Staun Selena L, Wu Guang, Lukens Wayne W, Hayton Trevor W
Department of Chemistry and Biochemistry, University of California, Santa Barbara Santa Barbara California 93106 USA
Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley California 94720 USA
Chem Sci. 2021 Nov 15;12(47):15519-15527. doi: 10.1039/d1sc05072a. eCollection 2021 Dec 8.
Reaction of [K(DME)][Th{(R)(SiMe H)}(NR)] (R = SiMe) with 1 equiv. of [U(NR)(NH)] (1) in THF, in the presence of 18-crown-6, results in formation of a bridged uranium-thorium nitride complex, [K(18-crown-6)(THF)][(NR)U(μ-N)Th(NR)] (2), which can be isolated in 48% yield after work-up. Complex 2 is the first isolable molecular mixed-actinide nitride complex. Also formed in the reaction is the methylene-bridged mixed-actinide nitride, [K(18-crown-6)][K(18-crown-6)(EtO)][(NR)U(μ-N)(μ-κ-,-CHSiMeNR)Th(NR)] (3), which can be isolated in 34% yield after work-up. Complex 3 is likely generated by deprotonation of a methyl group in 2 by [NR], yielding the new μ-CH moiety and HNR. Reaction of 2 with 0.5 equiv. of I results in formation of a U/Th bridged nitride, [(NR)U(μ-N)Th(NR)] (4), which can be isolated in 42% yield after work-up. The electronic structure of 4 was analyzed with EPR spectroscopy, SQUID magnetometry, and NIR-visible spectroscopy. This analysis demonstrated that the energies of 5f orbitals of 4 are largely determined by the strong ligand field exerted by the nitride ligand.
在四氢呋喃中，18 - 冠 - 6存在下，[K(DME)][Th{(R)(SiMe₂H)}(NR₂)]（R = SiMe₂）与1当量的[U(NR₂)(NH₂)]（1）反应，生成一种桥联铀 - 钍氮化物配合物[K(18 - 冠 - 6)(THF)][(NR₂)U(μ - N)Th(NR₂)]（2），后处理后可分离得到，产率为48%。配合物2是首个可分离的分子型混合锕系氮化物配合物。反应中还生成了亚甲基桥联的混合锕系氮化物[K(18 - 冠 - 6)][K(18 - 冠 - 6)(EtO)][(NR₂)U(μ - N)(μ - κ²,η² - CH₂SiMe₂NR₂)Th(NR₂)]（3），后处理后可分离得到，产率为34%。配合物3可能是由[NR₂]使2中的一个甲基去质子化生成新的μ - CH₂部分和HNR₂而产生的。2与0.5当量的I反应生成U/Th桥联氮化物[(NR₂)U(μ - N)Th(NR₂)]（4），后处理后可分离得到，产率为42%。用电子顺磁共振光谱、超导量子干涉仪磁强计和近红外 - 可见光谱对4的电子结构进行了分析。该分析表明，4的5f轨道能量在很大程度上由氮化物配体施加的强配体场决定。
