Coupling of trifluoromethyl isocyanide ligands in binuclear iron carbonyl complexes
Coupling of trifluoromethyl isocyanide ligands in binuclear iron carbonyl complexes
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双核羰基铁配合物中三氟甲基异氰配体的偶联
DOI：
10.1016/j.jfluchem.2014.06.022
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发表时间：
2014-10-01
影响因子：
1.9
通讯作者：
King, R. Bruce
中科院分区：
文献类型：
--
作者：
Li, Guoliang;Liu, Lihua;King, R. Bruce
三氟甲基异氰酸酯配体CF3NC是一种类似于一氧化碳的强背键配体。此外，Lentz和他的同事已经证明，在低温下，游离CF3NC在自由态下足够稳定，可以用作合成金属络合物的试剂。在这方面，用密度泛函理论研究了双核(CF3NC)(2)Fe-2(CO)(N)(n=7，6，5)和单核(CF3NC)Fe(CO)(N)(n=4，3)。在最低能双核(CF3NC)(2)Fe-2(CO)(N)(n=6，5)结构中，CF3NC配体偶联形成桥联ETA(2)，ETA(2)-MU-CF3NCCNCF3配体。(CF3NC)(2)Fe-2(CO)(7)(ETA(2)，ETA(2)-MU-CF3NCCNCF3)结构也是相似的。然而，该结构在能量上类似于最低能量Fe-2(CO)(6)(Mu-CO)(Mu-CF3CN)(2)异构体之上的11kcal/mol，具有类似于众所周知的三重桥联Fe-2(CO)(9)结构的单独桥联CF3NC配体。单核化合物(CF3NC)Fe(CO)(4)与Fe(CO)(4)(CS)相似，其赤道和轴向取代的三角双锥异构体的能量在1kcal/mol范围内几乎相同。预测了双核(CF3NC)(2)Fe-2(CO)(N)(n=7，6)衍生物在超过29千卡/摩尔的能量下能够解离成单核碎片(CF3NC)Fe(CO)(M)(m=4和/或3)。(C)2014爱思唯尔B.V.保留所有权利。
The trifluoromethyl isocyanide ligand, CF3NC is of interest in being a strong back-bonding ligand similar to carbon monoxide. Furthermore, Lentz and coworkers have shown that free CF3NC is stable enough in the free state at low temperatures to use as a reagent for the synthesis of metal complexes. In this connection the binuclear (CF3NC)(2)Fe-2(CO)(n) (n = 7, 6,5) and mononuclear (CF3NC)Fe(CO)(n) (n = 4,3) have been studied by density functional theory. Coupling of CF3NC ligands to form a bridging eta(2),eta(2)-mu-CF3NCCNCF3 ligand is predicted to occur in the lowest energy binuclear (CF3NC)(2)Fe-2(CO)(n) (n = 6, 5) structures. A similarly coupled Fe-2(CO)(7)(eta(2),eta(2)-mu-CF3NCCNCF3) structure is also found for (CF3NC)(2)Fe-2(CO)(7). However, this structure lies similar to 11 kcal/mol in energy above the lowest energy Fe-2(CO)(6)(mu-CO)(mu-CF3CN)(2) isomer having separate bridging CF3NC ligands analogous to the well-known triply bridged Fe-2(CO)(9) structure. The mononuclear derivative (CF3NC)Fe(CO)(4) is shown to be similar to Fe(CO)(4)(CS) in having equatorial and axially substituted trigonal bipyramidal isomers of nearly identical energies within 1 kcal/mol. The binuclear (CF3NC)(2)Fe-2(CO)(n) (n = 7, 6) derivatives are predicted to be viable toward dissociation into the mononuclear fragments (CF3NC)Fe(CO)(m) (m = 4 and/or 3) by substantial energies exceeding 29 kcal/mol. (C) 2014 Elsevier B.V. All rights reserved.