Investigation of α-amino acid N-carboxyanhydrides by X-ray diffraction for controlled ring-opening polymerization

The silicon-bridged [1]ferrocenophane Fe(η-C5H3SiMe3)2(SiMe2) (5) was synthesized via the reaction of Li2[Fe(η-C5H3SiMe3)2]•tmeda (tmeda = tetramethylethylenediamine) with Me2SiCl2 in hexanes. The disilane-bridged [2]ferrocenophane Fe(η-C5H3SiMe3)2(Si2Me4) (7) was prepared using a similar route from the disilane ClMe2SiSiMe2Cl. Despite the presence of sterically demanding SiMe3 substituents on the cyclopentadienyl rings, compound 5 was found to undergo thermal ring-opening polymerization at 170 °C to produce very soluble, high molecular weight poly(ferrocenylsilane) 6 with Mw = 1.4 × 105, Mn = 8.4 × 104. However, the [2]ferrocenophane 7 was found to be resistant to thermal ring-opening polymerization even at 350 °C and decomposed above 380 °C. A single-crystal X-ray diffraction study of 7 revealed that the steric interactions between the bulky SiMe3 groups are relieved by a significant twisting of the disilane bridge with respect to the plane defined by the centroids of the cyclopentadienyl ligands and the metal atom. The angle between the planes of the cyclopentadienyl rings in 7 was found to be 5.4(6)°, slightly greater than that in the non-silylated analogue Fe(η-C5H4)2(Si2Me4) (4a) (4.19(2)°), and dramatically less than the corresponding tilt angle of the strained, polymerizable, silicon-bridged [1]ferrocenophane Fe(η-C5H4)2(SiMe2) (1) (20.8(5)°). The length of the Si—Si bond in 7 (2.342(3) Å) was found to be close to the sum of the covalent radii (2.34 Å). Crystals of 7 are monoclinic, space group C2/c, with a = 23.689(3) Å, b = 11.174(1) Å, c = 31.027(3) Å, β = 109.16(1)°, V = 7758(2) Å3, and Z = 12. Keywords: ring-opening polymerization, ferrocenophane, organometallic polymers.

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Synthesis, Characterization and Optical Properties of PLA / P3HT Blends Thin Films

NeuroQuantology ◽

10.14704/nq.2021.19.5.nq21057 ◽

2021 ◽

Vol 19 (5) ◽

pp. 132-138

Author(s):

Maan Abd-Alameer Salih ◽

Q.S. Kareem ◽

Mohammed Hadi Shinen

Keyword(s):

Thin Films ◽

Optical Properties ◽

Spin Coating ◽

Ring Opening ◽

Energy Gap ◽

Ring Opening Polymerization ◽

X Ray Diffraction ◽

X Ray ◽

Conductivity Increase ◽

Ft Ir

In this exploration Poly lactic corrosive (PLA) was orchestrated the ring-opening polymerization Poly lactic corrosive (PLA) blended with poly(3-hexylthiophene) (P3HT) which prepared by solution. Blends thin films Synthesis by spin coating technique and using Tetrahydrofuran (THF) as solvent. PLA powder was 'characterized by' 'X-ray' 'diffraction', '(FT-IR)'. pure Optical properties (PLA), (PLA)/P3HT blends thin films with different percentage of P3HT (0, 1, 2, and 3) wt% were investigated using UV-VS spectroscopy The results showed that the absorption, absorption coefficient, extinction coefficient and conductivity increase with increasing the rate of deformation P3HT, The energy gap decreases with increasing deformation.

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Synthesis, characterization, and structures of zircona- and boracyclosiloxanes with ferrocenyl substituents

Canadian Journal of Chemistry ◽

10.1139/v02-129 ◽

2002 ◽

Vol 80 (11) ◽

pp. 1469-1480 ◽

Cited By ~ 6

Author(s):

Karena Thieme ◽

Sara C Bourke ◽

Juan Zheng ◽

Mark J MacLachlan ◽

Fojan Zamanian ◽

...

