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1. Quaternary cerium( iv ) containing fluorides exhibiting Ce ₃ F ₁₆ sheets and Ce ₆ F ₃₀ frameworks

   https://doi.org/10.1039/d0dt00616e  

   Ayer, Gyanendra B.; Klepov, Vladislav V.; Pace, Kristen A.; zur Loye, Hans-Conrad (May 2020, Dalton Transactions)

   null (Ed.)

   A series of new Ce( iv ) based fluorides with two different compositions, Cs 2 MCe 3 F 16 (M = Ni 2+ , Co 2+ , Mn 2+ , and Zn 2+ ) and Na 3 MCe 6 F 30 (M = Al 3+ , Ga 3+ , Fe 3+ , and Cr 3+ ) were synthesized as high quality single crystals via a mild hydrothermal route. The compounds with the composition Cs 2 MCe 3 F 16 (M = Ni 2+ , Co 2+ , Mn 2+ , and Zn 2+ ) crystallize in the hexagonal crystal system with space group P 6 3 / mmc and are isotypic with the uranium analogs, whereas the Na 3 MCe 6 F 30 (M = Al 3+ , Ga 3+ , Fe 3+ , and Cr 3+ ) compounds crystallize in the trigonal space group P 3̄ c 1 and are isotypic with the uranium and thorium analogs Na x MM′ 6 F 30 (M′ = Th, U). The Cs 2 MCe 3 F 16 compounds exhibit a complex 3D crystal structure constructed of edge-sharing cerium trimers, in which all three Ce atoms share a common μ 3 -F unit. The Na 3 MCe 6 F 30 compounds are constructed of edge- and vertex-sharing cerium polyhedra connected to each other to form Ce 6 F 30 6− framework, which can accommodate only relatively smaller trivalent cations (M 3+ = Al 3+ , Ga 3+ , Fe 3+ , and Cr 3+ ) as compared to uranium and thorium analogs. Magnetic susceptibility measurements were carried out on the samples of Cs 2 MCe 3 F 16 (M = Ni 2+ and Co 2+ ), which exhibit paramagnetic behavior. 

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2. Reactivity of Ce( iv ) imido compounds with heteroallenes

   https://doi.org/10.1039/C9CC10052K  

   Lapsheva, Ekaterina N.; Cheisson, Thibault; Álvarez Lamsfus, Carlos; Carroll, Patrick J.; Gau, Michael R.; Maron, Laurent; Schelter, Eric J. (April 2020, Chemical Communications)

   null (Ed.)

   The reactivity of alkali metal capped Ce( iv ) imido compounds [M(DME) 2 ][CeNAr F (TriNOx)] ( 1-M with M = K, Rb, Cs and Ar F = 3,5-bis(trifluoromethyl)phenyl) with CO 2 and organic isocyanates has been evaluated. 1-Cs reacted with CO 2 to yield an organocarbamate complex. Reaction of 1-K and 1-Rb with organic isocyanates yielded organoureate Ce( iv ) complexes. 

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3. Cerium( iv ) complexes with guanidinate ligands: intense colors and anomalous electronic structures

   https://doi.org/10.1039/D0SC05193D  

   Qiao, Yusen; Yin, Haolin; Moreau, Liane M.; Feng, Rulin; Higgins, Robert F.; Manor, Brian C.; Carroll, Patrick J.; Booth, Corwin H.; Autschbach, Jochen; Schelter, Eric J. (March 2021, Chemical Science)

   null (Ed.)

   A series of cerium( iv ) mixed-ligand guanidinate–amide complexes, {[(Me 3 Si) 2 NC(N i Pr) 2 ] x Ce IV [N(SiMe 3 ) 2 ] 3−x } + ( x = 0–3), was prepared by chemical oxidation of the corresponding cerium( iii ) complexes, where x = 1 and 2 represent novel complexes. The Ce( iv ) complexes exhibited a range of intense colors, including red, black, cyan, and green. Notably, increasing the number of the guanidinate ligands from zero to three resulted in significant redshift of the absorption bands from 503 nm (2.48 eV) to 785 nm (1.58 eV) in THF. X-ray absorption near edge structure (XANES) spectra indicated increasing f occupancy ( n f ) with more guanidinate ligands, and revealed the multiconfigurational ground states for all Ce( iv ) complexes. Cyclic voltammetry experiments demonstrated less stabilization of the Ce( iv ) oxidation state with more guanidinate ligands. Moreover, the Ce( iv ) tris(guanidinate) complex exhibited temperature independent paramagnetism (TIP) arising from the small energy gap between the ground- and excited states with considerable magnetic moments. Computational analysis suggested that the origin of the low energy absorption bands was a charge transfer between guanidinate π orbitals that were close in energy to the unoccupied Ce 4f orbitals. However, the incorporation of sterically hindered guanidinate ligands inhibited optimal overlaps between Ce 5d and ligand N 2p orbitals. As a result, there was an overall decrease of ligand-to-metal donation and a less stabilized Ce( iv ) oxidation state, while at the same time, more of the donated electron density ended up in the 4f shell. The results indicate that incorporating guanidinate ligands into Ce( iv ) complexes gives rise to intense charge transfer bands and noteworthy electronic structures, providing insights into the stabilization of tetravalent lanthanide oxidation states. 

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4. Visible light-activatable platinum( iv ) prodrugs harnessing CD36 for ovarian cancer therapy

   https://doi.org/10.1039/d3dt01292a  

   Jayawardhana, Amarasooriya M.; Bhandari, Srijana; Kaspi-Kaneti, Ariela W.; Kshetri, Man; Qiu, Zihan; Cheline, May; Shen, Hao; Dunietz, Barry D.; Zheng, Yao-Rong (August 2023, Dalton Transactions)

   Visible light-activatable Pt(iv) prodrugs harness the upregulated CD36 to facilitate cell entry and killing of drug resistant ovarian cancer cells. 

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5. Data-driven ligand field exploration of Fe( iv )–oxo sites for C–H activation

   https://doi.org/10.1039/D2QI01961B  

   Jones, Grier M.; Smith, Brett A.; Kirkland, Justin K.; Vogiatzis, Konstantinos D. (February 2023, Inorganic Chemistry Frontiers)

   We have explored the ligand topology of high-valent Fe(iv)–oxo complexes for screening a large molecular database with machine learning. 

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