Cis/trans isomers of PtX ₂ L ₂ (X = halogen, L = neutral ligand); the crystal structures of two polymorphs of cis-dichlorobis(dibenzyl sulfido-κS)platinum(II) in the temperature range 100–295 K

Abstract

The structures of two polymorphs, one triclinic and one monoclinic, of cis-dichlorobis(dibenzyl sulfido-kappaS)platinum(II), cis-PtCl(2)(Bz(2)S)(2), have been determined at 295, 250, 200, 150 and 100 K. In both polymorphs the complex has a structure where platinum(II) coordinates two dibenzyl sulfide molecules and two chloro ligands, forming a complex with pseudo-square-planar coordination geometry. The triclinic polymorph shows disorder at all temperatures. Both polymorphs have a packing arrangement involving centrosymmetric structural dimers. cis-PtCl(2)(Bz(2)S)(2) belongs to a group of complexes with the general formula PtX(2)L(2), where X is a halogen and L is a ligand with a donor atom from groups 14, 15 or 16. The distribution of structural classes among 173 cis-PtX(2)L(2) compounds found in the Cambridge Structural Database (CSD, Version 5.28, November 2006) has been investigated. The predominant structural class [notation according to Belsky & Zorkii (1977). Acta Cryst. A33, 1004-1006] among the cis compounds is P2(1)/c, Z = 4 (1) (73 structures, 42%), followed by P\bar 1, Z = 2 (1) (33 structures, 19%). Inversion centres combined with the screw-axis/glide plane are the dominating packing operators (56%) followed by the inversion centre (21%). The cis and trans influence in cis/trans-PtCl(2)L(2) compounds has been investigated using data from the CSD. The cis influence is small for donor atoms in groups 15 and 16. The trans influence is small for group 16 donor atoms and for nitrogen, but for phosphorus it is significantly greater than the other donor atoms studied.

Concomitant polymorphic behavior of di-μ-thiocyanato-κ2 N:S;κ2 S:N-bis[bis(tri-p-fluorophenylphosphine-κP)silver(I)]

“…These complexes are known to adopt a variety of geometries and nuclearities with different counterions and different ratios of phosphine (or other group 15 elements) ligands (Meijboom et al, 2009), and can crystallize in different polymorphic forms, a phenomenon that was discussed previously , showing the extreme differences such as 'cubic' (Teo & Calabrese, 1976a) or 'step' tetramers (Teo & Calabrese, 1976b). The environments of molecules in the crystals of polymorphic structures are often different and have an effect on the geometry of metal complexes (Hansson et al, 2008). This can easily be studied in cases where one of the polymorphs has more than one molecule in the asymmetric unit (Hansson et al, 2008).…”

“…The environments of molecules in the crystals of polymorphic structures are often different and have an effect on the geometry of metal complexes (Hansson et al, 2008). This can easily be studied in cases where one of the polymorphs has more than one molecule in the asymmetric unit (Hansson et al, 2008). Previous studies were performed on the roles played by different properties of ligands during the crystallization of simple silver(I) salts with Group 15 donor ligands, with the initial focus on tri-p-tolylphosphine complexes Meijboom, 2006Meijboom, , 2007Venter et al, 2006; which allowed for comparison with the isosteric triphenylphosphine complexes.…”

An X-ray powder diffraction study ofcis-dichloridobis(2-methyl-2H-tetrazol-5-amine-κN4)platinum(II), a tetrazole-containing analogue of cisplatin

“…Complex (I) belongs to 'structural class' P2 1 2 1 2 1 , Z = 4(1) (notation of Zorkii et al, 1977), which is rare among the cis isomers of PtX 2 L 2 . According to the analysis of Hansson et al (2008), based on the CSD, the distribution of structural classes of cis-PtX 2 L 2 complexes (X is a halogen and L is a ligand with a donor atom from group 14, 15 or 16) is dominated by P2 1 /c, Z = 4(1) (42% of compounds), followed by P1, Z = 2(1) (19%), and with a much lower representation for P2 1 2 1 2 1 , Z = 4(1) (5%).…”