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• 17997-47-6 2-tri-n-butylstannylpyridine 

Relevant academic research and scientific papers

Tuning the π -backbonding and σ - trans effect of N^C^N coordinated Pt(II) complexes. Kinetic and computational study

The nucleophilic substitution reaction of cyclometallated complexes; [PtL2Cl] (L2 = 3,5-di(2-pyridinyl)-fluorobenzene), [PtL3Cl] (L3 = 2,4-di(2-pyridinyl)-fluorobenzene), and [PtL4Cl] (L4 = 3,5-di(2-pyridinyl)-toluene) with a series of neutral nucleophiles with different steric properties, thiourea (TU), N,N-dimethylthiourea (DMTU), and N,N,N′,N′-tetramethylthiourea (TMTU), was studied under pseudo-first-order conditions in methanol solution of an ionic strength of 0.1 M (0.09 M LiCF3SO3 and 0.01 M LiCl). The rate of substitution of the chloro ligand was studied as a function of nucleophile concentration and temperature using UV-visible and stopped-flow spectrophotometric techniques. The observed pseudo-first-order rate constants for the substitution reactions obey the rate law kobs = k2[Nu] + k-2. The reactivity of the investigated complexes when [PtL1Cl] is used as a reference follows the order [PtL2Cl] > [PtL3Cl] > [PtL4Cl] > [PtL1Cl]. The lability of the chloro group is dependent on the extent of π-backbonding and the σ-trans effect of the ligand backbone. [PtL2Cl] and [PtL3Cl], which have a common electron-withdrawing fluoride on the ligand trans to the leaving group, have a higher reaction rate compared to [PtL4Cl], which has an electron-donating methyl group attached to the ligand backbone. The position of the substituent on the phenyl group trans to the leaving group also influences the overlap of frontier molecular orbitals which result in controlling the reactivity of the fluoro complexes. In general, the results show that the nature of the substituent, either electron withdrawing or electron donating, results in an increase in the rate of substitution. Second-order kinetics and large negative activation entropies (ΔS#) support an associative substitution mechanism. The experimental data are supported by DFT calculations.

Cyclometallated platinum(ii) complexes of 1,3-di(2-pyridyl)benzenes for solution-processable WOLEDs exploiting monomer and excimer phosphorescence

Two cyclometallated platinum(ii) complexes, N^C^N-5-fluoro-1,3-di(2- pyridyl)benzene platinum(ii) chloride, FPtCl, and N^C^N-5-methyl-1,3-di(2- pyridyl)benzene platinum(ii) isothiocyanate, MePtNCS, have been synthesized and characterized. Both complexes are highly efficient phosphorescent green emitters which can also display excimer emission in the red region. They have been studied as triplet emitters in solution-processed, multilayer organic light-emitting diodes (OLEDs), together with the known complex of 5-methyl-1,3-di(2-pyridyl)benzene, MePtCl, for comparison. The trend in efficiencies of the OLEDs prepared correlates with the charge-trapping properties of the complexes. The most efficiently emitting complex, FPtCl, was used as the dopant in a solution-processed white OLED, employing monomer and excimer emission.

Facile synthesis and characterization of phosphorescent Pt(N ^C^N)X complexes

In order to investigate the ground state and excited state properties of Pt(N^C^N)X, we have prepared a series of Pt complexes, where N^C^N aromatic chelates are derivatives of m-di(2-pyridinyl)benzene (dpb) and X are monoanionic and monodentate ancillary ligands including halide and phenoxide. Facile synthesis of platinum m-di(2-pyridinyl)benzene chloride and its derivatives, using controlled microwave heating, was reported. This method not only shortened the reaction time but also improved the reaction yield for most of the Pt complexes. Two Pt(N^C^N)X complexes have been structurally characterized by X-ray crystallography. The change of functional group does not affect the structure of the core Pt(N^C^N)Cl fragment. Both molecules pack as head-to-tail dimers, each molecule of the dimer related to the other by a center of inversion. The electrochemical studies of all Pt complexes demonstrate that the oxidation process occurs on the metal-phenyl fragment and the reduction process is associated with the electron accepting groups like pyridinyl groups and their derivatives. The maximum emission wavelength of the Pt(N^C^N)X complexes ranges between 471 and 610 nm, crossing the spectrum of visible light. Most of the Pt complexes are strongly luminescent (Φ = 0.32-0.63) and have short luminescence lifetimes (τ = 4-7 μs) at room temperature. The lowest excited state of the Pt(N ^C^N)X complexes is identified as a dominant ligand-centered 3π-π* state with some 1MLCT/3MLCT character, which appears to have a larger 1MLCT component than their bidentate and tridentate analogs. This results in a high radiative decay rate and high quantum yield for Pt(dpb)Cl and its analogs. However, the excited state properties of the Pt(N^C ^N)X complexes are strongly dependent on the nature of the electron-accepting groups and substituents to the metal-phenyl fragment. A rational design will be needed to tune the emission energies of the Pt(N ^C^N)X complexes over a wide range while maintaining their high luminescent efficiency.

PLATINUM COMPLEXES

The invention aims at providing platinum complexes useful as materials for light emitting devices and extremely excellent in heat stability, luminous characteristics, and luminous efficiency, and a process for effective preparation thereof. The invention relates to platinum complexes represented by the general formula [1]: wherein any two of A, B and C are each independently an optionally substituted nitrogenous aromatic heterocyclic group and the other is optionally substituted aryl or optionally substituted heteroaryl; and Y is halogeno or an optionally substituted aryl or heteroaryl group which is bonded either directly or through oxygen (-O-) or sulfur (-S-) (with the proviso that when the adjacent two rings are nitrogenous aromatic heterocyclic groups, the cases wherein Y is chloro are excepted, while when the nonadjacent two rings are nitrogenous aromatic heterocyclic groups, the cases wherein Y is not halogeno are excepted).