Ammoniacal Synthesis of Lanthanum Aryloxide Complexes and Observation of a Unique Interconversion between Oxygen- and .eta.-Arene-Bridged Dimeric Species. X-ray Crystal Structures of La2(OAr)6(NH3)n (n = 0, 2), La(OAr)3(NH3)4, and La(OAr)3(THF)2 (Ar = 2,6-i-Pr2C6H3)
Ammoniacal Synthesis of Lanthanum Aryloxide Complexes and Observation of a Unique Interconversion between Oxygen- and .eta.-Arene-Bridged Dimeric Species. X-ray Crystal Structures of La2(OAr)6(NH3)n (n = 0, 2), La(OAr)3(NH3)4, and La(OAr)3(THF)2 (Ar = 2,6-i-Pr2C6H3)
复制标题
芳基氧化镧络合物的氨合成以及氧-芳烃桥二聚体和η-芳烃桥二聚体之间独特相互转化的观察。
DOI：
--
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
J. Watkin
中科院分区：
文献类型：
--
作者：
R. Butcher;D. L. Clark;S. Grumbine;Rebecca L. Vincent;B. Scott;J. Watkin
LaCl{sub 3}在-78{°}C的液氨中与3等量的金属钠反应，然后在甲苯中加入3等量的HOAr (Ar = 2,6-i- pr {sub 2}C{sub 6}H{sub 3})，加热至室温后生成La(OAr){sub 3}(NH{sub 3}){sub x}(1)。1在甲苯中溶解后回流6 h，可得到产率较高的La{sub 2}(OAr){sub 6}(2)。x射线晶体学研究表明，2含有一个二聚体单元，由两个由芳酰配体形成的{eta}{sup 6}-芳烃桥连接在一起，La-C(av) = 3.062(10){埃}。末端和桥接芳基氧化物配体的La-O距离平均分别为2.193(5)和2.273(5){埃}。1在甲苯中溶解，然后真空过滤和无回流的甲苯结晶，高产得La{sub 2}(OAr){sub 6}(NH{sub 3}){sub 2}(3)。3的x射线晶体结构揭示了由芳基氧化物配体氧原子桥接的交替二聚体结构。x射线晶体学表明，通过重力过滤和1的结晶可以分离出第三种化合物La(OAr){sub 3}(NH{sub 3}){sub 4}(4)。4在金属中心周围呈盖状伪八面体结构，面芳氧配体平均为2.252(6){埃}。NH{sub 3}配体的La-N距离平均为2.750(9){埃}，且无明显的La-N键延长。«少
Reaction of LaCl{sub 3} with 3 equiv of sodium metal in liquid ammonia at -78 {degrees}C, followed by addition of 3 equiv of HOAr (Ar = 2,6-i-Pr{sub 2}C{sub 6}H{sub 3}) in toluene produces La(OAr){sub 3}(NH{sub 3}){sub x} (1) after warming to room temperature. Dissolution of 1 in toluene followed by 6 h reflux provides La{sub 2}(OAr){sub 6} (2) in good yield. An X-ray crystallographic study revealed that 2 contains a dimeric unit held together with two {eta}{sup 6}-arene bridges formed from aryloxide ligands with La-C(av) = 3.062(10) {Angstrom}. The La-O distances average 2.193(5) and 2.273(5) {Angstrom} for terminal and bridging aryloxide ligands, respectively. Dissolution of 1 in toluene followed by vacuum filtration and crystallization from toluene without reflux yields La{sub 2}(OAr){sub 6}(NH{sub 3}){sub 2}(3) in high yield. The X-ray crystal structure of 3 reveals an alternate dimeric structure bridged by oxygen atoms of the aryloxide ligands. X-ray crystallography has shown that a third compound may be isolated by gravity filtration and crystallization of 1 to produce La(OAr){sub 3}(NH{sub 3}){sub 4} (4). 4 displays a capped pseudo-octahedral geometry around the metal center with facial aryloxide ligands average 2.252(6) {Angstrom}. The La-N distances for the NH{sub 3} ligands average 2.750(9) {Angstrom} withmore » no significant lengthening of the capped La-N bond.« less