Tetra- and Pentaisopropylcyclopentadienyl Complexes of Group 15 Elements

Abstract

Pentaisopropylcyclopentadienyl dichloropnictogen complexes have been synthesized and studied in solution and in the solid state. The coordination mode of the group 15 element to the Cp ligand varies, with the lighter elements phosphorus and arsenic featuring η1 σ-bonded Cp groups and the heavier elements antimony and bismuth exhibiting η3 and η5 bonded Cp groups, respectively. In the case of ≤η3 bonded Cp groups, a rapid sigmatropic rearrangement is observed at room temperature in solution and was examined by VT-NMR spectroscopy and DFT calculations. Furthermore, bis­(cyclopentadienyl)­diphosphenes with tetra- and pentaisopropylcyclopentadienyl groups could be obtained in good yields from the corresponding dichlorophosphanes, and a related silver­(I) complex of a diphosphene was characterized.

Pentaisopropyl Cyclopentadienyl: An Overview across the Periodic Table

“… Synthesis of pentaisopropylcyclopentadienyl phosphorus dichloride (E=P), 10 , pentaisopropylcyclopentadienyl arsenic dichloride (E=As), 11 , pentaisopropylcyclopentadienyl antimony dichloride (E=Sb), 12 , and pentaisopropylcyclopentadienyl bismuth dichloride (E=Bi), 13 , as reported by Schäfer et al. in 2021 [26] …”

“… Synthesis of bis(pentaisopropyl cyclopentadienyl)diphosphene, 14 , as reported by Schäfer et al. in 2021 [26] …”

“…More recently, the 5 Cp ligand was also utilized in group 15 chemistry and several mono‐Cp‐substituted compounds were reported by Schäfer et al [26] . Treatment of 5 CpLi(Et 2 O), 2 , with the corresponding pnictogen trichloride gives the matching cyclopentadienyl pnictogen dichloride (Scheme 7).…”

Phosphine-catalysed reductive coupling of Dihalophosphanes

“…The Dip-substituents are arranged in trans fashion with the P−P bond [2.0293(7) Å] in the expected range for diphosphenes [cf. ( iPr4 CpP) 2 2.0282(10) Å] 51. The C−P−P angles [99.59(4) °] are narrower compared to (Mes*P) 2 [cf.102.8(1) °] in agreement with the lesser steric demand of the Dip-substituent compared to Mes*.…”

2,6‐Diisopropylphenyl substituted Bismuth Halide and Interpnictogen Compounds

“…Aryl or alkyl dihalido bismuthanes can be prepared via salt metathesis from BiX 3 (X=Cl, Br, I) and metalloganic nucleophiles, [1a,b,2,1c–p,3,1q–t,4,1u,5] scrambling reactions of BiR 3 and BiX 3 (X=Cl, Br) [6,3,7–11] or oxidation of BiR 3 with I 2 and subsequent reductive elimination of R−I [12,4] . Halido bismuthanes show a tendency towards intermolecular secondary bonding interactions and thus compounds of the form RBiX 2 show a rich variety of structural motifs in their solid state structures.…”