The preparation, photophysics, and solid state structures of octahedral organometallic Ir complexes with several different cyclometalated ligands are reported. IrCl3.nH2O cleanly cyclometalates a number of different compounds (i.e., 2-phenylpyridine, 2-(p-tolyl)pyridine, benzoquinoline, 2-phenylbenzothiazole, 2-(1-naphthyl)benzothiazole, and 2-phenylquinoline), forming the corresponding chloride-bridged dimers, CwedgeN2Ir(mu-Cl)2IrCwedgeN2 (CwedgeNis a cyclometalated ligand) in good yield. These chloride-bridged dimers react with acetyl acetone (acacH) and other bidentate, monoanionic ligands such as picolinic acid (picH) and N-methylsalicylimine (salH), to give monomeric CwedgeN2Ir(LX) complexes (LX = acac, pic, sal). The emission spectra of these complexes are largely governed by the nature of the cyclometalating ligand, leading to lambda(max) values from 510 to 606 nm for the complexes reported here. The strong spin-orbit coupling of iridium mixes the formally forbidden 3MLCT and 3pi-pi* transitions with the allowed 1MLCT, leading to a strong phosphorescence with good quantum efficiencies (0.1-0.4) and room temperature lifetimes in the microsecond regime. The emission spectra of the CwedgeN2Ir(LX) complexes are surprisingly similar to the fac-IrCwedgeN3 complex of the same ligand, even though the structures of the two complexes are markedly different. The crystal structures of two of the CwedgeN2Ir(acac) complexes (i.e., CwedgeN = ppy and tpy) have been determined. Both complexes show cis-C,C', trans-N,N' disposition of the two cyclometalated ligands, similar to the structures reported for other complexes with a "CwedgeN2Ir" fragment. NMR data (1H and 13C) support a similar structure for all of the CwedgeN2Ir(LX) complexes. Close intermolecular contacts in both (ppy)2Ir(acac) and (tpy)2Ir(acac) lead to significantly red shifted emission spectra for crystalline samples of the ppy and tpy complexes relative to their solution spectra.

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The combination of the three types of vibrational spectroscopy, infrared, Raman, and inelastic neutron scattering, has enabled all of the internal, and most of the external, modes of Mg2FeH6 and Mg2FeD6 to be observed and assigned, as well as some of the modes of Mg2FeD5H. As an aid to the assignment, a reliable, empirical force field has been developed. The spectra also show evidence for a dynamic distortion of the hexahydrido complex, an effect that is not observed for the deuterated species.

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Mg 3 MnH 7 , Containing the First Known Hexahydridomanganese(I) Complex. -The new hydride compound of title is synthesized by reaction of MgH 2 with Mn powder in a 3:1 molar ratio (1070 K, 20 kbar, 120 min). The deuteride is prepared in the same way. The structure is investigated by neutron powder diffraction on the deuteride compound. The new phase crystallizes with the hexagonal Mg 3 ReH 7 type structure (space group P6 3 /mmc, Z = 2). Mg 3 MnH 7 decomposes between 530 K and 640 K under 1 bar hydrogen pressure into elemental manganese and magnesium. -(BORTZ, M.; BERTHEVILLE, B.; YVON, K.; MOVLAEV, E. A.; VERBETSKY, V. N.; FAUTH, F.; J. Alloys Compd. 279 (1998) 2, L8-L10; Lab. Cristallogr., Univ. Geneve, CH-1211 Geneve 4, Switz.; EN)