Oligo- and polymerization of phospha [2]ferrocenophanes to one dimensional phosphorus chains with ferrocenylene handles

Controlled Ring Opening of a Tetracyclic Tetraphosphane with Twofold Metallocene Bridging

“…With an authentic sample in hand, tetracyclic oligophosphane 1 could be identified as identical to a previously observed trace impurity in the thermal polymerization of [2]ferrocenophane 2 b (Fe(CpP t Bu) 2 ) at high temperature (Scheme 1, path II), albeit in much lower yield (Figures S1-S4, ESI). [12] X-ray crystallography revealed the molecular structure of compound 1 in the solid state (Figure 2), confirming the tetracyclic tetraphosphane core with ferrocenylene handles connecting the phosphorus atoms in the alternating positions. In contrast to most of its congeners A and E (Figure 1), 1 features a rectangular (PÀ PÀ P angle φ � 90°) and comparatively more planar (ring-fold angle ψ = 160.6°) geometry of the P 4 moiety, similar to phosphaalkyne cyclotetramer B, ate-complexes of aluminacyclopentadienes C and D, and inorganic ferrocene analogue F (Figure 1).…”

“…Recently we reported the formation of an isolable linear tetraand polyphosphane, where the unique axial flexibility of the ferrocenylene substituent enabled all-trans conformation of the P 4 -chain. [12] Inspired by the configurational stability of some ferrocene based oligophosphorus compounds, [7c,13] we set out to explore the possibility of synthesizing a maximally condensed phosphaferrocenophane 1. Herein, we report preparation and reactivity of such an unprecedented tetracyclic oligophosphane,1.…”

Toward efficient functionalization of polystyrene backbone through ketene chemistry: Synthesis, characterization, and DFT study

“…The mechanism of thermolysis of poly(St‐co‐SMA) with two different conformations in monomer and dimer systems was evaluated. Figure 4 shows that poly(St‐co‐SMA) can exist in conformations, either syndiotactic by weak π‐π interaction or isotactic by less steric effects 39–41 . Therefore, we investigated the mechanism of poly(St‐co‐SEDA) preparation through two different conformers of poly(St‐co‐SMA) as a dimer structure for reaction with EDA nucleophile.…”

“…Figure 4 shows that poly(St-co-SMA) can exist in conformations, either syndiotactic by weak π-π interaction or isotactic by less steric effects. [39][40][41] Therefore, we investigated the mechanism of poly(St-co-SEDA) preparation through two different conformers of poly(St-co-SMA) as a dimer structure for reaction with EDA nucleophile. Relative Gibbs free energies (ΔG, kcal mol À1 ) of transition states, intermediates, and products are given in Figure 4.…”

Tailoring the Fe → Pd interaction in cationic Pd(ii) complexesviastructural variation of the ligand scaffold of sterically demanding dppf-analogs and their P,N-counterparts

“…Ferrocene, an extremely useful and unique building block, has remained at the centre of attraction for several decades now. 1,2 Being an essential component in organometallic polymers, [3][4][5][6][7][8][9][10] redox-tunable substances, 6,[11][12][13] organometallic drugs, 14,15 and functional materials, 9,[16][17][18][19][20] ferrocene has played a vital role in homogenous catalysis. [21][22][23][24][25] The principle reasons for its popularity in homogenous catalysis lie in the easy syntheses of its P-functionalized derivatives (such as dppf ) and a flexible backbone, 26,27 which provides an opportunity to stabilize various metal centers by attaining facile geometric changes.…”