Bridge cleavage reactions of late transition-metal dimers with [Ph2P(E)NP(E′)Ph2]– (E = E′ = S or Se; E = O or S, E′ = S or Se)

Abstract

Reaction of the dinuclear complexes [{Pd(µ-Cl)(L–L)}₂] (L–L = C₉H₁₂N or C₁₂H₁₂N), [{Pt(µ-OMe)(C₈H₁₂OMe)}₂], [{RuCl(µ-Cl)(η⁶-p-MeC₆H₄Prⁱ)}₂] or [{RhCl(µ-Cl)(η⁵-C₅Me₅)}₂] with K[Ph₂P(E)NP(E)Ph₂] (E = S or Se) in thf gave the corresponding bridge cleaved, mononuclear compounds [Pd(L–L){Ph₂P(E)NP(E)Ph₂-E,E′}], [Pt(C₈H₁₂OMe){Ph₂P(E)NP(E)Ph₂-E,E′}], [RuCl{Ph₂P(E)NP(E)Ph₂-E,E′}(η⁶-p-MeC₆H₄Prⁱ)] or [Rh(η⁵-C₅Me₅)Cl{Ph₂P(E)NP(E)Ph₂-E,E′}] in high yields (64–97%). Transmetallation of K[Ph₂P(E)NP(E)Ph₂] (E = S or Se) with [{Pd(µ-Cl)(η³-C₃H₅)}₂] in a 1∶1 ratio gave [Pd(η³-C₃H₅){Ph₂P(E)NP(E)Ph₂-E,E′}]. In contrast, reaction of the potassium salt K[Ph₂P(O)NP(E)Ph₂] (E = S or Se) with [{Pd(µ-Cl)(η³-C₃H₅)}₂] under analogous conditions gave instead the dimeric species [{Pd(η³-C₃H₅)[Ph₂P(O)NP(E)Ph₂-E]}₂]. All new compounds have been characterised by a combination of multinuclear NMR [¹H, ³¹P-{¹H}, ¹⁹⁵Pt-{¹H}] and IR spectroscopy, elemental analyses and in four cases by single crystal X-ray crystallography. The six-membered ME₂P₂N metallacycles [Pd(C₉H₁₂N){Ph₂P(Se)NP(Se)Ph₂-Se,Se′}], [Pt(C₈H₁₂OMe){Ph₂P(S)NP(S)Ph₂-S,S′}] and [Pd(η³-C₃H₅){Ph₂P(S)NP(S)Ph₂-S,S′}] all adopt pseudo-boat conformations. In contrast [{Pd(η³-C₃H₅)[Ph₂P(O)NP(Se)Ph₂-Se]}₂] is binuclear with a central four-membered Pd₂Se₂ core and two pendant P(O)Ph₂ moieties. The synthesis, characterisation and preliminary complexation studies of a new potassium salt, K[Ph₂P(S)NP(Se)Ph₂], prepared by deprotonation of Ph₂P(S)NHP(Se)Ph₂ with KOBu^t are also described.