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ABSTRACT: The reaction of 2-lithio-1,3,5-trimethyl-1,3,5-triazacyclohexane with YCp(2)Cl leads to the formation of a donor-functionalised mono-anionic amide ligand, 1,3,5-trimethyl-2-(methylamidomethyl)-1,3,5-triazacyclohexane, bonded to the YCp(2) unit. The reaction involves a cleavage of the 1,3,5-triazacyclohexane ring and such a cleavage is also observed in the analogous reaction with (Me(3)C)(2)GaCl, where a MeN[double bond, length as m-dash]CH(-) fragment is formed. No such cleavage occurs in the reaction of the related dilithiated bicyclic bis(3-methyl-1,3-diazacyclohex-1-yl)methane with YCpCl(2).3thf, which affords a mixed lithium-yttrium organyl.
Chemical Communications 09/2010; 46(35):6536-8. · 6.17 Impact Factor
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ABSTRACT: The reaction of the donor functionalised N,N-bis[2-(pyrid-2-yl)ethyl]hydroxylamine [HON(C2H4-o-py)2] and three equivalents of the Lewis-acids AlMe3, GaMe3 or InMe3 resulted in the formation of dimethylhydroxylaminato-metal complexes of the general constitution [MMe2ON(C2H4-o-py)2 x 2 MMe3] with M = Al (1), Ga (2) or In (3) by methane elimination. An alternative method to generate complexes 1 and 2 is the transmetalation of [YCp2ON(C2H4-o-py)2] with an excess of AlMe3 or GaMe3, respectively. All compounds were characterised by elemental analysis, NMR spectroscopy and single-crystal X-ray diffraction. The complexes [GaMe2ON(C2H4-o-py)2 x 2 GaMe3] (2) and [InMe2ON(C2H4-o-py)2 x 2 InMe3] (3) show highly dynamic behaviour in solution with the two pyridine nitrogen atoms changing their coordination to the metal atoms rapidly at ambient temperature. VT 1H NMR experiments showed that this dynamic exchange can be frozen on the NMR time scale. In contrast to 2 and 3, complex 1 does not change its coordination mode at ambient temperature in non-coordinating solvents.
Dalton Transactions 08/2010; 39(30):7073-9. · 3.84 Impact Factor
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Berichte der deutschen chemischen Gesellschaft 05/2010; 2010(18):2774 - 2786. · 2.94 Impact Factor
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Chemistry 09/2009; 15(43):11701 - 11709. · 5.93 Impact Factor
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ABSTRACT: The reaction of the donor-functionalised N,N-bis(2-{pyrid-2-yl}ethyl)hydroxylamine and [LnCp3] (Cp=cyclopentadiene) resulted in the formation of bis(cyclopentadienyl) hydroxylaminato rare-earth metal complexes of the general constitution [Ln(C5H5)2{ON(C2H4-o-Py)2}] (Py=pyridyl) with Ln=Lu (1), Y (2), Ho (3), Sm (4), Nd (5), Pr (6), La (7). These compounds were characterised by elemental analysis, mass spectrometry, NMR spectroscopy (for compounds 1, 2, 4 and 7) and single-crystal X-ray diffraction experiments. The complexes exhibit three different aggregation modes and binding motifs in the solid state. The late rare-earth metal atoms (Lu, Y, Ho and Sm) form monomeric complexes of the formula [Ln(C5H5)2{eta2-ON(C2H4-eta1-o-Py)(C2H4-o-Py)}] (1-4, respectively), in which one of the pyridyl nitrogen donor atoms is bonded to the metal atom in addition to the side-on coordinating hydroxylaminato unit. The larger Nd3+ and Pr3+ ions in 5 and 6 make the hydroxylaminato unit capable of dimerising through the oxygen atoms. This leads to the dimeric complexes [(Ln(C5H5)2{mu-eta1:eta2-ON(C2H4-o-Py)2})2] without metal-pyridine bonds. Compound 7 exhibits a dimeric coordination mode similar to the complexes 5 and 6, but, in addition, two pyridyl functions coordinate to the lanthanum atoms leading to the [(La(C5H5)2{ON(C2H4-o-Py)}{mu-eta1:eta2-ON(C2H4-eta1-o-Py)})2] complex. The aggregation trend is directly related to the size of the metal ions. The complexes with coordinative pyridine-metal bonds show highly dynamic behaviour in solution. The two pyridine nitrogen atoms rapidly change their coordination to the metal atom at ambient temperature. Variable-temperature (VT) NMR experiments showed that this dynamic exchange can be frozen on the NMR timescale.
Chemistry 09/2009; 15(43):11701-9. · 5.93 Impact Factor
