Synthesis and Structures of Polyhedral Hexa‐ and Octagallium Cluster Compounds

Abstract

The novel polyhedral closo‐Ga6 and Ga8 cluster ions [Ga6(R5)6]2– and [Ga8I4(R5)4]2– have been prepared as their lithium salts from reaction of the corresponding lithium silanide with a gallium subtriflate and “GaI”, respectively, together with the expected disproportionation products. All new compounds have been structurally characterized by single crystal X ray crystallography. The hexagallium cluster has a regular octahedral core, which is expected for a seven‐SEP cluster. The unexpected disphenoidal structure for the octagallium nine‐SEP cluster was compared to the square antiprismatic isomer by means of DFT calculations. In addition DFT calculations with dispersion correction on digallanes(4) R4Ga2 allow a new look on bonding in this gallium–gallium bonded compounds.

Reactivity of Silylene with Gallium‐ and Boron Trihalide at Reductive Conditions Resulting in Unforeseen Products

“…Where one gallium is coordinated by four substituents two silylene ligands and two iodine atoms, while the second GaI 3 is only coordinated by one silylene atom (Figure 1). The lengths for the Si−Ga bonds range from 2.4162(12)–2.4292(12) Å, which is within the range of previously reported Si−Ga−Si bond lengths [9,22–25] . The Si−N distances in the ligand backbone are similar within this complex series ( 1 – 3 ) (1.797(3)–1.809(3) Å for 1 , 1.8162(14)–1.8214(14) Å for 2 , 1.815(2)–1.819(2) Å for 3 ) and correspond with other complexes of this ligand platform (Table 1).…”

“…The lengths for the SiÀ Ga bonds range from 2.4162(12)-2.4292(12) Å, which is within the range of previously reported SiÀ GaÀ Si bond lengths. [9,[22][23][24][25] The SiÀ N distances in the ligand backbone are similar within this complex series (1-3) (1.797(3)-1.809(3) Å for 1, 1.8162( 14)-1.8214(14) Å for 2, 1.815(2)-1.819(2) Å for 3) and correspond with other complexes of this ligand platform (Table 1). [26][27][28][29] Same applies for the NÀ SiÀ N angles, which range from 72.38(6)°to 72.82(15)°f or 1-3, respectively.…”

“… [26–29] Same applies for the N−Si−N angles, which range from 72.38(6)° to 72.82(15)° for 1–3 , respectively [26–29] . The Si−Ga−Si angle (121.04(4)°) is smaller compared to the angle in [{(Me 3 Si) 3 Si} 2 Ga(μ‐Cl) 2 Li(thf) 2 ] [30] (138.0(2)°) or [{(Me 3 Si) 3 Si} 2 Ga(μ‐Br) 2 Li(thf) 2 ] [31] (137.81(9)°), but larger than in [Li(thf) 4 ][GaI(SiPh 3 ) 3 ] [25] (111.5(5)°–117.6(5)°) or Li(thf) 4 ][GaI(Si t BuPh 2 ) 3 ] [32] (115.78(1)°).…”