Tony Hascall

Reactions between primary amines and magnesium or zinc dialkyls: intermediates in metal imide formation

Abstract The reactions of several different primary amines with diorganomagnesium or dialkylzinc compounds are reported. Treatment of Mg(η5-C5H5)2 with t-BuNH2 or DippNH2 (Dipp = 2,6-i-Pr2C6H3−) leads to the adduct Mg(η5-C5H5)(η2-C5H5) {NH2(t-Bu)}THF (1a) or the amide Mg(η5-C5H5)(NHDipp)THF (1b). Reaction between Mg(t-Bu)2 or commercially available Mg‘Bu’2 (‘Bu’ = statistical mixture of n-Bu and s-Bu groups) gave the dimeric amide species [t-BuMg{NH(t-Bu)}THF]2 (2a) or [‘Bu’Mg{NH(t-Bu)}THF]2 (2b). In contrast reaction of Mg‘Bu’2 with MesNH2 or TriphNH2 (Mes = 2,4,6-Me3C6H2−, Triph = 2,4,5-Ph3C6H2−) gave, after suitable workup, the bisamides Mg{(NHMes)2{OP(NMe2})3}2 (3a) or Mg(NHTriph)2(THF)2·THF (3b ·THF). A bisamide, the dimer {Mg(NCy2)2} 2 (4), was isolated in almost quantitative yield by the reaction of dibutylmagnesium with 2 equiv. of HNCy2 (Cy = cyclohexyl) whereas the trimetallic amide Mg3(μ-NHDipp)4N(SiMe3)22 (5) was isolated from the transamination reaction between DippNH2 and [MgN(SiMe3)22]2. A unique product with a rare dodecameric ring structure, (EtMgNHDipp)12 (6), was observed when MgEt2 reacts with DippNH2. Reaction between ZnEt2 or Zn(CH2SiMe3)2 and a variety of primary amines afforded a selection of structurally diverse products. The compounds isolated were: {EtZn(NHPh)THF}3 (7), {EtZn(NHMes)THF}2·0.5THF (8·0.5THF), Et2Zn4(NHDipp)4(OEt)2 (9), {EtZnNH(t-Bu)}3 (10) and (Me3SiCH2ZnNHDipp)2 (11). Crystal data: 1a, a = 10.863(2), b = 9.299(2), c = 17.787(5) A , β = 98.56(2)° , monoclinic, space group P21/c, Z = 4, R = 0.048 for 2337 (I>2σ(1)) data; 2a, a = 8.922(2), b = 16.101(4), c = 11.132(2) A , β = 111.18(2)° , monoclinic, space group P21/n, Z = 2, R = 0.081 for 2076 (I>2σ(1)) data; 3a, a = 11.174(2), b = 18.161(4), c = 18.808(6) A , β = 92.34(3)° , monoclinic, space group P21/n, Z = 8, R = 0.145 for 4945 (I>2σ(I)) data; 4, a = 22.828(5), b = 10.768(2), c = 21.350(4) A , β = 117.74(3)° , monoclinic, space group P21/c, Z = 4, R = 0.067 for 6264 (I>2σ(I)) data; 5, a = 21.754(5), b = 15.214(2), c = 20.657(4) A , orthorhombic, space group Pbcn, Z = 4, R = 0.063 for 2338 (I > 2σ(I)) data; 6, a = 26.063(5), b = 35.332(4), c = 24.535(4) A , orthorhombic, space group Pnma, Z = 4, R = 0.178 for 10408 (I > 2σ(I)) data; 7, a = 12.715; (3), b = 13.606(3), c = 22.339(5) A , α = 90.53(3) , β = 96.20(3), γ = 93.85(3)°, triclinic, space group P 1 , Z = 4, R = 0.143 for 4483 (I > 2σ(I)) data; 8·0.5THF, a = 43.58(2), b = 8.724(2), c = 38.90(1) A , β = 117.49(2)° ; monoclinic, space group C2/c, Z = 16, R = 0.058 for 5587 (I>2σ(I)) data; 9, a = 10.875(2), b = 11.669(2), c = 11.968(2) A , α = 76.17(2), β = 86.52(2), γ = 69.69(2)° , triclinic, space group P 1 , Z = 1, R = 0.043 for 2733 (I > 2σ(I)) data; 10, a = 11.281(3), b = 14.891(4), c = 15.103(5) A , β = 90.88(2)° , monoclinic, space group P21/n, Z = 4, R = 0.060 for 2363 (I>2σ(I)) data; 11, a = 10.147(2), b = 11.640(2), c = 17.521(2) A , α = 71.23(1), β = 77.50(1), γ = 69.78(1)° , triclinic, space group P 1 , Z = 2, R = 0.065 for 4752 (I > 2σ(I)) data.

Subvalent germanium and tin complexes supported by a dianionic calixarene ligand: structural characterization of exo and endo isomers of [Butcalix(TMS)2]Ge

The 1,3-bis(trimethylsilyl) ether of p-tert-butylcalix[4]arene, [Butcalix(TMS)2]H2, has been synthesized and used as a dianionic ligand for Ge and Sn; notably, the Ge complex [Butcalix(TMS)2]Ge exhibits exo/endo isomerism, and provides the first calixarene system for which both isomers have been structurally characterized.

The synthesis and structure of {[η4-Me8taa]Sn(µ-O)}2: a bridging oxo complex in a system that yields terminal sulfido and selenido counterparts

Oxo transfer from N2O to divalent [η4-Me8taa]Sn (Me8taaH2 = octamethyldibenzotetraaza[14]annulene) yields the oxo complex, {[η4-Me8taa]Sn(µ-O)}2; the bridging nature of the oxo ligand provides a marked contrast with the terminal sulfido and selenido counterparts, [η4-Me8taa]SnE (E = S, Se).