RESUMO
The boron and aluminium dimers [Me2E(micro-py)]2 [E=B (1); Al (2)] are formed as mixtures of two isomers in which the group 13 centres are coordinated by the bridging 2-py ligands in a cis or trans manner, however, in contrast to previous studies, we find that simply heating the mixtures of these isomers of and gives the more thermodynamically stable (synthetically useful) trans isomers exclusively (the trans isomer being the only product in the case of the gallium analogue ).
RESUMO
The reactions of [MeAl(2-py)3Li.thf] (1) with FeCl2 or Cp2Mn in toluene-thf give simple access to the Group 13-transition metal heterometallic complexes [{MeAl(2-py)3}2M][M = Fe (2), Mn (3)]; complex has been shown to be a highly selective styrene epoxidation catalyst in air.
RESUMO
The reaction of (Me(3)Si)(3)SiK[middle dot]18-crown-6 with SbCl(3)(3 : 1 equiv.) provides a simple route to the title complex [(Me(3)Si)(3)SiSb](4). The potassium base initially acts as a nucleophile and then as a coupling agent, forming Sb-Sb bonds.
RESUMO
The low-temperature reaction of MeSiCl3 with 2-Li-C5H4N (1:3 equivalents) in thf gives [MeSi(2-C5H4N)3LiX](X = 0.2Br, 0.8Cl), containing the first example of a Si-bridged tris(pyridyl) ligand.
Assuntos
Compostos Heterocíclicos de Anel em Ponte/química , Compostos Organometálicos/química , Compostos de Organossilício/química , Piridinas/química , Compostos Heterocíclicos de Anel em Ponte/síntese química , Ligantes , Modelos Moleculares , Conformação Molecular , Compostos Organometálicos/síntese química , Compostos de Organossilício/síntese química , TemperaturaRESUMO
The reaction of CyPHNa with Sn(NMe2)2 in the presence of PMDETA (= (Me2NCH2CH2)2NMe) gives the title compound [(Sn(mu-PCy))3(Na x PMDETA)2] (1), containing an electron-deficient [(Sn(mu-PCy))]3(2-) dianion with a novel two-electron, three centre (2e-3c) bonding arrangement.
RESUMO
In contrast to the reactions of Sn(NMe(2))(2) with unfunctionalized primary amines (RNH(2)), which yield the simple imido Sn(II) cubanes [SnNR](4), the reactions of 2-pyridyl or 2-pyrimidinyl amines give the mixed-oxidation-state Sn(II)/Sn(IV) double cubanes [Sn(7)(NR)(8)]. In addition to [Sn(7)[2-N(5-Mepy)](8)] x 2thf (1 x 2thf) (py = pyridine) and [Sn(7)[2-N(pm)](8)] x 0.33thf (2 x 0.33thf) (pm = pyrimidine), which were communicated previously, the syntheses and structures of the new complexes [Sn(7)[2-N(4-Mepm)](8)] x 2thf (3 x 2thf), [Sn(7)[2-N(4,6-Me(2)pm)](8)] x 4thf (4 x 4thf), [Sn(7)[2-N(4-Me-6-MeO-pm)](8)] (5), and [Sn(7)[2-N(4-MeO-6-MeO-pm)](8)] (6) are reported. Model DFT calculations on the reactions of Sn(NMe(2))(2) with 2-pmNH(2) or PhNH(2), producing the cubanes [Sn[2-N(pm)]](4) and [SnNPh](4) (respectively), and the corresponding double cubanes [Sn(7)[2-N(pm)](8)] and [Sn(7)(NPh)(8)], show that the presence of intramolecular Sn...N bonding which spans the cubane halves of the complexes is crucial to the formation of the double-cubane structure.
RESUMO
The reactions of [Sb(NMe(2))(3)] with the primary (amido)lithiums [PhCH(2)CH(2)N(H)Li](n)(), [CyN(H)Li](n)() (Cy = C(6)H(11)), [2,4-dmpN(H)Li](n)() [2,4-dmp = 2,4-(MeO)(2)C(6)H(3)], and [(t)()BuN(H)HLi](n)() give the heterobimetallic cage complexes [{Sb(NCH(2)CH(2)Ph)(3)}(2)Li(6).2THF] (1), [{Sb(NCy)(3)}(2)Li(6).2HNMe(2)].2C(6)H(5)CH(3) (2), [Sb{N(2,4-dmp)}(3)](2)Li(6).2THF.2C(6)H(5)CH(3) (3), and [{Sb(NBu(t)())(3)}(2)Li(6)] (4), respectively. The low-temperature X-ray structures of 1-4 show that they are composed of 14-membered polyhedral cages constructed from the association of two [Sb(NR)(3)](3)(-) trianions with six Li(+) cations. Crystal data; 2, triclinic, P&onemacr;, a = 12.775(6) Å, b = 13.191(9) Å, c = 11.015(5) Å, alpha = 111.55(4) degrees, beta = 95.39(4) degrees, gamma = 115.26(4) degrees; 3, triclinic P&onemacr;, a = 10.435(4) Å, b = 12.654(5) Å, c = 14.278(6) Å, alpha = 75.31(4) degrees, beta = 79.33(4) degrees, gamma = 84.33(4) degrees; 4, monoclinic P2(1)/c, a = 9.994(1) Å, b = 17.421(2) Å, c = 10.680(2) Å, beta = 111.33(1) degrees (the structure of 1 being reported previously). Lewis base solvation of the N(6)Li(6) substructures of 1-3 results in distortion and deformation of the Li frameworks. The structural variations in the cores of 1-4 indicate that the bonding in these species is dominated by the valence and bonding demands of the p block metal centers.
