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

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