Dalton Transactions

doi: 10.1039/c5dt90073epmid: N/A

doi: 10.1039/C5DT90073Epmid: N/A

doi: 10.1039/c5dt90074cpmid: N/A

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Johnson, Sara A.; Bart, Suzanne C.

doi: 10.1039/c4dt01621apmid: 25283733

Organouranium complexes containing uranium–carbon σ-bonds have been highly sought after since the initial exploration of these complexes during the 1950s. Since this time, a variety of uranium starting materials have been developed and alkylating reagents used in order to generate such species. Trivalent uranium alkyl compounds have recently moved past using the bis(trimethylsilyl)methyl ligand with the use of larger ancillary hydrotris(pyrazolyl)borate ligands. The uranium(iv) congeners are dominated by cyclopentadienyl ligands, but recent developments have shown that amides, alkoxides, and phosphines are also suitable ligand frameworks for supporting such species. A family of uranium(iv) alkyls formed via cyclometallation and neutral homoleptics have also been described. Highly reactive uranium(v) and (vi) alkyl complexes have recently been synthesized at low temperatures. The representative studies highlighted herein have helped to pioneer the field of organouranium alkyl chemistry.

Berthet, Jean-Claude; Thuéry, Pierre; Ephritikhine, Michel

doi: 10.1039/c5dt00692apmid: 25811407

This Dalton perspective gives an overview of the development of cyanide chemistry of 4f- and 5f-elements, a field which was poorly explored in contrast to the attention paid to the cyanide complexes of the d transition metals. The use of the cyanide ligand led to the discovery of mono- and polycyanide complexes which exhibit unprecedented and unexpected coordination geometries. A new type of linear metallocenes including [U(Cp*)2(CN)5]3− (Cp* = C5Me5) and the first bent actinocenes [An(Cot)2(CN)]− (An = Th, U; Cot = C8H8) were isolated. Thorocene was found to be much more reactive than uranocene since a series of sterically crowded cyanide complexes have been obtained only from [Th(Cot)2]. A series of cyanido-bridged dinuclear compounds and mononuclear mono-, bis- and tris(cyanide) complexes were prepared by addition of cyanide salts to [MN*3] (M = Ce, U) and [UN*3]+ [N* = N(SiMe3)2]. The CeIII, UIII and UIV ions were clearly differentiated in these reactions by cyanide linkage isomerism, as shown for example by the structures of the cyanide complex [UIIIN*3(CN)2]2− and of the isocyanide derivatives [CeIIIN*3(NC)2]2− and [UIVN*3(NC)]−. While the U–CN/NC coordination preference towards the UIII/UIV pair is related to the subtle balance between steric, covalent and ionic factors, DFT computations and in particular the calculated total bonding energies between the metal and the cyanide ligand allowed the observed coordination mode to be predicted. The ability of the cyanide ligand to stabilize the high oxidation states was assessed with the synthesis of UV and UVI complexes in the inorganic and organometallic series.

Zhang, Yang; Liu, Xiaoming; Li, Xuejiao; Li, Kai; Lian, Hongzhou; Shang, Mengmeng; Lin, Jun

doi: 10.1039/c4dt03095hpmid: 25524047

We demonstrate a strategy to manipulate the valence state of Eu in CaGdAlO4 based on breaking down geometrical restrictions on the activators. This strategy could promote the search for novel phosphors for white light emission diodes (WLEDs).

Merhi, Areej; Grelaud, Guillaume; Green, Katy A.; Minh, Ngo Hoang; Reynolds, Michael; Ledoux, Isabelle; Barlow, Adam; Wang, Genmiao; Cifuentes, Marie P.; Humphrey, Mark G.; Paul, Frédéric; Paul-Roth, Christine O.

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