The synthesis and polymerization behaviour of silicon-bridged [1]- and [2]ferrocenophanes with sterically demanding trimethylsilyl substituents attached to the cyclopentadienyl rings

1995 ◽  
Vol 73 (11) ◽  
pp. 2069-2078 ◽  
Author(s):  
Timothy J. Peckham ◽  
Daniel A. Foucher ◽  
Alan J. Lough ◽  
Ian Manners
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Monoclinic Space Group ◽  
Organometallic Polymers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
Sterically Demanding ◽  
High Molecular Weight Poly

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.

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

2016 ◽  
Vol 71 (8) ◽  
pp. 843-848 ◽  
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.

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

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.

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

2002 ◽  
Vol 80 (11) ◽  
pp. 1469-1480 ◽  
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, UV–vis, IR, Raman, and multinuclear NMR spectroscopy, as well as single crystal X-ray diffraction. Thermogravimetric analysis and differential scanning calorimetry investigation of 6–9 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.

scholarly journals 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

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.

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

2013 ◽  
Vol 275-277 ◽  
pp. 1742-1745 ◽  
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.

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

2019 ◽  
Vol 60 (3) ◽  
pp. 272-275 ◽  
Author(s):  
Olga Schäfer ◽  
Dieter Schollmeyer ◽  
Alexander Birke ◽  
Regina Holm ◽  
Kerstin Johann ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
X Ray Diffraction ◽  
X Ray

Chemical synthesis of novel biodegradable polyesters

1995 ◽  
Vol 41 (13) ◽  
pp. 282-288 ◽  
Author(s):  
Y. Hori ◽  
Y. Takahashi ◽  
A. Yamaguchi ◽  
T. Hagiwara
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Lactone Ring ◽  
Ring Opening Polymerization ◽  
Optically Active ◽  
Bond Breaking ◽  
Carbonyl Carbon ◽  
Biodegradable Polyesters ◽  
Molecular Weights ◽  
High Molecular Weight Poly

Distannoxane complexes catalyze the ring-opening polymerization of optically active β-butyrolactone (β-BL) to afford a high molecular weight poly(3-hydroxybutyrate). When 1-ethoxy-3-chlorotetrabutyldistannoxane was used as a catalyst (catalyst/(R)-β-BL = 1/8000 at 100 °C for 4 h), poly((R)-3-hydroxybutyrate) was obtained from (R)-β-BL in a yield of 99%. The copolymerizations of (R)-β-BL with racemic β-BL in several ratios gave corresponding stereocopolymers. The copolymerizations of (R)-β-BL with ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone, and L-lactide afforded novel optically active and biodegradable polyesters of high molecular weights, comprising (R)-3-hydroxybutyrate (3HB). The polymerization of (R)-β-BL catalyzed by the distannoxane complexes proceeded by bond breaking between the carbonyl carbon and oxygen atom of the lactone ring (acyl cleavage) with retention of the configuration and little or no racemization. Polymers that have over 80 mol% of the (R)-3HB unit were found to have almost the same degree of biodegradability as the copolyester of 3-hydroxybutyrate and 11% 3-hydroxyvalerate produced by the microbial method.Key words: distannoxane, ring-opening polymerization, poly(3-hydroxybutyrate), poly(3-hydroxyalkanoates), biodegradable polymer.

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