Cyclic polymers from alkynes: a review.

Cyclic polymers have applications across various fields, including material science, biomedicine, and inorganic chemistry. Cyclic polymers derived from alkyne monomers have expanded the application scope to include electronic materials and polyolefins. This review highlights recent advancements in the synthesis of cyclic polymers from both mono- and disubstituted alkynes.

Snapshot of cyclooctyne ring-opening to a tethered alkylidene cyclic polymer catalyst.

Cyclooctyne reacts with the trianionic pincer ligand supported alkylidyne [ BuOCO]WCC(CH)(THF) (1) to yield tungstacyclopropene (3) and tungstacyclopentadiene (4) complexes. The ratio of 3 and 4 in the reaction mixture depends on the stoichiometry of the reaction. The maximum concentration of 3 occurs with one equiv.

Heparin-Bead Extraction Enhanced Fluorogenic Aptamer-Thrombin Composite Reporter Enables Sensitive and Rapid Detection of Functional Antithrombin.

Antithrombin (AT) deficiency in the extracorporeal circulation during cardiac surgery leads to uncontrolled inflammation and vascular damage in patients. AT levels decrease in sepsis, major trauma, extracorporeal membrane oxygenation, and eclampsia. Monitoring plasma AT levels facilitates the accurate restoration of AT to baseline values through precise supplementation.

Tethered Alkylidenes for REMP from Carbon Disulfide Cleavage.

Reactions between tungsten alkylidyne [BuOCO]W≡CBu(THF) and sulfur containing small molecules are reported. Complex reacts with CS to produce intermediate η bound CS complex [OC(BuC═)W(η-(,)-CS)(THF)] . Heating complex provides a mixture of a monomeric tungsten sulfido complex and a dimeric complex in a 4:1 ratio, respectively.

Vanadium Alkylidyne Initiated Cyclic Polymer Synthesis: The Importance of a Deprotiovanadacyclobutadiene Moiety.

Reported is the catalytic cyclic polymer synthesis by a 3d transition metal complex: a V(V) alkylidyne, [(dBDI)V≡CBu(OEt)] (), supported by the deprotonated β-diketiminate dBDI (dBDI = ArNC(CH)CHC(CH)NAr, Ar = 2,6-PrCH). Complex is a precatalyst for the polymerization of phenylacetylene (PhCCH) to give cyclic poly(phenylacetylene) (-PPA), whereas its precursor, complex [(BDI)V≡CBu(OTf)] (; BDI = [ArNC(CH)]CH, Ar = 2,6-PrCH, OTf = OSOCF), and the zwitterion [((CF)B-dBDI)V≡CBu(OEt)] () exhibit low catalytic activity despite having a neopentylidyne ligand. Cyclic polymer topologies were verified by size-exclusion chromatography (SEC) and intrinsic viscosity studies.

Metallacyclobuta-(2,3)-diene: A Bidentate Ligand for Stream-line Synthesis of First Row Transition Metal Catalysts for Cyclic Polymerization of Phenylacetylene.

Described here is a direct entry to two examples of 3d transition metal catalysts that are active for the cyclic polymerization of phenylacetylene, namely, [(BDI)M{κ -C,C-(Me SiC SiMe )}] (2-M) (BDI=[ArNC(CH )] CH , Ar=2,6- Pr C H ; M=Ti, V). Catalysts are prepared in one step by the treatment of [(BDI)MCl ] (1-M, M=Ti, V) with 1,3-dilithioallene [Li (Me SiC SiMe )]. Complexes 2-M have been spectroscopically and structurally characterized and the polymers that are catalytically formed from phenylacetylene were verified to have a cyclic topology based on a combination of size-exclusion chromatography (SEC) and intrinsic viscosity studies.

Influence of solvent on cyclic polynorbornene tacticity.

Tacticity is critical to polymer properties. The influence of solvent on tacticity in the catalytic synthesis of cyclic polynorbornene (c-PNB) is reported. In toluene , c-PNB forms; in THF, / c-PNB forms.

A case of alkylidyne-imine metathesis.

Reactions between imines and tungsten alkylidyne complexes are studied. The trianionic pincer ligand supported alkylidyne [BuOCO]WCC(CH)(THF) (1) reacts with -(R)-1-phenylmethanimine (PMI-R, R = Me, Ph, Bn, and TMS) yielding [BuOC(H)O]W(ηBuCCPh)N(R) (4-R), products from metathesis reaction. In contrast, the non-pincer alkylidyne (BuO)WCC(CH) does not react with PMI-R imines.

Ring Expansion Alkyne Metathesis Polymerization.

The synthesis, characterization, and preliminary activity of an unprecedented tethered alkylidyne tungsten complex for ring expansion alkyne metathesis polymerization (REAMP) are reported. The tethered alkylidyne is generated rapidly by combining alkylidyne W(CBu)(CHBu)(O-2,6--CH) () with 1 equiv of an yne-ol proligand (). Characterized by NMR studies and nuclear Overhauser effect spectroscopy, complex is a dimer.

Probing borafluorene B-C bond insertion with gold acetylide and azide.

The reaction of PhPAuN with 9-Ph-9-borafluorene resulted in complexation of the azide to boron while a gold acetylide reacted with 9-Ph-9-borafluorene to insert the acetylide carbon to access a six-membered boracycle with an exocyclic double bond.

iClick synthesis of network metallopolymers.

Described is an approach to preparing the first iClick network metallopolymers with porous properties. Treating digoldazido complex 2-AuN3 with trigoldacetylide 3-AuPPh3 or 3-AuPEt3, trialkyne 3-H, tetragoldacetylide 4-AuPPh3, or tetraalkyne 4-H in CHCl affords five iClick network metallopolymers 5-AuPPh3, 5-AuPEt3, 5-H, 6-AuPPh3, and 6-H. Confirmation of the iClick network metallopolymers comes from FTIR, C solid-state cross-coupling magic angle spinning (CPMAS) NMR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and nitrogen and CO sorption analysis.

