Stable Cyclic Germanediyls (“Cyclogermylenes”): Synthesis, Structure, Metal Complexes, and Thermolyses

Abstract

The new germandiyls 1 and 2 which sublime at 50 °C are monomeric in the solid state, in solution, and in the gas phase. They are available from germanium dichloride · 1,4‐dioxane and the appropriate lithium diamides in high yields, and react smoothly with [Ni(CO)4] to give 3 and 4. According to ab initio calculations, the π electrons in 2 are delocalized. cod = cyclooctadiene.

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]

“…Interestingly, the nonequivalence of the isopropyl groups in the solid state cannot be observed in solution. The 13 C NMR spectra in benzene-D 6 display one signal for carbonyl and also one signal for both isopropyl groups, indicating a high fluxionality in 4 on the NMR time scale, similar to that observed 2 and analogous Ni(CO) 2 (L) 2 complexes [42,43]. The IR showed two characteristic stretching signals at 2039 (A 1 ) and 1,967 cm -1 (B 1 ), confirming that GaL is a ligand with good r-donor and poor p-acceptor qualities.…”

“…The structure of 3 displays a very distorted, approximately trigonal bipyramidal geometry at nickel in which an apical position is unoccupied. The coordination geometry of the nickel is similar to that of the silylene-nickel complexes [43]. The Ni-Ga bond is in the known range of bond lengths for nickelgallanediyl complexes [13] and may be compared to the 2.191(1)-2.210(1) Å range for the terminal Ni-Ga distances in the complex (tmpGa) 2 Ni(l-Gatmp) 3 Ni(Gatmp) 2 (tmp = 2,2,6,6-tetramethylpiperidido) [44] or the 2.1700(4) Å Ni{C(SiMe 3 ) 3 } 4 in which the gallium carries a monodentate ligand [45].…”

“…Reactions of GaL with Ni(CO) 4 : Synthesis and Structure of Ni(CO) 3 (GaL) (3) and Ni(CO) 2 (GaL) 2 (4) Reaction of GaL with Ni(CO) 4 at room temperature in benzene or hexane led to an immediate evolution of CO and formation of the nickel complex Ni(CO) 3 Ni ( [42,43]. To unambiguously characterize this compound single crystals were grown for an X-ray diffraction analysis.…”

One-Pot Synthesis of Heavier Group 14 N-Heterocyclic Carbene Using Organosilicon Reductant

“…In the case of NHGe and NHSn, the initial step involves the reduction of N-substituted 1,4-diaza-1,3-butadiene by lithium metal, followed by cyclization of the dianion with the corresponding Group 14 E(II) halides [12][13][14][15]. While in the case of NHSi, the precursor cyclic diaminodichlorosilane was obtained by the cyclization of the dilithiated diazabutadiene with SiCl 4 [16][17][18].…”

“…Inorganics 2018, 6, x FOR PEER REVIEW 2 of 6 the choice of reductant play crucial role in the reductive dehalogenation step [12][13][14][15][16][17][18]. Moreover, the syntheses suffer from involvement of multiple steps, associated metal salts as byproduct and hence product isolation difficulties, and sometimes cases of over reduction.…”