- 9,10-dihydroplatinaanthracenes with aromatic diimine ligands: Syntheses and spectroscopic and computational studies of new luminescent materials
-
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.
- De Crisci, Antonio G.,Lough, Alan J.,Multani, Kanwarpal,Fekl, Ulrich
-
p. 1765 - 1779
(2009/02/01)
-
- Cis-Dichloridobis(diethyl sulfide-κS)platinum(II) at 295 and 150 K
-
The title compound, cis-[PtCl2(C4H10S)2], crystallizes in the space group P21/n with pseudo-square-planar coordination geometry. The orientation of the ethyl groups on the S atoms is staggered with respect to the coordination plane, giving the complex approximate C 2v symmetry. The complex does not form dimeric packing units with short Pt...S intra-dimeric distances as seen in some related complexes, but instead displays C - H...Cl inter-actions in three dimensions. These C - H...Cl - Pt contacts are compared with those of related compounds reported in the Cambridge Structural Database, which show a frequency maximum in the range 120-170° for the C - H...Cl angle. International Union of Crystallography 2007.
- Hansson, Christian
-
p. m361-m363
(2008/09/16)
-
- 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
-
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.
- Tobe, Martin L.,Treadgold, Andrew T.
-
p. 2347 - 2352
(2007/10/02)
-
- Fast Cis-Trans Isomerization of Square-Planar Bis(diethyl sulfide)platinum(II) Complexes. Reaction of cis-Dichlorobis(diethyl sulfide)platinum(II) with Mesityllithium
-
Reaction of cis- with a slight excess of mesityllithium in benzene-ether mixture afforded trans- (Mes=2,4,6-trimethylphenyl; SEt2=diethyl sulfide) as a major product.When mesityllithium reagent containing lithium bromide was used, trans- was obtained.Acceleration of cis-trans isomerization in the presence of mesityllithium was observed.
- Tobita, Hiromi,Habazaki, Hiroki,Ogino, Hiroshi
-
p. 797 - 799
(2007/10/02)
-