Spectroscopic and theoretical studies on the excited state in diimine dithiolate complexes of platinum(II)

Journal Article · Wed Jun 10 00:00:00 EDT 1992 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00038a019· OSTI ID:7180121

Zuleta, J A; Bevilacqua, J M; Eisenberg, R ^[1]; Proserpio, D M ^[2]; Harvey, P D ^[3]

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1. Univ. of Rochester, NY (United States)
2. Cornel Univ., Ithaca, NY (United States)
3. Univ. of Sherbrooke, PQ (Canada)

The photophysical properties of a series of Pt(N-N)(S-S) complexes have been studied where (N-N) is either an [alpha],[alpha][prime]-diimine or saturated diamine chelating ligand and (S-S) is either a dithiolate chelating ligand or two monothiolate ligands in order to determine the orbital composition of the excited state. The solvent dependence of the absorption spectra of these complexes and the temperature dependence of their emission intensities and lifetimes have been examined while the ligands have been systematically varied. The electronic spectra are found to be dependent on whether or not the nitrogen chelating ligand is unsaturated (contains a vacant [pi]* orbital). On the basis of the spectroscopic data, the lowest energy absorption band in the diimine complexes is assigned as a metal-dithiolate to [pi]*(diimine) transition, whereas in the diamine complexes it is assigned as a metal-to-dithiolate MLCT transition. The only room-temperature emissive complexes are those that contain an [alpha],[alpha][prime]-diimine chelating ligand. The nature of the emission in these complexes at all temperatures depends on the dithiolate ligand, and the temperature dependence of the emission spectra has been examined. The nature of the HOMO and LUMO has been examined experimentally using cyclic voltammetry. On the basis of the electrochemical and spectroscopic data, the emission from all of the Pt(diimine)(S-S) complexes except those of 1,2-dithiolate maleonitriledithiolate (mnt) is assigned as a [sup 3](d(Pt)/p(S)-[pi]*(diimine)) transition, while, for the mnt complexes, it corresponds to a [sup 3](d(Pt)/p(S)-[pi]*(mnt)) transition. These assignments are supported by extended Hueckel molecular orbital calculations.

• OSTI ID: 7180121
• Journal Information: Inorganic Chemistry; (United States), Vol. 31:12; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PLATINUM COMPLEXES
PHOTOCHEMISTRY
PHYSICAL PROPERTIES
ABSORPTION SPECTRA
AMBIENT TEMPERATURE
AMINES
CHELATING AGENTS
ENERGY LEVELS
EXCITED STATES
IMINES
LIGANDS
MOLECULAR STRUCTURE
SOLVENT PROPERTIES
TEMPERATURE DEPENDENCE
THEORETICAL DATA
THIOLS
VOLTAMETRY
CHEMISTRY
COMPLEXES
DATA
INFORMATION
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
SPECTRA
TRANSITION ELEMENT COMPLEXES
400500* - Photochemistry