Synthesis of high-molecular-weight poly(ε-caprolactone) catalyzed by highly active bis(amidinate) tin(<scp>ii</scp>) complexes

Phomphrai, Khamphee; Pongchan-o, Chatyapha; Thumrongpatanaraks, Wipavee; Sangtrirutnugul, Preeyanuch; Kongsaeree, Palangpon; Pohmakotr, Manat

doi:10.1039/c0dt01050b

Cited by 36 publications

(42 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The substantial distortion of pseudoaxial vector away from linearity is caused by the restricted bite angle of the ligands, typical of other amidinate and guanidinate compounds. The geometry about the Sn(II) centre in 10 is more accurately described as pseudo square based pyramidal despite the Sn-N bond lengths and bite angles in 10 being comparable to related 2,6-disopropylphenyl-substituted amidinate 27,28 and formamidinate 29 complexes in which the geometries are defined as distorted trigonal bipyramid.…”

Section: Resultsmentioning

confidence: 96%

Tin guanidinato complexes: oxidative control of Sn, SnS, SnSe and SnTe thin film deposition

et al. 2018

View full text Add to dashboard Cite

A family of tin(ii) guanidinate complexes of the general form [{RNC(NMe2)NR}2Sn] (R = iPr (6), Cy (7), Tol (9) and Dipp (10)) and [{tBuNC(NMe2)NtBu}Sn{NMe2}] (8) have been synthesised and isolated from the reaction of tin(ii) bis-dimethylamide and a series of carbodiimides (1-5). The cyclic poly-chalcogenide compounds [{CyNC(NMe2)NCy}2Sn{Chx}] (Ch = S, x = 4 (11); Ch = Se, x = 4 (12), and Ch = S, x = 6 (13)) with {SnChx} rings were prepared by the oxidative addition of elemental sulfur and selenium to the heteroleptic stannylene complex [{CyNC(NMe2)NCy}2Sn] (7) in THF at room temperature. Similarly, reaction of compounds 6 and 7 with an equimolar amount of the chalcogen transfer reagents (SC3H6 and Se[double bond, length as m-dash]PEt3, respectively) led to the formation of the chalcogenide tin(iv) complexes [{RNC(NMe2)NR}Sn(Ch)] (R = Cy: Ch = S (14); R = iPr, Ch = Se (15); R = Cy, Ch = Se (16)) with terminal Sn[double bond, length as m-dash]Ch (14 and 16) and dimeric bridged seleno-tin {Sn2Se2} rings (15), respectively. The mono telluro-compounds [{RNC(NMe2)NR}Sn(Te)] (R = iPr (17); R = Cy (18)) were similarly prepared by the oxidative addition of elemental tellurium to 7 and 8, respectively. All of the tin containing compounds have been investigated by multinuclear NMR (1H, 13C 119Sn and 77Se/125Te, where possible), elemental analysis and single crystal X-ray structural analysis (7, 8, 10-13, 15-18). Thermogravimetric analysis (TGA) was used to probe the possible utility of complexes 6-8, 11-12 and 14-18 as single source Sn and SnCh precursors. The Sn(ii) compounds 6 and 7 have been utilised in the growth of thin films by aerosol-assisted chemical vapor deposition (AACVD) at both 300 and 400 °C. The thin films have been analysed by pXRD, EDS, SEM and AFM and shown to be Sn metal. Subsequent studies provided film growth at temperatures as low as 200 °C. Similarly, the mono-chalcogenide systems 14, 16 and 18 have been utilised in the AACVD of thin films. These latter studies provided films, grown at 300 and 400 °C, which have also been analysed by pXRD, Raman spectroscopy, AFM, and SEM and are shown to comprise phase pure SnS, SnSe and SnTe, respectively. These preliminary results demonstrate the potential of such simple guanidinate complexes to act as single source precursors with a high degree of oxidative control over the deposited thin films.

show abstract

Section: Resultsmentioning

confidence: 96%

Tin guanidinato complexes: oxidative control of Sn, SnS, SnSe and SnTe thin film deposition

et al. 2018

View full text Add to dashboard Cite

show abstract

“…However, the drawbacks include low polymerization activity and undesirable inter-and intramolecular transesterification reactions. Numerous researchers [22,[34][35][36][37][38][39][40] have attempted to synthesize Sn complexes to overcome these issues; however, they have encountered difficulties resulting from the sensitivity to air requiring that they be prepared under N 2 , making them difficult to manufacture or research without the glove box and vacuum lines.…”

