Diaconescu Paula L, Cummins Christopher C
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA.
Dalton Trans. 2015 Feb 14;44(6):2676-83. doi: 10.1039/c4dt02422b.
The synthesis and characterization of (bipy)(2)U(N[t-Bu]Ar)(2) (1-(bipy)(2), bipy = 2,2'-bipyridyl, Ar = 3,5-C(6)H(3)Me(2)), (bipy)U(N[(1)Ad]Ar)(3) (2-bipy), (bipy)(2)U(NC[t-Bu]Mes)(3) (3-(bipy)(2), Mes = 2,4,6-C(6)H(2)Me(3)), and IU(bipy)(NC[t-Bu]Mes)(3) (3-I-bipy) are reported. X-ray crystallography studies indicate that bipy coordinates as a radical anion in 1-(bipy)(2) and 2-bipy, and as a neutral ligand in 3-I-bipy. In 3-(bipy)(2), one of the bipy ligands is best viewed as a radical anion, the other as a neutral ligand. The electronic structure assignments are supported by NMR spectroscopy studies of exchange experiments with 4,4'-dimethyl-2,2'-bipyridyl and also by optical spectroscopy. In all complexes, uranium was assigned a +4 formal oxidation state.
报道了(bipy)(2)U(N[t-Bu]Ar)(2)（1-(bipy)(2)，bipy = 2,2'-联吡啶，Ar = 3,5-C(6)H(3)Me(2)）、(bipy)U(N[(1)Ad]Ar)(3)（2-bipy）、(bipy)(2)U(NC[t-Bu]Mes)(3)（3-(bipy)(2)，Mes = 2,4,6-C(6)H(2)Me(3)）和IU(bipy)(NC[t-Bu]Mes)(3)（3-I-bipy）的合成与表征。X射线晶体学研究表明，在1-(bipy)(2)和2-bipy中，联吡啶作为自由基阴离子配位，在3-I-bipy中作为中性配体配位。在3-(bipy)(2)中，一个联吡啶配体最好看作是自由基阴离子，另一个是中性配体。电子结构归属得到了与4,4'-二甲基-2,2'-联吡啶交换实验的核磁共振光谱研究以及光谱学的支持。在所有配合物中，铀的形式氧化态为+4。