Keyword(s):

Mass Spectrometry ◽

Differential Scanning Calorimetry ◽

Thermogravimetric Analysis ◽

Ring Opening ◽

Ring Opening Polymerization ◽

The Novel ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Multinuclear Nmr Spectroscopy

The novel zirconatetraferrocenylcyclotrisiloxane Cp2Zr(OSiFc2)2O (6), dizirconatetraferrocenylcyclotetrasiloxane [Cp2Zr(OSiFc2)O]2 (7), boratetraferrocenylcyclotrisiloxane (C6H5)B(OSiFc2)2O (8), and diboratetraferrocenylcyclotetrasiloxane [(C6H5)B(OSiFc2)O]2 (9) with ferrocenyl (Fc = Fe(η-C5H4)(η-C5H5)) substituents at silicon have been prepared from the reactions of Cp2Zr(NMe2)2 and PhBCl2 with diferrocenylsilanediol Fc2Si(OH)2 (3) and tetraferrocenyldisiloxanediol [Fc2SiOH]2O (5). The compounds were characterized by mass spectrometry, elemental analysis, UVvis, IR, Raman, and multinuclear NMR spectroscopy, as well as single crystal X-ray diffraction. Thermogravimetric analysis and differential scanning calorimetry investigation of 69 showed that the cycles decompose before they can undergo any thermal ring-opening polymerization. In addition, no polymerization was detected in the presence of either KOSiMe3 or HOTf. The bulky ferrocenyl substituents on the Si atoms are likely to be at least partially responsible for the inability of these heterocycles to undergo ring-opening polymerization. Key words: heterocyclosiloxanes, ferrocenyl.

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Synthesis of functionalized pyrazole derivatives by regioselective [3+2] cycloadditions of N-Boc-α-amino acid-derived ynones

Zeitschrift für Naturforschung B ◽

10.1515/znb-2018-0013 ◽

2018 ◽

Vol 73 (7) ◽

pp. 467-480 ◽

Cited By ~ 1

Author(s):

Eva Pušavec Kirar ◽

Uroš Grošelj ◽

Amalija Golobič ◽

Franc Požgan ◽

Sebastijan Ričko ◽

...

Keyword(s):

Amino Acids ◽

Nuclear Magnetic Resonance ◽

Amino Acid ◽

Ring Opening ◽

Pyrazole Derivatives ◽

X Ray Diffraction ◽

X Ray ◽

Acid Catalyzed ◽

Azomethine Imines

Abstract [3+2] cycloadditions of ynones derived from glycine and (S)-alanine and some other dipolarophiles with azomethine imines, nitrile oxides, diazoacetate, and azidoacetate were studied. The dipolarophiles were obtained from α-amino acids, either by the reduction of the carboxy function with ethynylmagnesium bromide or by propiolation of the amino function. Cu-catalyzed cycloadditions of ynones to azomethine imines were regioselective and gave the expected cycloadducts as inseparable mixtures of diastereomers. In some instances, further oxidative hydrolytic ring-opening took place to afford 3,3-dimethyl-3-(1H-pyrazol-1-yl)propanoic acids. Acid-catalyzed cycloadditions of 3-butenone were also regioselective and provided mixtures of diastereomeric cycloadducts, which were separated by chromatography. In the reactions of title ynones with alkyl diazoacetates, in situ-formed benzonitrile oxides, and tert-butyl azidoacetate, all cycloadducts were obtained as single regioisomers. The structures of all novel compounds were established by nuclear magnetic resonance and X-ray diffraction.

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Yttrium and Lithium Keto-β-Diketiminate Complexes [{2,6-Me2C6H3N=C(Me)}2CС(tert-Bu)=O]2Y(μ2-Cl)2Li(THF)2 and {[{2,6-Me2C6H3N=C(Me)}2CС(tert-Bu)=O]Li(THF)}n. Synthesis, Molecular Structures, and Catalytic Activity in ε-Caprolactone Polymerization

Russian Journal of Coordination Chemistry ◽

10.1134/s107032842102007x ◽

2021 ◽

Vol 47 (2) ◽

pp. 144-154

Author(s):

G. G. Skvortsov ◽

A. V. Cherkasov ◽

D. L. Vorozhtsov ◽

E. S. Shchegravina ◽

A. A. Trifonov

Keyword(s):

