STEPWISE ELIMINATION OF ETHANE TO SYNTHESISE NEW CYCLIC AND CAGE-LIKE GALLIUM-PHOSPHORUS COMPOUNDS

Abstract

The reaction of GaEt₃ with H₂PSiMe₂R (R = CMe₂] initially yields the cyclic compound [(Et₂Ga)₂{P(H)SiMe₂R}₂] 1. 1 appears as a mixture of cis and trans isomers and has been characterized by ³¹P NMR spectroscopy, IR spectroscopy, and mass spectrometry. 1 decomposes at 180°C under elimination of ethane during 1 h to form the cage-like compound [EtGaPSiMe₂R]₄ (2). Central structural motif of 2 is a Ga₄P₄ heterocubane cage.

Keywords:

• Cluster
• crystal structure
• gallium
• phosphorus
• silicon

Notes

* 2: a = 1069.5(2), b = 1284.1(3), c = 2179.2(4) pm, β = 103.81(3), V = 2906.4(9) × 10⁶ pm³; monoclinic, P2/n, Z = 2, ρ_calc = 1.246 g/cm³, μ (Mo_Kα) = 2.051 mm⁻¹, T = 200 K, 2 Θ_max = 45°, 9447 reflections measured, 3287 independent reflections (R _int = 0.0603). The structure was solved by direct methods and refined by full-matrix least square techniques against F ², 235 parameters (Ga, P, Si, C refined anisotropically, H atoms were calculated at ideal positions); R1 = 0.0476; wR2 = 0.1422 (all data); maximum peak 0.479 eÅ⁻³. CCDC-217207 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or from Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB21EZ, UK; fax: [phone]; or [email protected]).