Axial Functionalization of Sterically Hindered Titanium Phthalocyanines

Abstract

Several axially functionalized, weakly aggregating titanium phthalocyanines (Pc) have been synthesized and characterized. Soluble titanium dichlorido tetrakis-(1,1,4,4-tetramethyl-6,7-tetralino)-porphyrazine [Pc^#TiCl₂] (<b>5</b>) has been prepared by reductive cyclotetramerization of the respective dinitrile precursor in the presence of TiCl₄. <b>5</b> and the analogous oxido compound [Pc^#TiO] (<b>1</b>) are versatile starting materials for the formation of other axially functionalized titanium phthalocyanines such as organoimido (<b>6</b>, <b>7</b>), alkoxido and aryloxido (<b>8</b>, <b>9</b>), peroxido (<b>10</b>), sulfido (<b>12</b>), disulfido (<b>11</b>), selenido (<b>14</b>) or diselenido (<b>13</b>) species. Furthermore the deprotonated ligand salts [Pc^#M₂] (M = Li (<b>2</b>), Na (<b>3</b>), K (<b>4</b>) are described. The reactivity of the titanium compounds was studied in atom group transfer reactions and ethene polymerization. The crystal structures of <b>5</b> and the free ligand Pc^#H₂ are reported. <b>5</b> crystallizes from dichloromethane in the cubic space group <i>Im</i>3̅. The two chlorido ligands exhibit a cis arrangement. The free ligand Pc^#H₂ crystallizes in the trigonal space group <i>R</i>3̅