Section: Introductionmentioning

confidence: 99%

Improving the ring-opening polymerization of ε-caprolactone and l-lactide using stannous octanoate

et al. 2012

View full text Add to dashboard Cite

A series of ligands were tested to meliorate the catalytic activity of e-caprolactone (CL) and L-lactide (LA) polymerization by Sn(Oct) 2 and BnOH. There are seven ligands (methyl 2-(dibenzylamino)acetate (MDBAA), di(1H-pyrazol-1-yl)methane, benzanide, 8-aminoquinoline, 2-bromo-1-phenylethanone, 2,6-di-tert-butyl-4-methylphenol, and dipyridine) were found to be useful in increasing the polymerization rate for CL polymerization. For LA polymerization, there are only two ligands (8-aminoquinoline and p-thiocresol) effectively raised the polymerization rate. Moreover, the kinetic study reveals a first-order dependency on [CL] and second-order dependency on [LA], indicating different polymerization mechanisms in Sn(Oct) 2 catalytic system. The mechanistic study also explains that MDBAA could potentially modify the framework of the catalytic intermediate and produce the hydrogen, thereby increasing the rate of CL polymerization.

show abstract

“…The exposed lone‐pair electrons on the tin centers, as presumed from their structures from the X‐ray crystallography, are expected to behave similarly to NHCs in ROP of lactones. From our previous reports, polymerizations of lactide in the absence and presence of benzyl alcohol (BnOH) gave cyclic and linear PLA, respectively. Thus, complex 2a was tested in the polymerizations of l ‐LA at low l ‐LA: 2a molar ratio of 20:1 at 120 °C for 10 min in a solvent‐free polymerization condition both with and without the addition of benzyl alcohol.…”

Section: Resultsmentioning

confidence: 99%

“…Being isoelectronic to carbene, stannylene, tin(II) complexes have been shown to catalyze lactone polymerization in a similar fashion. Our group previously reported the bis(salicylaldiminato) and bis(amidinate) tin(II) complexes that catalyzed ROP of LA and CL to cyclic polymers, respectively . In the presence of benzyl alcohol as initiator, linear structure was obtained.…”

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

Synthesis and characterizations of bis(phenoxy)‐amine tin(II) complexes for ring‐opening polymerization of lactide

Praban

Yimthachote

Kiriratnikom

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

Self Cite

View full text Add to dashboard Cite

A series of tin(II) complexes supported by N 2 O 2 bis(phenol)-amine ligands were prepared from the reactions of the corresponding ligands with Sn[N(SiMe 3 ) 2 ] 2 in benzene at room temperature. The ligands were designed to have different substituted group at the ortho-position on the aryl rings (R = t Bu, CH 3 ) and N-containing side arm (E = CH 2 NEt 2 and pyridine) giving a variation of tin(II) complexes (R = t Bu, E = CH 2 NEt 2 , 2a; R = t Bu, E = py, 2b; R = CH 3 , E = CH 2 NEt 2 , 2c; R = CH 3 , E = py, 2d). All complexes were characterized by NMR spectroscopy and single-crystal X-ray analysis. The single-crystal X-ray crystallography revealed that all complexes have a monomeric four-coordinate tin center with a distorted seesaw structure. All complexes are active for solvent-free polymerization of L-lactide at 120 C giving poly(L-lactide) with narrow to moderate dispersity (Ð = 1.12-1.56). In the presence of benzyl alcohol during the polymerization, the resulting polymer was found to be linear having benzyl alcohol as the end group while, in the absence of benzyl alcohol, the polymer was cyclic. The large t Bu group at the ortho-position was found to decrease polymerization activity while the more basic CH 2 NEt 2 group was found to increase the polymerization activity. The polymerization of rac-lactide under a similar condition gave PLA having a slight heterotactic bias for all catalysts.

show abstract

Synthesis of high-molecular-weight poly(ε-caprolactone) catalyzed by highly active bis(amidinate) tin(ii) complexes

Cited by 36 publications

References 37 publications

Tin guanidinato complexes: oxidative control of Sn, SnS, SnSe and SnTe thin film deposition

Tin guanidinato complexes: oxidative control of Sn, SnS, SnSe and SnTe thin film deposition

Improving the ring-opening polymerization of ε-caprolactone and l-lactide using stannous octanoate

Synthesis and characterizations of bis(phenoxy)‐amine tin(II) complexes for ring‐opening polymerization of lactide

Contact Info

Product

Resources

About