Spectra of square-planar complexes

Circular Dichroism Spectra of Square Planar Complexes Containing Prochiral Olefins and Their Stereoselective Olefin Exchange... 

L. I. Elding, and L. F. Olsson, Electronic absorption spectra of square-planar chloro-aqua and bromo-aqua complexes of palladium (11) and platinum (11), J. Phys. Cherru 82(1), 69—74 (1978)... 

The Ni—N bond distances, N-N bite distances, and N-M-N bite angles of Ni(II) macrocyclic complexes depend on the coordination number of the metal ion and the type of macrocycle. These structural parameters influence the electronic spectra and the electrochemical data. In general, Ni—N bond distances of square-planar complexes are shorter than those of the octahedral complexes because of the absence of electrons in dx2 . Furthermore, as the Ni—N bond distance in-... 

Square-planar metallo(diimine)(dithiolene) complexes generally display intense, solvatochromatic absorptions in the visible region of the spectrum that are not found in the corresponding metallo-bis(dithiolene) or metallo-bis (diimine) complexes. Futhermore, the LLCT transition energy does not vary appreciably as a function of the metal ion. Extended Hiickel calculations on Ni, Pt, and Zn metallo(diimine)(dithiolene) complexes indicate that the HOMO is comprised almost entirely of dithiolene orbital character (Figure 2), while the LUMO was found to possess essentially all diimine n orbital character (112, 252, 268). In stark contrast to the spectra of square-planar Ni and Pt metallo (diimine)(dithiolene) complexes, the psuedo-tetrahedral complexes of Zn possess extremely weak LLCT transitions. Now, it is of interest to discuss the differences in LLCT intensity as a function of geometry from a MO point of view. This discussion should help to explain important orientation-dependent differences in photoinduced electron delocalization and charge separation. 

IR spectra were consistent with the structure shown for (92), where X = F, Cl, R = Me, Et.549 The IR spectra of square-planar-coordinated dimers LPtCl2PtL, where L = range of thiosemicarbazone ligands, show that L is 7V,.S -bidentate.550 IR data for Pt(II) complexes of bioactive thiosemicarbazones derived from 4-amino-antipyrine show that they are coordinated as N,N,S-donors.551... 

Masai H, Sonogashira K, Hagihara N (1971) Electronic spectra of square-planar bis(tertiary phosphine)dialkynyl complexes of nickel(II), palladium(II), and platinum(II). Bull Chem Soc Jpn 44(8) 2226-2230... 

Wang F, Ziegler T (2005) Theoretical study of the electronic spectra of square-planar platinum (II) complexes based on the two-component relativistic time-dependent density-functional theory. J Qiem Phys 123... 

Fig. 8. Electronic absorption spectra of some planar square Pt(II) complexes of chloride and ammonia in aqueous solution (from Chatt, J., Gamlen, G. A., Orgel, L. E. J. Chem. Soc. 486 (1958))...

The tetracyanonickelate(II) ion is the most extensively studied square planar complex of nickel(II). TTie electronic spectrum is characterized by d-d bands at 31 000-32 000 cm-1 (eM 500-800) and charge transfer bands (eM = 6000-15 000) at 33 000-37 000 cm-1. In Figure 22 the electronic and MCD spectra of K2Ni(CN)4 are shown. In the MCD spectrum of the low energy band (d-d), since C terms are zero because the ground state is lAlg, the presence of the... 

---