Metallocalixarenes: Syntheses and X-ray Crystal Structures of Titanium(IV), Iron(III), and Cobalt(II) Complexes of p-tert-Butylcalixarene

Article abstract of DOI:10.1021/ja00312a049

The reactions of the metal amides , 3>, and <(Co2)2> with p-tert-butylcalix<4>areneH4 (1) have resulted in the isolation and structural characterization of the first three ?-bonded transition-metal derivatives of a calixarene.Complete exchange of the four -OH protons in 1 with gives the complex <arene)>2>*6PhMe (2) as orange-red crystals.The conformationally mobile cone configuration of 1 acquires rigidity in the titanium complex which exist in a dimeric form with bridging through one of the ligand oxygens resulting in a distorted tetrahedral coordination at titanium.The reactions of 1 with 3> or <(Co2)2> are more complex and involve -SiMe3 shifts from silylamide groups to a ligand oxygen giving, for iron, an unusual complex of formula <areneOSiMe3)>2>*3n-C6H14 (3) and the new cluster areneOSiMe3)2(THF)>*5PhMe (4) for cobalt.The remarcable inclusion of ammonia (which derives from an -N(SiMe3)2 group) in 3 appears to be unprecedented.The cluster 4 also appears to be unique since it is the only structurally characterized cobalt alkoxide.The crystal data at 140 K, Mo Kα (λ=0.71069 Angstroem), are as follows: 2 - a=12.427(5) Angstroem, b=13.409(5) Angstroem, c=18.754(13) Angstroem, α=98.60(5) deg, β=106.26(4) deg, γ=108.33(3) deg, Z=2, space group P<*>, R=0.067; 3 - a=12.815(10) Angstroem, b=15.061(13) Angstroem, c=16.870(10) Angstroem, α=111.67(6) deg, β=91.66(6) deg, γ=111.81(7) deg, Z=2, space group P<*>, R=0.083; 4 - a=10.152(10) Angstroem, b=22.551(11) Angstroem, c=27.142(11) Angstroem, β=105.02(3) deg, Z=4, space group = P2₁/n, R=0.14.