Catalytic Activity ◽

Diffraction Analysis ◽

Exchange Reaction ◽

Ring Opening ◽

Crystalline State ◽

Ring Opening Polymerization ◽

Molecular Structures ◽

Molar Ratio ◽

X Ray Diffraction ◽

X Ray

Abstract The reaction of lithium β-diketiminate [{2,6-Me2C6H3N=CMe}2CH]Li with benzophenone in toluene at 25°C affords the coordination complex [{2,6-Me2C6H3N=CMe}2CH]Li(Ph2C=O) (I). New keto-β-diketimine {2,6-Me2C6H3N=C(Me)}2CHC(tert-Bu)=O (II) is synthesized by the reaction of tert-Bu(C=O)Cl with [{2,6-Me2C6H3N=CMe}2CH]Li. The metallation of keto-β-diketimine II with n-butyllithium in THF at 0°C gives lithium keto-β-diketiminate {[{2,6-Me2C6H3N=C(Me)}2CС(tert-Bu)=O]Li(THF)}n (III). The exchange reaction of YCl3 with compound III (molar ratio 1 : 2, THF) affords the yttrium bis(keto-diketiminate) complex [{2,6-Me2C6H3N=C(Me)}2CС(tert-Bu)=O]2Y(μ2-Cl)2L-(THF)2 (IV). The molecular structures of complexes I, III, and IV are determined by X-ray diffraction analysis (CIF files CCDC nos. 2001131 (I), 2001132 (III), and 2001133 (IV)). Complex IV in the crystalline state exists as an ate complex with one LiCl molecule. Complexes I, III, and IV are catalysts of ring-opening polymerization of ε-caprolactone in toluene at 25°С.

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Grafting Polymerization of D,L-Lactide on the Surface of Halloysite Nanotubes

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.275-277.1742 ◽

2013 ◽

Vol 275-277 ◽

pp. 1742-1745 ◽

Cited By ~ 1

Author(s):

Jing Jing Li ◽

Bing Hong Luo ◽

Jin Xi Zhang ◽

Ru Qiu Huo ◽

Chang Ren Zhou

Keyword(s):

Ring Opening ◽

Halloysite Nanotubes ◽

Ring Opening Polymerization ◽

Gravimetric Analysis ◽

Structure And Properties ◽

Thermal Gravimetric ◽

X Ray Diffraction ◽

Potential Measurement ◽

X Ray ◽

Before And After

Halloysite nanotubes (HNTs) surface-grafting poly(D,L-lactide) (g-HNTs) were synthesized by bulk ring-opening polymerization of D,L-lactide using stannous octoate as catalyst and HNTs as co-initiator. Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and zeta potential measurement were employed to elucidate the structure and properties of HNTs before and after grafting with D,L-lactide. FTIR spectrum certified the existence of poly(D,L-lactide) chains on the surface of g-HNTs. The amount of surface-grafted poly(D,L-lactide) measured by TGA was 4.6% in weight. The grafted poly(D,L-lactide) chains on the surfaces of HNTs can relieve the clustering effect of HNTs to some extents.

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Polymers of ε-Caprolactone Using New Copper(II) and Zinc(II) Complexes as Initiators: Synthesis, Characterization and X-Ray Crystal Structures

Polymers ◽

10.3390/polym10111239 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1239 ◽

Cited By ~ 5

Author(s):

Andrés Posada ◽

Mario Macías ◽

Santiago Movilla ◽

Gian Miscione ◽

León Pérez ◽

...

Keyword(s):

Single Crystal ◽

Ring Opening ◽

Ring Opening Polymerization ◽

Nmr Analysis ◽

X Ray Diffraction ◽

X Ray ◽

Molecular Weights ◽

Full Characterization ◽

Solvent Free Conditions

Five of six new Zn(II) and Cu(II) complexes were active in the ring-opening polymerization (ROP) of ε-caprolactone (CL) under solvent-free conditions, producing polycaprolactones (PCLs) of high crystallinity with molecular weights between 22,900 and 38,700 g mol−1 and decomposition temperatures above 260 °C. 1H NMR analysis demonstrated that the PCLs obtained were mainly linear, having hydroxymethylene groups at the chain ends. The results obtained indicated a significant improvement in terms of the ratio of monomer:initiator compared to related Cu(II) and Zn(II) complexes. In addition, the structures of the complexes 1 and 4 were determined by single-crystal X-ray diffraction. The synthesis and full characterization of all complexes are described in this paper.

