The first examples of a crown ether intramolecularly encapsulating mono- and diorganotin dications: synthesis and structures of [PhSnCH2([16]crown-5)][ClO4]2 and [HOSnCH2([16]crown-5)][Y]2 (Y=ClO4, CF3SO3).

The reaction of silver perchlorate with [PhI(2)SnCH(2)([16]crown-5)] (1) and [I(3)SnCH(2)([16]crown-5)] (2) gave the organotin(IV)-substituted crown ether complexes [PhSnCH(2)([16]crown-5)][ClO(4)](2) (3) and [HOSnCH(2)([16]crown-5)][Y](2) (4: Y=ClO(4), 5: Y=CF(3)SO(3)), respectively. All compounds have been isolated as air-stable materials and characterised by (1)H, (13)C, (119)Sn and (119)Sn MAS (5) NMR spectroscopy, ESIMS spectrometry, elemental analysis and by single-crystal X-ray diffraction analysis. The molecular structures of 3-5 show that the tin(IV) cation fits perfectly into the crown ether cavity and is coordinated by the five oxygen atoms of the ring to give a pentagonal bipyramidal configuration about the central metal cation. Notably, compounds 4 and 5 contain the first monomeric monoorganotin dication. Moreover, there are (3)J((1)H,(119)Sn) coupling constants to the CH(2)CH proton of 377 (3) and 470 Hz (4, 5) that are, to the best of our knowledge, the biggest such couplings ever reported.