Molecular Structure of Bis(hexamethylbenzene)‐ruthenium(0)

Abstract

Highly viscous liquids were obtained as by-products, which were not examined but presumably are polyphosphorus acids formed by condensation. Reaction with iodine is very slow; in ether it leads to red precipitates consisting, according to the reaction conditions, of red phosphorus or PJ4.The acid ( I ) can also be obtained by mild partial hydrolysis of POC1,F. POCI,F+H,O --t H[PO,CIF]+ HCI (1) The acids ( I ) and (2) are liquid at room temperature and insoluble in apolar solvents. ( I ) : d:'= 1.522 g cm-', n; ' = 1.3674. (2) : di0 = 2.140 g ern-,. B. p. 215 "C was extrapolated from a few vapor pressure values for ( I ) below 40°C; the evaporation enthalpy amounts to AH,,, = 10900calmol-', and the evaporation entropy to AS,,8 = 25.1calrnol-' OK-'. Although ( I ) is stable when moisture is excluded, (2) slowly becomes yellow (Br,), especially in light. Both compounds are hydrolyzed in aqueous solution, and then consume 3 equivalents of alkali hydroxide. Accordingly, H,[PO,F] and HCI or HBr are formed, as was confirmed by chromatography. Li[PO,ClF] (3) andLi [PO,BrF] ( 4 ) were obtained on treatment of ethereal solutions of (1) or (2), respectively, with LiBr; they also are hydrolyzed and then require 2 equivalents of NaOH for neutralization.Doublets appear in the I9F-and 31P-NMR spectra (external standards: CF,COOH, 85% H,PO,) of ( I ) and (2) because of F P and PF coupling. H[PO,CIF] ( I ) H[PO,BrF] (2) 19F-NMR 6= -33.3ppm 6 = -46.3 ppm 3'P-NMR 6=+1.96ppm 6 = + 15.9 ppm JF,= 1055 Hz JpF = 1050 HZ J,,= 1106 Hz J,, = 1103 Hz

Synthesis, structure, and physical properties of the bis(7,7,8,8-tetracyano-p-quinodimethane) salt of the paramagnetic cluster tris[(di-.mu.-chloro)(hexamethylbenzene)niobium], [Nb3(.mu.-Cl)6(C6Me6)3]2+(TCNQ)22-

“…The distortions from planarity observed in the present cluster ap-parently are the result of steric rather than electronic factors as observed for (CeMes^Ru. 31 The mean C-C bonds within the rings are 1.447 (7) and 1.429 ( 16) Á for the hexamethylbenzenes occupying general and special positions, respectively.…”

“…218 ( 23) C( 28) 185 (27) 211 (24) 252( 24) C( 29) 197 ( 28) 241 ( 27) 292 ( 24) C( 30) 190 ( 29) 235 ( 26) 271 ( 24) C (31) 229 ( 26) 246 ( 25) 256 ( 25) C( 32) 175 ( 28) 196 ( 28) 286 ( 24)…”

The Redox Functions of Metallodendrimers

“…Indeed, such a tetrahapto mode was known even in stable complexes such as for instance in the seminal example of [Ru(g 6 -C 6 Me 6 )(g 4 -C 6 Me 6 )] [134], and its formation is all the more facile that 17-electron and 19-electron complexes have energy levels that are very close and these states very rapidly interconvert [54,135,136]. In this case of the sandwich series [Fe(g 5 -C 5 R 5 )(g 6 -arene)] ?/0 , it thus appears that these electron-reservoir complexes behave as redox catalysts.…”

Scandium‐Mediated Formation of a Bis(tetrahydropentalene)

“…[11] By contrast, crystallization in the presence of diglyme yielded the solvate [Li(diglyme)Sc(COT'') 2 ]( 1b), featuring aL i-COT'' contact just like that in the earlier reported THF solvate [Li(THF) 2 Sc(COT) 2 ]. [14] In an attempt to prepare the scandium triple-decker complex Sc 2 (COT'') 3 (2)i na ccordance with the previously described lanthanide analogues, [12] the precursor complex 1 was treated with anhydrous CoCl 2 in toluene (Scheme 1). Thes econd COT'' ligand adopts am uch less symmetric coordination mode,w ith only three ring Catoms being in ad istinct binding distance to scandium.…”

“…[11] This structural feature is probably the cause for the unique reactivity of the scandium sandwich complex as one of the two (COT'') 2À ligands is likely activated by the mentioned loss of aromaticity.C omparable ligand deformations have also been observed in numerous other sandwich complexes. [14] In an attempt to prepare the scandium triple-decker complex Sc 2 (COT'') 3 (2)i na ccordance with the previously described lanthanide analogues, [12] the precursor complex 1 was treated with anhydrous CoCl 2 in toluene (Scheme 1).…”