixing and matching of a diverse range of metals that might permit the fine-tuning of molecular properties where one day they may be exploited as magnetic materials or luminescent agents