Poly[(μ4-adamantane-1,3-dicarboxylato-κ5O1:O1′:O3,O3′:O3′)(μ3-adamantane-1,3-dicarboxylato-κ5O1,O1′:O3,O3′:O3′)dimagnesium]: a layered coordination polymer

The title compound, [Mg-2(C12H14O4)(2)](n), is the first example of an s-block metal adamantanedicarboxylate coordination polymer. The asymmetric unit comprises two crystallographically unique Mg-II centers and two adamantane-1,3-dicarboxylate ligands. The compound is constructed from a combination of chains of corner-sharing magnesium-centered polyhedra, parallel to the a axis, connected by organic linkers to form a layered polymer. The two Mg-II centers are present in distorted tetrahedral and octahedral coordination environments derived from carboxylate O atoms. Tetrahedrally coordinated Mg-II centers have been reported in organometallic compounds, but this is the first time that such coordination has been observed in a magnesium-based coordination polymer. The bond valance sums of the two Mg-II centers are 2.05 and 2.11 valence units, matching well with the expected value of 2.