Structural Diversity and Catalytic Properties in a Family of Ag(I)-Benzotriazole Based Coordination Compounds

Abstract

In this work we study the coordination chemistry of a series of semirigid benzotriazole based ligands (L1-L3) along with the low coordination number but versatile AgI ions. This has led to nine new coordination compounds formulated [Ag(L1)(CF3CO2)] (1), [Ag2(L1T)2(CF3SO3)2]·2Me2CO (2), [Ag(L2T)(ClO4)(Me2CO)] (3), [Ag(L2T)(BF4)(Et2O)] (4), [Ag2(L3T)2(ClO4)2]2 (5), [Ag(L3)(NO3)] (6), [Ag2(L3T)2(CF3CO2)2] (7), [Ag2(L3T)(CF3SO3)2] (8), and [Ag2(L3T)2(CF3CF2CO2)2]·2Me2CO (9). These compounds show structural diversity including dimers (5, 7, 9) and one-dimensional (1D) (3, 4, 6) and two-dimensional (2D) (1, 2, 8) coordination polymers. The presence of the two -CH2- units between the three rigid backbones, benzotriazole/-C6H4-/benzotriazole, provides a limited, but significant, flexibility in L1-L3, influencing their variety coordination abilities. Interestingly, certain structures exhibit an isomerism effect (L1T-L3T) in the benzotriazole unit when in solid state; a series of studies are indicative of the 1,1-form which is generally dominant in solution even in cases where the crystal structure does not contain this tautomer. The homogeneous catalytic efficacy of all compounds against the well-known multicomponent A3 coupling reaction and the hydration of alkynes were investigated. Compound 4 was identified as the optimal catalyst for both reactions, promoting the multicomponent coupling as well as the alkyne hydration reaction under low loadings (0.5 and 3 mol %, respectively) and in high yields (up to 99 and 93% in each case).