Tl-203,Tl-205 NMR studies of crystallographically characterized thallium alkoxides. X-ray structures of [Tl(OCH2CMe3)](4) and [Tl(OAr)](infinity), where OAr=OC6H3(Me)(2)-2,6 and OC6H3(CHMe2)(2)-2,6

[Tl(OCH2Me)]4 (1) was reacted with excess HOR to prepare a series of [Tl(OR )](n), where OR = OCHMe2 (2, n = 4), OCMe3 (3, n = 4), OCH2CMe3 (4, n = 4), OC6H3(Me)(2)-2,6 (5, n = infinity), and OC6H3(CHMe2)(2)-2,6 (6, n = infini ty). Single-crystal X-ray diffraction experiments revealed that in the soli d state the alkoxide-ligated compound 4 adopts a cubane structure, whereas the aryloxide derivatives, 5 and 6, formed polymeric chains. Compounds 1-6 were also characterized by Tl-203,Tl-205 solution and Tl-205 solid-state NM R spectroscopy. In solution it was determined that 1-4 retained the [Tl-O]4 cube structure, whereas the polymeric species 5 and 6 appeared to be fluxi onal. Variations in the solution and solid-state structures for the [Tl(OR) ](4) cubes and polymeric (Tl(OAr)](infinity) are influenced by the steric h indrance of the ligand. The acidity of the parent alcohol influences the de gree of covalency at the Ti metal center, which is reflected in the Tl-203, Tl-205 chemical shifts for 1-6.