15442-57-6Relevant articles and documents
9,10-dihydroplatinaanthracenes with aromatic diimine ligands: Syntheses and spectroscopic and computational studies of new luminescent materials
De Crisci, Antonio G.,Lough, Alan J.,Multani, Kanwarpal,Fekl, Ulrich
, p. 1765 - 1779 (2009/02/01)
9,10-Dihydroplatinaanthracenes with aromatic nitrogen ligands were synthesized, derived from 2,2′-bipyridine, 4,4′-dichloro-2,2′- bipyridine, 4,4′-dimethoxy-2,2′-bipyridine, 4,4′- bis(dimethylamino)-2,2′-bipyridine, 4,4′-di-tert-butyl-2,2′- bipyridine, 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, and 2,2′-biquinoline. For comparison purposes, the N,N,N′,N′-tetramethylethylenediamine- derived compound was also obtained. A single-crystal X-ray structure determination was carried out on [H2C(C6H 4)2]Pt(2,9-dimethyl-1,10-phenanthroline), revealing a pronounced boat conformation of the metallacyclic ring. The diimine-derived compounds are highly luminescent in the solid state at room temperature, as well as in frozen solution. The luminescent complexes are easily prepared by ligand substitution from the new organometallic platinum precursor {[H 2C-(C6H4)2]Pt(SEt2)} n (n = 2, 3). Spectroscopic data are provided on absorbance and emission in the UV-visible range. In order to obtain insight into orbital energies and the tunability of the optical properties, electrochemical data, as well as DFT and TD-DFT data, were obtained. The lowest-energy absorbances are due to charge transfer from orbitals located largely on the electron-rich metallacyclic ligand with some coefficient on Pt into π* orbitals of the diimine. Computations suggest that the low-energy bands mostly originate from charge transfer from the HOMO-2, HOMO-1, and HOMO to the LUMO (rarely LUMO+1 and LUMO+2) molecular orbitals. Emission maxima range from 536 to 690 nm.
Nucleophilic Discrimination and the trans Effect. The Kinetics of Displacement of X from trans-n- (L=Me2SO, Et2S, PMe3, PEt3, PPh3, or AsEt3; X=Cl, n=1; X=MeOH, n=0) by Neutral and Anionic Nucleophiles
Tobe, Martin L.,Treadgold, Andrew T.
, p. 2347 - 2352 (2007/10/02)
The kinetics of the reaction trans-n- + L' trans-n'- + X (X=Cl-, n=1, L=Me2SO, Et2S, PMe3, PEt3, PPh3, or AsEt3, L'=pyridine (py), Me2S, Et2S, PPh3, Me2SO, thiourea (tu), or NNN'N'-tetramethylthiourea (tmtu), n'=0; L'=Cl-, Br-, I-, or SCN-, n'=1; X=MeOH, n=0, L'=Cl-, Br-, I-, or SCN-, n'=1) have been studied in 95percent methanol and 5percent water at 25 deg C.The second-order rate constants, k2, for the anionic substrates do not follow the usual dependence upon n0Pt, the anionic nucleophiles being much less reactive than predicted.A new nucleophilicity scale, based on - as standard substrate, does give linear relationships for all the anionic substrates.The relationship between the nucleophilic discrimination and the nature of the trans ligand is discussed.
