Uncommon Optical Properties and Silver-responsive Turn-off/on Luminescence in a Pt(II) heteroleptic dithiolene complex

Complex [Pt(iPr2pipdt)(Quinoxdt)](iPr2pipdt=1,4-diisopropyl-piperazine-2,3-dithione;Quinoxdt=[1,4]dithii-no[2,3-b]quinoxaline-2,3-dithiolate) exhibitsaremarkablegreenemission at 570 nm (roomtemperature),whichisabovethelowestexcitedstate.Thecomplexischaracterizedby negativesolvatochromismas well as ahigh second-orderpolarizability.Additionof AgIionsinduces1) hypsochromicshiftof the lowestfrequenciesand 2) reversible quenchingof luminescence. The corresponding Ni andPd complexeshavealso beenprepared and investigatedto assistinterpre-tationof opticalproperties withinthe triad.Computationalstudies basedon DFT and time-dependent DFT highlighttheelectronicpropertiesof [Pt(iPr2pipdt)(Quinoxdt)].The prefer-entialsite of interaction between the Pt complex and incom-ingAgIisevidencedbytheshapeoftheFukuifunctions,pointingtothe thiolicsulfurandplatinumatomsas themostreactivesitestowardsasoft cation.Calculatedopticalproperties are in agreementwithexperimental findings. Thisstudyshedslighton the structure–property relationship forthis classof compounds.