Alkyl complexes of uranium supported by ferrocene diamide ligands are described along with the corresponding cationic species. Synthesis of uranium dialkyl compounds fc(NSi t BuMe 2 ) 2 UR 2 [R ) Np (neo-pentyl), Bz (benzyl)] was accomplished by salt metathesis between fc(NSi t BuMe 2 ) 2 UI 2 (THF) and neo-pentyl lithium or benzyl potassium. Protonation of one alkyl ligand led to the isolation of a cationic uranium alkyl complex. DFT calculations and X-ray crystallography data support the existence of a donor-acceptor, weak interaction between iron and uranium.

The uranium(III) and uranium(IV) iodide complexes UI3(1,4-dioxane)1.5 and UI4(1,4-dioxane)2 have been easily prepared in high yield by reacting uranium turnings with a 1,4-dioxane solution of iodine under mild conditions. The two complexes exhibit outstanding thermal stability and are excellent precursors to a variety of uranium(III), uranium(IV), and uranium(VI) alkoxide, amide, organometallic, and halide compounds, including a safe, room-temperature synthesis of [UCl4(1,4-dioxane)]2, which is a useful synthetic alternative to UCl4.

A new family of low-coordinate nickel imides supported by 1,2-bis(di-tert-butylphosphino)ethane was synthesized. The oxidation of nickel(II) complexes led to the formation of both aryl- and alkyl-substituted nickel(III) imides, and examples of both types have been isolated and fully characterized. The aryl substituent that proved most useful in stabilizing the Ni(III)-imide moiety was the bulky 2,6-dimesitylphenyl. The two nickel(III)-imide compounds showed different variable-temperature magnetic properties, but analogous EPR spectra at low temperatures. In order to account for this discrepancy, a low-spin/high-spin equilibrium was proposed to take place for the alkyl-substituted imide nickel(III) complex. This proposal was supported by DFT calculations. DFT calculations also indicated that the unpaired electron is mostly localized on the imide nitrogen for the nickel(III) complexes. The results of reactions carried out in the presence of hydrogen donors supported the findings from DFT calculations that the adamantyl substituent was a significantly more reactive hydrogen-atom abstractor. Interestingly, the steric properties of the 2,6-dimesitylphenyl substituent are important not only in protecting the Ni=N core but also in favoring one rotamer of the resulting nickel(III) imide, by locking in the phenyl ring in a perpendicular orientation with respect to the NiPP plane.

Synthesis of a scandium dimethylbenzyl complex supported by a ferrocene diamide ligand was accomplished by alkane elimination from Sc(CH 2 Xy-3,5) 3 (THF) 2 . The scandium dimethylbenzyl complex Sc(fc[NSi(t-Bu)Me 2 ] 2 )(CH 2 Xy-3,5)(THF), 2-(CH 2 Xy-3,5)(THF), was used as a starting material for the synthesis of the corresponding chloride-bridged dimer, (2-Cl) 2 , which, in turn, led to a scandium bis(neo-pentyl) ate salt, Li[2-Np 2 ]. Attempts to remove the coordinated THF molecule from 2-(CH 2 Xy-3,5)(THF) with AlMe 3 led to the isolation of a scandium methyl complex with two coordinated AlMe 3 molecules, 2-Me(AlMe 3 ) 2 . Compound 2-Me(AlMe 3 ) 2 led to a scandium methyl complex, 2-Me(THF) 2 , by stirring in THF. All ferrocene diamido compounds were characterized by X-ray crystallography. DFT calculations on model compounds were used to explain the stability of the compounds synthesized and to probe the existence of an iron-scandium interaction. Compounds 2-(CH 2 Xy-3,5)(THF) and 2-Me(AlMe 3 ) 2 polymerize L-lactide.

Oxidation of a uranium(IV) bis(1,1'-diamidoferrocene) gives a compound which is best described as a mixed-valence bisferrocene complex in which uranium mediates the electronic communication.