The Instability of Ni{N(SiMe3 )2 }2 : A Fifty Year Old Transition Metal Silylamide Mystery.

The characterization of the unstable Ni(II) bis(silylamide) Ni{N(SiMe3 )2 }2 (1), its THF complex Ni{N(SiMe3 )2 }2 (THF) (2), and the stable bis(pyridine) derivative trans-Ni{N(SiMe3 )2 }2 (py)2 (3), is described. Both 1 and 2 decompose at ca. 25 °C to a tetrameric Ni(I) species, [Ni{N(SiMe3 )2 }]4 (4), also obtainable from LiN(SiMe3 )2 and NiCl2 (DME). Experimental and computational data indicate that the instability of 1 is likely due to ease of reduction of Ni(II) to Ni(I) and the stabilization of 4 through dispersion forces.

Polarized neutron diffraction and Mössbauer spectral study of short-range magnetic correlations in the ferrimagnetic layered compounds(PPh4)[FeIIFeIII(ox)3]and(NBu4)[FeIIFeIII(ox)3]

Short-range antiferromagnetic correlations have been studied in the layered compounds (PPh 4 ) [Fe I I Fe I I I (ox) 3 ] and (NBu 4 ) [Fe I I Fe I I I (ox) 3 ] by neutron polarization analysis and Mossbauer spectroscopy. Polarized neutron diffraction profiles obtained between 2 and 50 K on (d 2 0 -PPh 4 ) [Fe I I Fe I I I (ox) 3 ] show no magnetic Bragg scattering; the lack of such scattering indicates the absence of long-range magnetic order. However, a broad asymmetric feature observed at a Q of ca. 0.8 A - 1 is attributed to two-dimensional short-range magnetic correlations, which are described by a Warren function. The correlation length is ca. 50 A between 2 and 30 K and then decreases…

Mössbauer Spectral Study of Two Layered Honeycomb Molecular Magnets: PPh4FeIIFeIII(ox)3 and NBu4FeIIFeIII(ox)3

The Mossbauer spectra of the layer ferrimagnets PPh4FeIIFeIII(ox)3 and NBu4FeIIFeIII(ox)3 have been measured between 1.9 and 315 K. The paramagnetic spectra exhibit both high-spin iron(II) and iron(III) doublets. The iron(II) quadrupole splittings are negative and decrease substantially upon cooling as a result of a low-symmetry crystal field splitting. In contrast, the iron(III) splittings are small, positive, and virtually independent of temperature. The respective magnetic ordering temperatures of 30 and 42.5 K agree well with the phase observed by bulk magnetometry and the magnetic sextets yield hyperfine fields of ca. 60 kOe for iron(II) and 540 kOe for iron(III). The unusually low iro…

The Instability of Ni{N(SiMe3)2}2: A Fifty Year Old Transition Metal Silylamide Mystery

The characterization of the unstable NiII bis(silylamide) Ni{N(SiMe3)2}2 (1), its THF complex Ni{N(SiMe3)2}2(THF) (2), and the stable bis(pyridine) derivative trans-Ni{N(SiMe3)2}2(py)2 (3), is described. Both 1 and 2 decompose at ca. 25 °C to a tetrameric NiI species, [Ni{N(SiMe3)2}]4 (4), also obtainable from LiN(SiMe3)2 and NiCl2(DME). Experimental and computational data indicate that the instability of 1 is likely due to ease of reduction of NiII to NiI and the stabilization of 4 through dispersion forces. peerReviewed

Poster contributions

CCDC 1401116: Experimental Crystal Structure Determination

Related Article: Michelle Faust, Aimee M. Bryan, Akseli Mansikkamäki, Petra Vasko, Marilyn M. Olmstead, Heikki M. Tuononen, Fernande Grandjean, Gary J. Long and Philip P. Power|2015|Angew.Chem.,Int.Ed.|54|12914|doi:10.1002/anie.201505518

CCDC 1401114: Experimental Crystal Structure Determination

Related Article: Michelle Faust, Aimee M. Bryan, Akseli Mansikkamäki, Petra Vasko, Marilyn M. Olmstead, Heikki M. Tuononen, Fernande Grandjean, Gary J. Long and Philip P. Power|2015|Angew.Chem.,Int.Ed.|54|12914|doi:10.1002/anie.201505518

CCDC 1401113: Experimental Crystal Structure Determination

Related Article: Michelle Faust, Aimee M. Bryan, Akseli Mansikkamäki, Petra Vasko, Marilyn M. Olmstead, Heikki M. Tuononen, Fernande Grandjean, Gary J. Long and Philip P. Power|2015|Angew.Chem.,Int.Ed.|54|12914|doi:10.1002/anie.201505518

CCDC 1401115: Experimental Crystal Structure Determination

Related Article: Michelle Faust, Aimee M. Bryan, Akseli Mansikkamäki, Petra Vasko, Marilyn M. Olmstead, Heikki M. Tuononen, Fernande Grandjean, Gary J. Long and Philip P. Power|2015|Angew.Chem.,Int.Ed.|54|12914|doi:10.1002/anie.201505518