Spectroscopy and electrochemical properties of a homologous series of acetylacetonato and hexafluoroacetylacetonato cyclopalladated and cycloplatinated complexes

Abstract

A photophysical, electrochemical and computational study has been performed on a homologous series of cyclometallated Pd(II) (1a-f) and Pt(II) (2a-f) complexes of general formula [(C,N)M(O,O)]; (H(C,N) = azobenzene, 2-phenylpyridine, benzo[h]quinoline; M = Pd, Pt; H(O,O) = acetylacetone, hexafluoroacetylacetone). Experimental and computational data have shown the strong influence exerted by electronegativity of the ancillary ligand on the frontier orbitals of the complexes, such an effect being enhanced for the Pt(II) species.

1H, 13C, 15N and 195Pt NMR studies of Au(III) and Pt(II) chloride organometallics with 2‐phenylpyridine

“…[Au(2ppy * [3] trans(S,N)-[Au(2ppy * )(SCN)(NCS)] -ILETOI; [7] trans(C,N)-[Au(2ppy * )(CH 2 COCH 3 )Cl] -BIGRAL and trans(C,N)-[Au(2ppy * ) (CH 2 COCH 3 )(ONO 2 )] -BIGREP; [8] [9] [Pt(2ppy * )(NH 2 CH 2 CH 2 NH 2 )]Cl -ZUDGIO; [4] trans(C,N)-[Pt(2ppy * ) (DMSO)(CH 3 )] -BEZPEC; [10] trans(C,N)-[Pt(2ppy * )(DMSO)(C 6 H 5 )] -TICSII and trans(C,N)-[Pt(2ppy * )(DMSO) (3,5-dimethylphenyl)] -TICSEE; [11] trans(N,N)-[Pt(2ppy * )(8-oxyquinolinate)] -WESQUH; [12] cis-[Pt(2ppy * ) 2 ] -CULWUB; [13] K[Pt(2ppy * )(CN) 2 ]· 2(CH 3 COC H 3 ). [14] These or similar compounds were also investigated by 1 H and/or 13 C NMR methods: [Au(2ppy * )Cl 2 ]; [1,3,15] [Au(2ppy * ) (OCOCH 3 [3] [Au(2ppy * )(SC H 2 CH 2 S)] and [Au(2ppy * )(SCH 2 CH 2 NH 2 )] + ; [15] trans(S,N)-[Au(2p py * )(SCN)(NCS)]; [7] trans(C,N)-[Au(2ppy * )(CH 2 COCH 3 )(ONO 2 )]; [8] [Au(2ppy * )(NH 2 CH 2 CH 2 NH 2 )] 2+ and [Au(2ppy * )(2,2 -bipyridine )] 2+ ; [16] trans(N,N)-[Pt(2ppy * )(2ppy)Cl]; [2,5,9,17 -19] [Pt(2ppy * )(2ppy) X] (X = Br, I, SCN, ONO 2 , NO 2 ); [19] [Pt(2ppy * )Cl 2 ] − ; [2] [Pt(2ppy * ) (CO)Cl]; [5,17,20] [Pt(2ppy * )(NH 3 )Cl]; [17] trans(S,N)-[Pt(2ppy * )(DMSO) Cl]; [9,17,21] [Pt(2ppy * )(P(C 6 H 5 ) 3 )Cl] and [Pt(2ppy * )(py)Cl]; [22] [Pt(2p py * )(CN) 2 ] − ; [14,23] [Pt(2ppy * )(2,4-pentanedionate)], [Pt(2ppy * )(1,1, 1,5,5,5-hexafluoro-2,4-pentanedionate)], [Pt(2ppy * )(2,2,6,6-tetramethyl-3,5-heptanedionate)] and [Pt(2ppy * )(benzoylacetonate )]; [21,...…”

Structural studies of SrTcO3, CaTcO3and Pb2Tc2O7−d

“…The only previous report on these materials was by Muller, White and Roy in 1964 [3]. They reported the existence of these materials and suggested the CaTcO 3 and SrTcO 3 were orthorhombic whereas the Pb 2 Tc 2 O 7-d was reported as being pyrochlore.…”

“…We found that CaTcO 3 and SrTcO 3 both adopt a distorted perovskite structure with G-type antiferromagnetic ordering with surprisingly high Neel temperatures, ~ 800 K for CaTcO 3 [4] and ~1000K for SrTcO 3 [5]. The Pb 2 Tc 2 O 7-d was found to be a pyrochlore of stoichiometry of Pb 2 Tc 2 O 6.86 and did not exhibit any magnetic properties.…”

“…Tc is a 4d element, and like its lighter analogue Mn a 3d element it can adopt a number of oxidation states. 3d oxides are generally, but not always magnetic, while 4d and 5d oxides, with their more spatially extended d-orbitals tend not to be magnetic although SrRuO 3 [2] is a notable exception.…”

“…Moreover, segregation effects of fluoroaliphatic groups, in terms of micro-segregation of hydrophilic versus hydrophobic parts of molecules, is a specific tool for the generation of layered and/or columnar structures, which are tailored solid state organizations able to generate specific properties in molecular materials [2]. We have recently used this approach in the generation of new cyclometalated complexes, molecular materials of great interest as a result of their photophysical and mesogenic properties [3]. In particular, fluorine substitution proves to be a useful strategy in the promotion of different and enhanced photophysical properties as well as phase-segregated structures favorable for the appearance of columnar mesomorphism, due to the delicate balance between incompatible parts of the molecules, in acetylacetonate and hexafluoro-acetylacetonate cyclopalladated and cycloplatinated complexes [4,5].…”