Facile synthesis of novel hybrid POSS biomolecules via “Click” reactions

Abstract

A novel alkyne-terminated cubic-octameric POSS was synthesised in high yield (82-90%). The X-ray crystal structure revealed intra-and intermolecular hydrogen bonding between the amide groups of the arms.Hybrid biomaterials were synthesised in nearly quantitative yields via a click reaction with (i) azido-NFmoc-norleucine and (ii) 3 0 -azido-3 0 -deoxythymidine.Among the most commonly studied scaffolds for developing hybrid biomaterials 1-4 is polyhedral oligomeric silsesquioxane (POSS). POSS units are symmetrical, three-dimensional cubic molecules, which are unique nanometer-sized hybrid inorganicorganic materials 5,6 with the formula ( 'click' chemistry, is a simple method for coupling organic molecules containing azide and alkyne functional groups in high yields and its use in the elds of peptide and protein biomedical and material sciences is accelerating.22,23 The click reaction has been used to synthesise POSS biomaterials such as hybrid POSS-PEG hydrogels 24 that support chondrocyte attachment and proliferation. Only one synthetic approach towards peptidyl silsesquioxanes using click chemistry has been reported to date.25-30 focussing on the synthesis of octa(3-azidopropyl)polyhedral oligomeric silsesquioxane POSS-(N 3 ) 8 (Fig. 1) and its reaction with a variety of alkynes.25-36 The preparation of octa(3-azidopropyl)polyhedral oligomeric silsesquioxane POSS-(N 3 ) 8 requires a multi-step synthesis and suffers from a poor overall yield of 30-32%. 32The synthesis and click reaction of mono alkyneheptaisobutyl POSS were rst reported by Müller et al. 37 and Wu et al. 38 Müller et al. 37 have used aminopropylheptaisobutyl polyhedral oligomeric silsesquioxane (POSS) to produce monoalkyne-POSS in three steps and the click coupling occurred between the azido-terminated polystyrenes and alkyne-POSS to afford mono-, di-, and pentafunctional POSS-containing hybrid polystyrenes as star-shaped telechelic POSS-containing hybrid polymers. Wu et al.38 have prepared alkyne-functionalized-POSS in three steps from allyl-heptaisobutyl substituted-POSS and the product was linked to an azido-functionalized elastomer of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEB-CH 2 N 3 ) via a click coupling reaction to form a novel hybrid copolymer. These approaches focused mostly on the preparation of a hybrid copolymer based on mono-alkyne-heptaisobutyl and azido polystyrene. However, the preparation of octa-alkyne-terminated POSS and their click coupling reactions with azido-biomolecules to produce hybrid biomaterials has not been investigated yet. We believe that this approach will open a wide range of biomedical applications that were not accessible in the past.Herein we report a novel synthetic approach to hybrid biomaterials based on octa-alkyne-terminated POSS and their reaction with (i) azido-N-Fmoc-L-norleucine and (ii) 3 0 -azido-3 0 -deoxythymidine, using the CuAAC reaction. Our approach Fig. 1 Octa(3-azidopropyl)POSS.

Two Complementary Approaches to Silicon-Supported Soluble [FeFe]-Hydrogenase Mimics

“…Once the efficiency of the CuACC to prepare diverse silicon-supported [FeFe]-H 2 -ase mimics was demonstrated, we tested our procedure with alkyne-POSS derivative 23a . Octamethylsilsesquioxanes are nanosized stable tridimensional structures having alternate Si–O bond forming cage structures with Si atoms in the vertices .…”

Dendritic hybrid materials comprising polyhedral oligomeric silsesquioxane (POSS) and hyperbranched polyglycerol for effective antifungal drug delivery and therapy in systemic candidiasis

“…Next, the resulting dendrons were reacted with POSS core through a click chemistry reaction to successfully prepare novel hybrid dendritic nanostructures (POSS-HPG@Chol). [19][20][21] For the click reaction, POSS-alkyne and azide-functionalized HPG@Chol dendritic nanostructures were prepared separately and combined under mild reaction condition. The molecular weight and chemical structures of POSS-HPG@Chol dendritic nanostructures were characterized and confirmed by size exclusion chromatography (SEC) and spectroscopic analyses (FTIR and NMR).…”

Synthesis of polyhedral oligomeric silsesquioxane nano‐crosslinked poly(ethylene glycol)‐based hybrid hydrogels for drug delivery and antibacterial activity

“…Due to their unique properties such as high affinity for water, biocompatibility and tissue‐like properties, hydrogels are used widely in biomedical applications for soft tissue regeneration and drug delivery . In the last decade, polyhedral oligomeric silsesquioxanes (POSS), due to their biocompatibility, high structural stability and ease of surface functionalization, have been used to synthesize a broad range of organic–inorganic hybrid hydrogels using a variety of organic functional groups . POSS nanoparticles with a symmetric cubic cage‐like nanostructure can be incorporated in the structure of hydrogels via chemical and physical crosslinking.…”

“…[4][5][6] In the last decade, polyhedral oligomeric silsesquioxanes (POSS), due to their biocompatibility, high structural stability and ease of surface functionalization, have been used to synthesize a broad range of organic-inorganic hybrid hydrogels using a variety of organic functional groups. [7][8][9][10][11][12][13] POSS nanoparticles with a symmetric cubic cage-like nanostructure can be incorporated in the structure of hydrogels via chemical and physical crosslinking. For example, Zhang and co-workers 14 synthesized thermo-responsive hybrid poly(N-isopropylacrylamide) hydrogels by -ray irradiation with octamethacrylate POSS as a crosslinking agent, and investigated their swelling/deswelling properties.…”