Electronic Spectra of Square-Planar Bis(tertiary phosphine)dialkynyl Complexes of Nickel(II), Palladium(II), and Platinum(II)

Abstract

Abstract Electronic spectra of trans-[L2M(C≡CR)2], (L=tertiary phosphine or tertiary stibine, and M=Ni, Pd or Pt) have been studied in solution from 220 mμ to 360 mμ. Nickel and platinum complexes showed three intense absorption bands. The lowest energy band was particularly sensitive to substituents of alkynyl groups. This band was assigned empirically to the transition between the molecular orbitals involved in metal-alkynyl bonds. The possibility of π-interaction between the two alkynyl groups through central metal was discussed in relation to the influence of R.