Synthesis of the Sterically Related Nickel Gallanediyl Complexes [Ni(CO)3(GaAr′)] (Ar′ = C6H3-2,6-(C6H3-2,6-iPr2)2) and [Ni(CO)3(GaL)] (L = HC[C(CH3)N(C6H3-2,6-iPr2)]2): Thermal Decomposition of [Ni(CO)3(GaAr′)] to give the Cluster [Ni4(CO)7(GaAr′)3]

Abstract

Reaction of Ni(CO) 4 in toluene at room temperature with one equivalent of GaAr 0 (Ar 0 = C 6 H 3 -2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ) and GaL (L = HC[C(Me)N(C 6 H 3 -2,6-iPr 2 )] 2 ) formed the mono-substituted Ni(CO) 3 (GaAr 0 ) (1) and Ni(CO) 3 (GaL) (3), respectively. Compound 1 decomposed under reduced pressure or upon heating in toluene to give the new cluster species Ni 4 (CO) 7 (GaAr 0 ) 3 (2). Reaction of 3 with a second equivalent of GaL in toluene at 95°C afforded the disubstituted complex Ni(CO) 2 (GaL) 2 (4). All the compounds were characterized by IR, 1 H and 13 C{ 1 H} NMR spectroscopy and X-ray crystallographic studies were undertaken to elucidate the structures of the complexes 2, 3 and 4.

Reactions of Terphenyl-Substituted Digallene AriPr4GaGaAriPr4 (AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2) with Transition Metal Carbonyls and Theoretical Investigation of the Mechanism of Addition

“…Other published examples of mono- and bis­(gallanediyl) complexes include those by Jones and co-workers, which feature bonds between gallium analogues of N-heterocyclic carbenes and a variety of transition metal species, including several carbonyl complexes ( IV and VIII ) . A number of gallanediyl complexes of group 10 carbonyls such as Ni 4 (GaAr i Pr 4 ) 3 (CO) 7 , Ni­(GaL)­(CO) 3 , and Ni­(GaL) 2 (CO) 2 (L = HC­[C­(Me)­N­(C 6 H 3 -2,6- i Pr 2 )] 2 ) have also been reported …”

[CpArNi{Ga(nacnac)}]: An Open-Shell Nickel(I) Complex Supported by a Gallium(I) Carbenoid (CpAr = C5(C6H4-4-Et)5, nacnac = HC[C(Me)N-(C6H3)-2,6-iPr2]2)

“…The Ni–Ga bond length (av. 2.2688(8) Å) is slightly shorter than that in [Ni­(CO) 3 {Ga­(nacnac)}] (2.289(6) Å), and considerably shorter than that in [Ni­(CDT)­{Ga­(nacnac)}] (2.3482(6) Å) . The Ni–Br bond length (av.…”

“…Low-valent organyl gallium species of the general type Ga-R (R = C 5 Me 5 {= Cp*}, C­(SiMe 3 ) 3 , terphenyl, nacnac, and related ligands) have been widely used as supporting ligands for metal-to-metal bonded complexes and clusters. − Among these, Ga­(nacnac), having a bulky nacnac ligand on gallium, has drawn special attention due to its ability to stabilize coordinately unsaturated metal complexes, such as [L 2 NiGa­(nacnac)] (L = C 2 H 4 , styrene; L 2 = 1,1,3,3-tetramethyl 1,3-divinyldisiloxane (dvds); Figure ). , Several other 18 VE electron Ni–Ga­(nacnac) complexes such as [L 2 NiGa­(nacnac)] (L = CO; L 3 = 1,5,9-cyclododecatriene (CDT); Figure ) were obtained by ligand substitution reactions. ,, Interestingly, Ga­(nacnac) can also insert into metal halide bonds, leading to M–Ga bonded complexes, although only a few examples are known involving transition metals. − The reaction with [AuCl­(PPh 3 )] gives the linear complexes [Au­{GaCl­(nacnac)}­(PPh 3 )] and [Au­{Ga­(nacnac)}­{GaCl­(nacnac)}] . A unique observation is the reaction of [RhCl­(PPh 3 ) 3 ] with Ga­(nacnac), which gave the “frozen-insertion intermediate” [Rh­(μ-Cl)­Ga­(nacnac)­(PPh 3 ) 2 ] …”

Quantifying the Donor Strength of Ligand-Stabilized Main Group Fragments

“…The nucleophilicity of electron-rich main group compounds and fragments, often stabilized by supporting ligands or substituents, can be illustrated by coordination to suitable metal centers. − All too often, their application as ligands in transition-metal complexes is limited only to exemplify their nucleophilic nature, whereas their coordination chemistry has not yet been systematically explored. In homogeneous catalysis, neutral ligands with tunable steric and electronic properties can serve as versatile spectator ligands. − Thus, the investigation of the coordination properties of nucleophilic main group compounds generally offers the potential to replace common spectator ligands, such as phosphines and carbenes.…”