Powder diffraction study of a coordination polymer comprised of rigid building blocks:: [Rh2(O2CCH3)4•μ2-Se2C5H8-Se,Se′]∞

The crystal structure of a new hybrid product comprised of two rigid building blocks, namely dirhodium(II) tetraacetate, [Rh-2(O2CCH3)(4)] (1), and 2,6-diselenaspiro[3.3]heptane, Se2C5H8 (2), has been solved ab initio using laboratory source X-ray powder diffraction (XRPD) data. The rigid body refinement approach has been applied to assist in finding an adequate model and to reduce the number of the refined parameters. Complex [Rh-2(O2CCH3)(4).mu(2)Se(2)C(5)H(8)-Se,Se'] (3) conforms to the triclinic unit cell with lattice parameters of a = 8.1357(4), b = 8.7736(4), and c = 15.2183(8) Angstrom, alpha = 77.417(3), beta = 88.837(3), and gamma = 69.276(4)degrees, V = 989.66(8) Angstrom(3), and Z = 2. The centrosymmetric P (1) over bar space group was selected for calculations. The final values of the reduced wR(p), R-p, and chi(2) were calculated at 0.0579, 0.0433, and 5.95, respectively. The structure of 3 is a one-dimensional zigzag polymer built on axial Rh...Se interactions at 2.632(6) Angstrom. The 2,6-diselenaspiro[3.3]heptane ligand acts as a bidentate linker bridging dirhodium units via both selenium atoms. The geometrical parameters of individual groups for rigid body refinement have been obtained from X-ray powder data for dirhodium(II) tetraacetate (1) and from single-crystal X-ray diffraction for diselenium molecule 2. The crystal structures of 1 and 2 are reported here for the first time. For 1 indexing based on XRPD data has resulted in the triclinic unit cell P (1) over bar with lattice parameters of a = 8.3392(7), b = 5.2216(5), and c = 7.5264(6) Angstrom, alpha = 95.547(10), beta = 78.101(6), and gamma = 104.714(13)degrees, V = 309.51(5) Angstrom(3), and Z = 1. The final values were wR(p) = 0.0452, R-p = 0.0340, and chi(2) = 1.99. The 1D polymeric motif built on axial Rh...O interactions of the centrosymmetric dirhodium units has been confirmed for the solid-state structure of 1. Compound 2,6-diselenaspiro[3.3]heptane (2) conforms to the monoclinic space group P2(1)/c with the unit cell parameters of a = 5.9123(4), b = 19.6400(13), and c = 5.8877(4) Angstrom, beta = 108.5500(10)degrees, V = 648.15(8) Angstrom(3), and Z = 4.