Photophysical characteristics and reactivity of bis(2,9-di-tert-butyl-1,10-phenanthroline)copper(I).

The recently synthesized sterically constrained copper(I) complex [Cu(dtbp)(2)](+) (1), where dtbp is 2,9-di-tert-butyl-1,10-phenanthroline, exhibits unique photophysical and reactivity properties. Complex 1 (lambda(abs), 425 nm; epsilon, 3100 L M(-1) cm(-1); lambda(emission), 599 nm) has the longest metal-to-ligand charge-transfer (MLCT) emission lifetime (tau, 3260 ns) and largest quantum yield (varphi, 5.6%) of all [Cu(R(2)phen)(2)](+) complexes.

Facile oxidation-based synthesis of sterically encumbered four-coordinate bis(2,9-di-tert-butyl-1,10-phenanthroline)copper(I) and related three-coordinate copper(I) complexes.

A new oxidation-based synthetic route was developed for synthesis of Cu(I) complexes with weakly coordinating ligands, leading to the synthesis of the elusive [Cu(dtbp)2]+ (dtbp, 2,9-di-tert-butyl-1,10-phenanthroline) complex that may be useful as a sensor or as a dye for dye-sensitized solar cells. An acetone solution of either 1 or 2 equiv of dtbp was added to excess Cu(0) and 1 equiv of AgY (Y is O3SCF3-, BF4-, SbF6-, or B(C6F5)4-) in a nitrogen-filled glove box. Following filtration and evaporation under vacuum, crystallization from CH2Cl2 and hexanes results in X-ray quality crystals of Cu(dtbp)(O3SCF3) (1), Cu(dtbp)(BF4) (2), [Cu(dtbp)(acetone)][SbF6] (3), [Cu(dtbp)2][B(C6F5)4].

A new class of oxo-bridged high-valent hexamanganese clusters supported by sterically hindered carboxylate ligands.

A new class of oxo-bridged high-valent hexamanganese (Mn6) clusters containing a novel (Mn6O8)6+ core, [MnIV(4)MnIII2(mu-O)4(mu3-O)4(dmb)6(O2CR)2]4+ (where dmb=4,4'-dimethyl-2,2'-bipyridine, and RCO2=2,6-di(p-tolyl)benzoate (Ar(Tol)CO2-) (3) or 2,6-di(4-tert-butylphenyl)benzoate (Ar(4-tBuPh)CO2-) (4)), was synthesized using sterically hindered m-terphenyl-derived carboxylate ligands. These complexes can be synthesized by oxidizing the MnII mononuclear complexes, [Mn(dmb)2(OH2)(O2CR)]+ (where RCO2=Ar(Tol)CO2- (1) or Ar(4-tBuPh)CO2- (2)) with (n-Bu4N)MnO4, by direct Mn(II) + Mn(VII) in situ comproportionation reactions, or by ligand substitution on the dinuclear manganese (III,IV) or (IV,IV) complexes, [(Mn2(mu-O)2(dmb)4)](3+/4+). The compound [MnIV4MnIII2(mu-O)4(mu3-O)4(dmb)6(Ar(Tol)CO2)2](OTf)4 [3(OTf)4] crystallizes in the monoclinic space group P2(1)/n, with the cell parameters a=15.