| Abstract: | Alkaline earth metal iodides were used as templates for the synthesis of novel silicon-based ligands. Siloxane moieties were (cross-)coupled and ion-specific, silicon-rich crown ether analogues were obtained. The reaction of 1,2,7,8-tetrasila12]crown-4 ( I ) and 1,2-disila9]crown-3 ( II ) with MgI2 yielded exclusively Mg(1,2,7,8-tetrasila12]crown-4)I2] ( 1 ). The larger Ca2+ ion was then employed for cross-coupling of I and II and yielded the complex Ca(1,2,7,8-tetrasila15]crown-5)I2] ( 2 ). Cross-coupling of I and 1,2,4,5-tetrasila9]crown-3 ( III ) with SrI2 enables the synthesis of the silicon-dominant 1,2,4,5,10,11-hexasila15]crown-5 ether complex of SrI2 ( 3 ). Further, the compounds Sr(1,2,10,11-tetrasila18]crown-6)I2] ( 4 ), Sr(1,2,13,14-tetrasila24]crown-8)I2] ( 5 ), and Sr(1,2,13,14-tetrasila-dibenzo24]crown-8)I2] ( 6 ) were obtained by coupling I , 1,2-disila12]crown-4 ( IV ) or 1,2-disila-benzo12]crown-4 ( V ), respectively. Using various anions, the (cross-)coupled ligands were also observed in an X-ray structure within the mentioned complexes. These template-assisted (cross-)couplings of various ligands are the first of their kind and a novel method to obtain macrocycles and/or their metal complexes to be established. Further, the Si?O bond activations presented herein might be of importance for silane or even organic functionalization. |