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Original Macromolecular Architectures Based on poly(ε-caprolactone) and poly(ε-thiocaprolactone) Grafted onto Chitosan Backbone

International Journal of Molecular Sciences ◽

10.3390/ijms19123799 ◽

2018 ◽

Vol 19 (12) ◽

pp. 3799 ◽

Cited By ~ 3

Author(s):

Cüneyt Ünlü ◽

Eric Pollet ◽

Luc Avérous

Keyword(s):

Ring Opening ◽

Ring Opening Polymerization ◽

Hexamethylene Diisocyanate ◽

Proton Nuclear Magnetic Resonance ◽

High Yield ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Molar Ratios ◽

Grafting Onto

Polyester and/or polythioester grafted chitosan copolymers were synthesized. For that, poly(ε-caprolactone) (PCL), poly(ε-thiocaprolactone) (PTCL), and their copolymers were first synthesized by ring opening polymerization. Copolymers with caprolactone:thiocaprolactone (CL:TCL) molar ratios of 2:1, 1:1, 1:2 were synthesized. All of the synthesized macromolecular architectures were characterized using different spectral (Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H-NMR), X-Ray diffraction (XRD)) and thermal (Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA)) methods. Grafting was then performed according two distinct routes: (i) using a blend of both homopolymers (PCL and PTCL) or (ii) using pre-synthesized copolymers with controlled CL:TCL ratios. Hexamethylene diisocyanate was used as a grafting/coupling agent through urethane bonds with high yield. Grafting preferentially occurred at sulfur sites. The results indicated that PTCL is more reactive and favorable than PCL for grafting onto chitosan. With the homopolymers blend grafting route, the corresponding materials mostly had a higher PTCL portion than expected. To obtain polyester grafted chitosan with a determined CL:TCL ratio, the copolymer grafting route would yield better results.

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Synthesis and properties of polyimides from 1,4-bis(4-amino-2-phenylphenoxy) benzene and 4,4′-bis(4-amino-2-phenylphenoxy) biphenyl

High Performance Polymers ◽

10.1177/0954008312453062 ◽

2012 ◽

Vol 24 (8) ◽

pp. 783-792 ◽

Cited By ~ 7

Author(s):

Atsushi Morikawa ◽

Fumi Miyata ◽

Jun Nishimura

Keyword(s):

Ring Opening ◽

Mechanical Analysis ◽

Ring Opening Polymerization ◽

Dielectric Constants ◽

Structure Property ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Structure Property Relationships ◽

Step Procedure

Diamines, namely, 1,4-bis(4-amino-2-phenylphenoxy) benzene (1) and 4,4′-bis(4-amino-2-phenylphenoxy) biphenyl (2), were synthesized from 4-fluoro-3-phenyl nitrobenzene. Two series of polyimides were synthesized from these diamines with nine types of dianhydrides by a conventional two-step procedure that included ring-opening polymerization in N-methyl-2-pyrrolidone and subsequent thermal cyclic dehydration. The polyimides were characterized by x-ray diffraction, differential scanning calorimetry, thermogravimetry and dynamic mechanical analysis. The polyimides from 1 and 2 had a glass transition temperature in the range of 221–254°C and 222–271°C, respectively, and all the polymers were amorphous. The structure–property relationships of these polyimides were examined and compared with those of the previously prepared analogous polyimides from the bis(4-amino-2-biphenyl)ether (3). Water absorption and dielectric constants ( ∊) of the polyimides were compared and discussed on the basis of imide content per repeating unit.

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A tetranuclear Sn(IV) 4-thiazolecarboxylate complex: synthesis, structure and catalytic behavior in the bulk ring-opening polymerization of glycolide

Zeitschrift für Naturforschung B ◽

10.1515/znb-2015-0211 ◽

2016 ◽

Vol 71 (8) ◽

pp. 843-848 ◽

Cited By ~ 1

Author(s):

Jian Gao ◽

Yu Yuan ◽

Ai-Jun Cui ◽

Feng Tian ◽

Ming-Yang He ◽

...

Keyword(s):

Molecular Weight ◽

Single Crystal ◽

Ring Opening ◽

Glycolic Acid ◽

Average Molecular Weight ◽

Ring Opening Polymerization ◽

Number Average Molecular Weight ◽

X Ray Diffraction ◽

Catalytic Behavior ◽

X Ray

AbstractThe reaction of 4-thiazolecarboxylic acid (Htzc) and dimethyltin(IV) dichloride with NaOH in mixed MeOH-H2O solvent led to the formation of a new Sn(IV) complex (Me2Sn)4(μ3-O)2(tzc)4 (1). Its structure has been characterized by elemental analysis, IR spectroscopy and single crystal and powder X-ray diffraction. Single-crystal X-ray diffraction revealed that complex 1 crystallizes in the monoclinic P21/c space group with Z = 2 and has a tetranuclear structure with crystallographically imposed centrosymmetry. The as-synthesized complex 1 was found to be active toward the bulk solvent-free polymerization of glycolide, producing poly(glycolic acid) with a number-average molecular weight up to 55.5 kDa.

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