Selective synthesis of new half-lantern benzoquinolate platinum complexes. DFT and photophysical studies on the platinum (II,II) derivative

作者：Sicilia Violeta^*; Borja Pilar; Ma Casas Jose; Fuertes Sara; Martin Antonio

来源：Journal of Organometallic Chemistry, 2013, 731: 10-17.

DOI：10.1016/j.jorganchem.2013.01.027

• Platinum
• Half-lantern compound
• X-ray study
• Luminescence
• TD-DFT calculation
• Coordination chemistry

The half-lantern compound [{Pt(bzq)(mu-C7H4NOS-kappa N,S)}(2)] (2) (bzq = benzo[h]quinoline, C7H4NOS = 2-mercaptobenzoxazolate) was prepared selectively by reaction of equimolar amounts of potassium 2-mercaptobenzoxazolate (KC7H4NOS, 1) and [Pt(bzq)(NCMe)(2)]ClO4. Complex 2 undergoes two-electron oxidation by reaction with halogens X-2 (X-2: Cl-2, Br-2 or I-2) to give the corresponding dihalodiplatinum (111) complexes [{Pt(bzq)(mu-C7H4NOS-kappa N,S)X}(2)] (X = Cl 3, Br 4, I 5). The X-ray structures of 3-5 confirm the retention of the half-lantern structure and the shortening of the Pt-Pt distance (Pt-Pt = 2.6383 (3) angstrom 3, = 2.6671 (9) angstrom 4, 2.6810 (5) angstrom 5) with respect to that in 2 (2. 9726 (8) angstrom) because of the Pt-Pt bond formation. The trend of increasing Pt-Pt distances is in accordance with the vans-influence of the axial ligand (Cl %26lt; Br %26lt; I). DET calculations on complex 2 in CH2Cl2 indicate the lowest energy absorption band to be mainly due to singlet metal-metal-to-ligand charge transfer ((MMLCT)-M-1) [d sigma(Pt-Pt) -%26gt; pi* (bzq)] really affected by the pi center dot center dot center dot pi contacts in the complex, with just a little ligand-to-ligand charge transfer/intraligand (L%26apos;LCT/IL) character. The triplet (MMLCT)-M-3 excited state seems to be the responsible of the structureless red emission of 2 in the solid state and in solution at room temperature. The quantum yield (90%) of this red emission in toluene solution at room temperature is really high. This fact added to the neutral character and the thermal stability of 2 make it a potential compound to be incorporated as phosphorescent dopant in multi-layer OLEDs.

• 出版日期2013-5-1