Iridium, tris structure

Ir4(CO)ii(PPh3)149 The structures of the di- and tri-substituted iridium derivative are shown in Fig. 14. In all cases, the phosphines are around the basal plane. However, whereas the two phosphines are in relative trans-positions in the di-substituted compound, in the tris-derivative two of the phosphines are obliged to occupy relative c/s-position and, as a result, are involved in more steric interaction. 

Fig. 1. The di-, tri-, and tetranuclear structures observed in X-ray crystal structures of hydroxo-bridged oligomers of cobalt(III), rhodium(III), iridium(III), or chromium(III) structures 4b, 7b, and 7c have never been observed, but the last two have been mentioned as possible structures for two of the known isomers of Cj4(OH)66+...

There are several examples of well-characterized tri- and tetranu-clear hydroxo-bridged complexes of chromium(III) and cobalt(III). Penta- and hexanuclear aqua chromium(III) complexes have been prepared in solution, but their structure and properties are unknown. Oligomers of nuclearity higher than four have not been reported for cobalt(IIl), with the exception of some hetero-bridged heteronuclear species (193, 194). There appear to be no reports of rhodium(III) or iridium(III) complexes of nuclearity higher than two. 

The other carbon dioxide complex characterized by x-ray crystallography contains two linked C02 molecules in the coordination sphere (116). This complex, [IrCl(C204)(PMe3)3], was prepared by the interaction of C02 with chloro(cyclooctene)[tris(trimethylphosphine)]iridium(I), [IrCl(C8 H j 4)-(PMe3)3], in benzene solution. The structure, (25), shows essentially octahedral coordination about the iridium center, with one metal-carbon bond and a five-membered chelate ring formed with the second C02 molecule. 

The X-ray structure of 170 has been reported (56). Generally only unsubstituted sp -hybridized carbon atoms of butadiene ligands are attacked by HFA (133). Different behavior has been found in the reactions of iridium complexes with HFA. With tris(triphenylphosphane)nitrosyliridium the geometry is retained [Eq. (139)] (63). However, the Vaska complexes lead to... 

Three iridium complexes of formula [Ir(acac)(L)2] have been synthesized, [k(dpp)2 (acac)], [Ir(bpp)2(acac)j and [Ir(fpp)2(acac)j, where L is a substituted arylpyridine (dpp = 2,4-diphenylpyridine bpp = 2-(4-f-butylphenyl)-4-phenylpyridine fpp = 2-(4-fluoroph-enyl)-4-phenylpyridine). The OLEDs based on these materials, with structure ito/Ir com-plexipvk/F-tbb/Alqs/LiF/Al (F-tbb = l,3,5-tris(4-fiuorobiphenyl-4 -yl)benzene), showed maximum luminances of 8776, 8838 and 14180 cdm , and maximum external efficiencies of 11.5, 12.9 and 17.0 cdA, repectively ° . 

Since the determination of the structure of tris(acetylacetonato)scandium (Sc—O of 2.061-2.082 A, average Sc—O 2.070(9) A), several other diketonates have been examined, though no detailed structures have been reported. The compound mer-[Sc(CF3COCHCOCH3)3] is isostruc-tural with the aluminium, gallium, rhodium, and iridium analogues, as well as those of the 3d metals V-Co whilst the dipivaloylmethanide [Sc(Me3COCHCOMe3)3] is isostructural with the iron and indium analogues. Scandium a-diketonates such as [Sc(tropolonate)3] form adducts in... 

Fig. 15.30 Square pyramidal structure of tris(triethylphosphine)-(2,5-dimethylpentadienyl)-iridium. The six-membered ring is nearly planar and the carbon-carbon distances (137-140 pm) are consistent with extensive delocalization. The complex is an example of a metallabenzene. [From Bleeke, J. R. Xie, Y-F. Peng, W-J. Chiang, M. J. Am. Chem. Soc. 1989, III, 4118-4120. Reproduced with permission.)...

Several trifluoromethylpyrazoles, for instance 3(5)-trifluoromethyl-5(3)-methylpyrazole (44) were used to prepare platinum complexes and the x-ray structure of the resulting complex reported <83 C774>. The ligand tris[3-trifluoromethyl-5-methyl(pyrazol-l-yl)]borate (82) yields a hydridovinyl iridium complex more stable than its j/ -ethylene isomer <89JA5480>. The x-ray structure of the related platinum complex (83) has been described <831C774>. 

Fig. 11.3 Chemical structures of commonly used Ir-dyes with blue, green and red emission bis(2-(4,6-difluorophenyl)pyridyl-N,C2 )iridiumpicolinate (FIrpic), /nc-tris(2-phenylpyridine) iridium Ir(ppy)3 and bis(2-(2 -benzothienyl)-pyridinato-N,C3)iridium(acetylacetonate) btp2l r(acac).

The structure of a further iridium bis(boryl) complex, the cationic species [(tbbpy)(cod)Ir(Bpin)2]+[OTf] (9.33), together with that of a related neutral tris(boryl) system (vide infra), has been reported as part of a study to elucidate the mechanism and intermediates of arene borylation chemistry [136]. 9.33 features an approximately octahedral coordination geometry with mutually cis pairs of bipyridyl, diene and Bpin ligands. The two Ir-B bond lengths [2.06(2) and 2.12(1) A] are effectively identical within the standard 3a limit. 

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