Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 30. Synthetic and Structural Studies on Oxide Ion Encapsulating Tetralanthanide Tetrahedra Surrounded by “Carbons Apart” C2B4-Carborane Ligands (Ln(III) = La, Nd, Gd, Tb, Ho, Lu)

The reactions of closo-exo-5,6-Na(THF)2-1-Na(THF)2-2,4-(SiMe3)2-2,4-C2B4H4 (1) with
anhydrous LnCl3 (Ln = La, Nd, Gd, Tb, Ho, Lu) and freshly distilled H2O in molar ratios of
5:4:1 gave crystalline solids, identified as the new oxolanthanacarboranes {[η5-1-Ln(THF)n-2,4-(SiMe3)2-2,4-C2B4H4]4(μ-Cl)2(μ4-O)}·yTHF (Ln = La (2), n = 0, y = 1; Ln = Nd (3), n = 1,
y = 0; Ln = Gd (4), n = 0, y = 1; Ln = Tb (5), n = 1, y = 0; Ln = Ho (6), n = 0, y = 1; Ln
= Lu (7), n = 1, y = 0), in 73−86% yields. All new compounds were characterized by IR
spectroscopy and elemental analyses. While the diamagnetic compounds 2 and 7 were also
studied by 1H, 13C, and 11B NMR spectroscopy, the lanthanacarboranes 3 and 5−7 were
further characterized by single-crystal X-ray diffraction analyses. The species 3, 5, and 7
were found to be isostructural, all containing oxide ion encapsulating tetralanthanide cores,
Ln(μ4-O), that are stabilized by coordinating two carborane ligands:  one in an η5 fashion
via the C2B3-bonding face and the other via two Ln−H−B bridges to a neighboring cage.
Complexes 3 and 5−7 crystallized in the monoclinic space group C2/c with a = 23.748(5),
23.577(5), 28.403(5), and 23.544(5) Å, b = 18.632(5), 18.513(5), 12.835(2), and 18.440(5) Å,
c = 22.798(5), 22.602(5), 27.879(5), and 22.480(5) Å, β = 104.338(5), 104.092(5), 117.820(3),
and 104.153(5)°, and V = 9774(64), 9568(4), 8989(13), and 9464(4) Å3, respectively (Z = 4).
The final refinements of 3 and 5−7 converged at R1 = 0.0795, 0.0703, 0.0367, and 0.0904;
wR2 =0.1793, 0.1686, 0.794, and 0.1844, and GOF = 1.401, 1.305, 1.446, and 1.498,
respectively. The room-temperature magnetic susceptibility of the holmium compound 6 was
found to be 10.3 μB per lanthanide metal.

与无水LnCl3（Ln分别为La、Nd、Gd、Tb、Ho、Lu）及新鲜蒸馏的水在摩尔比5:4:1的反应中，closo-exo-5,6-Na(THF)2-1-Na(THF)2-2,4-(SiMe3)2-2,4-C2B4H4 (1)生成了结晶固体，经鉴定为新型氧化氧化兰碳硼烷{[η5-1-Ln(THF)n-2,4-(SiMe3)2-2,4-C2B4H4]4(μ-Cl)2(μ4-O)}·yTHF（Ln=La (2)，n=0，y=1；Ln=Nd (3)，n=1，y=0；Ln=Gd (4)，n=0，y=1；Ln=Tb (5)，n=1，y=0；Ln=Ho (6)，n=0，y=1；Ln=Lu (7)，n=1，y=0），产率为73%-86%。所有新化合物均通过红外光谱和元素分析进行了表征。其中抗磁性化合物2和7还通过1H、13C和11B核磁共振光谱进行了研究，而镧碳硼烷3和5-7则进一步通过单晶X射线衍射分析进行了表征。发现物种3、5和7具有同构性，均包含封装四镧核的氧化物离子Ln(μ4-O)，这些核通过两个碳硼烷配体进行稳定：一个通过η5方式通过C2B3-键合面，另一个通过两个Ln-H-B桥与相邻笼体相连。复合物3和5-7结晶于单斜晶系C2/c空间群，其a、b、c轴长分别为23.748(5)、23.577(5)、28.403(5)和23.544(5)埃，β角为104.338(5)、104.092(5)、117.820(3)和104.153(5)°，体积分别为9774(64)、9568(4)、8989(13)和9464(4)埃立方，Z值为4。3和5-7的最终精修收敛于R1 = 0.0795、0.0703、0.0367和0.0904；wR2 =0.1793、0.1686、0.794和0.1844，GOF分别为1.401、1.305、1.446和1.498。钬化合物6的室温磁化率被测得为每镧金属10.3μB。