Chelate Ring Effects: The presence of chelate rings can have a significant effect on the 31P NMR chemical shift position of M-P complexes (Cf., Garrou, Chem. 1981, 229): Rev., 81, Similarly, the metal center can also have a considerable shifting effect. Consider the following dppm chelates with 4-member rings: W(CO)4(2-dppm) ppm 23.7 0 ppm Mo(CO)4(2-dppm) 23.5 ppm Cr(CO)4(2-dppm) NMR, as with and methods, can be exceptionally useful in 31P 1H 13C characterizing metal-phosphine complexes and structures: Problem: Which of the following complexes will have the highest stretching frequency in the IR? Why? CO A) [Mn(CO)3{P(OPh)3}3]+ B) W(CO)3(PEt3)3 C) [(PF3)Ag(CO)]+ Problem: Which of the following complexes will have the lowest stretching frequency in the IR? Why? CO
Chelate Ring Effects: The presence of chelate rings can have a significant effect on the 31P NMR chemical shift position of M-P complexes (Cf., Garrou, Chem. Rev., 1981, 81, 229): Similarly, the metal center can also have a considerable shifting effect. Consider the following dppm chelates with 4-member rings: W(CO)4(2-dppm) 23.7 ppm Mo(CO)4(2-dppm) 0 ppm Cr(CO)4(2-dppm) 23.5 ppm 31P NMR, as with 1H and 13C methods, can be exceptionally useful in characterizing metal-phosphine complexes and structures: Problem: Which of the following complexes will have the highest CO stretching frequency in the IR? Why? A) [Mn(CO)3{P(OPh)3}3]+ B) W(CO)3(PEt3)3 C) [(PF3)Ag(CO)]+ Problem: Which of the following complexes will have the lowest CO stretching frequency in the IR? Why?
chap04-phosphines.docx