Structural variation in ethylenediamine and -diphosphine adducts of (2,6-Me2C6H3S)2Pb: a single crystal X-ray diffraction and 207Pb solid-state NMR spectroscopy study

Abstract

Coordination complexes of (2,6-Me2C6H3S)2Pb (1) with flexible bidentate ligands have been prepared to explore new bonding environments for Pb(II) thiolates. The reaction of 1 with a series of ethylenediamine and ethylenediphosphine ligands resulted in isolation of the adducts [(2,6-Me2C6H3S)2Pb]2(tmeda) (9), [(2,6-Me2C6H3S)2Pb]3(dmpe) (10) and [(2,6-Me2C6H3S)2Pb]2(dppe) (11) [tmeda = N,N,N',N'-tetramethylethylenediamine; dmpe = bis(dimethylphosphino)ethane; dppe = bis(diphenylphosphino)ethane]. The X-ray crystal structure of 9 shows a dinuclear species in which tmeda is chelating a ψ-trigonal bipyramidal S2N2 Pb centre via axial and equatorial sites. The structure of 10 displays a trinuclear structural unit in which dmpe is chelating a ψ-trigonal bipyramidal S2P2 Pb centre via equatorial sites. Compounds 9 and 10 also contain a second unique metal centre with ψ-tetrahedral S3Pb bonding motifs. The structure of 11 shows the dppe ligand bridging two Pb ψ-tetrahedral S2P metal bonding environments. Static (207)Pb solid-state NMR (SSNMR) spectra of 9-11 and [Ph4As][(PhS)3Pb] (12) were acquired with cross polarization (CP)-CPMG and frequency swept pulse (WURST)-CPMG pulse sequences, and the efficiencies of these pulse sequences are compared. The (207)Pb SSNMR spectra reveal that the lead chemical shift anisotropies (CSA) vary greatly between the different Pb sites, and are generally large in magnitude. DFT calculations are utilized to relate the orientations of the (207)Pb nuclear magnetic shielding tensors to the molecular structures, and to aid in spectral assignment where multiple Pb centres are present. The combination of X-ray diffraction, (207)Pb SSNMR and DFT is shown to be invaluable for the structural characterization of these important structural motifs, and should find wide-ranging application to numerous lead coordination compounds.

A Facile Route to Cesium Lead Bromoiodide Perovskite Microcrystals and Their Potential Application as Sensors for Nitrophenol Explosives

“…In the present study, a mixture of TOP and DMF was used to dissolve PbBr 2 and CsI salts and it was observed that both salts were completely soluble in (DMF/TOP) mixture on slight heating. The phosphorus adduct with Pb compounds is reported in the literature, the presence of TOP may result in the interaction of phosphorus of trioctylphosphine with Pb ions . The phosphorus of trioctylphosphine will prefer to coordinate with Pb 2+ ion as compared to the Cs + ion due to higher charge density on Pb 2+ .…”

Chemical-shift tensors of heavy nuclei in network solids: a DFT/ZORA investigation of 207Pb chemical-shift tensors using the bond-valence method

“…Several recipes have been proposed to employ clusters in magnetic-shielding calculations. [13][14][15][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] By calculation with clusters of different sizes, the components of the magnetic-shielding tensor tend towards a limit as the size of the cluster is increased. Because the magneticshielding tensor depends most strongly on the electronic structure near the nucleus, [39][40][41][42] agreement with experiment is obtained with calculations on moderate-size clusters, as discussed below.…”

Calculation of chemical-shift tensors of heavy nuclei: a DFT/ZORA investigation of 199Hg chemical-shift tensors in solids, and the effects of cluster size and electronic-state approximations

“…[27][28][29] The cluster-based approach has been employed in some cases to obtain solid-state NMR parameters of heavy nuclei such as 207 Pb and 199 Hg. [30][31][32][33][34][35][36][37][38][39] In general, NMR calculations on clusters have centered on the effects of nearest neighbors, principally due to the large number of electrons in these systems. The agreement with experimental data is usually qualitative.…”