Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
Inorg Chem. 2011 Feb 21;50(4):1459-69. doi: 10.1021/ic102016k. Epub 2011 Jan 4.
New syntheses of complexes containing the recently discovered (N(2))(3-) radical trianion have been developed by examining variations on the LnA(3)/M reductive system that delivers "LnA(2)" reactivity when Ln = scandium, yttrium, or a lanthanide, M = an alkali metal, and A = N(SiMe(3))(2) and C(5)R(5). The first examples of LnA(3)/M reduction of dinitrogen with aryloxide ligands (A = OC(6)R(5)) are reported: the combination of Dy(OAr)(3) (OAr = OC(6)H(3)(t)Bu(2)-2,6) with KC(8) under dinitrogen was found to produce both (N(2))(2-) and (N(2))(3-) products, (ArO)(2)Dy(THF)(2)(μ-η(2):η(2)-N(2)), 1, and (ArO)(2)Dy(THF)(μ-η(2):η(2)-N(2))[K(THF)(6)], 2a, respectively. The range of metals that form (N(2))(3-) complexes with N(SiMe(3))(2) ancillary ligands has been expanded from Y to Lu, Er, and La. LnN(SiMe(3))(2)/M reactions with M = Na as well as KC(8) are reported. Reduction of the isolated (N(2))(2-) complex {(Me(3)Si)(2)NY(THF)}(2)(μ-η(2):η(2)-N(2)), 3, with KC(8) forms the (N(2))(3-) complex, {(Me(3)Si)(2)NY(THF)}(2)(μ-η(2):η(2)-N(2))[K(THF)(6)], 4a, in high yield. The reverse transformation, the conversion of 4a to 3 can be accomplished cleanly with elemental Hg. The crown ether derivative {(Me(3)Si)(2)NY(THF)}(2)(μ-η(2):η(2)-N(2))[K(18-crown-6)(THF)(2)] was isolated from reduction of 3 with KC(8) in the presence of 18-crown-6 and found to be much less soluble in tetrahydrofuran (THF) than the K(THF)(6) salt, which facilitates its separation from 3. Evidence for ligand metalation in the YN(SiMe(3))(2)/KC(8) reaction was obtained through the crystal structure of the metallacyclic complex {(Me(3)Si)(2)NY[CH(2)Si(Me(2))NSiMe(3)]}[K(18-crown-6)(THF)(toluene)]. Density functional theory previously used only with reduced dinitrogen complexes of closed shell Sc(3+) and Y(3+) was extended to Lu(3+) as well as to open shell 4f(9) Dy(3+) complexes to allow the first comparison of bonding between these four metals.
新合成的配合物包含最近发现的（N(2))(3-)自由基三阴离子，是通过研究镧系元素 A(3)/M 还原系统的变化来开发的，当 Ln = 钪、钇或镧系元素，M = 碱金属，A = N(SiMe(3))(2) 和 C(5)R(5) 时，该系统会提供“LnA(2)”反应性。首次报道了带有芳氧基配体的 LnA(3)/M 还原二氮的例子：发现 Dy(OAr)(3)（OAr = OC(6)H(3)(t)Bu(2)-2,6）与 KC(8)在氮气下反应，会同时产生（N(2))(2-)和（N(2))(3-)产物，(ArO)(2)Dy(THF)(2)(μ-η(2):η(2)-N(2)), 1，和 (ArO)(2)Dy(THF)(2)(μ-η(2):η(2)-N(2))[K(THF)(6)], 2a，分别。与 N(SiMe(3))(2)辅助配体形成（N(2))(3-)配合物的金属范围已从 Y 扩展到 Lu、Er 和 La。报道了 LnN(SiMe(3))(2)/M 与 M = Na 以及 KC(8)的反应。用 KC(8)还原分离出的（N(2))(2-)配合物{(Me(3)Si)(2)NY(THF)}(2)(μ-η(2):η(2)-N(2)), 3，形成（N(2))(3-)配合物，{(Me(3)Si)(2)NY(THF)}(2)(μ-η(2):η(2)-N(2))[K(THF)(6)], 4a，产率很高。通过用元素 Hg 完成 4a 到 3 的逆向转化，可以将其完全转化。冠醚衍生物{(Me(3)Si)(2)NY(THF)}(2)(μ-η(2):η(2)-N(2))[K(18-crown-6)(THF)(2)]是从 3 与 KC(8)在 18-冠-6存在下反应得到的，发现其在四氢呋喃（THF）中的溶解度比K(THF)(6)盐低得多，这有利于其与 3 的分离。通过晶体结构{(Me(3)Si)(2)NY[CH(2)Si(Me(2))NSiMe(3)]}[K(18-crown-6)(THF)(甲苯)]获得了 YN(SiMe(3))(2)/KC(8)反应中配体金属化的证据。密度泛函理论以前仅用于封闭壳层 Sc(3+)和 Y(3+)的简化二氮配合物，现在也扩展到了 Lu(3+)以及开放壳层 4f(9)Dy(3+)配合物，从而可以首次比较这四种金属之间的键合。
