Potassium complexes of the 'super' formamidine (2,6-Pr2iC6H3)NC(H)NH(2,6-Pr2iC6H3), HDippForm.: Synthesis and molecular structure of [{K(DippForM)2K(THF)2}n]•nTHF and [K(DippForm)(THF)3]•HDippForm

Ambient temperature treatment of the formamidine (2,6-(Pr2C6H3)-C-i)NC(H)NH(2,6-(Pr2C6H3)-C-i), HDippForm, with one equivalent of potassium bis(trimethylsilyl)amide yields the formamidinate species [{K(DippForM)(2)K(THF)(2)}(n)](.)nTHF (1), which exhibits a macromolecular structure of alternating eta(6)-arene:eta(1)-amide bound potassium di-amidinate and potassium di-THF units ill a one-dimensional polymeric array. Addition of a further equivalent of HDippForm to I affords hydrogen bound [K(DippForm)(THF)(3)]. HDippForm (2). The supramolecular structure of 2 resembles a 'topochemical' arrangement of K(DippForm) and HDippForm moieties that, in tandem with H-1-NMR data, corroborate a putative [K(DippForm)(HDippForm)] composition in solution. (C) 2002 Elsevier Science B.V. All rights reserved.