Reaction of Ni₂Cp₂(μ-CO)₂with the Alkylgallium(I) and Alkylindium(I) Compounds E₄[C(SiMe₃)₃]₄(E = Ga, In). Insertion of E−R Groups into the Ni−Ni Bond versus Replacement of CO by the Isolobal E−R Ligands

Abstract

The monomeric fragment In-C(SiMe3)3 was inserted into the Ni-Ni bond of Ni2Cp2(mu-CO)2 upon treatment of the carbonyl complex with the tetraindium(I) compound In4[C(SiMe3)3]4, 1, in a molar ratio of 4 to 1. The product (3) contains an indium atom coordinated to one alkyl substituent and two Ni(Cp)CO groups in a planar coordination sphere. Reaction of the starting compounds in a molar ratio of 2 to 1 led to the replacement of both CO ligands by two InR groups. A compound (4) was formed that is isostructural to the carbonyl nickel complex and has a Ni2 couple bridged by two InR ligands and two terminally coordinated cyclopentadienyl groups. The insertion product was not observed with the gallium derivative Ga4[C(SiMe3)3]4 (2); instead, a nickel gallium complex (5) analogous to 4 containing two bridging GaR ligands was isolated as the only product regardless of the ratio of the starting compounds. On the basis of quantum chemical calculations, we conclude that there is no evidence for an In-In or Ga-Ga bond in complexes 4 or 5, respectively. This, however, supports a butterfly geometry, which is isostructural to the starting carbonyl complex Ni2Cp2(mu-CO)2.

On the reactions of the tetraindium cluster In4[C(SiMe3)3]4: Insertion of the monomeric fragments InC(SiMe3)3 into chalcogen–chalcogen bonds

“…Å in 2, 3 and 5, respectively, while expectedly the bond lengths to the bridging chalcogen atoms are lengthened to 2.594, 2.744 and 2.929 Å on average. These values correspond well to those reported previously [10][11][12][13][14][15][16][17][18][35][36][37][38][39][40]. All bridging chalcogen atoms adopt a trigonal pyramidal coordination sphere.…”

“…In contrast to the cyclopentadienyl compounds it exhibits strong In-In bonding interactions and has an almost undistorted tetrahedral cluster of four indium atoms in an oxidation state of +I [8,9]. Compound 1 is soluble in hydrocarbons and is applicable as a facile source of monomeric InR fragments [R = C(SiMe 3 ) 3 ] in a number of unprecedented and remarkable chemical reactions [10][11][12][13][14][15][16][17][18]. For instance, novel indium(III) chalcogenides were obtained through the complete oxidation of the cluster atoms by elemental chalcogens or suitable chalcogen atom donors to give heterocubane-type molecules In 4 R 4 E 4 (E = O, S, Se, Te) [8,[19][20][21].…”

Transition Metal Chemistry of Low Valent Group 13 Organyls

“…The electron density of the transition metal centre on coordination should therefore increase considerably. [10,16,17,24,31,41] This is an intrinsically interesting feature especially from the point of view of classical bond activation reactions being relevant in organometallic chemistry (H 2 , CϪH, SiϪH, BϪH, etc. 3 (AlCp*Ph)] (11) in almost quantitative yields (Scheme 9).…”

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]

“…Later, the range of available examples was further expanded with use of terphenyl [4][5][6] and b-diketiminate and related ligands [7][8][9][10][11]. The ability of these low-valent metal (I) compounds to act as strong terminal or bridging r-donor ligands has been well demonstrated by the experimental studies of Fischer, Jutzi and Uhl and by the theoretical work of Frenking [12][13][14][15][16][17][18][19][20]. Such species are of interest not only from a fundamental structure/bonding perspective [20,21], but also from the viewpoint of potential applications of this class of compounds (e.g.…”