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)(C(12)H(14)O(4))(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.