The Monomerization of a Binuclear Molybdenum(VI) Dioxo Complex by an Unusual Silylation Reaction

Ma, Xiaoli; Yang, Zhi; Schulzke, Carola; Ringe, Arne; Magull, Jörg

doi:10.1002/zaac.200700125

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…two oxygen atoms at 1.870(15) Å, which were assigned to “surface siloxide ligands”. These bond lengths for the MoO and Mo–O bonds are in the range of those observed for bis-oxo siloxy Mo molecular complexes (Table S1 in the Supporting Information). − Similar parameters were obtained when fitting the k 2 ·χ( k ) spectrum. The fit could be improved by adding a layer of further backscatterers with approximately one oxygen and two silicon atoms at 2.39(4) and 3.27(5) Å, respectively, due to a surface oxygen atom from a siloxane bridge of the silica support and the silicon atoms of the surface siloxide ligands.…”

Section: Resultssupporting

confidence: 66%

Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)₂Mo(═O)₂

et al. 2018

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The catalytic oxidation of cis-2-butene and propylene with molecular oxygen in the presence of a well-defined surface coordination compound, (SiO)2Mo(O)2, affords acetaldehyde. Using a cis-2-butene/O2 feed at 350–400 °C, the reaction yields a conversion of approximately 10% and an acetaldehyde selectivity of approximately 70%. This performance is maintained up to an experimental time of 20 h in a continuous flow reactor. The Mo(bis-oxo) surface compound was fully characterized by multiple spectroscopic techniques as well as surface microanalysis. The results from quantum mechanics calculations indicate that the reaction proceeds via [2 + 2] cycloaddition/cycloelimination steps with the formation of metalla-oxacyclobutane intermediates, analogous to the Chauvin mechanism in olefin metathesis.

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Section: Resultssupporting

confidence: 66%

Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)₂Mo(═O)₂

et al. 2018

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“…To further support our proposed mechanism, we note that oxo silylation is a well-established transformation. − Moreover, HN(SiMe 3 ) 2 is well known to act as a [SiMe 3 ] + source. − With that said, unactivated uranyl is not known to undergo silylation with such a weakly electrophilic silyl source, suggesting that the coordination of the tripodal silsesquioxane ligand to the uranyl ion activates the uranyl ion toward oxo silylation. This activation may be a consequence of some O yl –U–O yl bending upon ligation of the silsesquioxane, which increases the O yl nucleophilicity. − In this regard, the reaction of the tripodal TREN ligand, [Li] 3 [N(CH 2 CH 2 NR) 3 ] (R = Si t BuMe 2 ), with uranyl resulted in the isolation of an oxo substitution product, [{UO(μ-NCH 2 CH 2 N(CH 2 CH 2 NR) 2 )} 2 ] − , which was hypothesized to form via a reactive cis -uranyl intermediate .…”

Section: Resultsmentioning

confidence: 57%

Uranyl Oxo Silylation Promoted by Silsesquioxane Coordination

Assefa

Hayton

2020

J. Am. Chem. Soc.

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The reaction of [UO2(N(SiMe3)2)2(THF)2] with 1 equiv of Cy7Si7O9(OH)3 in THF affords [U(OSiMe3)3(Cy7Si7O12)] (1) as orange plates in 24% isolated yield. Its X-ray crystal structure reveals three silylated Oyl ligands, confirming the unprecedented conversion of the uranyl ion to a U(VI) silyloxide. We propose that the formation of 1 proceeds through a transient uranyl silsesquioxide intermediate, [{Cy7Si7O11(OH)}UO2], which undergoes rapid oxo silylation by HN(SiMe3)2, followed by silyloxy ligand scrambling, to form 1 and the U(VI) bis(silsesquioxane) complex, [U(Cy7Si7O12)2] (3), among other products. The formation of 3 was confirmed by its independent synthesis and comparison of its 29Si{1H} NMR spectrum with that of the in situ reaction mixture. In contrast to the reaction in THF, the reaction of [UO2(N(SiMe3)2)2(THF)2] with Cy7Si7O9(OH)3 in hexanes, followed by recrystallization from Et2O/MeCN, results in the formation of the uranyl cluster, [(UO2)3(Cy7Si7O12)2(Et2O)(MeCN)2] (2), as yellow rods in 42% isolated yield. Complex 2 features two Oyl···U dative interactions, but in contrast to 1, none of its three uranyl fragments are silylated. Overall, the conversion of [UO2(N(SiMe3)2)2(THF)2] to 1 and 3 is likely promoted by the strong electron donor ability of the silsesquioxane ligand and suggests that the actinide coordination chemistry of mineral surface mimics, such as silsesquioxane, is a fruitful arena for the discovery of new reactivity.

