Stabilisation of trivalent platinum by structurally accommodating thiamacrocycles

Abstract

The complex cation [Pt(1)2]2+ [(l) = 1,4,7-trithiacyclononane] shows a quasi square based pyramidal structure with one non-bonding sulphur donor atom; electrochemical oxidation at +0.5 V. vs. FcO/Fc+ (Fc = ferrocene) at 20 "C in MeCN affords a paramagnetic platinum(iri) species.

Anion and Solvent Effects upon the Structures of Platinum(II) Complexes with Thiacrown Ligands: The Crystal Structures of [Pt(9S3)2](PF6)2·2 CH3NO2, [Pt(9S3)2](BF4)2·2 CH3NO2, [Pt(9S3)2](OTf)2·2 CH3NO2, and [Pt(18S6)](BF4)2

“…Notably, all three structures contrast with the prior structure of [Pt(9S3) 2 ](PF 6 ) 2 , which shows one exodentate sulfur, non-centrosymmetrical binding of the two ligands, and no solvent molecules. [6] Our structural results, therefore, do not support the hypothesis that [S 4 ϩ S 1 ] binding of 9S3 to Pt II is its common and preferred coordination mode due to the conformation of the ligand. [11] Rather, packing effects, which depend upon the specific counterion and crystallization solvent, control whether [S 4 2 structure Ϫ a dramatic effect arising from packing forces.…”

“…[11] Rather, packing effects, which depend upon the specific counterion and crystallization solvent, control whether [S 4 2 structure Ϫ a dramatic effect arising from packing forces. [6] SϪPtϪS chelate bite angles in the three structures are slightly less than 90°, with a commensurate expansion of the non-chelate angle to slightly above 90°. This effect is also seen in the S equatorial ϪPtϪS axial angles (Table 1), which are less than 90°, showing the axial sulfur bending towards the metal center.…”

“…The previous structure shows one short S···F contact (3.43 Å ) between the exodentate sulfur and a fluorine atom in one hexafluorophosphate anion. [6] A second fluorine in the same anion, cis to this first fluorine, links to an equatorial sulfur in a different cation at 3.23 Å . For the triflate structure, the anions and solvent lie along the open side of the complex cation, away from the axial sulfur position.…”

“…[15] Also, the electronic nature of these interactions is of considerable theoretical interest as they serve as intermediate cases between bonding and non-bonding situations. [16] The initial report of the crystal structure of the complex [Pt(9S3) 2 ](PF 6 ) 2 revealed, surprisingly, [6] an elongated Figure 1, Structure 3). In the reported structure, the two 9S3 ligands were not centrosymmetrically bound to the Pt II .…”

mer-Bis[2,6-bis(1-phenyliminoethyl)pyridine-N,N',N'']copper(II) Diperchlorate

“…In contrast to this effect observed at the d 9 Cu I1 centre in compound (1), the two ligands around the d 8 Ni n centre in bis{2,6-bis[ 1-(3-phenylpropylimino)ethyl]-pyridine-N,N~,N"}nickel(II) bis(tetrafluoroborate), (2) (Blake, Lavery, Hyde & Schr6der, 1989), are equivalent. Although the nickel coordination sphere is also distorted octahedral, the Ni--Nimine separations [2.121 (7), 2.135 (7), 2.142 (7) and 2.160 (7) ,~,; mean 2.140 (141 ,&] occupy a narrow range.…”