Reactions of toluene-p-sulfonyl azide and isocyanate with low valent transition-metal complexes

The reactions of toluene-p-sulphonyl azide (RN3) with the complexes Pd(PPh3)3CO and M(NO)(CO)(PPh3)2(M = Rh or Ir) in benzene yield urea derivatives of the type Pd(PPh3)2(RNCONR) and M(NO)(PPh3)2(RNCONR)(R =p-CH3C6H4SO2). From Pt(PPh3)n(CO)4 –n(n= 2 or 3) and RN3 however a more complex compound (PPh3)2Pt(R2N4CO) is obtained, whilst the platinum ureylene complex Pt(PPh3)2(RNCONR) can be synthesized by oxidative addition of NN′-ditoluene-p-sulphonyl urea to Pt(PPh3)4. The urea complexes have also been prepared by treatment of M(PPh3)4(M = Pd or Pt) and M(NO)(PPh3)3(M = Rh or Ir) with toluene-p-sulphonyl isocyanate. Similarly RhCl(PPh3)2(RNCONR) has been isolated from the reactions of Rh(PPh3)3Cl with RNCO or RNHCONHR. In protic solvents such as alcohols R′OH (R′= Me, Et, or Prn) the reactions of RN3 with complexes Pt(PPh3)n(CO)4 –n(n= 2 or 3) lead to different products, as expected. For n= 2, the bis-alkoxycarbonyl derivative trans-Pt(PPh3)2(CO2R′)2 has been isolated, whereas for n= 3, Pt(PPh3)2N3(–[graphic omitted]–COOR′) is the main product. Treatment of the hydride complex RhH(Ph2PCH2CH2PPh2)2 with toluene-p-sulphonyl azide gives a dimeric complex, probably with a di-imide bridge (Ph2PCH2CH2PPh2)2Rh(RNNR)Rh(Ph2PCH2CH2PPh2)2.