Preparation, properties, and crystal structure of acetonedi-isothio-cyanato-dioxobis(triphenylphosphine oxide)uranium(VI)

The Uranium(VI) Oxoazides [UO2(N3)2⋅CH3CN], [(bipy)2(UO2)2(N3)4], [(bipy)UO2(N3)3]−, [UO2(N3)4]2−, and [(UO2)2(N3)8]4−

“…The U−N distances of 2.375(2) −2.411(1) Å are in good agreement with typical U−N single bond lengths such as in [U(N 3 ) 7 ] 3− (2.323(6) Å−2.431(7) Å), [U(NCS) 8 ] 4− (2.38(3) Å−2.46(3) Å), [UO 2 (NCS) 2 (OPPh 3 ) 2 ] (2.44(2) Å), and [((UO 2 ) 2 (NCO) 5 O) 2 ] 6− (2.45(1) Å), only slightly longer than in UNCl, UNBr and UNI (2.30 Å, 2.28 Å and 2.28 Å, respectively) but are significantly longer than U=N double bond distances such as in [((Me 3 Si) 2 N ) 3 FU=NSiMe 3 ] (1.85(2) Å), [((Me 3 Si) 2 N ) 3 FU=NPh] (1.979(8) Å), [((Me 3 Si) 2 N ) 3 U=NSiMe 3 ] (1.91(2) Å) and [(C 6 F 5 ) 3 BN=U(N( t Bu)Ar) 3 ] − (1.916(4) Å), as well as U≡N triple bond distances such as in [(( Ad ArO) 3 n )U≡NSiMe 3 ] (1.943(3) Å), [(Tren TIPS )U≡N] − (1.825(15) Å) and [(Tren TIPS )U≡N] (1.799(7) Å) …”

“…This is a distinct difference to the structures of the [MoO 2 (N 3 ) 4 ] 2− and [WO 2 (N 3 ) 4 ] 2− anions which feature both oxygen atoms in the equatorial positions. The average U−N azide distances of 2.370(2) and 2.371(2) Å for the [UO 2 (N 3 ) 4 ] 2− anions in the solvent free and CH 3 CN containing salts, respectively, are slightly shorter than in the [(bipy)UO 2 (N 3 ) 3 ] − anion (2.391(2) Å) but are in good agreement with the ones in [UO 2 (NCS) 2 (OPPh 3 ) 2 ] (2.44(2) Å), and [((UO 2 ) 2 (NCO) 5 O) 2 ] 6− (2.45(1) Å) …”

Synthesis and crystal and molecular structure of bis(nitrato)[diisopropyl (N,N-diethylcarbamyl)methylenephosphonate]dioxouranium(VI)

“…* *3"6 *Both absorptions in 1 appear at significantly lower frequencies than the corresponding frequencies in the free ligand, 1648 and 1253 cm'1, and such down-frequency shifts, Avqo = -41 cm"1 and Avro = -61 cm"1, have been used previously to indicate bidentate coordination of C=0 and P==0 groups with a metal ion.13'15 Similary, Horwitz and co-workers8 have reported Avco = -45 cm"1 and Avpo = -69 to -71 cm"1 for a uranyl nitrate-DHDECMP species, but they have concluded that the smaller AvCo is consistent with the formation of a weak ligand carbonyl oxygen atom-U022+ association or the presence of an uncoordinated ligand C=0 group inductively weakened by a strong P=0 -* U interaction. On the other hand, we have observed similar shifts in Th(N03)4(DiPDECMP)24 (2) and Sm(N03)3(DiP-DECMP) 26 (3) of Avc0 = -51 cm"1, Aj/ro = -93 to -70 cm"1 and 00 = -55 to -31 cm"1, Ar-ro = -47 cm"1, respectively.16…”

Exploring the coordination modes of pyrrolyl ligands in bis(imido) uranium(vi) complexes

“…13 In addition, this trans configuration is also prevalent in other actinide dihalide complexes. [28][29][30][31][32] Given the successful coordination of a monodentate pyrrolyl ligand to the [U(NR 2 ) 2+ ] 2+ ion, we investigated reactions with the bidentate dipyrrolylmethane species H 2 dpm (H 2 dpm = 5,5dimethyldipyrrolylmethane). The addition of K 2 dpm to a THF solution of U(N t Bu) 2 (I) 2 (THF) 2 affords the dipyrrolylmethane uranium(VI) complex U(N t Bu) 2 (dpm)(THF) 2 (4) as a red solid in reasonable yield (Scheme 2).…”