Benchmarking of Halogen Bond Strength in Solution with Nickel Fluorides: Bromine versus Iodine and Perfluoroaryl versus Perfluoroalkyl Donors.
Benchmarking of Halogen Bond Strength in Solution with Nickel Fluorides: Bromine versus Iodine and Perfluoroaryl versus Perfluoroalkyl Donors.
复制标题
氟化镍溶液中卤素键强度的基准测试：溴与碘以及全氟芳基与全氟烷基供体。
DOI：
10.1002/chem.201900924
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Pike SJ
中科院分区：
文献类型：
--
作者：
Pike SJ
研究了一系列氟化镍卤键受体在溶液中形成卤键的热力学;反式-[NiF（2-C5 NF 4）（PEt 3）2]（A1）、反式-[NiF{2-C5 NF 3（4-H）}（PEt 3）2]（A2）、反式-[NiF{2-C5 NF 3（4-NMe 2）}（PEt 3）2]（A3）和反式-[NiF{2-C5 NF 2 H（4-CF 3）}（PCy 3）2]（A4）与中性有机卤素键供体，碘代五氟苯（D1），1-碘代九氟丁烷（D2）和溴代五氟苯（D3），以建立从全氟芳基到全氟烷基供体和从碘到溴供体的变化的意义。19 F NMR滴定实验已被用于获得这些供体-受体伙伴之间形成的卤素键在原甲苯中的缔合常数，焓和熵。对于A2-A4，与碘代全氟烷烃（D2）形成的卤键的缔合常数始终大于与碘代全氟芳烃（D1）形成的类似络合物的缔合常数。对于与A2-A4形成的络合物，当卤素供体原子从I（inD 1）变为Br（inD 3）时，卤素键的强度显著降低（对于D1：5≤K285≤ 12 m −1，对于D3：1.0≤K193≤1.6m−1）。与A1、A2和A4与相同给电子体形成的卤键络合物相比，受体A3的吡啶环上的NMe 2给电子取代基的存在导致与D1-D3形成的卤键络合物的-ΔH和缔合常数增加.
The energetics of halogen bond formation in solution have been investigated for a series of nickel fluoride halogen bond acceptors;trans‐[NiF(2‐C5NF4)(PEt3)2] (A1),trans‐[NiF{2‐C5NF3(4‐H)}(PEt3)2] (A2),trans‐[NiF{2‐C5NF3(4‐NMe2)}(PEt3)2] (A3) andtrans‐[NiF{2‐C5NF2H(4‐CF3)}(PCy3)2] (A4) with neutral organic halogen bond donors, iodopentafluorobenzene (D1), 1‐iodononafluorobutane (D2) and bromopentafluorobenzene (D3), in order to establish the significance of changes from perfluoroaryl to perfluoroalkyl donors and from iodine to bromine donors.19F NMR titration experiments have been employed to obtain the association constants, enthalpy, and entropy for the halogen bond formed between these donor‐acceptor partners in protiotoluene. ForA2–A4, association constants of the halogen bonds formed with iodoperfluoroalkane (D2) are consistently larger than those obtained for analogous complexes with the iodoperfluoroarene (D1). For complexes formed withA2–A4, the strength of the halogen bond is significantly lowered upon modification of the halogen donor atom from I (inD1) to Br (inD3) (forD1: 5≤K285≤12m−1, forD3: 1.0≤K193≤1.6m−1). The presence of the electron donating NMe2substituent on the pyridyl ring of acceptorA3led to an increase in −ΔH, and the association constants of the halogen bond complexes formed withD1–D3, compared to those formed byA1,A2andA4with the same donors.