The different nonmolecular polyadamantanoid crystal structures of Cd(SPh)2 and Cd(SC6H4Me-4)2. Analogies with microporous aluminosilicate frameworks

Article abstract of DOI:10.1021/ic00271a019

Cd(SPh)₂ (2) crystallizes unsolvated from DMF with a structure (orthorhombic, P2₁2₁2₁, a = 15.490 (2) A, b = 15.626 (2) A, c = 20.803 (3) A, Z = 16 (CdS₂C₁₂H₁₀), 3626 observed data, Mo Kα, R = 0.034) in which adamantanoid cages comprised of four Cd atoms and six doubly bridging SPh ligands are connected in three dimensions by doubly bridging SPh ligands. The lattice arrangement of the linked tetrahedral adamantanoid cages is almost identical with that of the α-cristobalite form of SiO₂. The structure of crystalline Cd(SC₆H₄Me-4)₂ (3) (monoclinic, P2₁/c, a = 27.196 (9) A, b = 15.722 (5) A, c = 37.046 (13) A, β = 132.03 (1)°, Z = 32 (CdS₂C₁₄H₁₄), 12003 observed data with (sin θ)/λ > 0.1 A^-1, Mo Kα, R = 0.065) is also three-dimensionally nonmolecular with vertex-linked adamantanoid tetrahedra, but in a very different linkage pattern involving closed four-, six-, and eight-membered rings of tetrahedra, resembling microporous zeolite lattices. In 3 there exist very large centrosymmetric cavities in the Cd,S array, surrounded by 12 adamantanoid cages whose centroids constitute a trans truncated octahedron. Channels encycled by eight-membered rings also exist in the lattice. The cavities are lined with 44 S atoms connected by 32 Cd atoms, contain 10 ligand substituents, and are connected through four- and six-membered rings to other cavities. Within the cavities the S - S diagonals through the inversion center range from 16.6 to 19.1 A. The volumes excluded by the Cd,S cores of the adamantanoid tetrahedra are 12% and 10% of the unit cell volumes in 2 and 3, respectively, and the remaining volumes occupied by the substituents are partially empty. Both of these poly-linked-adamantanoid structures are unique.