128910-39-4Relevant articles and documents
Partially OH Depleted Calixarenes
Grynszpan, Flavio,Goren, Zafrir,Biali, Silvio E.
, p. 532 - 536 (1991)
The partially OH depleted dihydroxy- and trihydroxycalixarenes 2 and 3 were synthesized in order to assess the relative importance of the cyclic hydrogen bond on the conformation of p-tert-butylcalixarene.Both compounds were prepared from the same diethyl diphosphate ester precursor under different reductive cleavage conditions.The ring inversion barriers of 2 and 3 are -1, respectively.The completely OH depleted calixarene 5 and the MeOH solvate of dihydroxycalixarene 2 exist in the crystal in a 1,2-alternate conformation.Trihydroxycalixarene 3 crystallizes as a 1:2 pyridine solvate in which 3 adopts a cone conformation.One pyridine molecule is hydrogen bonded to one OH group of 3, while simultaneously being included into the cavity of another molecule of 3.It is concluded that three phenolic units are sufficient to stabilize the cone conformation.
Multiple Reductive Cleavage of Calixarene Diethyl Phosphate Esters: a Route to n>metacyclophanes
Goren, Zafrir,Biali, Silvio E.
, p. 1484 - 1487 (1990)
The OH groups of p-t-butylcalixarene (n = 4 and 8) were converted into diethyl phosphate esters and reductively cleaved by treatment with K/NH3 to yield tetra-p-t-butyl4>- and octa-p-t-butyl8>metacyclophanes (4) and (7).
Titanacalixarenes in homogeneous catalysis: Synthesis, conformation and catalytic activity in ethylene polymerisation
Espinas, Jeff,Darbost, Ulrich,Pelletier, Jeremie,Jeanneau, Erwan,Duchamp, Christian,Bayard, Francois,Boyron, Olivier,Broyer, Jean-Pierre,Thivolle-Cazat, Jean,Basset, Jean-Marie,Taoufik, Mostafa,Bonnamour, Isabelle
experimental part, p. 1349 - 1359 (2010/07/16)
Variously substituted titanacalixarenes were synthesised and tested for their performance as catalysts in ethylene polymerisation: p-tert-butylcalix[4] arene was derivatised to afford distal diether p-tert-butylcalix[4]arenes L1-L4, distal dihydroxy-depleted L5, proximal dihydroxy-depleted L6, proximal diether p-tert-butylcalix[4]arene L7, proximal intra-bridged disiloxane L8 and proximal monoether L9. (Dichlorotitana)-p-tert-butylcalix[4]arenes 1-8 and (monochlorotitana)-p-tertbutylcalix[4]arene 9 have been successfully synthesised by reacting L1-L4 with TiCl4·2THF or L5-L9 with TiCl 4. The structural conformation of complexes 1-9 in solution were determined by 1H NMR, 13C NMR, NOESY and COSY spectroscopic studies. Compounds 2, 3 and 4 have been structurally characterised by single-crystal X-ray diffraction. Upon activation with methylaluminoxane, compounds 1-8 revealed low to moderate activities for the production of high-density polyethylene (HDPE) to ultra-high-molecular-weight polyethylene (UHMWPE). 6/MAO gave the best activity at 770 kgPE(molTi) -1h-1.
