A mixed lithium–strontium polynuclear complex formed within the hexa-deprotonated calix[8]arene framework; the synthesis and structure of Li4Sr2(H2L)(O2CC4H9)2(dmf )8 [H8L = p-Pri- or p-Bui-calix[8]arene] †

Clague, Nicholas P.; Crane, Jonathan D.; Moreton, David; Sinn, Ekkehard; Teat, Simon J.; Young, Nigel A.

doi:10.1039/a906694b

Cited by 15 publications

(7 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mixed-metal systems can also exhibit interesting catalytic behavior, and it has been shown that the presence of one metal can impact on the catalytic potential of another . In terms of the larger calix[ n ]arenes, few lithiated species have appeared in the literature, , and none have been utilized in the ROP of cyclic esters. Reports include mixed lithium/strontium complexes available via the use of n BuLi with L 8 H 8 (or its p -isopropyl analogue) and subsequent treatment with SrBr 2 .…”

Section: Introductionmentioning

confidence: 99%

Lithiated Calix[n]arenes (n = 6 or 8): Synthesis, Structures, and Use in the Ring-Opening Polymerization of Cyclic Esters

et al. 2021

View full text Add to dashboard Cite

A variety of lithiated calix[n]arenes, for which n = 6 or 8, have been isolated, structurally characterized, and evaluated as catalysts for the ring-opening polymerization (ROP) of the cyclic esters ε-caprolactone (ε-CL), δ-valerolactone (δ-VL), and rac-lactide (r-LA). In particular, interaction of p-tert-butylcalix[6]areneH6 (L6H6) with LiOtBu in THF led to the isolation of [Li14(L6H)2(CO3)2(THF)6(OH2)6]·14THF (1·14THF), the core of which has a chain of five Li2O2 diamonds. Similar use of p-tert-butylcalix[8]areneH8 (L8H8) afforded [Li10(L8)(OH)2(THF)8]·7THF (2·7THF), where the core is composed of a six-rung Li–O ladder. Use of debutylated calix[8]areneH8 (deBuL8H8) led to an elongated dimer [Li18(deBuL8)2(OtBu)2(THF)14]·4THF (3·4THF) in which the calix[8]arenes possess a wavelike conformation forming bridges to link three separate Li x O y clusters (where x and y = 6, ignoring the THF donor oxygens). Interaction of L8H8 with LiOH·H2O afforded [Li4(L8H4)(OH2)4(THF)6]·5.5THF (4·5.5THF), where intramolecular H-bond interactions involving Li, O, and H construct a cage in the core of the structure with six- and eight-membered rings. Lastly, addition of Me3Al to the solution generated from L8H8 and LiOtBu led to the isolation of [(AlMe2)2Li20(L8H2)2(OH2)4(O2–)4(OH)2(NCMe)12]·10MeCN (5·10MeCN) in which Li, O, Al, and N centers build a polyhedral core. These complexes have been screened for their potential to act as precatalysts in the ring-opening polymerization (ROP) of ε-CL, δ-VL, and r-LA. For the ROP of ε-CL, δ-VL, and r-LA, systems 1–4 exhibited moderate activity at 130 °C over 8 h. In the case of ROP using the mixed-metal (Li/Al) system 5, better conversions and high molecular weight polymers were achieved. In the case of the ROP of ω-pentadecalactone (ω-PDL), the systems proved to be inactive under the conditions employed herein.

show abstract

Section: Introductionmentioning

confidence: 99%

Lithiated Calix[n]arenes (n = 6 or 8): Synthesis, Structures, and Use in the Ring-Opening Polymerization of Cyclic Esters

et al. 2021

View full text Add to dashboard Cite

show abstract

“…1) confirms its identity as an acetonitrile solvate of the expected bis(bora)calixarene. Although a wide range of lower-rim main-group functionalised calixarenes has been described, 9,10 to our knowledge, 3 is the first example of a lowerrim boron derivatised calixarene to have been structurally characterized.…”

mentioning

confidence: 97%

Synthesis and structural characterisation of the first bis(bora)calixarene: a selective, bidentate, fluorescent fluoride sensor

et al. 2004

View full text Add to dashboard Cite

show abstract

“… 14 Moreover, a number of molybdocalix[4]arenes incorporating lithium, primarily as part of a bridging ligand have also been reported, 15 as have mixed lithium–strontium complexes. 16 We have previously structurally characterized the two complexes [L 4 H 2 (OMe)(OLi)] 2 ·4MeCN and {L 4 H 2 (OLi)[OLi(NCMe) 2 ]} 2 ·8MeCN resulting from the use of n BuLi. 17 …”

Section: Introductionmentioning

confidence: 99%

Lithium calix[4]arenes: structural studies and use in the ring opening polymerization of cyclic esters

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

A mixed lithium–strontium polynuclear complex formed within the hexa-deprotonated calix[8]arene framework; the synthesis and structure of Li4Sr2(H2L)(O2CC4H9)2(dmf )8 [H8L = p-Pri- or p-Bui-calix[8]arene] †

Cited by 15 publications

References 19 publications

Lithiated Calix[n]arenes (n = 6 or 8): Synthesis, Structures, and Use in the Ring-Opening Polymerization of Cyclic Esters

Lithiated Calix[n]arenes (n = 6 or 8): Synthesis, Structures, and Use in the Ring-Opening Polymerization of Cyclic Esters

Synthesis and structural characterisation of the first bis(bora)calixarene: a selective, bidentate, fluorescent fluoride sensor

Lithium calix[4]arenes: structural studies and use in the ring opening polymerization of cyclic esters

Contact Info

Product

Resources

About