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Uranium- and thorium-iridium multimetallic species with unprecedented actinide–iridium interactions are preparedviasalt-elimination reactions between U/Th halides and K[IrCp*H₃].

 

The reaction of a terminal Mo(II) nitride with a U(III) complex yields an heterodimetallic U-Mo nitride which is the first example of a transition metal-capped uranium nitride. The nitride is triply bonded to U(V) and singly bonded to Mo(0) and supports a U-Mo interaction. This compound shows reactivity toward CO oxidation. 

This study presents the role of 5d orbitals in the bonding, and electronic and magnetic structure of Ce imido and oxo complexes synthesized with a tris(hydroxylaminato) [((2- t BuNO)C 6 H 4 CH 2 ) 3 N] 3− (TriNO x 3− ) ligand framework, including the reported synthesis and characterization of two new alkali metal-capped Ce oxo species. X-ray spectroscopy measurements reveal that the imido and oxo materials exhibit an intermediate valent ground state of the Ce, displaying hallmark features in the Ce L III absorption of partial f-orbital occupancy that are relatively constant for all measured compounds. These spectra feature a double peak consistent with other formal Ce( iv ) compounds. Magnetic susceptibility measurements reveal enhanced levels of temperature-independent paramagnetism (TIP). In contrast to systems with direct bonding to an aromatic ligand, no clear correlation between the level of TIP and f-orbital occupancy is observed. CASSCF calculations defy a conventional van Vleck explanation of the TIP, indicating a single-reference ground state with no low-lying triplet excited state, despite accurately predicting the measured values of f-orbital occupancy. The calculations do, however, predict strong 4f/5d hybridization. In fact, within these complexes, despite having similar f-orbital occupancies and therefore levels of 4f/5d hybridization, the d-state distributions vary depending on the bonding motif (CeO vs. CeN) of the complex, and can also be fine-tuned based on varying alkali metal cation capping species. This system therefore provides a platform for understanding the characteristic nature of Ce multiple bonds and potential impact that the associated d-state distribution may have on resulting reactivity. 

Reaction of the complexes [Fe 2 (μ 2 -NP(pip) 3 ) 2 (NP(pip) 3 ) 2 ] ( 1-Fe ) and [Co 2 (μ 2 -NP(pip) 3 ) 2 (NP(pip) 3 ) 2 ] ( 1-Co ), where [NP(pip) 3 ] 1− is tris(piperidinyl)imidophosphorane, with nitrous oxide, S 8 , or Se 0 results in divergent reactivity. With nitrous oxide, 1-Fe forms [Fe 2 (μ 2 -O)(μ 2 -NP(pip) 3 ) 2 (NP(pip) 3 ) 2 ] ( 2-Fe ), with a very short Fe 3+ –Fe 3+ distance. Reactions of 1-Fe with S 8 or Se 0 result in the bridging, side-on coordination (μ-κ 1 :κ 1 -E 2 2− ) of the heavy chalcogens in complexes [Fe 2 (μ-κ 1 :κ 1 -E 2 )(μ 2 -NP(pip) 3 ) 2 (NP(pip) 3 ) 2 ] (E = S, 3-Fe , or Se, 4-Fe ). In all cases, the complex 1-Co is inert. 

Salt metathesis reactions between a low-valent rhenium( i ) complex, Na[Re(η 5 -Cp)(BDI)] (BDI = N , N ′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate), and a series of amidinate-supported tetrylenes of the form ECl[PhC(N t Bu) 2 ] (E = Si, Ge, Sn) led to rhenium metallotetrylenes Re(E[PhC(N t Bu) 2 ])(η 5 -Cp)(BDI) (E = Si ( 1a ), Ge ( 2 ), Sn ( 4 )) with varying extents of Re–E multiple bonding. Whereas the rhenium–stannylene 4 adopts a σ-metallotetrylene arrangement featuring a Re–E single bond, the rhenium–silylene ( 1a ) and –germylene ( 2 ) both engage in π-interactions to form short Re–E multiple bonds. Temperature was found to play a crucial role in reactions between Na[Re(η 5 -Cp)(BDI)] and SiCl[PhC(N t Bu) 2 ], as manipulation of reaction conditions led to isolation of an unusual rhenium–silane, (BDI)Re(μ-η 5 :η 1 -C 5 H 4 )(SiH[PhC(N t Bu) 2 ]) ( 1b ) and a dinitrogen bridged rhenium–silylene, (η 5 -Cp)(BDI)Re(μ-N 2 )Si[PhC(N t Bu) 2 ] ( 1c ), in addition to 1a . Finally, the reaction of Na[Re(η 5 -Cp)(BDI)] with GeCl 2 ·dioxane led to a rare μ 2 -tetrelido complex, μ 2 -Ge[Re(η 5 -Cp)(BDI)] 2 ( 3 ). Bonding interactions within these complexes are discussed through the lens of various spectroscopic, structural, and computational investigations. 

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. 

A magnesium hydride cation [(L)MgH] + supported by a macrocyclic ligand (L = Me 4 TACD; 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane) has been prepared by partial protonolysis of a mixed amide hydride [(L)MgH 2 Mg{N(SiMe 3 ) 2 } 2 ] and shown to undergo a variety of reactions with unsaturated substrates, including pyridine.