(C(5)Me(4)H)(3)U, 1, reacts with 1 equiv of NO to form the first f element nitrosyl complex (C(5)Me(4)H)(3)UNO, 2. X-ray crystallography revealed a 180° U-N-O bond angle, typical for (NO)(1+) complexes. However, 2 has a 1.231(5) Å N═O distance in the range for (NO)(1-) complexes and a short 2.013(4) Å U-N bond like the U═N bond of uranium imido complexes. Structural, spectroscopic, and magnetic data as well as DFT calculations suggest that reduction of NO by U(3+) has occurred to form a U(4+) complex of (NO)(1-) that has π interactions between uranium 5f orbitals and NO π* orbitals. These bonding interactions account for the linear geometry and short U-N bond. The complex displays temperature-independent paramagnetism with a magnetic moment of 1.36 μ(B) at room temperature. Complex 2 reacts with Al(2)Me(6) to form the adduct (C(5)Me(4)H)(3)UNO(AlMe(3)), 3.

Hydrogenolysis of the dimethyl actinide metallocenes (C 5 Me 4 SiMe 3 ) 2 UMe 2 and (C 5 Me 4 H) 2 AnMe 2 (An = Th, U) was examined for comparison with the hydrogenolysis of (C 5 Me 5 ) 2 AnMe 2 that forms the hydrides [(C 5 Me 5 ) 2 ThH 2 ] 2 , [(C 5 Me 5 ) 2 UH 2 ] 2 , and [(C 5 Me 5 ) 2 UH] 2 . Parallel reactivity is not found with the (C 5 Me 4 SiMe 3 ) − and (C 5 Me 4 H) − complexes. Instead, this study led to the first example of a "tuck-over" [μ-η 5 -C 5 Me 3 H(CH 2 )-κC] 2− dianion derived from (C 5 Me 4 H) − ligands by C−H bond activation and rare examples of a polymetallic thorium polyhydride compound and an organometallic Th 3+ complex. (C 5 Me 4 SiMe 3 ) 2 UMe 2 reacts with H 2 to form the bis(tethered alkyl) complex (η 5 -C 5 Me 4 SiMe 2 CH 2 -κC) 2 U, a product of C−H bond activation of the silylmethyl groups. The only identifiable product of hydrogenolysis of (C 5 Me 4 H) 2 UMe 2 is (C 5 Me 4 H) 3 U. The first thorium complex of (C 5 Me 4 H) − was synthesized by reaction of 2 equiv of (C 5 Me 4 H)MgCl(THF) with ThBr 4 (THF) 4 to produce (C 5 Me 4 H) 2 ThBr 2 . This complex reacts with MeLi to make (C 5 Me 4 H) 2 ThMe 2 . The latter complex reacts with H 2 to form the ligand redistribution product (C 5 Me 4 H) 3 ThMe and the tetrametallic octahydride tuck-over complex (C 5 Me 4 H) 4 [μ-η 5 -C 5 Me 3 H(CH 2 )-κC] 2 Th 4 (μ-H) 4 -(μ 3 -H) 4 . For comparison with the (C 5 Me 4 H) 3 U product, the thorium analogue, (C 5 Me 4 H) 3 Th, was synthesized by potassium reduction of a [(C 5 Me 4 H) 3 Th][BPh 4 ] intermediate obtained in situ from (C 5 Me 4 H) 3 ThMe and [HNEt 3 ][BPh 4 ]. (C 5 Me 4 H) 3 Th can also be prepared from KC 8 and (C 5 Me 4 H) 3 ThBr, obtained from KC 5 Me 4 H and ThBr 4 (THF) 4 .

Five different first-row transition metal precursors (V(III), Cr(III), Mn(II), Co(II), Ni(II)) were successfully incorporated into a catechol porous organic polymer (POP) and characterized using ATR-IR and XAS analysis. The resulting metallated POPs were then evaluated for catalytic alkyne hydrogenation using high-throughput screening techniques. All POPs were unexpectedly found to be active and selective catalysts for alkyne semihydrogenation. Three of the metallated POPs (V, Cr, Mn) are the first of their kind to be active single-site hydrogenation catalysts. These results highlight the advantages of using a POP platform to develop new catalysts which are otherwise difficult to achieve through traditional heterogeneous and homogeneous routes.

Investigation of the insertion reactivity of the tethered silylalkyl complex (η(5)-C(5)Me(4)SiMe(2)CH(2)-κC)(2)U (1) has led to a series of new reactions for U-C bonds. Elemental sulfur reacts with 1 by inserting two sulfur atoms into each of the U-C bonds to form the bis(tethered alkyl disulfide) complex (η(5):η(2)-C(5)Me(4)SiMe(2)CH(2)S(2))(2)U (2). The bulky substrate N,N'-diisopropylcarbodiimide, (i)PrN═C═N(i)Pr, inserts into only one of the U-C bonds of 1 to produce the mixed-tether complex (η(5)-C(5)Me(4)SiMe(2)CH(2)-κC)U[η(5)-C(5)Me(4)SiMe(2)CH(2)C((i)PrN)(2)-κ(2)N,N'] (3). Carbon monoxide did not exclusively undergo a simple insertion into the U-C bond of 3 but instead formed {μ-[η(5)-C(5)Me(4)SiMe(2)CH(2)C(═N(i)Pr)O-κ(2)O,N]U[OC(C(5)Me(4)SiMe(2)CH(2))CN((i)Pr)-κ(2)O,N](2) (4) in a cascade of reactions that formally includes U-C bond cleavage, C-N bond cleavage of the amidinate ligand, alkyl or silyl migration, U-O, C-C, and C-N bond formations, and CO insertion. The reaction of 3 with isoelectronic tert-butyl isocyanide led to insertion of the substrate into the U-C bond, but with a rearrangement of the amidinate ligand binding mode from κ(2) to κ(1) to form [η(5):η(2)-C(5)Me(4)SiMe(2)CH(2)C(═N(t)Bu)]U[η(5)-C(5)Me(4)SiMe(2)CH(2)C(═N(i)Pr)N((i)Pr)-κN] (5). The product of double insertion of (t)BuN≡C into the U-C bonds of 1, namely [η(5):η(2)-C(5)Me(4)SiMe(2)CH(2)C(═N(t)Bu)](2)U (6), was found to undergo an unusual thermal rearrangement that formally involves C-H bond activation, C-C bond cleavage, and C-C bond coupling to form the first formimidoyl actinide complex, [η(5):η(5):η(3)-(t)BuNC(CH(2)SiMe(2)C(5)Me(4))(CHSiMe(2)C(5)Me(4))]U(η(2)-HC═N(t)Bu) (7).

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