Neutral and Cationic Trimethylsilylmethyl Complexes of Indium

Peckermann, Ilja; Robert, Dominique; Englert, Ulli; Spaniol, Thomas P.; Okuda, Jun

doi:10.1021/om800562z

Cited by 22 publications

(11 citation statements)

References 40 publications

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“…The solution structures of complexes 3 – 6 are consistent with only one diastereomer of the product containing a κ 3 -coordinated ligand. The 1 H NMR spectra of the complexes show significant differences, while the 19 F{ 1 H} NMR spectra are identical to those of reported noncoordinated anions. − …”

Section: Resultssupporting

confidence: 64%

Indium-Catalyzed Block Copolymerization of Lactide and Methyl Methacrylate by Sequential Addition

Jung

Nyamayaro

et al. 2020

ACS Catal.

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We report a metal-mediated sequential addition synthetic route for copolymerization of lactide (or ε-caprolactone) and methyl methacrylate. We synthesized a series of neutral and cationic indium complexes supported by tridentate Schiff base ligands and investigated their reactivities for the homo-and copolymerization of lactide or εcaprolactone and methyl methacrylate. We showed that the neutral indium complex (±)-(NN i O tBu )In(CH 2 SiMe 3 ) 2 (2) catalyzes the sequential block copolymerization of lactide/ε-caprolactone and methyl methacrylate without any additional reagents or synthetic steps. The block copolymers were stringently characterized by size exclusion chromatography (SEC), diffusion ordered NMR spectroscopy (DOSY), differential scanning calorimetry (DSC), and fractional precipitation techniques.

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Section: Resultssupporting

confidence: 64%

Indium-Catalyzed Block Copolymerization of Lactide and Methyl Methacrylate by Sequential Addition

Jung

Nyamayaro

et al. 2020

ACS Catal.

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“…The reaction took place in dry toluene at room temperature with concomitant elimination of 1 equiv of methane (Scheme ). The synthesis of dialkylindium complexes was achieved also by protonolysis using two different precursors, namely [InMe 3 ] n generated in situ from InCl 3 and MeLi and the discrete homoleptic precursor In(CH 2 SiMe 3 ) 3 (Scheme ) . The former protonolysis reaction proved selective only toward two proligands, namely {ONN qui }H ( a ) and {ON pipeBn }H ( m ), resulting in the corresponding dimethylindium complexes {ONN qui }InMe 2 ( 2a ) and {ON pipeBn }InMe 2 ( 2m ), isolated in 47% and 77% yields, respectively.…”

Section: Resultsmentioning

confidence: 99%

{Phenoxy-imine}aluminum versus -indium Complexes for the Immortal ROP of Lactide: Different Stereocontrol, Different Mechanisms

et al. 2013

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International audienceA series of dialkylaluminum and -indium {ONR}MR′2 complexes (M = Al, R′ = Me; M = In, R′ = Me, CH2SiMe3) stabilized by a phenoxy-imine {ONR}− ligand platform, with variable R-imino substituents and functionalized by a bulky o-SiPh3 in the phenoxy moiety, has been prepared and structurally characterized in solution and in the solid state. {ONR}AlMe2 complexes reacted with alcohols, in particular with alkyl (S)-H-lactate, to generate the corresponding {ONR}Al(OR)2 compounds. On the other hand, the indium complexes {ONR}InR′2 proved largely inert toward alcohols. When they were combined with an alcohol (iPrOH, BnOH), the {ONR}AlMe2 complexes promoted the living (immortal) ring-opening polymerization ((i)ROP) of racemic lactide (rac-LA) with a good control over the molecular weights and various microstructures, dependent on the R-imino substituent. Complexes having benzyl-type imino substituents enabled the achievement of significant isotacticity (Pm up to 0.80), following grossly the bulkiness of the aryl moiety. The analogous {ONR}InR′2 proved similarly active for the (i)ROP of rac-LA in presence of an external alcohol, but the polymerizations were less controlled and none of the complexes induced stereoselectivity, except one (3a,Pm = 0.70). Kinetic studies revealed different rate laws, with an apparent zero-order dependence on monomer for the aluminum system 1m/iPrOH and a first-order dependence on monomer for the analogous indium system 3m/iPrOH. On the basis of the stoichiometric reactivity of model compounds, two different operative ROP mechanisms are suggested, depending on the nature of the metal center: Al-based complexes proceed through coordination-insertion, while In-based complexes are proposed to operate through an activated monomer mechanism

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“… 95 , 102 Protonolysis of the neutral In(CH 2 SiMe 3 ) 3 complex in THF therefore yields a penta-coordinated indium cation: [In(CH 2 SiMe 3 ) 2 (THF) 3 ] + . 191 Moreover, In + [OTf] – 192 , 193 and [In(arene) n ] + 168 ( n = 2, 3) can be reacted with the crown ether [18]crown-6, yielding cationic indium complexes with similar structures to the gallium congener ( cf. Fig.…”

Section: Reactive P-block Cationsmentioning

confidence: 99%