The reaction of the azastannatranes RSn(NMeCH2CH2)(3)N 1 (R = Me), 2 (R = n-Bu), and 3 (R = Ph) with BF3 . Et2O in THF gave the novel six-coordinate tin compounds 4-6, respectively, in which BF3 adds across one of the three covalent Sn-N bonds to give a F-Sn<--NMe(BF2) linkage. The tricyclic atrane framework retained in the reaction with BF3 . Et2O is preserved under hydrolysis conditions with substoichiometric amounts of water. A hydrolysis product of 4 is the new fluorotin salt [FMeSn(HMeNCH2CH2)(2)N(CH2CH2NMe)]BF4 [7(BF4)] whose structure, determined by X-ray analysis, also features a six-coordinate tin atom. The TR and NMR spectra of 4-6 confirm their six-coordinate nature. The H-1 and C-13 NMR spectra are assigned using COSY, NOESY, and selectively proton decoupled C-13 NMR spectral techniques. Crystallographic parameters for 7(BF4) are as follows : triclinic space group , a = 8.295(2) Angstrom, b = 8.924(2) Angstrom, c = 13.639(2) Angstrom, alpha = 88.59(2)degrees, beta = 74.83(2)degrees, gamma = 79.99(2)degrees, and Z = 2.