Dibutyltin Dicarboxylic Acid Esters

Macrocycles, 16. Macrocyclic Dibutyltin Dicarboxylates via Thermodynamically Controlled Polycondensations

“…[11,12] In order to characterize the molar masses of products 6 a-h more accurately, the following analytical methods were applied: vapor pressure osmometry (VPO) in chloroform, classical mass spectrometry, fast-atom bombardment (FAB) mass spectrometry and MALDI-TOF mass spectrometry. The VPO data obtained from chloroform solutions (Table 1) were somewhat lower than those revealed by cryoscopic measurements reported by Andrews et al [13] on the basis of the Rast method. This difference is particularly noteworthy for the dibutyltin sebacate condensation product, which was initially assumed to be a linear polymer with a number-average molecular weight of 3 000 Da, [13] whereas values around 1 600 Da were evaluated in the present work.…”

“…The VPO data obtained from chloroform solutions (Table 1) were somewhat lower than those revealed by cryoscopic measurements reported by Andrews et al [13] on the basis of the Rast method. This difference is particularly noteworthy for the dibutyltin sebacate condensation product, which was initially assumed to be a linear polymer with a number-average molecular weight of 3 000 Da, [13] whereas values around 1 600 Da were evaluated in the present work. These values and those obtained for products 6 b, 6 c and 6 e-6 g suggest that the tin dicarboxylates obtained mainly consist of cyclic dimers and trimers.…”

“…On the basis of this procedure all products listed in Table 1 were isolated. All these dibutyltin dicarboxylates were characterized by elemental analysis, IR spectroscopy 1 H, 13 C and 119 Sn NMR spectroscopy to identify the structure of the repeat units. All resulting analytical data were in good agreement with the expected structures, and the high yields indicated clean reactions occurring with high conversion.…”

“…Bu 2 Sn succinate (6, n = 2) and Bu 2 Sn adipate (6, n = 4) were described in 1957 by Andrews et al, [13] and on the basis of cryoscopic measurements in camphor, the existence of a cyclic tetramer and a cyclic trimer respectively were postulated. For the sebacate a linear polymer structure (such as 5) with a numberaverage molecular weight (M -n ) around 3 000 Da was postulated [13] on the basis of cryoskopic measurements. More reliable mass spectroscopic or chromatographic methods were not available at the time.…”

Organotin Polymers

“…The materials are said to be useful as wood preservatives, in the treatment of textiles for imparting insect resistance, and as surface coatings. 177 Similar products were also reported by Janson and Fields.…”