ARYL-BIS(TRIORGANYLPHOSPHINE)NICKEL PHENOXIDES

Compounds of general formula trans-ArNi(PR(3))(2)OAr' (R = Et, cyclohe xyl; Ar = 2-MeC(6)H(4), 2-FC6H4; Ar' = 4-FC6H4, 4-NO2C6H4) were synthe sized by the reaction of Ar'OK with cationic nickel complexes generate d by treatment of ArNi(PR(3))(2)Cl with TlBF4. Syntheses of 4-fluoroph enoxide complexes, ArNi(PR(3))(2)OC6H4F-4, additionally give some quan tities of trans-[ArNi(PR(3))2OC(6)H(4)F-4]...[HOC6H4F-4] adducts. Exch ange reactions MeC(6)H(4)Ni(PEt(3))(2)OC6H4F-4 + XC(6)H(4)OH reversibl e arrow 2-MeC(6)H(4)Ni(PEt(3))(2)OC(6)H(4)X + 4-FC6H4OH were studied i n THF. The equilibrium is shifted to the right as the acidity of ArOH increases. A linear relationship between IgK(eq) and pK(a) of XC(6)H(4 )OH in DMSO was found. A conclusion concerning the strong polarization of the Ni-O bond was made on the basis of an analysis of the chemical shifts of fluorine atoms in 2-MeC(6)H(4)Ni(PEt(3))(2)OC6H4F-4.