Electronic spectra of square planar

Electronic spectra of square-planar halides and cyanides... 

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... 

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)... 

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. 

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 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-... 

The [Au(CN)4]- has square planar stereochmistry as determined for the acid H[Au(CN)4]-2H20 and the salt K[Au(CN)4] H20.636,637 The ions [Au(CN)2X2]- (X = C1, Br, I) have trans stereochemistry and are formed by oxidation of [Au(CN)2]- with the corresponding halogen.638-642 The oxidation of [Au(CN)2] by Ij is much faster than by I2 and a single step trans oxidative addition has been suggested.643 The electronic spectra of these complexes and of frans-[Au(CN)2BrCl]- have been assigned.664... 

A detailed study of the electronic spectra of the d8 complexes [M(dto)2]2 (M = Ni, Pd, Pt) and [Au(dto)2] has been reported. The spectra are virtually identical in a variety of solvents, indicating that axial perturbations due to the solvent are minimal. Dithiooxalate has a high position among square-planar NiS4 chromophores in the spectrochemical series for dithio ligands the series is maleonitriledithiolate < (CF3)2C2S2 < diethyl dithiophosphate < ethyl xanthate < diethyl dithio-carbamate < 2,3-dimercaptopropanol anion < dithiomalonate dithiooxalate.145... 

The crystal structure of the dithioacetylacetone (sacsacH) complex of cobalt(n), Co(sacsac)2, shows it to be monomeric square planar,164 in marked contrast to the acacH analogue. Pyridine 2-thiol (LH), which can exist as the thione tautomer (31) forms Co(LH)2X2 (X = Cl, Br, or I) complexes these contain the ligand bonded through the sulphur, as evidenced by the presence of a v(N—H) vibration in the i.r. spectra.165 Morpholine 4-thiocarbonic acid (32) also appears to be S-bonded in the CoL2X2 complexes (X = Cl, Br, or I), since the v(C=S) frequency is lowered upon co-ordination.166 The electronic spectra of the CoL2C12 complexes (L = thiourea, A-phenylthiourea, and TViV -diphenylthiourea) have been recorded.167... 

Although simple copper(n) cyanides cannot be prepared, stable complexes can be obtained with o-phenanthroline [Cu(phen)2CN]Y,nH20 Y = Cl, Br, I, N03, C104, or [Cu(phen)CN2]. The i.r. and electronic spectra of these compounds are consistent with trigonal-bipyramidal copper with an equatorial CN group. A square-planar [Cu(phen)(CN)2] was also prepared.680... 

Table III. Electronic Spectra of Some Square-Planar Rhodium (I) Complexes...

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