The methods of synthesis, elemental analysis, IR and NMR spectroscopic data and fungicidal activity against Ceratocystis ulmi are reported for a series of triorganotin esters of N-arylideneo-amino acids of general formula R 3 SnO-CO(CH 2 ) n N = CHAr (R = Ph, n-Bu; Ar = 2-HOC 6 H 4 , 2-HOC 10 H 6 ; n = 1, 2, 3 and 5). The crystal structures for two of the compounds, tributyltin N-2-hydroxynaphthalidene glycinate (1) and tributyltin N-2-hydroxynaphthalideneb-alaninate (2), have been determined. Although both of these compounds have a trans-R 3 SnO 2 structure, in compound 1 the carboxylate group is monodentate and the fifth coordination position around the tin atom is taken up by a coordinated phenolic group, whereas in 2 the carboxylate group is bridging. These two examples thus correspond to the two different structures reported for trans-R 3 SnO 2 complexes. Both compounds were found to be active against Ceratocystis ulmi, but there was no significant difference in their levels of biological activity against this particular fungus. Apart from compound 1, the other tributyltin compounds reported are believed to adopt the carboxylate bridging mode shown by compound (2).
Crystal data: for 1, crystals monoclinic, space group P2 1 /c, a = 12.9435( 11) A ˚, b = 13.5769(10) A ˚, c = 15.7715(12) A ˚, b = 108.919(6)°, Z = 4, R f = 0.046 and R w = 0.058 for 1448 significant reflections; for 2, crystals monoclinic, space group C 2/c, a = 24.588(14) A ˚, b = 9.733(3) A ˚, c = 27.611(12) A ˚, b = 113.49(4)°, Z = 8, R f = 0.053 and R w = 0.069 for 3822 significant reflections.