Isolation of an Elusive Phosphametallacyclobutadiene and Its Role in Reversible Carbon-Carbon Bond Cleavage.

The reactivity of phosphaalkynes, the isolobal and isoelectronic congeners to alkynes, with metal alkylidyne complexes is explored in this work. Treating the tungsten alkylidyne [ BuOCO]W≡C Bu(THF) (1) with phosphaalkyne (10) results in the formation of [O C( BuC=)W{η -(P,C)-P≡C-Ad}(THF)] (13- Bu ) and [O C(AdC=)W{η -(P,C)-P≡C- Bu}(THF)] (13-Ad ); derived from the formal reductive migratory insertion of the alkylidyne moiety into a W-C bond. Analogous to alkyne metathesis, a stable phosphametallacyclobutadiene complex [ BuOCO]W[κ -C( Bu)PC(Ad)] (14) forms upon loss of THF from the coordination sphere of either 13- Bu or 13-Ad .

A High-Throughput Approach to Repurposing Olefin Polymerization Catalysts for Polymer Upcycling.

Efficient and economical plastic waste upcycling relies on the development of catalysts capable of polymer degradation. A systematic high-throughput screening of twenty-eight polymerization catalyst precursors, belonging to the catalyst families of metallocenes, ansa-metallocenes, and hemi- and post-metallocenes, in cis-1,4-polybutadiene (PB) degradation reveals, for the first time, important structure-activity correlations. The upcycling conditions involve activation of the catalysts (at 0.

SPAAC iClick: progress towards a bioorthogonal reaction in-corporating metal ions.

Combining strain-promoted azide-alkyne cycloaddition (SPAAC) and inorganic click (iClick) reactivity provides access to metal 1,2,3-triazolates. Experimental and computational insights demonstrate that iClick reactivity of the tested metal azides (LM-N, M = Au, W, Re, Ru and Pt) depends on the accessibility of the azide functionality rather than electronic effects imparted by the metal. SPAAC iClick reactivity with cyclooctyne is observed when the azide functionality is sterically unencumbered, [Au(N)(PPh)] (Au-N3), [W(η-allyl)(N)(bpy)(CO)] (W-N3), and [Re(N)(bpy)(CO)] [bpy = 2,2'-bipyridine] (Re-N3).

Cyclic polyacetylene.

Here we demonstrate the synthesis of cyclic polyacetylene (c-PA), or [∞]annulene, via homogeneous tungsten-catalysed polymerization of acetylene. Unique to the cyclic structure and evidence for its topology, the c-PA contains >99% trans double bonds, even when synthesized at -94 °C. High activity with low catalyst loadings allows for the synthesis of temporarily soluble c-PA, thus opening the opportunity to derivatize the polymer in solution.

Precise NMR Method for Titering Organometal Reagents.

The concentration of organometal reagents can be conveniently determined by obtaining the NMR spectra of the neat reagent solution, and, in a second NMR tube, of a neat reference solvent. The PULCON relationship, implemented in all major NMR software, is then used to calculate the concentration of the reagent based on the absolute integrals in the spectra, the known concentration of the reference, and the number of protons under the integrals.

Tethered Tungsten-Alkylidenes for the Synthesis of Cyclic Polynorbornene via Ring Expansion Metathesis: Unprecedented Stereoselectivity and Trapping of Key Catalytic Intermediates.

This report describes an approach for preparing tethered tungsten-imido alkylidene complexes featuring a tetra-anionic pincer ligand. Treating the tungsten alkylidyne [BuOCO]W≡CBu(THF) () with isocyanates (RNCO; R = Bu, Cy, and Ph) leads to cycloaddition occurring exclusively at the C═N bond to generate the tethered tungsten-imido alkylidenes (). Unanticipated intermediates reveal themselves, including the discovery of [(OCBuC═)W(η-(,)-RNCO)(THF)] () and an unprecedented decarbonylation product [(BuOCO)W(≡NR)(BuCCO)] (), on the pathway to the formation of .

Excited-State Turn-On of Aurophilicity and Tunability of Relativistic Effects in a Series of Digold Triazolates Synthesized via iClick.

iClick reactions between Au(I) acetylides PPhAu-C≡CR, where R = nitrophenyl (PhNO), phenyl (Ph), thiophene (Th), bithiophene (biTh), and dimethyl aniline (PhNMe), and Au(I)-azide PPhAuN provide digold complexes of the general formula -1,5-bis-triphenylphosphinegold(I) 1,2,3-triazolate (). Within the digold triazolate complexes the Au(I) atoms are held in close proximity but beyond the distance typically observed for aurophilic bonding. Though no bond exists in the ground state, time-dependent density functional theory interrogation of the complexes reveals excited states with significant aurophilic bonding.

An Application Exploiting Aurophilic Bonding and iClick to Produce White Light Emitting Materials.

The paper focuses on exploiting aurophilic bonding to produce white light emitting materials. Inorganic Click (iClick) is employed to link two or four Au(I) metal ions through a triazolate bridge. Depending on the choice of phosphine ligand (PEt or PPh), dinuclear Au-FO or tetranuclear Au-FO complexes can be controllably synthesized (FO = 2-(9,9-dioctylfluoreneyl-)).

A catalytically relevant intermediate in the synthesis of cyclic polymers from alkynes.

A tungsten metallacyclopentadiene complex is generated upon treating a trianionic pincer tungsten alkylidyne with dipropargyl fluorene. The metallacyclopentadiene initiates the polymerization of alkynes to give cyclic polyacetylenes via ring expansion polymerization (REP).