- Synthesis and characterization of four-membered gallium-arsenic ring compounds containing a bridging As(SiMe3)2 group: crystal structures of and
-
The first organogallium four-membered ring compounds with arsenic, halogen mixed bridging to be characterized completely, Ph2(X = Cl (1) and X = Br (2) were prepared by the reaction of (Me3Si)3As (3) with Ph2GaCl and Ph2GaBr, respectively.X-ray crystallographic analyses show the compounds to be isostructural with each containing a non-planar Ga-As-Ga-X four membered ring.Isomorphous crystals of 1 and 2 belong to the monoclinic system, space group P21/c (C52h), with four molecules in unit cells of dimensions: a 10.560(3), b 15.797(3), c 20.591(4) Angstroem, β 92.17(2) deg, V 3433(2) Angstroem3 for 1, and a 10.653(1), b 15.777(2), c 20.517(2) Angstroem, β 91.97(1) deg, V 3446(1) Angstroem3 for 2.The non-planarity of the rings is manifested in the halogen atom displacements of 0.256 Angstroem in 1 and 0.293 Angstroem in 2 from the respective Ga-As-Ga' planes.Deviations from overall C2y symmetry serve to relieve unfavorable intramolecular bulky ring substituent interaction present in such a symmetric form.The dimer 2 (4), obtained from the reaction of Ph2GaCl and LiAs(SiMe3)2, has been characterized by partial elemental analysis, NMR spectroscopy and cryoscopic molecular weight determination.An alternative route to the synthesis of 1 by reaction of 4 and Ph2GaCl was investigated via NMR spectroscopy.
- Holley, William K.,Wells, Richard L.,Shafieezad, Soheila,McPhail, Andrew T.,Pitt, Colin G.
-
-
Read Online
- Synthesis and thermolysis of alkyl- and phenylamido diphenylgallium, [Ph2GaN(H)R]2. Isolation and structural characterization of (PhGaNMe)7 and (PhGaNPh)4
-
Alkyl- and phenylamido diphenylgallium compounds, [Ph2GaN(H)R]2 (R = Me, 1; Et, 2; nPr, 3; iBu, 4; Ph, 5), were prepared from the reactions of Ph3Ga with the corresponding primary amines and aniline at elevated temperatures and were characterized by elemental analysis, mass spectroscopy, and 1H NMR and IR spectroscopy. These dimeric compounds contained bridging amido groups and exhibited both trans and cis isomers in sulution. Thermolysis of compounds 1 and 5 was carried out either without solvent or in dodecane solutions, and two clusters, (PhGaNMe)7 6 and (PhGaNPh)4 7, were isolated in 24% and 55% yields and characterized. The structure of 6 consisted of a heptameric Ga7N7 core constructed with Ga2N2 and Ga3N3 rings, and the structure of 7 possessed a Ga4N4 cubane core.
- Luo, Bing,Gladfelter, Wayne L.
-
-
Read Online
- The Alkylaluminate/Gallate Trap: Metalation of Benzene by Heterobimetallic Yttrocene Complexes [Cp*2Y(MMe3R)] (M = Al, Ga)
-
Yttrocene derivatives [Cp*2Y(MMe4)] (Cp? = C5Me5; M = Al, Ga) and Cp*2Y[Me3Al{B(NDippCH)2}] (Dipp = C6H3iPr2-2,6) deprotonate benzene at elevated temperatures via the release of methane. The formation of [Cp*2Y(Me2MPh2)] (M = Al, Ga), Cp*2Y(MPh4) (M = Al, Ga), Cp*2Y[Me2AlPh{B(NDippCH)2}], and Cp*2Y[AlPh3{B(NDippCH)2}] can be controlled via the temperature applied. The activation temperature and formation of the coordinatively unsaturated reactive [Cp*2YMe] strongly depend on the coordination strength of the displaceable Lewis acids [AlMe3]2, GaMe3, and [Me2Al{B(NDippCH)2}]2. Hence, [Cp*2Y(AlMe4)] requires temperatures above 100 °C to metalate benzene, while Cp*2Y[AlMe3{B(NDippCH)2}] undergoes C-H-bond activation even at ambient temperatures. A kinetic deuterium isotope effect was observed for the reactions in C6D6 solutions. Distinct differences in the stabilities of the bulky Group 13 anions ([Me2MPh2]-, [MPh4]-, [Me3Al{B(NDippCH)2}]-, [Me2AlPh{B(NDippCH)2}]-, and [AlPh3{B(NDippCH)2}]-) are assessed by detailed studies of the coordination chemistry with tetrahydrofuran (THF) and by variable-temperature 1H NMR spectroscopy. Thus, increased steric bulk or a reduced Lewis acidity of the Group 13 metal center promote temperature-sensitive dissociation of trivalent Group 13 alkyl entities. Consequently, compound Cp*2Y[AlPh3{B(NDippCH)2}] was found to engage in a dissociation equilibrium with [Cp*2YPh] and AlPh2{B(NDippCH)2} in a C6D6 solution at ambient temperature. The reaction of Cp*2Y[AlPh3{B(NDippCH)2}] with THF results in the concomitant formation of monometallic Cp*2YPh(THF) and the solvent-separated ion pair [Cp*2Y(THF)2][AlPh3{B(NDippCH)2}].
- Bonath, Martin,Sch?dle, Dorothea,Maichle-M?ssmer, C?cilia,Anwander, Reiner
-
supporting information
p. 14952 - 14968
(2021/09/28)
-
- Aryl(dimethyl)gallium compounds and methyl(diphenyl)gallium: Synthesis, structure, and redistribution reactions
-
Treatment of diphenylmercury with an excess of trimethylgallium at higher temperatures resulted in the formation of dimethyl(phenyl)gallium (1). Similarly, reaction of 1-chloromercurio(4-methylbenzene) and 1-chloromercurio(4-tert-butylbenzene) with an excess of trimethylgallium gave dimethyl(4methylphenyl)gallium (2) and dimethyl(4-tert-butylphenyl)gallium (3), respectively. Treatment of diphenylmercury with an equivalent amount of trimethylgallium resulted in the formation of methyl(diphenyl)gallium (4). The X-ray crystallographic studies of compounds 1, 2, 3, and 4 revealed the presence of trigonal planar coordinate gallium atoms in monomeric molecules, which associate to polymeric strands by additional intermolecular gallium π-aryl contacts, thus leading to an overall trigonal bipyramidal coordination geometry at gallium. Compounds 1-4 are stable in the solid state and in solution. Substituent redistribution reactions take place at higher temperatures and at room temperature in the presence of THF. Compound 1 could also be prepared by the reaction of triphenylgallium with an excess of trimethylgallium at higher temperatures.
- Jutzi, Peter,Izundu, Joseph,Neumann, Beate,Mix, Andreas,Stammler, Hans-Georg
-
p. 4565 - 4571
(2009/02/07)
-