Organotin(IV) trifluoromethanesulfonate chemistry: isolation and characterization of novel 1,10-phenanthroline-based derivatives

The reactivity of the hydroxo di-n-butyltin trifluoromethanesulfonato dimer complex [n-Bu 2 Sn(µ-OH)(H 2 O)(CF 3 SO 3 )] 2 (1) toward 1,10-phenanthroline (phen) has been investigated, leading to the formation of two novel di-n-butyltin(IV) trifluoromethanesulfonate complexes [n-Bu 2 Sn(µ-OH)(phen)] 2 [CF 3 SO 3 ] 2 (5) and [n-Bu 2 Sn(phen) 2 ][CF 3 SO 3 ] 2 (6), in which the tin atoms are bischelated by one and two bidentate phen ligands, respectively.Salts 5 and 6 were characterized by single crystal X-ray diffraction analysis, elemental analysis, mass spectrometry, and infrared spectroscopy as well as 1 H, 19 F, 13 C{ 1 H}, and 119 Sn{ 1 H} NMR spectroscopy.Monitoring by 119 Sn{ 1 H} NMR spectroscopy in CD 3 CN solution of the reaction proceeding with successive addition of phen revealed the in situ formation of three organotin(IV) trifluoromethanesulfonate intermediate species.Two of these, namely {[n-Bu 2 Sn(H 2 O)] 2 O•n-Bu 2 Sn(OH) 2 }[CF 3 SO 3 ] 2 (2) and [n-Bu 2 Sn 2 (OH)(CF 3 SO 3 )] 2 O (4), were already known and could be clearly identified on the basis of their 119 Sn{ 119 H} NMR chemical shifts.The composition of the third intermediate, 3, with an unknown chemical shift value, was investigated.A possible structure, especially suggested by electrospray-ionization mass spectrometry, is proposed as [{n-Bu 2 Sn(phen)(CF 3 SO 3 )} 2 (µ-CF 3 SO 3 )][CF 3 SO 3 ].Furthermore, from a mixture of 1 and phen in equimolar ratio, in dichloromethane solvent and at -20 °C, temperature-sensitive crystals of a new hydrated di-n-butyltin cation, [n-Bu 2 Sn(phen)(OH)(H 2 O)][CF 3 SO 3 ] ( 7), were isolated.Crystals of the organic salt 1,10-phenanthrolinium trifluoromethanesulfonate (phenHOTf) were also obtained from the filtrate of the mother-liquor.The reactivity of 1 toward 2,9-dimethyl-1,10-phenanthroline was also explored (dmphen), leading to the detection of characteristic fingerprints of distannoxanes 2 and 4 by 119 Sn{ 119 H} NMR, and to the crystallization of phenanthrolinium triflate salts, which were characterized by X-ray diffraction analysis as dmphenHOTf and dmphenHOTf•dmphen.