Synthesis, characterisation and fluxional behaviour of [Ni(η5-P2C3Bu3t) (η3-P2C3Bu3t)]

Synthesis and Properties of [NiCp*(2,5‐tBu2PC4H2)], a 20‐Valence‐Electron Phosphanickelocene

“…The factors determining the structural changes upon passing from 2 to 10 and 11 are less obvious. 1,1',2,2',4,4'-hexa(tert-butyl)nickelocene is unknown and the cocondensation of nickel atoms with 1,2,4-tri(tert-butyl)cyclopentadiene gives the h 3 -cyclopentenyl nickel complex 21 [54] so it is possible that the 18ve structure observed in 11 [13] may reflect steric issues. [55] However, the hindrance in complex 10 [12] is rotationally quite nicely equilibrated and in this case the multiple tBu substitution alone seems unlikely to impose a ring-slipped 18ve configuration.…”

“…Chemical stability; reaction with trimethylphosphine: Given the existence of products 10-12, [7,12,13] and the stronger calculated binding of sp 2 phosphorus than carbon to the metal centre in some phosphametallocenes, [40,41] it seems likely that the energy barrier for ring slippage reactions of the phospholyl ligands at nickel may be relatively small. Furthermore, the spatial accessibility of the lone pairs in unhindered phosphanickelocenes and phosphanickelocenium salts will probably drive the ring-slip process.…”

“…[ 13] One of these was fluxional, [13] but neither showed paramagnetism. A related nickel h 3 -triphosphacyclopentenyl complex was also prepared.…”

“…These confirm a broadly cylindrical electron density distribution about the centroid-Ni-centroid axis which is in sharp contrast with more localised bonding schemes found for the slipped di-and triphospholyl ligands in the 18ve nickel-containing complexes 10 [22] and 11. [13] The major differences between the phosphaferrocene 17 and the phosphanickelocene 2 are found in the metal-ring distances. These are all longer in 2 but show a distinct trend, moving from MÀC b (7.3 % longer in the Ni case) to MÀC a (6.1 %) and MÀP (4.2 %) with values to the Cp* also being between 7.0 to 5.7 % longer in 2.…”

Synthesis and structural characterisation of lanthanide and actinide phosphaorganometallic complexes derived from the 3,5-di-tert-butyl-1,2,4-triphospholyl ring anion, P3C2But−2: Crystal and molecular structures of [M(η5-P3C2But2)2(η2-P3C2But2)] (M=Sc, Y, Tm, and U)

“…Sc [3], Ti [4,5], V [6], Cr [17], Mn [18], Fe [7][8][9][10][11][12][13], Co [19], Ni [21][22][23][24][25], Ru [13][14][15][16], and Rh [16,20]) and main group elements (e.g. Ga [26], In [27][28][29], Tl [26], Sr [30], and Pb [31]).…”