Anion-Templated Nanosized Silver Alkynyl Clusters: Cluster Engineering and Solution Behavior.

Assembly of nanosized polynuclear metal clusters from simple building blocks usually involves complicated self-organization processes and thus is a long-standing challenge. Here, we demonstrate the controllable assembly, single-crystal structures and solution behaviors of four molecular assemblies based on nanosized silver alkynyl clusters, formulated as {[(CrO4 )2 Cl@Ag42 (PhC≡C)34 (CF3 COO)2 ]⋅CF3 COO} (1), {(NH4 )[(CrO4 )2 Cl@Ag42 (PhC≡C)34 (CrO4 )(H2 O)2 ]⋅2BF4 ⋅CH3 OH}n (2), [(CrO4 )@Ag22 (PhC≡C)16 (CF3 SO3 )4 ]n (3), and {[(CrO4 )2 @Ag31 (PhC≡C)22 (CF3 SO3 )4 ]⋅CF3 SO3 ⋅2CH3 OH⋅H2 O}n (4). In the presence of concomitant CrO42- and Cl- templates, we could isolate a discrete cluster 1 and a polymeric chain-like compound 2 by using different silver salts. Both 1 and 2 have a similar 42-metallic cage, which traps two CrO42- and one Cl- as anion templates. Using sole CrO42- template, 3 and 4 were simultaneously isolated in a one-pot reaction. Both of them are 1D chain structures based on single CrO42- templated Ag18 and double CrO42- templated Ag30 clusters, respectively. HR-ESI-MS was used to study the solution behaviors of 1-4. This work has the following purposes: i) it presents the cluster engineering concept used in the assembly of polynuclear silver alkynyl clusters; ii) it exemplifies template effects from hetero and homo anions; and iii) it provides a controllable way to achieve assembly of silver alkynyl clusters.