Square‐Planar (Pentafluorophenyl)nickel(II) Complexes by Derivatization of a C–F Activation Product

Abstract

The NHC‐stabilized C–F activation product [Ni(iPr2Im)2(F)(C6F5)] (1) was isolated from the reaction of [Ni(cod)2] with 1,3‐diisopropylimidazol‐2‐ylidene (iPr2Im) and hexafluorobenzene. Square‐planar (pentafluorophenyl)nickel complexes of the type [Ni(iPr2Im)2(X)(C6F5)] were obtained by a systematic derivatization of 1. The reaction of 1 with silylated compounds and organyllithium compounds led smoothly to replacement of the fluorido ligand in 1 by halogenido, trifluoromethanesulfonato, cyanido, organyl, selenolato, thiolato, and hydrido ligands. According to these procedures, the NHC‐stabilized (pentafluorophenyl)nickel complexes [Ni(iPr2Im)2(X)(C6F5)] (X = Cl 2, I 3, CF3SO3 4, CN 5), [Ni(iPr2Im)2(R)(C6F5)] (R = Me 6, Ph 7, C2Ph 8, η1‐Cp 9), [Ni(iPr2Im)2(SR)(C6F5)] (R = Ph 10, nPr 11), [Ni(iPr2Im)2(SeR)(C6F5)] (R = Ph 12, iPr 13), and [Ni(iPr2Im)2(H)(C6F5)] (14) were prepared. The complexes 4, 6. 9, 11, 13 and 14 were structurally characterized.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Nickel N-heterocyclic carbene complexes and their utility in homogeneous catalysis

“…The oxidation method (Scheme 15) is quite popular for synthesizing these neutral (NHC) 2 (Ar)NiX (X = anion) type complexes as observed for the (458), [143] (459−461), [61] (462−463), [147] (464−469), [41] (470−471), [40] (472−478), [153] (479−488), [154] (489), [155] (507−513), [42] (514) [156] and (515−516) [42] complexes. …”

Catalytic C–F bond activation of geminal difluorocyclopropanes by nickel(i) complexes via a radical mechanism

“…It was thus essential to probe whether the significantly stronger C-F bond could be activated by the isolated nickel(I) species. To this end, stoichiometric transformations involving the geminal difluorocyclopropane 5a 1) 92.34 (7), N(3)-Ni-N(1) 175.28( 7); (3b) Ni-N(2) 1.9301 (18), Ni-N(1) 1.8955 (19), Ni-N(3) 1.8903 (18), N(1)-Ni-N(2) 95.26 (8), N(2)-Ni-N(3) 96.12(8), N(3)-Ni-N(1) 168.60 (7).…”

“…Hydrogen atoms are omitted for clarity. Selected bond length [Å] and angles [1]: (1b) Ni-F 1.8308(17), Ni-N(1) 1.8847(18), Ni-N(2) 1.885(2), Ni-N(3) 1.8884(18), F-Ni-N(1) 87.30(6), F-Ni-N(2) 178.96(6), F-Ni-N(3) 88.04(6), N(2)-Ni-N(1) 92.34(7), N(3)-Ni-N(1) 175.28(7); (3b) Ni-N(2) 1.9301(18), Ni-N(1) 1.8955(19), Ni-N(3) 1.8903(18), N(1)-Ni-N(2) 95.26(8), N(2)-Ni-N(3) 96.12(8), N(3)-Ni-N(1) 168.60(7).…”

Liquid injection field desorption/ionization of transition metal fluoride complexes

“…They are prone to rearrangements involving other ligands especially phosphines [1,2], they are highly polar and readily form complexes with hydrogen bond donors and halogen bond donors [3][4][5], they are capable of C-F reductive elimination in special circumstances [4,6]. They may be formed with the aid of a wide variety of fluorinating agents such as XeF 2 , Et 3 NÁ3HF and AgF [1,4,7,8], but a method of particular interest to us has been C-F oxidative addition [9][10][11][12][13][14][15][16][17][18][19][20][21].…”