TY - JOUR
T1 - Tuning coordination in s-block carbazol-9-Yl complexes
AU - Ortu, Fabrizio
AU - Moxey, Graeme J.
AU - Blake, Alexander J.
AU - Lewis, William
AU - Kays, Deborah L.
N1 - Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2015/4/27
Y1 - 2015/4/27
N2 - 1,3,6,8-Tetra-tert-butylcarbazol-9-yl and 1,8-diaryl-3,6-di(tert-butyl)carbazol-9-yl ligands have been utilized in the synthesis of potassium and magnesium complexes. The potassium complexes (1,3,6,8-tBu4carb)K(THF)4 (1; carb=C12H4N), [(1,8-Xyl2-3,6-tBu2carb)K(THF)]2 (2; Xyl=3,5-Me2C6H3) and (1,8-Mes2-3,6-tBu2carb)K(THF)2 (3; Mes=2,4,6-Me3C6H2) were reacted with MgI2 to give the Hauser bases 1,3,6,8-tBu4carbMgI(THF)2 (4) and 1,8-Ar2-3,6-tBu2carbMgI(THF) (Ar=Xyl 5, Ar=Mes 6). Structural investigations of the potassium and magnesium derivatives highlight significant differences in the coordination motifs, which depend on the nature of the 1- and 8-substituents: 1,8-di(tert-butyl)-substituted ligands gave π-type compounds (1 and 4), in which the carbazolyl ligand acts as a multi-hapto donor, with the metal cations positioned below the coordination plane in a half-sandwich conformation, whereas the use of 1,8-diaryl substituted ligands gave σ-type complexes (2 and 6). Space-filling diagrams and percent buried volume calculations indicated that aryl-substituted carbazolyl ligands offer a steric cleft better suited to stabilization of low-coordinate magnesium complexes.
AB - 1,3,6,8-Tetra-tert-butylcarbazol-9-yl and 1,8-diaryl-3,6-di(tert-butyl)carbazol-9-yl ligands have been utilized in the synthesis of potassium and magnesium complexes. The potassium complexes (1,3,6,8-tBu4carb)K(THF)4 (1; carb=C12H4N), [(1,8-Xyl2-3,6-tBu2carb)K(THF)]2 (2; Xyl=3,5-Me2C6H3) and (1,8-Mes2-3,6-tBu2carb)K(THF)2 (3; Mes=2,4,6-Me3C6H2) were reacted with MgI2 to give the Hauser bases 1,3,6,8-tBu4carbMgI(THF)2 (4) and 1,8-Ar2-3,6-tBu2carbMgI(THF) (Ar=Xyl 5, Ar=Mes 6). Structural investigations of the potassium and magnesium derivatives highlight significant differences in the coordination motifs, which depend on the nature of the 1- and 8-substituents: 1,8-di(tert-butyl)-substituted ligands gave π-type compounds (1 and 4), in which the carbazolyl ligand acts as a multi-hapto donor, with the metal cations positioned below the coordination plane in a half-sandwich conformation, whereas the use of 1,8-diaryl substituted ligands gave σ-type complexes (2 and 6). Space-filling diagrams and percent buried volume calculations indicated that aryl-substituted carbazolyl ligands offer a steric cleft better suited to stabilization of low-coordinate magnesium complexes.
KW - N ligands
KW - alkaline earth metals
KW - ligand effects
KW - magnesium
KW - potassium
UR - http://www.scopus.com/inward/record.url?scp=84927617487&partnerID=8YFLogxK
U2 - 10.1002/chem.201406490
DO - 10.1002/chem.201406490
M3 - Article
SN - 0947-6539
VL - 21
SP - 6949
EP - 6956
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 18
ER -