ABSTRACT
The reaction between diphosphorus derivatives [(Cl ImDipp )P2 (Dipp)]OTf (1[OTf]) and [(Cl ImDipp )P2 (Dipp)Cl] (1[Cl]) with the cyclotetraphosphido cobalt complex [K(18c-6)][(PHDI)Co(η4 -cyclo-P4 )] (2) leads to the formation of complex [(PHDI)Co{η4 -cyclo-P6 (Dipp)(Cl ImDipp )}] (3), which features an unusual hexaphosphido ligand [Cl ImDipp =4,5-dichloro-1,3-bis(2,6-diisopropylphenyl)imidazol-2-yl, Dipp=2,6-diisopropylphenyl, 18c-6=18-crown-6, PHDI=bis(2,6-diisopropylphenyl)phenanthrene-9,10-diimine]. Complex 3 was obtained as a crystalline material with a moderate yield at low temperature. Upon exposure to ambient temperature, compound 3 slowly transforms into two other compounds, [K(18c-6)][(PHDI)Co(η4 -P7 Dipp)] (4) and [(PHDI)Co{cyclo-P5 (Cl ImDipp )}] (5). The novel complexes 3-5 were characterized using multinuclear NMR spectroscopy and single-crystal X-ray diffraction. To shed light on the formation of these compounds, a proposed mechanism based on 31 Pâ NMR monitoring studies is presented.
ABSTRACT
Transition-metal mediated white phosphorus activation is of high interest as an ecological alternative to P4 chlorination pathway to the practically useful phosphorus products. Herein, we report a facile approach for P4 activation, transformation and subsequent functionalization using cobalt complexes bearing PNP ligands. The use of N,N-bis(diphenylphosphino)amine as a ligand allows one to transform P4 tetrahedron into a zig-zag chain with the formation of complex [Co(Ph2 PNHP(Ph2 )PPPPP(Ph2 )NHPPh2 )]BF4 (4). The presence of organic substituent at nitrogen atom in PNP ligand enables one to obtain complexes with η1 -coordinated P4 molecule, which indicates a crucial role of N-H bond in transformation of white phosphorus tetrahedron. Additionally, complex 4 can readily be functionalized by means of the reaction with Ph2 PCl leading to the formation of a new complex bearing unique P9 -ligand. The obtained results provide opportunities for facile construction of new polyphosphorus ligands in the coordination sphere of transition metal complexes.
ABSTRACT
An example of an octaphosphane of type R2 P8 (R=(DDP)Ga) was isolated by treatment of cage compound (DDP)GaP4 (2, DDP=(2,6-diisopropylphenyl)(4-((2,6-diisopropylphenyl)imino)pent-2-en-2-yl)amide) with (C6 F5 )2 PBr. The initially formed endo-exo butterfly shaped pentaphosphane 7 rapidly rearranges to the more stable exo-exo isomer 8, which undergoes dimerization to decaphosphane 11. Compound 11 unexpectedly eliminates tetraaryldiphosphane 13 to give tetracyclo[3.3.0.02,7 .04,6 ]octaphosphane [(DDP)GaBr]2 P8 (12). The reaction steps were confirmed by crystal structure analysis of the key intermediates and supported by kinetic studies using NMR techniques.