The broadband luminescence of isolated Cr+3 ions in the title lattices is investigated. The 4T2g lowest excited state is found to undergo Jahn–Teller distortion in the eg coordinate, in addition to expanding along the a1g. Quantitative determination of these displacements is made by analysis of extremely rich fine structure, the Ham quenched spin-orbit splitting of the electronic origins, and the Stokes shifts. The Jahn–Teller effect is found to influence the temperature dependence of lifetimes at less than 50 K. In the yttrium containing hosts, nonradiative deactivation of the 4T2g is observed above 200 K. Analysis of lifetime data with four models for nonradiative decay indicates that the active vibrations are again the a1g and eg. The trends observed among the host materials are rationalized on the basis of the freedom of the 4T2g to relax along the a1g and eg directions.

All aligned: A cubic 3d5–4f7 network of Mn2+ and Gd3+ ions is assembled by oxydiacetate (O(CH2CO2−)2). The network, which is reminiscent of Prussian blue analogues (see picture; Gd coordination polyhedra: purple, Mn coordination polyhedra: blue, [Mn(H2O)6]2+: green, H2O: red), has a weak but definite ferromagnetic interaction.

Two new iodobromides [I 2 Br 6 2-(analogue of I 8 2and Br 8 2-) and IBr 4 -(analogue of Br 5 and I 2 Br 3 -)] and new chains formed from Br 3 -, Br 2 and IBr 4 have been obtained in three compounds all containing the same Cu II tris-chelate cation Cu(dafone) 3 2+ {[Cu(dafone) 3 ](Br 3 )(Br 5 ) (1), [Cu(dafone) 3 ]-(Br 5 )(Br 8 ) 0.5 ·CH 3 CN (2) and [Cu(dafone) 3 ](IBr 4 )(I 2 Br 6 ) 0.5 ·-[a]4689 CH 3 CN (3)} by a procedure employing bromine, iodine, Cu II bromide and dafone in acetonitrile. The formation of chains and isolated polyhalide ions is facilitated by templating with the tris-chelate cation. The Raman spectra of the polyhalides and EPR and other spectral characteristics of the fluxional Cu II complex cation are presented.

The trinuclear manganese complex [Mn(3)O(4)(phen)(4)(H(2)O)(2)](NO(3))(4).2.5H(2)O, 1 (where, phen = 1,10-phenanthroline), has been synthesized by the Ce(IV) oxidation of a concentrated solution of manganese(II) acetate and phen in 1.6 N nitric acid. The complex crystallizes in the triclinic space group P&onemacr; with a = 10.700(2) Å, b = 12.643(3) Å, c = 20.509(4) Å, alpha = 78.37(3) degrees, beta = 83.12(3) degrees, gamma = 82.50(3) degrees, and Z = 2. The structure was solved by direct methods and refined by least-squares techniques to the conventional R (R(w)) factors of 0.055 (0.076) based on 4609 unique reflections with F(o) >/= 6.0sigma(F(o)). The structure of the cation consists of an oxo-bridged Mn(3)O(4)(4+) core, with the geometry of the manganese atoms being octahedral. The coordination polyhedron of one of the manganese atoms (Mn(1)) consists of two &mgr; oxo ligands and two pairs of nitrogen atoms of two phen moieties, whereas that of each of the remaining two manganese atoms consists of three &mgr;-oxo ligands, two nitrogen atoms of a phen moiety, and the oxygen atom of a water molecule. The complex represents the second example for water coordination to manganese(IV) centers in complexes with a Mn(3)O(4)(4+) core. Optical spectra in ligand buffer (pH 4.5) reveal complete conversion of the complex into a Mn(III)Mn(IV) species. The observed room-temperature (298 K) magnetic moment of 3.75 &mgr;(B) indicates the presence of strong antiferromagnetic coupling in the complex.