Amino Acid Derived Nickelacycles:  Intermediates in Nickel-Mediated Polypeptide Synthesis

Deming, Timothy J.

doi:10.1021/ja980313i

Cited by 114 publications

(97 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The block copolypeptide synthesis was performed using the zero valent nickel initiator 2,2′-bipyridyl-Ni(1,5-cyclooctadiene) (BpyNi-COD) [32] to polymerize N e -Z-L-lysine (Z-Lys), Glycine (Gly), and/ or L-Alanine (Ala) NCAs [33] using the procedure developed by Deming [34][35][36]. The details are provided in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Jan

Shantz

2007

Advanced Materials

View full text Add to dashboard Cite

Developing new technologies as a consequence of controlling structure, chemistry, and functionality at the nanometer length scale is the ultimate goal of nanotechnology. One route to this goal is to draw lessons from nature, which has developed the ability to fabricate inorganic and inorganic-hybrid materials such as silica diatoms and nacre that have properties that the materials science community can only aspire to achieve. [1][2][3][4][5][6][7] The development of so-called biomimetic or bioinspired synthesis methods to develop hard matter with new or unusual properties has become an area of tremendous growth. One aspect of this problem is the synthesis of silica materials using amines or polyamines under ambient conditions. Numerous works have demonstrated materials with unusual properties, particularly with respect to morphology and microstructure. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Of particular relevance to the current work are the numerous reports of silicas made in the presence of poly-L-lysine. From this body of literature it is clear that one can make silicas with various morphologies through manipulation of pH, salt, flow versus quiescent conditions, etc. Further, recent works from several labs have shown the poly-L-lysine chain conformation can be used to control silica morphology. [25,26] It is this point in particular that is explored in the current investigation. Our lab has made two contributions to this blossoming area. First, we have demonstrated that the conformation of polypeptide chains can be used to manipulate the porosity of the oxide obtained. [27,28] Second, we have shown that individual supramolecular objects (vesicles) formed by block copolypeptides can be used as templates to form nanostructured hard materials. [29] In the latter case the block copolypeptides studied were Lys-b-Phe block copolypeptides that form kinetically trapped structures in solution. Here we report the formation of silicas in the presence of a series of block copolypeptides, but mainly Lys-b-Gly block copolypeptides which appear to form more reversible structures as compared to the materials we reported previously. This manuscript reports on how the polypeptide chemistry and solution conditions influence both the morphology and porosity of the hard material they assemble. This latter point has been sparingly studied, yet for many applications this property will be essential. In all cases the block copolypeptides investigated here form supramolecular structures in solution, typically vesicles. However, the Lys-b-Gly block copolypeptides form structures that appear to be more reversible in nature as compared to the objects formed by the Lys-b-Ala and Lys-b-Phe block copolypeptides that appear to be kinetically trapped structures. The critical aggregation concentrations for the polymers studied below are given in the supporting information and are between 0.8-1.7 lM. The syntheses described below use between 3.0-4.0 lM solutions (Methods II, III) or 9.0-10.0 lM solutions (Method I), a...

show abstract

Section: Methodsmentioning

confidence: 99%

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Jan

Shantz

2007

Advanced Materials

View full text Add to dashboard Cite

show abstract

“…The polymerizations initiated by HMDS and N-TMS amines usually complete within 24 h at ambient temperature with quantitative monomer consumption. These polymerizations in general are slower than those mediated by Deming's Ni(0) or Co (0) initiators (about 30-60 min at ambient temperature) [19,24,25], but are much faster than those initiated by amines at low temperature or using amine hydrochloride initiators [20]. These HMDS and N-TMS amine-mediated NCA polymerizations can also be applied to the preparation of block copolypeptides of defined sequence and composition [22].…”

Section: Nmr and Mass Spectroscopy (Ms) Analysis Of An Equimolarmentioning

confidence: 99%

“…Mechanistic studies on the initiation process showed that both these metals react identically with NCA monomers to form metallacyclic complexes by oxidative addition across the anhydride bonds of NCAs [19,24,25]. These oxidative-addition reactions were followed by addition of a second NCA monomer to yield complexes identified as six-membered amido-alkyl metallacycles (Scheme 4).…”

Section: Transition Metal Initiatorsmentioning

confidence: 99%

Synthesis of Polypeptides by Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydrides

Cheng

Deming

2011

Topics in Current Chemistry

Self Cite

135

111

View full text Add to dashboard Cite

This chapter summarizes methods for the synthesis of polypeptides by ring-opening polymerization. Traditional and recently improved methods used to polymerize α-amino acid N-carboxyanhydrides (NCAs) for the synthesis of homopolypeptides are described. Use of these methods and strategies for the preparation of block copolypeptides and side-chain-functionalized polypeptides are also presented, as well as an analysis of the synthetic scope of different approaches. Finally, issues relating to obtaining highly functional polypeptides in pure form are detailed.

show abstract

“…Schematische Darstellung der Sekundärstrukturen, die bei einer durch primäre Amine initiierten Polymerisation von l-Ala-NCA entstehen: [68] a) niedriger Umsatz (die wurmartigen Moleküle repräsentieren lösliche Oligomere mit P n < 10), b) mittlerer Umsatz, c) hoher Umsatz. [88][89][90] Dieser Polymerisationsverlauf hat den Vorteil, manche Nebenreaktionen zu vermeiden, z. B. die in Schema 5 formulierte Abbruchreaktion oder die Reaktion von NH 2 -Gruppen mit DMF (bei der Formamid-Endgruppen entstehen).…”

Section: Neue Metallorganische Initiatorenunclassified

Polypeptide und 100 Jahre Chemie der α‐Aminosäure‐N‐carboxyanhydride

Kricheldorf

2006

Angewandte Chemie

View full text Add to dashboard Cite

Synthese und Polymerisation von α‐Aminosäure‐N‐carboxyanhydriden (NCAs) wurden erstmals im Jahre 1906 von Herrmann Leuchs beschrieben. Seit dieser Zeit wurden diese cyclischen, sehr reaktiven α‐Aminosäurederivate mehrfach zur schrittweisen Peptidsynthese eingesetzt, sie wurden aber vor allem zur Herstellung von Polypeptiden durch ringöffnende Polymerisation (ROP) verwendet. Es werden nun neue Aspekte der ringöffnenden Polymerisation diskutiert, z. B. die Verwendung neuartiger metallorganischer Initiatoren oder die Entstehung cyclischer Polypeptide. Des Weiteren werden Architekturen wie Diblock‐, Triblock‐ und Multiblockcopolymere sowie sternförmige oder hochverzweigte Polypeptide vorgestellt. Ferner werden lyotrope und thermotrope Polypeptide sowie die Verwendung von Polypeptiden als Pharmaka oder Pharmakaträger besprochen. Schließlich wird die Rolle von NCAs im Konzept der molekularen Evolution diskutiert.

show abstract

Amino Acid Derived Nickelacycles: Intermediates in Nickel-Mediated Polypeptide Synthesis

Cited by 114 publications

References 8 publications

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Synthesis of Polypeptides by Ring-Opening Polymerization of α-Amino Acid N-Carboxyanhydrides

Polypeptide und 100 Jahre Chemie der α‐Aminosäure‐N‐carboxyanhydride

Contact Info

Product

Resources

About