The ¹⁹⁵Pt NMR of L₂Pt(1,2-dithiolene) Complexes

Abstract

The syntheses and characterizations of the novel platinum(II) mono-1,2-dithiolenes (COD)Pt(dddt) (1), (Ph3P)2Pt(dddt) (2), (COD)Pt(edt) (3), (Ph3P)2Pt(edt) (4), (bipy)Pt(edt) (5), and (Ph3P)(CO)Pt(dddt) (6) (COD = 1,5-cyclooctadiene; dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate; edt = ethylene-1,2-dithiolate, bipy = 2,2‘-bipyridyl) are reported. 195Pt NMR spectral analysis was performed on the above-mentioned compounds along with the previously reported compounds (COD)Pt(dmid) (7), (Ph3P)2Pt(dmid) (8), (Ph3P)2Pt(dmit) (9), (COD)Pt(mnt) (10), (Ph3P)2Pt(mnt) (11), (COD)Pt(dt) (12), and (Ph3P)2Pt(dt) (13) (dmid = 1,3-dithiole-2-oxo-4,5-dithiolate; dmit = 1,3-dithiole-2-thione-4,5-dithiolate; mnt = maleonitrile-1,2-dithiolate; dt = ethane-1,2-dithiolate). 195Pt NMR results show that, depending on the nature of L2 in L2Pt(1,2-dithiolene) complexes, the 1,2-dithiolene ligands behave as either π donors or acceptors toward the Pt metal center. 195Pt NMR is also sensitive to the relative electron-withdrawing ability of the substituents on the 1,2-dithiolene backbone which results in an ordering of chemical shifts into a series independent of L2. Support is also provided by electrochemistry, UV−vis spectroscopy, and 13C NMR. X-ray structural analysis results are given for 1, monoclinic, P21/a, a = 10.2420(10) Å, b = 10.7510(10) Å, c = 13.2890(20) Å, β = 102.870(10), Z = 4, and for 5, monoclinic, I2/a, a = 7.2294(2) Å, b = 11.4574(4) Å, c = 14.9103(6) Å, β = 89.380(15), Z = 4.

Labile Pd-sulphur and Pt-sulphur bonds in organometallic palladium and platinum complexes [(COD)M(alkyl)(S-ligand)]n+—A speciation study

“…The Pt II ion in both structures exhibits completely square planar stereochemistry, taking the centroids of the C=C olefin bond, the methyl coligands and the S atom of the S ligand, giving an almost perfect sum of angles around Pt (Table 3). Overall, the bonding parameters of the two complexes such as the X-Pt-X angles and the Pt-X and PtMe bond lengths are very similar to related [(COD)Pt(Me)] complexes [43][44][45][46][47]49,50,52,[90][91][92]. The same is true of the Pt-S bonds when compared with similar complexes [50,52,79,91].…”

“…Overall, the bonding parameters of the two complexes such as the X-Pt-X angles and the Pt-X and PtMe bond lengths are very similar to related [(COD)Pt(Me)] complexes [43][44][45][46][47]49,50,52,[90][91][92]. The same is true of the Pt-S bonds when compared with similar complexes [50,52,79,91]. A closer look reveals that the Pt-S bond is shorter for the DMSO ligand [91], respectively, are slightly longer than is found for the DMSO complex, although the NMR data suggest stronger Pt-S binding in these neutral complexes.…”

“…From the 1 H-195 Pt coupling constant of the trans-oriented olefin proton the bond strength could be quantified quite reliably. In the same way other nuclei such as 31 P in Pt phosphane complexes or 15 N in Pt amine complexes have been used to determine the binding strength of ligands [52][53][54][55][56][57][58][59].…”

Synthesis of μ-C2S44− Cobalt Complexes by Activation of the 1,3,4,6-tetrathiapentalene-2,5-dione, and Electrochemical Study of [(Cp*Co)2(μ-C2S4)]

“…This method was found unsuccessful, however, or led to the desired product in low yield. [9,10] Another reactivity pattern of dithiocarbonate groups has already been employed for the synthesis of cobaltocene dithiolene complexes, used as model for the molybdenum cofactor. [11] The reaction consists of the oxidative addition of 1,3-dithiol-2-one or 1,3-dithiole-2-thione to [CpCo(cod)] (cod ϭ cyclooctadiene).…”

Synthesis and Characterization of {Re(CO)3}4-n{PtMe3}n(OH)4, (n = 1−3). A Set of Heterobimetallic Hydroxy Cubane Complexes

“…Although a number of factors may be involved, the direction of the shift is consistent with the expectation that weaker donors will lead to upfield shifts. 26 Conclusion. We have synthesized and characterized the set of heterobimetallic hydroxy cubanes {Re(CO) 3 } 4-n {PtMe 3 } n -(OH) 4 , (n ) 1-3).…”