Tunable from Blue to Red Emissive Composites and Solids of Silver Diphosphane Systems with Higher Quantum Yields than the Diphosphane Ligands.

PMMA composites and solids of complexes of formulas [AgX(P-P)]n [n = 1 and 2; X = Cl, NO3, ClO4, CF3COO, and OTf; P-P = dppb, xantphos, (PR2)2C2B10H10 (R = Ph and iPr)] display the whole palette of colors from blue to red upon selection of the anionic ligand (X) and the diphosphane (P-P). The diphosphane seems to play the most important role in tuning the emission energy and thermally activated delayed fluorescence (TADF) behavior. The PMMA composites of the complexes exhibit higher quantum yields than that of the diphosphane ligands and those with dppb are between 28 and 53%. Remarkably, instead of blue-green emissions which dominate the luminescence of silver diphosphane complexes in rigid phases, those with carborane diphosphanes are yellow-orange or orange-red emitters. Theoretical studies have been carried out for complexes with P-P = dppb, X = Cl; P-P = dppic, X = NO3; P-P = dppcc, X = Cl, NO3, and OTf and the mononuclear complexes [AgX(xantphos)] (X = Cl, Br). Optimization of the first excited triplet state was only possible for [AgX(xantphos)] (X = Cl and Br). A mixed MLCT and MC nature could be attributed to the S0 → T1 transition in these three-coordinated complexes.

A comparative study of structural patterns and luminescent properties of silver-DAFO complexes with carborane- versus "classical"-diphosphanes.

New complexes with the DAFO (4,5-diazafluoren-9-one) ligand of stoichiometry [Ag(DAFO)(P-P)]OTf [P-P = dppe, 1,2-bis(diphenylphosphane)ethane; dppp, 1,3-bis(diphenylphosphane)propane; dppph, ortho-bis(diphenylphosphane)benzene; dppcc, 1,2-bis(diphenylphosphane)-1,2-dicarba-closo-dodecaborane; dipcc, 1,2-bis(diisopropylphosphane)-1,2-dicarba-nido-dodecaborane], [Ag(DAFO)(P-P*)] [P-P* = dppnc, 7,8-bis(diphenylphosphane)-7,8-dicarba-nido-undecaborate(-1); dipnc, 7,8-bis(diisopropylphosphane)-7,8-dicarba-closo-undecaborate(-1)] and [Ag(DAFO)(OTf)L] [L = PPh3; dpccMe, 1-diphenylphosphane-2-methyl-1,2-dicarba-closo-dodecaborane] are reported. The structures of the complexes depend on the skeleton of the diphosphane. Most of these compounds are luminescent and their emissions seem to have originated from IL (DAFO) transitions, modified upon coordination to silver.