Structures and photoluminescence of dinuclear platinum(II) and palladium(II) complexes with bridging thiolates and 2,2′-bipyridine or 2,2′∶6′,2″-terpyridine ligands

Abstract

A series of mononuclear and dinuclear platinum() thiolates with 2,2Ј-bipyridine (bpy) and 2,2Ј : 6Ј,2Љ-terpyridine (terpy) ligands having emissive LLCT (ligand-to-ligand charge-transfer) excited states were prepared and characterized by X-ray diffraction analyses. The [M 2 (dtbpy) 2 (NS) 2 ][ClO 4 ] 2 (M = Pt or Pd; dtbpy = 4,4Ј-di-tert-butyl-2,2Ј-bipyridine, NS Ϫ = pyridine-2-thiolate) complexes are isostructural to each other with intramolecular Pt ؒ ؒ ؒ Pt and Pd ؒ ؒ ؒ Pd distances being 2.917(2) and 2.891(4) Å, respectively. Assignment of LLCT absorption bands for the platinum() complexes was based on the shift in absorption energy with the substituents on the diimine and thiolate ligands. In the solid state or in solution at room temperature the platinum() complexes show photoluminescence with λ max ranging from 603 to 710 nm. The Pt II ؒ ؒ ؒ Pt II and/or ligand-ligand interactions are not primarily responsible for the emissions of the dinuclear platinum() thiolates which have intramolecular metal-metal separations greater than 2.9 Å.

The luminescence properties of multinuclear platinum complexes

“…pyridine-2-thiolate (pyS -) could act as a bridging ligand between two bpy-coordinated Pt(II) ions, generating [Pt(N^N-t Bubpy)(µ-pyS)] 2 2+[60], similar to earlier work on thiolate-bridged Pt(en) units -22 -by Compounds 46 and 47 have been successfully tested as red emitters in phosphorescent OLEDs. ‡ The complexes 42 and 44 were depicted in the original articles by Balashev and colleagues with inclusion of a Pt-Pt bond and explicitly described as comprising a metal-metal bond[63][64].…”

Half-Lantern Pt(II) and Pt(III) Complexes. New Cyclometalated Platinum Derivatives

“…Tzeng and co-workers prepared the dinuclear diimine complexes syn-or anti-[Pt 2 (μ-NS) 2 (dtbpy) 2 ] 2+ dtbpy = 4,4'-di-tert-butyl-2,2'-bipyridine, NHS = pyridine-2-thiol (Hpyt), 2-mercaptobenzothiazole (HNS 2 ), 2-mercaptobenzimidazole (HN 2 S), 2-mercaptobenzoxazole (HNOS)) by reaction of the mononuclear derivative [Pt(dtbpy)Cl 2 ] with the corresponding HNS in the presence of NaOMe [11,12] [17]. All three complexes show an anti configuration, with the N of the bridging groups coordinated at the trans position to C, and intermetallic distances of 2.91 Å, 2.97 Å (bzq) and 3.02 Å (ppy).…”

Bis(4,6-dimethyl-2-pyrimidinethiolato-κ2N,S)bis(methanol-κO)manganese(II)

“…For the chemistry, properties, and medicinal and biological relevance of metal thiolates, see Das & Seth (1997); Halcrow & Christou (1994); Tzeng et al (1999); Zhao et al (2001). For structural studies of metal thiolates, see Castro et al (1995); Constable et al (1991); Costes et al (2004); Cotton & Ilsley (1981); Eichhö fer & Buth (2005); Hadjikakou et al (2005); Han et al (2004); Lang et al (2003); MacGillvray et al 2000; Mikuriya et al (1991); Rodríguez et al (2003); Stephens (1977); Zhang et al (2003).…”

“…Data collection: CrystalClear (Rigaku/MSC, 2001); cell refinement: CrystalClear; data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXL97; software used to prepare material for publication: SHELXL97. Over past decades considerable attention has been paid to the synthesis and characterization of metal complexes of heterocyclic thiones due to their aesthetically interesting structures (Zhao et al, 2001), their luminescence properties (Tzeng et al, 1999), medicinal applications (Das & Seth, 1997) and their potential relevance to active sites in metalloenzymes (Halcrow & Christou, 1994). Among the heterocyclic thiols, pyrimidinethiols, are some of the most versatile sulfur donor ligands as they can act as monodentate, chelating and bridging ligands to yield complexes with variable nuclearity and a wide range of structural geometries (Rodríguez et al, 2003).…”