Structures of anhydrous and hydrated copper(II) hexafluoroacetylacetonate.

Crystal structure analyses are reported for anhydrous copper(II) hexafluoroacetylacetonate (Cu(hfac)(2)) and for two of its hydrates. The anhydrous compound (Cu(hfac)(2), 1: P1; at 100 K, a = 5.428(1), b = 5.

Electronic Absorption Spectra and Phosphorescence of Oxygen-Containing Molybdenum(IV) Complexes.

Electronic absorption and emission spectra are reported for salts of two oxomolybdenum(IV) cations, [MoOCl(CN-t-Bu)(4)](+) and [MoOCl(Ph(2)PCH(2)CH(2)PPh(2))(2)](+), and for the new Mo(IV) complex [trans-Mo(OCH(3))(2)(CN-t-Bu)(4)](2+). All three ions show absorption bands (lambda(max,abs) 550-570 nm; epsilon 45-120 M(-)(1) cm(-)(1)) attributable to the (1)A(1)[(d(xy)())(2)] --> (1)E[(d(xy)())(1)(d(xz)()(,)(yz)())(1)] (C(4)(v)()) transition, and the last two show weak shoulders in the 700-750 nm range due to the analogous spin-forbidden ((1)A(1) --> (3)E) transition. Phosphorescence (lambda(max,em) 850-960 nm) occurs in the solid state for all three compounds at both room temperature and 77 K, and for [MoOCl(CN-t-Bu)(4)](+) in CH(2)Cl(2) at room temperature.

Solution Photophysics, One-Electron Photooxidation, and Photoinitiated Two-Electron Oxidation of Molybdenum(III) Complexes.

Several six-coordinate Mo(III) complexes phosphoresce and undergo photooxidation in room-temperature solution. The phosphorescence of (Me(3)[9]aneN(3))MoX(3) (Me(3)[9]aneN(3) = 1,4,7-trimethyl-1,4,7-triazacyclononane) in CH(3)CN at room temperature occurs with the following maxima, lifetimes, and quantum yields: X = Cl, 1120 nm, 1.0 &mgr;s, and 6.