Novel complexes of nickel with N-heterocyclic ligands and the hemilabile [2-(dimethylamino)ethyl]cyclopentadienyl group

Synthesis, structural characterization, and reactivity of late transition-metal complexes bearing linked cyclopentadienyl–carboranyl ligands

“…8 The average Ni-C ring distances of 2.145(6) Å in 5, 2.17 ± 0.01 Å in 7, and 2.131(3) Å in 8 are very close to each other. They are also similar to the 2.102(6) Å in [Ni(h 5 -C 5 H 5 )(PPh 3 )C≡CCHO], 9 to the 2.182(3) Å in [(h 5 -1-TMS-C 9 H 5 )NiCl(PPh 3 ), 10 to the 2.114(7) Å in (h 5 :h 1 -C 5 H 4 CH 2 CH 2 NMe 2 )Ni(C 12 H 8 N), 11 and to the 2.098(9) Å in [(h 5 -C 5 H 4 CH 2 CH 2 NMe 2 )Ni(dmpe)][PF 6 ]. 12 The metal -cage carbon distances (M-C cage ) between 1.95 and 2.01 Å for 4-8 are comparable to the 1.998(9)-2.013(9) Å in [Ni{(C 2 B 10 H 10 ) 2 } 2 ] 2-, 13 17 and to the 2.134(1) Å in Cp*Ni(PPh 3 )(CH 2 COt-Bu).…”

“…The M-C bond distances of 1.838(3)/1.790(3) Å in 9/10 compare to those of 1.87(1)/1.89(1) Å in [Co(L C=O : N 2 (SO) 2 )(CNt-Bu) 2 ] -, 19 to 1.772(18)/1.963(18) Å in CoBr(PhCOCH)(CNC 6 H 3 Me 2 -2,6) 6 , 20 to 1.787(3) Å in Ni(triphos)(CNC 6 H 3 Me 2 -2,6), 21 to 1.820(4) Å in Ni{S 2 P(O)(OEt)}(CNC 6 H 3 Me 2 -2,6)(PCy 3 ), 22 and to 1.789(9)/ 1.789(8) Å in [Ni(m-t-Bu 2 As)(p-tol-NC) 2 ] 2 . 23 Reaction of 4 or 5 with 1 equiv of NHC (1,3-bis(2,6-diisopropylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene) in toluene at room temperature afforded [h 5 :s-Me 2 C(C 5 H 4 ) (C 2 B 10 H 10 )]M[C(2,6-i-Pr 2 C 6 H 3 -NCH) 2 ] (M = Co (11) or Ni (12)) in 51% and 60% isolated yield, respectively (Scheme 2). The characteristic 13 C resonance at 163.1 ppm corresponding to the NHC carbene carbon was observed in the 13 C NMR spectrum of 12.…”

“…of parameters varied). 11 B{ 1 H} NMR (C 6 D 6 ) d: -2.4 (5B), -6.0 (2B), -8.9 (3B). 31 (14) This complex was prepared as brown crystals from [h 5 :s-Me 2 C(C 5 H 4 )(C 2 B 10 H 10 )]Co(PPh 3 ) (4; 0.29 g, 0.50 mmol) and dppe (0.10 g, 0.25 mmol) in toluene (5 mL) using the same procedure as reported for 13; yield: 0.19 g (62%).…”

Novel nickel(II) complex bearing phthalimido ligands derived from oxime-mediated transformation of phthalonitrile

“…The m(C@O) band is significantly shifted to a lower-energy region than that of free phthalimide [1744 cm À1 ] [25], although being comparable to those of related Ni complexes [i.e. 1654-1650 cm À1 ] bearing phthalimido moieties [26,27]. The positive FAB-MS spectrum of 2 shows the molecular ion [M] + peak with the expected isotopic pattern at the m/z value of 470.…”

“…[Ni{trans-(L) 2 }(en) 2 ] {L = N-(5-chlorouracilato) [28], isothiocyanato [29] and salicylato [30]}. In contrast, the almost planar pti ligands in 2 are bound via the Ni1-N1 bond of 2.1235(13) Å that is significantly lengthened in comparison with the corresponding bond distances of 1.907(3) and 1.895(4) Å in [Ni{g 5 -(2-dimethylaminoethyl)cyclopentadienyl}(pti)] Á 0.5(C 7 H 8 ) [27] and [Ni(g 5 -1-methylindene)(pti)(PPh 3 )] [26], respectively, but comparable to that of ca. 2.102 Å encountered in the related [31].…”