Cu-Catalyzed Azide-Pt-Acetylide Cycloaddition: Progress toward a Conjugated Metallopolymer via iClick

Abstract

This report describes the iClick synthesis and characterization of a metallopolymer that contains contiguous conjugation across the polymer repeat units and Pt(II) ions. A bifunctional A−Pt-B monomer, where A = azido and B = acetylide, was synthesized. Using a Cu(I) source, the A−Pt-B monomer was polymerized via azide−alkyne cycloaddition to give a low-molecular-weight metallopolymer. Photophysical interrogation and computation modeling of the metallopolymer indicates limited conjugation and the spectra are dominated by ligand-centered transitions and emission.

Trapping of Terminal Platinapolyynes by Copper(I) Catalyzed Click Cycloadditions; Probes of Labile Intermediates in Syntheses of Complexes with Extended sp Carbon Chains, and Crystallographic Studies

“…These are illustrated for PtC x HN 3 Bz in Figure 1. As would be expected, the λ max and molar extinction coefficients (ɛ) of PtC x TES and PtC x TIPS are quite similar for equal values of x (14,16). The ɛ values reach as high as 216000 M À 1 cm À 1 with PtC 20 TES, but remain somewhat less than for related complexes with PtC x Pt linkages.…”

“…[5,20] Time dependent DFT calculations on model diplatinum complexes show that the intense longer wavelength absorptions acquire increasing HOMO!LUMO character as the sp chains lengthen. [33] For eight complexes, three weak bands at even longer wavelengths can also be detected (PtC x TES, x = 10, 12, 14; PtC 14 TIPS; PtC x HN 3 Bz, x = 10, 12, 14,16). By analogy to the spectra of other conjugated polyynes, [5b,8c,34] these can be attributed to C�C vibrational fine structure.…”

“…This was part of a broader effort involving click reactions in metal coordination spheres, [13] a topic for which there are now many contributors. [14,15] The "parent" transformation, involving benzyl azide and the easily isolated butadiynyl complex PtC 4 H, is depicted in Scheme 2. For n = 3-6 (x = 6/8/10/12), the terminal polyynes were generated in situ under special conditions from the corresponding triethylsilyl polyynes trans-(C 6 F 5 )(p-tol 3 P) 2 Pt (C�C) n SiEt 3 (PtC x TES).…”

Click chemistry strategies for the accelerated synthesis of functional macromolecules

“…27 Metal ions were recently incorporated into the propagating chain of polymers through AAC. The first in-chain metallopolytriazolate was synthesized via copper(I)catalyzed inorganic click(iclick) reaction of azido-platinum-acetylide (A-M-B) monomers (Scheme 19(E)).This new approach offers an exciting opportunity to access metallopolymers with diverse functions, such as conjugated metallooligomers 393 with potential application in sustainable heterogeneous catalysts, therapeutics for drug-resistant diseases, energy storage, and photovoltaics. 394 Although transition metal-mediated polymerizations are powerful tools for constructing multifunctional polymers with diverse structures, development of an alternative metal-free polymerization of azides and alkynes is still of significant importance.…”

“…The first in‐chain metallopolytriazolate was synthesized via copper(I)‐catalyzed inorganic click(iclick) reaction of azido–platinum–acetylide (A–M–B) monomers (Scheme 19(E)). This new approach offers an exciting opportunity to access metallopolymers with diverse functions, such as conjugated metallooligomers 393 with potential application in sustainable heterogeneous catalysts, therapeutics for drug‐resistant diseases, energy storage, and photovoltaics 394 …”