Tetra(diisopropylcarbodiimide‐ N )‐Beryllium‐bis‐Triiodide and 1,3‐Diisopropyl‐2,4‐bis(isopropylimino)‐1,3‐Diazetidine

Tetra(diisopropylcarbodiimide‐ N )‐beryllium‐bis‐triiodide, [Be( i ‐C 3 H 7 –NCN– i ‐C 3 H 7 ) 4 ](I 3 ) 2 ( 1 ), was prepared from beryllium powder and iodine in diisopropylcarbodiimide suspension to give red single crystals. Compound 1 catalyzes the cyclodimerization of diisopropylcarbodiimide forming 1,3‐diisopropyl‐2,4‐bis(isopropylimino)‐1,3‐diazetidine ( 2 ), which can be isolated as colourless single crystals. 1 and 2 were characterized by X‐ray diffration and IR spectroscopy. Compound 1 crystallizes tetragonally in the space group P $\bar4$ 2 1 c with two formula units per unit cell. Lattice dimensions at 193(2) K: a = b = 1292.2(1), c = 1411.2(2) pm, R 1 = 0.0497. The structure of 1 consists of distorted tetrahedral dications [Be( i ‐C 3 H 7 –NCN– i ‐C 3 H 7 ) 4 ] 2+ with site symmetry $\bar4$ and triiodide ions with site symmetry 2. Compound 2 : Space group P 2 1 / c , Z = 2, lattice dimensions at 100(2) K: a = 935.2(1), b = 795.5(1), c = 1141.0(1) pm, β = 112.54(1)°, R 1 = 0.0304. The structure of 2 forms centrosymmetric molecules with symmetry C i and planar four‐membered C 2 N 2 rings.