Crystal structure of sodium dichlorobis(acetylacetonato)rhodiate(iii) monohydrate Na[Rh(C5H7O2)2Cl2] · H2O. pseudoperiodicity as the consequence of the packing law of complexes in crystals

Abstract

The crystal structure of Na[Rh(acac)2Cl2] · H2O (acac) =C 5H7O 2 − )is determined The crystals are triclinic, space group P1, with unit cell dimensions a =12.616(2), b =8.411(4), c =8.499(4) a,a =108.37(4), Β =95.47(4), γ =110.45(4)‡, V =780.3(6) a 3, Z =2, d calc =1.758 g/cm 3, R =0.0461. The strong pseudoperiodicity observed experimentally (no reflections with odd indices h) led to a set of experimental data obtained in the unit cell that is reduced along the a axis (“Syntex P2 1 ” automatic diffractometer, λMoK α, graphite monochromator), 1466 measured and 1302 observed Ihkl included in the calculation. This is due to the alternation of the central atoms of octahedral complex onions at intervals of 1/2a. The Rh- 0 and Rh- Cl distances are, on the average, 2.001(3) and 2.325(2), respectively. The cis- angles of ClRhO type are close to 90‡, and the average value of the ORhO chelate angle is 95.1‡ (within 3Σ with Σ ≅ 0.1‡). The average interatomic distances and bond angles (according to types) in the acac ligand are as follows: O- C 1.274, (C- C)ring 1.397, Cring- Csub 1.506 a with Σ not higher than 0.006 a,RhOC 122.2‡, (OCC) ring 126.4‡, (OCC)term 114.2‡, (CCC)ring 127.3‡, (CC)ringcsub 119.3‡ (Σ within 0.2– 0.6‡). The distorted octahedron around the Na ion consists of five O atoms (of the H2O molecule and the neighboring acac ligands, distances within 2.364– 2.409 a) and one Cl ion lying at a distance of 2.970 a. The structure in general is of ribbon type: Rh1,2 and Na octahedra are linked by a common edge O(2′)O(1) and common face O(3)O(4′)O(2′) into infinite ribbons, which are extended along the [100] axis and which are translationally identical in the [010] and [001] directions. The H 2O molecule forms two Cl(l)...H2O...Cl(2′) hydrogen bonds: 3.116 and 3.179 a, respectively, which link the Rh octahedra into infinite chains in the [120] direction.