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“…The Mo VI –O phenol , Mo VI –O oxo , and Mo VI –S bond lengths span the ranges of 2.102(12)–2.183(13), 1.712(13)–1.782(13), and 2.732(5)-2.744(5) Å, respectively. Although MoSO 5 geometry was observed in some Mo-based compounds, − most previously reported examples have only one or two of five O atoms as the terminal oxo group (Table S1). After the metalation of TC4A 4– using Mo VI , MoO 3 –TC4A possesses more oxo groups, thereby exerting a similar role to an anion template by forming Ag–O bonds.…”

Section: Resultsmentioning

confidence: 99%

Stepwise Assembly of Ag₄₂ Nanocalices Based on a Mo^VI-Anchored Thiacalix[4]arene Metalloligand

Wang

Zhang

et al. 2022

ACS Nano

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Metalloligand strategy has been well recognized in the syntheses of heterometallic coordination polymers; however, such a strategy used in the assembly of silver nanoclusters is not broadly available. Herein, we report the stepwise syntheses of a family of halogen-templated Ag 42 nanoclusters (Ag42c−Ag42f) based on Mo VI -anchored p-tertbutylthiacalix[4]arene (H 4 TC4A) as a metalloligand (hereafter named MoO 3 −TC4A). X-ray crystallography demonstrates that they are similar C 3 -symmetric silver−organic nanocalices capped by six MoO 3 −TC4A metalloligands, which are evenly distributed up and down the base of 42 silver atoms. These nanoclusters can be disassembled to six bowl-shaped [Ag 11 (MoO 3 −TC4A)(RS) 3 ] secondary building units (SBUs, R = Et or n Pr), which are fused together in a face-sharing fashion surrounding Cl − or Br − as a central anion template. The electrospray mass spectrometry (ESI-MS) indicates their high stabilities in solution and verifies the formation of the MoO 3 −TC4A metalloligand, thereby rationalizing the overall stepwise assembly process for them. Moreover, Ag42c shows lower cytotoxicity and better activity against the HepG-2 cell line than MCF-7 and BGC-823. These results not only exemplify the effectiveness of a thiacalix[4]arene-based metalloligand in the assembly of silver nanoclusters but also give us profound insight about the step-by-step assembly process in silver nanoclusters.

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The Monomerization of a Binuclear Molybdenum(VI) Dioxo Complex by an Unusual Silylation Reaction

Abstract: The formation of a mononuclear molybdenum(VI) complex [MoO2{O(CH2)2S(CH2)2OH}(OSiButPh2)] (2) derived from its binuclear precursor [MoO2{O(CH2)2S(CH2)2O}]2 (1) by a silylation reaction accompanied by the conversion of methanol to chloromethane is reported.

Cited by 6 publications

References 17 publications

Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)₂Mo(═O)₂

Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)₂Mo(═O)₂

Uranyl Oxo Silylation Promoted by Silsesquioxane Coordination

Stepwise Assembly of Ag₄₂ Nanocalices Based on a Mo^VI-Anchored Thiacalix[4]arene Metalloligand

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The Monomerization of a Binuclear Molybdenum(VI) Dioxo Complex by an Unusual Silylation Reaction

Abstract: The formation of a mononuclear molybdenum(VI) complex [MoO2{O(CH2)2S(CH2)2OH}(OSiButPh2)] (2) derived from its binuclear precursor [MoO2{O(CH2)2S(CH2)2O}]2 (1) by a silylation reaction accompanied by the conversion of methanol to chloromethane is reported.

Cited by 6 publications

References 17 publications

Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)2Mo(═O)2

Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)2Mo(═O)2

Uranyl Oxo Silylation Promoted by Silsesquioxane Coordination

Stepwise Assembly of Ag42 Nanocalices Based on a MoVI-Anchored Thiacalix[4]arene Metalloligand

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Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)₂Mo(═O)₂

Metathetic Oxidation of 2-Butenes to Acetaldehyde by Molecular Oxygen Using the Single-Site Olefin Metathesis Catalyst (≡SiO)₂Mo(═O)₂

Stepwise Assembly of Ag₄₂ Nanocalices Based on a Mo^VI-Anchored Thiacalix[4]arene Metalloligand