The Pseudo-Symmetric Structure of Pb(SPh)₂

Abstract

The crystal structure of Pb(SC6Hs)2 is pseudo-C-centred orthorhombic, a = 54.06(1), b = 11.468 (1), c = 7.4387(8)A,, ~ = [3 = "7 = 90 ° , Z = 16, and may be described as a partial ordering of a 1:1 disordered parent structure of symmetry Pmcn, Z = 4 (a t = a/2, b t = b/2, c ~ = c), in which the mirror imposes a 1:1 disorder on two-dimensionally polymeric layers perpendicular to a*. An ideally ordered structure has monoclinic space group Cll2t/d (P21/c using an alternative axis system b, c, [a + b]/2), but may also be described as two inversion-related substructures of Cmc2~ pseudosymmetry, where the b-glide planes of one substructure coincide with the mirror planes of the other and vice versa. Moving one substructure by b/2 relative to the other creates a different orientation of the structure. The crystal studied showed a partial disorder of each substructure relative to origins b/2 apart [0.964 (4):0.036 for one substructure and 0.584 (3):0.416 for the other].This lowers the symmetry of the average structure to C1121 with intensities realistically described as K2[(1 -15)lF(hkl)l 2 + blF(hkl)12], where K 2 for h odd, k odd reflections is 0.444 (7) of the value for h even, k even reflections, 6 is 0.325 (5) and F(hkl) is the structure factor for an ideally ordered structure. Final values for R of 0.046 and 0.090 were obtained for the 844 h even, k even and 687 h odd, k odd reflections with l(h) > 3cr(l(h)) used in refinement. A bond-valence interpretation of the bonding within the polymeric layer structure is given.

The pseudo symmetric structure of bis(dicyclohexylammonium) bis(oxalatotriphenylstannate)

“…This behavior is reminiscent of that of lead(II) dithiophenolate (Rae et al, 1997) in which the symmetry of the average structure depends on the disorder parameters. In a similar fashion, for the present structure,…”

“…A further complication comes to light if such problems are re-described in terms of substructures (Rae et al, 1997). The Pca2 1 structures can be described as two cglide related interacting substructures of P2 1 /a parent symmetry, and the Pna2 1 structures as two n-glide related interacting subgroups also of parent symmetry P2 1 /a.…”

Four New Lead(II) Thiolate Cluster Complexes – Unexpected Products of a Conventional Synthesis

“…Interestingly, the structure is neither polymeric, as in [Pb(SC 6 H 5 ) 2 ] n [9] or [Pb(S-4-CH 3 C 6 H 4 ) 2 ] n , [10] nor trimeric, as in [Pb 3 (S-2,6-iC 3 H 7 C 6 H 3 ) 6 ], [12] but is found to be oligomeric [Pb 10 {S-2,6-(CH 3 ) 2 C 6 H 3 } 20 ] (1). Complex 1 crystallizes in the space group Pbcn with the molecule residing on an inversion center ( Figure 1).…”

“…Therefore, we became interested in the synthesis of lead thiolate complexes as starting materials for the synthesis of such cluster molecules. In order to avoid known solubility problems of the mostly polymeric lead thiolates [8][9][10] we followed a recent recommendation of Briand [11] concerning the use of 2,6- …”

Exploring the Self-Assembled Tacticity in Aurophilic Polymeric Arrangements of Diphosphanegold(I) Fluorothiolates

“…Pb(SR F ) 2 : All lead thiolates were prepared by modification of previously published methods [32,33,34,35,36]: To a solution of Pb(CH 3 COO) 2 (5.2 mmol) in 100 mL water, thiol (HSR F ) (10.0 mmol) dissolved in about 10 mL of ethanol was added under vigorous stirring at room temperature. A white or yellow precipitate was rapidly formed.…”