The vibrational spectra of co-ordination compounds of formula trans-MX2Y2. Part III. Low-frequency vibrations of group VIII complexes where X = Cl, Br, and I, and Y = Me2S, Me2Se, and Me2Te

Abstract

Infrared and Raman spectra of solid samples of co-ordination compounds of formula trans-[MX, Y,] where M =Pd" and Pt'l, X = Ci, Br, and I, and Y = Me&, Me,Se, and Me,Te have been recorded over the frequency range 100-500 cm.-l. Assignments of fundamental modes to observed spectra are suggested. The frequencies of the vibrations of the relevant bonds suggest strongly that in bond order M-CI > M-Br > M-l and M-S > M-Se < M-Te.IN Parts I and I1 an account was given of the infrared and Raman spectra of solid samples of a series of platinum(I1) and palladium(11) di-and tetra-ammine complexes. It was concluded that the rigidity of the metal-ligand bond declined in the order M-C1 > M-Br > M-I. A careful analysis of the spectra of the dimethyl chalcogenides has been completed recently 374 and it seemed logical to prepare complexes of these ligands and to examine their vibration spectra. In this Paper, the low-frequency vibrations are reported and discussed with particular reference to the stretching vibrations of the metal-ligand bonds.A few reports are to be found in the literature in which vibrations of platinum-and palladium-to-sulphur, -selenium, or -tellurium bonds are discussed5-' but the only reports to be found on complexes containing dimethyl chalcogenides are those of Greenwood 8 and Lewis and their co-workers.

PtIIDiimine Chromophores with Perfluorinated Thiolate Ligands: Nature and Dynamics of the Charge-Transfer-to-Diimine Lowest Excited State

“…Most of the vibrations of Pt(bpy)Cl 2 that are resonantly enhanced under 457.9 nm excitation belong to the coordinated bpy . In the 300−400 cm -1 region, Pt−Cl and Pt−N vibrations might also be anticipated …”

cis‐trans Isomerization of bis(Dialkylsulfide)Dihaloplatinum(II) Complexes in Solution

“…Thus the mechanism is probably the usual associative one for substitution in square planar d8-complexes. [13], cis-Pt(Bz,S),CI, [lo], [Pt(MezS)3Cl]BF4 [8] and trans-Pt(Me,Se),Cl, [9]. Prefiaration of cisaitd trans-Pt(MeSPh),Cl,: an ethanolic solution of thioanisol (5.7 mmol) was added to an aqueous solution of K,PtC14 (2,4 mmol) and the mixture stirred for 6 h. A yellow precipitate formed containing 60% of cis isomer.…”

Metal chelates of biologically important compounds. I. Complexes of DL-ethionine and S-methyl-L-cysteine

“…Metal-sulfur stretching vibrations have been reported to occur at 358-308 cm-1 for diethyldithiophosphato complexes,22 399-376 cm-1 for monothio-/3-diketone complexes,23 as a doublet at 373-338 and 359-333 cm-1 for some tris(1,2-dithiolato)rhenium complexes,24 and as a doublet at 320-317 and 310-305 cm-1 for cis-{ PtX2 [(CH3)2S]2} (X = Cl, Br). 25 However, in thiourea complexes of transition metals y(M-S) occurs in the range 298-205 cm-1. 26 The two bands at 331-321 and 305-288 cm-1 in the spectra of the chloro complexes are assigned as metalchlorine stretching vibrations, since the bromo complexes do not absorb in this region but display a band at 240-230 cm-1; however, this band was poorly resolved in the spectra which we were able to obtain.…”