Resorcinol Based Acyclic Dimeric and Cyclic Di- and Tetrameric Cyclodiphosphazanes: Synthesis, Structural Studies, and Transition Metal Complexes

The condensation reaction of resorcinol with <i>cis</i>-[ClP­(μ-N^<i>t</i>Bu)₂PN­(H)^<i>t</i>Bu] produced a difunctional derivative 1,3-C₆H₄[OP­(μ-N^<i>t</i>Bu)₂PN­(H)^<i>t</i>Bu]₂ (<b>1</b>), whereas the similar reaction with [ClP­(μ-N^<i>t</i>Bu)]₂ resulted in the formation of a 1:1 mixture of dimeric and tetrameric species, [{P­(μ-N^<i>t</i>Bu)}₂{1,3-(O)₂-C₆H₄}]₂ (<b>2a)</b> and [{P­(μ-N^<i>t</i>Bu)}₂{1,3-(O)₂-C₆H₄}]₄ (<b>2b</b>), which were separated by repeated fractional crystallization and column chromatography. The reaction of dimer <b>2a</b> with H₂O₂ and selenium produces tetrachalcogenides [{(O)­P­(μ-N^<i>t</i>Bu)}₂{1,3-(O)₂-C₆H₄}]₂ (<b>3</b>) and [{(Se)­P­(μ-N^<i>t</i>Bu)}₂{1,3-(O)₂-C₆H₄}]₂ (<b>4</b>), respectively. The reaction between the dimer (<b>2a</b>) and [Pd­(μ-Cl)­(η³-C₃H₅)]₂ or AuCl­(SMe₂) yielded the corresponding tetranuclear complexes, [{((Cl)­(η³-C₃H₅)­Pd)­P­(μ-N^<i>t</i>Bu)}₂{1,3-(O)₂-C₆H₄}]₂ (<b>5</b>) and [{(ClAu)­P­(μ-N^<i>t</i>Bu)}₂{1,3-(O)₂-C₆H₄}]₂ (<b>6</b>) in good yield. The complexes <b>5</b> and <b>6</b> are the rare examples of phosphorus macrocycles containing two or more exocyclic transition metal fragments. Treatment of <b>1</b> with copper halides in 1:1 molar ratio resulted in the formation of one-dimensional (1D) coordination polymers, [(CuX)­{1,3-C₆H₄{OP­(μ-N^<i>t</i>Bu)₂PN­(H)^<i>t</i>Bu}}₂]_<i>n</i> (<b>7</b>, X = Cl; <b>8</b>, X = Br; <b>9</b>, X = I), which showed the helical structure in solid state because of intramolecular hydrogen bonding, whereas similar reactions of <b>1</b> with 4 equiv of copper halides also produced 1D-coordination polymers, [(Cu₂X₂)₂{1,3-C₆H₄{OP­(μ-N^<i>t</i>Bu)₂PN­(H)^<i>t</i>Bu}₂}]_<i>n</i> (<b>10</b>, X = Cl; <b>11</b>, X = Br; <b>12</b>, X = I), but containing Cu₂X₂ rhomboids instead of CuX linkers. The crystal structures of <b>1</b>, <b>2a</b>, <b>2b</b>, <b>4</b>, <b>7</b>–<b>9</b>, and <b>12</b> were established by X-ray diffraction studies