14760-22-6Relevant academic research and scientific papers
Monomeric homoleptic (2-pyridylmethyl)(tert-butyldimethylsilyl)amido complexes of the divalent metals Mg, Mn, Fe, Co, and Zn
Koch, Christian,Malassa, Astrid,Agthe, Christine,Goerls, Helmar,Biedermann, Ralf,Krautscheid, Harald,Westerhausen, Matthias
, p. 375 - 382 (2008/10/09)
The transamination reaction of M[N(SiMe3)2] 2 with (2-pyridylmethyl)(tert-butyldimethylsilyl)amine yields the corresponding homoleptic metal bis[(2-pyridylmethyl)(tert-butyldimethylsilyl) amides] of Mg (1), Mn (2), Fe (3), Co (4) and Zn (5). All these compounds crystallize from hexane isotypic in the space group C2/c. From toluene the zinc derivative precipitates as toluene solvate 5·toluene. The molecular structures of these compounds are very similar with large NMN angles to the amide nitrogen atoms with NMN values of 148° (1) and 150° (5) for the diamagnetic compounds and 156° for the paramagnetic derivatives 2 and 3. The Co derivative 4 displays a rather small NCoN angle of 142°. Different synthetic routes have been explored for compound 3 which is also available via the metallation reaction of bis(2,4,6-trimethyl phenyl)iron with (2-pyridylmethyl)(tert-butyldimethylsilyl)amine and via the metathesis reaction of lithium (2-pyridylmethyl)(tertbutyldimethylsilyl)amide with [(thf) 2FeCl2]. In course of the metathesis reaction, an equimolar amount of lithium (2-pyridylmethyl)-(tert-butyldimethylsilyl)amide and [(thf)2FeCl2] yields heteroleptic (2-pyridylmethyl)(tert- butyldimethylsilyl)amido iron(II) chloride (6) which crystallizes as a centrosymmetric dimeric molecule. The oxidative C-C coupling reaction of 5 with Sn[N(SiMe3)2]2 leads to the formation of tin(II) 1,2-bis(2-pyridyl)-1,2-bis(tert-butyldimethylsilylamido)ethane, tin metal and Zn[N(SiMe3)2]2.
Synthesis of bis[bis(trimethylsilyl)amido]iron(II). Structure and bonding in M[N(SiMe3)2]2 (M = Mn, Fe, Co): Two-coordinate transition-metal amides
Andersen,Faegri Jr., Knut,Green, Jennifer C.,Haaland, Arne,Lappert,Leung, Wing-Por,Rypdal, Kristin
, p. 1782 - 1786 (2008/10/08)
Bis[bis(trimethylsilyl)amido]iron(II), Fe[N(SiMe3)2]2, has been prepared from FeBr2(THF)2 and LiN(SiMe3)2. The corresponding Co(II) and Mn(II) amides are known to be dimeric in the crystalline phase, and the Co amide is known to be monomeric in freezing benzene. All three amides are monomeric in the gas phase at 130-150°C/1 Torr. Gas electron diffraction data are consistent with monomers of S4 symmetry (which implies ∠NMN = 180°) and bond distances of Mn-N = 195 (2), Fe-N = 184 (2), and Co-N = 184 (2) pm. Intraligand strain is reduced by opening of the SiNSi angle to 130° and rotation of SiMe3 groups. Comparison with the structures of the amido-bridged dimers of the Mn and Co amides shows that dimer formation is accompanied by significant elongation of the terminal M-N bonds and compression of the SiNSi valence angle of the terminal ligand by about 10°. Both changes are interpreted as evidence for ligand-ligand repulsion in the dimers. SCF MO calculations on high-spin 6A1 Mn(NH2)2 yield an equilibrium bond distance of Mn-N = 193 pm. It is concluded that the monomeric Mn amide is high spin. The SCF calculations suggest that the Mn-N bonding is very polar and that N-Mn pπ-dπ bonding is negligible. The photoelectron (PE) spectra of the Mn and Fe amides have been recorded and assigned. The similarity of the PE spectra of the Fe and Co amides to that of the Mn analogue suggests (but does not prove) that these species are high-spin 2B1 and 3A2, respectively.
