Department of Chemistry, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.
Inorg Chem. 2010 Jan 4;49(1):271-84. doi: 10.1021/ic901999e.
The salt, [OsO(2)F(3)][Sb(2)F(11)], has been synthesized by dissolution of cis-OsO(2)F(4) in liquid SbF(5), followed by removal of excess SbF(5) at 0 degrees C to yield orange, crystalline [OsO(2)F(3)][Sb(2)F(11)]. The X-ray crystal structure (-173 degrees C) consists of an OsO(2)F(3)(+) cation fluorine bridged to an Sb(2)F(11)(-) anion. The light atoms of OsO(2)F(3)(+) and the bridging fluorine atom form a distorted octahedron around osmium in which the osmium atom is displaced from its center toward an oxygen atom and away from the trans-fluorine bridge atom. As in other transition metal dioxofluorides, the oxygen ligands are cis to one another and the fluorine bridge atom is trans to an oxygen ligand and cis to the remaining oxygen ligand. The Raman spectrum (-150 degrees C) of solid [OsO(2)F(3)][Sb(2)F(11)] was assigned on the basis of the ion pair observed in the low-temperature crystal structure. Under dynamic vacuum, [OsO(2)F(3)][Sb(2)F(11)] loses SbF(5), yielding the known [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)] salt with no evidence for [OsO(2)F(3)][SbF(6)] formation. Attempts to synthesize [OsO(2)F(3)][SbF(6)] by the reaction of [OsO(2)F(3)][Sb(2)F(11)] with an equimolar amount of cis-OsO(2)F(4) or by a 1:1 stoichiometric reaction of cis-OsO(2)F(4) with SbF(5) in anhydrous HF yielded only [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)]. Quantum-chemical calculations at the SVWN and B3LYP levels of theory and natural bond orbital analyses were used to calculate the gas-phase geometries, vibrational frequencies, natural population analysis charges, bond orders, and valencies of OsO(2)F(3)(+), [OsO(2)F(3)][Sb(2)F(11)], [OsO(2)F(3)][SbF(6)], and Sb(2)F(11)(-). The relative thermochemical stabilities of [OsO(2)F(3)][SbF(6)], [OsO(2)F(3)][Sb(2)F(11)], [OsO(2)F(3)][AsF(6)], [mu-F(OsO(2)F(3))(2)][SbF(6)], [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)], and [mu-F(OsO(2)F(3))(2)][AsF(6)] were assessed using the appropriate Born-Haber cycles to account for the preference for [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)] formation over [OsO(2)F(3)][SbF(6)] formation and for the inability to synthesize [OsO(2)F(3)][SbF(6)].
OsO2F3Sb2F11 的合成、晶体结构、拉曼光谱和量子化学计算
盐 [OsO(2)F(3)][Sb(2)F(11)] 通过 cis-OsO(2)F(4) 在液态 SbF(5) 中的溶解合成，然后在 0°C 下除去过量的 SbF(5)，得到橙色结晶的 [OsO(2)F(3)][Sb(2)F(11)]。X 射线晶体结构（-173°C）由一个 OsO(2)F(3)(+) 阳离子与一个 Sb(2)F(11)(-) 阴离子桥接的氟组成。OsO(2)F(3)(+) 和桥接氟原子的轻原子在其中形成一个扭曲的八面体，在该八面体中，锇原子从其中心向氧原子位移，并远离反式氟桥原子。与其他过渡金属二氧氟化物一样，氧配体彼此顺式，氟桥原子与一个氧配体反式，与另一个氧配体顺式。固态 [OsO(2)F(3)][Sb(2)F(11)] 的拉曼光谱（-150°C）根据在低温晶体结构中观察到的离子对进行了分配。在动态真空中，[OsO(2)F(3)][Sb(2)F(11)] 失去 SbF(5)，生成已知的 [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)] 盐，没有 [OsO(2)F(3)][SbF(6)] 形成的证据。试图通过 [OsO(2)F(3)][Sb(2)F(11)] 与等摩尔量的 cis-OsO(2)F(4)或 cis-OsO(2)F(4)与 SbF(5)在无水 HF 中的 1:1 化学计量反应合成 [OsO(2)F(3)][SbF(6)]，仅得到 [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)]。使用 SVWN 和 B3LYP 理论水平的量子化学计算和自然键轨道分析，计算了 OsO(2)F(3)(+)、[OsO(2)F(3)][Sb(2)F(11)]、[OsO(2)F(3)][SbF(6)]和 Sb(2)F(11)(-)的气相几何形状、振动频率、自然电荷分析电荷、键序和价态。[OsO(2)F(3)][SbF(6)]、[OsO(2)F(3)][Sb(2)F(11)]、[OsO(2)F(3)][AsF(6)]、[mu-F(OsO(2)F(3))(2)][SbF(6)]、[mu-F(OsO(2)F(3))(2)][Sb(2)F(11)]和[mu-F(OsO(2)F(3))(2)][AsF(6)]的相对热化学稳定性使用适当的 Born-Haber 循环进行评估，以说明形成 [mu-F(OsO(2)F(3))(2)][Sb(2)F(11)]的偏好超过形成 [OsO(2)F(3)][SbF(6)]的偏好，以及无法合成 [OsO(2)F(3)][SbF(6)]的原因。
