Syntheses, characterizations, and crystal and molecular structures of (pentamethylcyclopentadienyl)gallium chlorine compounds Ga(C5Me5)2Cl and Ga(C5Me5)Cl2

Abstract

The first (pentamethylcyclopentadienyl)gaUium compounds Ga(C5Me5)2Cl and Ga(C5Me5)Cl2 have been prepared and fully characterized by elemental analyses, cryoscopic molecular weight measurements, IR and NMR data, Lewis acid-base studies, and X-ray structural studies. The derivative Ga(C6Me5)2Cl can be readily prepared from GaCl3 and LiC5Me5 in diethyl ether. When the stoichiometry of the reagents LiC5Me5/GaCl3 was 3.2 or 2.2, the only gallium-containing product was Ga(C5Me5)2Cl. The identical product was isolated when the solvent was THF or the reaction mixture was refluxed. An X-ray structural study of a colorless crystal of bis(pentamethylcyclopentadienyl)gallium chloride demonstrates that the crystal consists of discrete isolated dimeric molecules of [Ga(C6Me=)2Cl]2. The compound crystallizes in the triclinic space group Pi with unit cell dimensions o = 7.825 (3) A, b = 14.341 (4) A, c = 23.853 (6) A, a = 79.20 (3)°, ß = 86.28 (3)°, 7 = 84.93 (3)°, and dcalcd = 1.28 g cm"1 23 for Z = 3. Full-matrix leas-squares refinement led to a final R value of 0.061 for 2007 observed reflections. The dimeric molecules have chlorine bridges, and the planar pentamethylcyclopentadienyl rings exhibit 1 coordination. In benzene solution, the dimeric molecule dissociates and only monomers are observed according to the concentration independent cryoscopic molecular weight data. The dichloro derivative Ga(C5Me5)Cl2 is readily prepared from Ga(C5Me5)2Cl and GaCl3 by a standard ligand redistribution reaction. An X-ray structural study of a light yellow crystal of [Ga(C5Me5)Cl2]2 demonstrates that the compound crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 8.804 (4) A, b = 8.337 (4) A, c = 17.086 (5) A, ß = 94.59 (5)°, and dcaicd = 1.465 g cm"3 for Z = 2. Full-matrix least-squares refinement led to a final R value of 0.052 for 1009 observed reflections. This dimeric molecule also contains chlorine bridges with planar ^-pentamethylcyclopentadienyl rings. Consequently, these new compounds have provided the first structural studies of organogallium halides and permit useful comparisons with the structural data for [GaCl3]2.

Group 13 decamethylmetallocenium cations

“…Compound 9 was synthesized by Beachley et al 22 via the metathetical reaction of two equivalents of Cp*Li with GaCl 3 and we employed essentially the same method for the preparation of 10. As expected, the 1 H and 13 C NMR spectra of 9 and 10 exhibit resonances that are typical of a single type of rapidly-migrating Cp* ligand.…”

“…22 Unfortunately, the crystal quality of 10 was poor but good enough to establish the connectivity (Fig. 4).…”

“…4). The molecular structures of 9 22 and 10 consist of halide dimers of the form Cp* 2 Ga(l 2 -X) 2 GaCp* 2 . The asymmetric unit of each structure contains three independent Cp* 2 GaX fragments (one complete dimer and a moiety that is completed by the crystallographic inversion center).…”

Organogallium compounds containing the neophyl substituent. Crystal and molecular structure of trans-[(PhMe2CCH2)2GaN(H)(Pr)]2

“…Consequently, our prior research involved investigations of the chemistry of gallium compounds with CH 2 SiMe 3 , 1 CH 2 CMe 3 , 2 2,4,6-Me 3-C6H2 3 , 4 and C 5Me5 5 , 6 substituents but only the mesityl derivative Ga(C 6 Me 3 H 2 )CI 2 displayed unusual chemistry. The compound Ga(C 6 Me 3 H 2 )C1 2 was characterized as a unique one dimensional polymer in which planar Ga(C 6 Me 3 H 2 )CI units with distorted tetrahedral geometry were linked by bridging chloride ligands.…”

Synthesis and characterization of cyclopentadienylgallium amide compounds as potential single source precursors to GaN

“…Cp 3 Ga [13], Cp 0 3 Ga (Cp 0 = C 5 Me 4 H) [14], Cp ⁄ 3 Ga (Cp ⁄ = C 5 Me 5 ) [15] and [Cp ⁄ 2 Ga(l-Cl)] 2 [16] were prepared as described in the literature. Anhydrous ammonia was purchased from Matheson TriÁGas and degassed by applying three freeze-pump-thaw cycles immediately prior use.…”