Tetra(diisopropylcarbodiimide-N)-beryllium-bis-triiodide and 1,3-diisopropyl- 2,4-bis(isopropylimino)-1,3-diazetidine

摘要

Tetra(diisopropylcarbodiimide-N)-beryllium-bis-triiodide, [Be(i-C _3H_7-NCN-i-C_3H_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 P4? 2_1c 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_3H_7-NCN-i- C_3H _7)_4]~(2+) with site symmetry 4? and triiodide ions with site symmetry 2. Compound 2: Space group P2_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_2N_2 rings.