Dipartimento di Scienze Ambientali, Università della Tuscia, L.go dell' Università, s.n.c., 01100 Viterbo, Italy.
J Phys Chem A. 2010 Jul 15;114(27):7382-90. doi: 10.1021/jp102018n.
Theoretical calculations at the B3LYP, MP2, and CCSD(T) levels of theory disclose the conceivable existence of cationic noble gas hydrides containing two Ng atoms. These species have a general formula of HNgFNgH(+) (Ng = He-Xe), and are the cationic counterparts of the neutral HNgF. The optimized geometries, harmonic frequencies, and bonding properties point to ion-dipole complexes between a fluoride anion and two covalent H-Ng(+) cations, best formulated as (H-Ng(+))(2)F(-). The HXeFXeH(+) is also isoelectronic with the recently experimentally observed HXeOXeH (Khriachtchev et al. J. Am. Chem. Soc. 2008, 130, 6114-6118). The resulting HNgFNgH(+) are thermochemically stable with respect to dissociation into HNg(+) + HNgF and HNg(+) + H + Ng + F, but are largely unstable with respect to both the loss of HF (with formation of HNg(+) + Ng) and H(2)F(+) (with formation of two Ng atoms). These decompositions pass through bent transition structures, and only the heaviest HArFArH(+), HKrFKrH(+), and HXeFXeH(+) are protected by energy barriers large enough (ca. 10-15 kcal mol(-1)) to support their conceivable metastability. In line with other series of noble gas compounds, the neon cation HNeFNeH(+) is the least stable among the various HNgFNgH(+).
理论计算在 B3LYP、MP2 和 CCSD(T) 理论水平上揭示了可能存在含有两个 Ng 原子的阳离子惰性气体氢化物。这些物种具有通式 HNgFNgH(+)（Ng=He-Xe），是中性 HNgF 的阳离子对应物。优化的几何形状、简正频率和键合性质表明，在氟阴离子和两个共价 H-Ng(+)阳离子之间存在离子偶极复合物，最好将其表示为（H-Ng(+))(2)F(-)。HXeFXeH(+)也与最近实验观察到的 HXeOXeH（Khriachtchev 等人，J. Am. Chem. Soc. 2008, 130, 6114-6118）具有等电子性。形成的 HNgFNgH(+)相对于分解为 HNg(+) + HNgF 和 HNg(+) + H + Ng + F 是热稳定的，但对于 HF 的损失（形成 HNg(+) + Ng）和 H(2)F(+)（形成两个 Ng 原子）的损失在很大程度上是不稳定的。这些分解通过弯曲过渡态进行，只有最重的 HArFArH(+)、HKrFKrH(+)和 HXeFXeH(+)被足够大的能量势垒（约 10-15 kcal mol(-1))保护，以支持其设想的亚稳性。与其他系列的惰性气体化合物一样，氖阳离子 HNeFNeH(+)是各种 HNgFNgH(+)中最不稳定的。
