Searching
for more sustainable materials as an alternative to petroleum-based
products is of increasing interest due to different environmental
issues. Cellulose and fatty acids are two very promising candidates
for biobased material design. Herein, we report a sustainable synthesis
of fatty acid cellulose esters (FACEs) via transesterification of
cellulose with methyl-10-undecenoate in a CO2-based switchable
solvent system. FACEs with a degree of substitution between 0.70 and
1.97 were synthesized by simple variation of reaction parameters and
characterized in detail. Subsequently, a FACE with a degree of substitution
(DS) of 0.70 was modified via thiol-ene reaction, demonstrating an
efficient and versatile method to tune the structure and properties
of the new cellulose derivatives. Films were produced from each sample
via solvent casting, and their mechanical properties were examined
using tensile tests. Elastic moduli (E) ranging from
90 to 635 MPa and elongations at break between 2 and 23% were observed,
depending on the DS of the FACE and the type of thiol employed for
the modification. Finally, contact angle measurements confirmed an
increase in the surface hydrophobicity (75–91°) for the
thiol-ene-modified samples.
Reduction of [Sm III (COT 1,4-SiiPr3 )(BH 4 )(thf)] (COT 1,4-SiiPr3 = 1,4-( i Pr 3 Si) 3 C 8 H 6 ) with KC 8 resulted in [Sm III/II/III (COT 1,4-SiiPr3 ) 4 ], the first example of a homoleptic lanthanide quadruple-decker. As indicated by an analysis of the bond metrics in the solid-state, the inner Sm ion is present in the divalent oxidation state, while the outer ones are trivalent. This observation could be confirmed by quantum chemical calculations. Mechanistic studies revealed not only insight into possible formation pathways of [Sm III/II/III (COT 1,4-SiiPr3 ) 4 ] but also resulted in the transformation to other mixed metal sandwich complexes with unique structural properties. These are the 1D-polymeric chain structured [KSm III (COT 1,4-SiiPr3 )] n and the hexametallic species [(tol)K(COT 1,4-SiiPr3 )Sm II (COT 1,4-
SiiPr3)K] 2 which were initially envisioned as possible building blocks as part of different retrosynthetically guided pathways that we developed.
Reduction of [Sm III (COT 1,4-SiiPr3 )(BH 4 )(thf)] (COT 1,4-SiiPr3 = 1,4-( i Pr 3 Si) 3 C 8 H 6 ) with KC 8 resulted in [Sm III/II/III (COT 1,4-SiiPr3 ) 4 ], the first example of a homoleptic lanthanide quadruple-decker. As indicated by an analysis of the bond metrics in the solid-state, the inner Sm ion is present in the divalent oxidation state, while the outer ones are trivalent. This observation could be confirmed by quantum chemical calculations. Mechanistic studies revealed not only insight into possible formation pathways of [Sm III/II/III (COT 1,4-SiiPr3 ) 4 ] but also resulted in the transformation to other mixed metal sandwich complexes with unique structural properties. These are the 1D-polymeric chain structured [KSm III (COT 1,4-SiiPr3 )] n and the hexametallic species [(tol)K(COT 1,4-SiiPr3 )Sm II (COT 1,4-
SiiPr3)K] 2 which were initially envisioned as possible building blocks as part of different retrosynthetically guided pathways that we developed.
The base free carbazolyl bromosilylene RSiBr (R = 1,8-bis(3,5-di-tert-butyl-phenyl)-3,6-di-tert-butyl-carbazolyl) reacts with (η2 C2H4)Pt(PPh3)2 and Pt(PCy3)2 to form platinasilacyclobutane R(Br)Si(C2H4)Pt(PPh3)2 (1) and silylene platinum complex R(Br)SiPt(PCy3)2 (2), respectively. When silylene complex...
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