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The straightforward room temperature synthesis of hybrid polymetallic manganese clusters is investigated, exploiting complementary ligand combinations of p-tert-butylcalix[4]arene and salicylaldoximes. Eight new [MnIII7MnII] clusters have been prepared wherein the simple substitution of alkyl or aryl groups at well-defined positions of the salicylaldoxime scaffold leads to two distinct structure types that, while exhibiting the same general topology, contain the unique MnIIion in different positions. Incorporation of a methyl, ethyl, or isopropyl group at the 3-position of the aromatic skeleton or a phenyl group at the oximic carbon gives structure type A that displays competing weak ferromagnetic and antiferromagnetic interactions. Substitution of a methyl or ethyl group at the oximic carbon atom invokes structure type B, incorporating an additional bulky chloride or nitrate into the metallic core due to the smaller steric imposition and position of the methyl or ethyl group. The distortion of the cluster core is consequently enhanced, switching the magnetic properties and resulting in single-molecule magnet behavior. The presence of tert-butyl groups at the 3- and 5-positions of the salicylaldoxime skeleton leads to a new [MnIV2MnIII2] cluster that is found to be a single-molecule magnet. The bulky tert-butyl group in the 3-position is too large to facilitate Mn8cluster formation, and thus assembly occurs by an alternative pathway. Characteristic bonding modes of the constituent ligands are retained in every case, and the results presented here give insight into the potential of ligand combinations in future studies, highlighting the importance of steric factors in evaluating their relevant compatibilities.

New ligands: The first examples of a neutral heteroborane and a neutral metallaheteroborane acting as simple σ‐bound ligands to transition metals are described. In [HCo(1,2‐closo‐P2B10H10)2(PEt3)2] (see structure, left) the P2B10H10ligand coordinates to Co through one P atom, and in μ‐[1,2‐{HRu(p‐cymene)}2‐7′,8′‐nido‐P2B9H9]‐3‐(p‐cymene)‐3,1,2‐closo‐RuP2B9H9(right) both closo‐RuP2B9and nido‐P2B9cages act as bridging κP:κP′ ligands.

Neue σ‐Ligandenfür Übergangsmetalle sind das neutrale Heteroboran [HCo(1,2‐closo‐P2B10H10)2(PEt3)2] (1, links) und das neutrale Metallaheteroboran μ‐[1,2‐{HRu(p‐cymol)}2‐7′,8′‐nido‐P2B9H9]‐3‐(p‐cymol)‐3,1,2‐closo‐RuP2B9H9(2, rechts). In 1koordiniert der P2B10H10‐Ligand über ein P‐Atom an Co, und in 2agieren der closo‐RuP2B9‐ und der nido‐P2B9‐Käfig als κP:κP′‐Brückenliganden.