Mononuclear and Polynuclear Chain Complexes of a Series of Multinucleating N/S Donor Ligands

We have prepared a series of five ligands with potentially N,S‐bidentate chelating arms derived from 3‐[2‐(methylsulfanyl)phenyl]pyrazole linked to central aromatic spacers by methylene units. Complexes with a variety of architectures have been obtained, including simple mononuclear complexes and polynuclear chain complexes. The p ‐xylyl‐spaced ligand L 1 forms one‐dimensional helical coordination polymers with copper( I ) and silver( I ) ions. These polymers display interligand aromatic stacking interactions within each helical chain. The m ‐xylyl‐spaced ligand L 2 forms a coordination polymer with copper( I ) but a mononuclear complex with the larger silver( I ) ion in which the central phenyl ring is involved in an η 1 π‐type Ag ··· C interaction with the Ag I . The 3,3′‐biphenyl‐spaced ligand L 3 also forms one‐dimensional polymers with silver( I ) and copper( I ) ions, but in this case the sequence of bridging ligands between one metal centre and the next follows a zig‐zag path rather than being helical. The 1,8‐naphthyl‐spaced ligand L 4 only forms mononuclear complexes with copper( I ) and silver( I ) ions showing that this spacer is not large enough to enforce a bridging coordination mode. The three‐armed ligand L 5 , prepared from 2,4,6‐tris(bromomethyl)mesitylene, also forms a mononuclear complex with silver( I ) ions, where one of the three arms is pendant. However, when excess silver( I ) ions are present two of these mononuclear complexes can be assembled into the trinuclear complex [Ag 3 (L 5 ) 2 ](ClO 4 ) 3 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)