End Group Functionalization of PFpP Macromolecules Via Fp Migration Insertion Reactions

Abstract

PFpP macromolecules, synthesized via migration insertion polymerization of CpFe(CO)2 (CH2)3 PPh2 (FpP), exhibit reactive Fp end groups for further migration insertion reactions in the presence of phosphines. A number of alkyl diphenylphosphines with varied alkyl length, Ph2PCn (n = 6, 10, 18), have been prepared for the reaction, resulting in PFpP-PPh2Cn (n = 6, 10, 18) amphiphiles. The phosphines with longer alkyl chains impose steric hindrance for the reaction and therefore require longer reaction times and excess phosphines relative to PFpP.

Chelation‐Induced Polymer Structural Hierarchy/Complexity in Water

“…However, the phase‐transition durations kept invariable (≈4 min) due to perfect chain‐flexibility. UV–vis spectroscopy revealed that PAEMA‐chelation started earlier and proceeded faster than PAHMA (Figure S8, Supporting Information) under both the most significant aggregation and the exhausted‐chelation conditions, presumably due to favored chelation by synergistic hydrogen bonding and geometric preference . These results demoinstrated the aliphatic spacer length played important roles in this CCISA.…”

“…As shown in Figure 1 a, the PAEMA block dehydrated more signifi cantly than PAHMA at low chelation-degrees, presumably due to favored chelation by synergistic hydrogen bonding [ 28 ] and geometric preference. [ 29 ] Moreover, PAEMA block aggregated at low chelation-degrees, as judged by signifi acnt increase of DLS intensity as compared to that of PAHMA (Figure 1 b). PAEMA-block aggregated most signifi cantly at pH 7.2 while PAHMA at pH 7.9, as judged by each maximal DLS intensity.…”

Flexibility and Stability of Metal Coordination Macromolecules

“…A weak signal at 34 ppm due to the oxidized phosphine is observed in the 31 P NMR spectrum (Figure a), suggesting that the product contains an uncoordinated phosphine end group . The 1 H NMR spectrum also reveals a weak signal at 4.68 ppm due to the Cp in the Fp end group (Figure b) . The number average molecular weight ( M n ) for P( 1/2 ) is therefore calculated through end‐group analysis and listed in Table .…”

Solvent-dependent chain conformation for ring closure of metal carbonyl oligomers via migration insertion polymerization (MIP) of CpFe(CO)2(CH2)6PPh2

“…3b) is not related to the Fp group. 27 It is there-fore reasonable to think that FpC6P oligomers in THF/hexane may adopt cyclic conformations, where the two end groups from the same molecules tend to capture each other for an intramolecular MIR cyclic reaction.…”