Synthesis and crystal structure of bis(tricobalt enneacarbonyl)-acetone. An application of a new method for sign determination

Metal–Metal (MM) Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc

“…The R MM value for Co 2 (CO) 6 (Ph 2 C 2 ) 03 (Figure h) is 2.47 Å, which may indicate Co–Co bonding, being less than twice the covalent radius of 1.26 Å for Co . The other structures in Table are tri- and polynuclear complexes. − These all contain Co–Co distances ranging from 2.47 to 2.50 Å, which could indicate either covalent bonding or three-center two-electron bonds through bridging carbonyl ligands.…”

Structural studies of derivatives of methinyltricobalt enneacarbonyls. V. Crystal structure of bis(methinyltricobalt enneacarbonyl), [CCo3(CO)9]2

“…H. Robinson, University of Otago, from BrCCo3(CO)g and toluene using the method previously reported. 2 Dark brown air-stable irregularly shaped crystals were obtained by recrystallization from the solvent. Crystallographic Data.9-Co6C2gOi8, mol wt 881.8, is monoclinic with a = 16.368 (3), b = 9.450 (2), c = 18.906 (4) k, ß = 106.79 (2)°; V = 2801 A3; doM = 2.10 (2) g/cm3; Z = 4; ¿caled =…”

Inorganic chemistry

“…This order is supported by the fact that electrophilic halogenation of a 1 -organo-1,2-carborane gives two monohalogenocarboranes but only one dihalogenocarborane,llla and by the synthesis (from appropriate halogenodecaboranes and acetylenes) of carboranes containing halogen atoms in specific 1ocations.lllb There is evidence of increased electron density in the carborane nucleus of 1 ,2-Me2C2BloHlo compared with 1 ,2-H2C2B10H10, though contrary t o some reports,l10 tetrabromo-derivatives of both have in fact been obtained.lllc 1,7-Dicarbaclovododecaboranes (mcarboranes) can be similarly halogenated, the sites of attack being initially B-9,10 (on the strength of electron densities and number of isomers obtained).llld The mechanism of the thermal isomerisation of icosahedral carboranes (and similar rearrangements) has been discussed. l2a Bulky R,Si substituents attached to the carbon atoms of the o-carborane cage facilitate isomerisation, suggesting that steric factors are important,112b and activation 151 enthalpies imply that some skeletal deformation required in the transition state is already present in the ground sta,te of the substituted carboranes. With the synthesis of C-carboranyl alkanes,113a cycloalkane deri~atives,ll~~ carboxylic acids, l1 * alcohols, 3d amines, 11% halides,llgf ketones,ll3g and substituted phenyl derivatives,113h an extensive organic chemistry of carboranes is taking shape.…”

“…The preparation of the complex [Co(CO),],C .CH2CH2C0,H is reported.l5* The X-ray structure of bis(tricoba1t enneacarbonyl)acetone, obtained by heating the compound [Co(CO),],CBr to 90°c, shows that insertion of a carbonyl group between the two carbon atoms of the dimers to give is involved. 151 The interaction of 3,3,3-trifluoropropyne with cobalt carbonyl has been investigated, 162 The crystal structure of the complex n-C,H,Fe(CO),Mn( CO), has been determined and shows that the molecule contains a metal-metal bond.156 The preparation of the mixed carbonyls (CO),Re-Mn(CO),, (CO),Re-Co(CO),, and some derivatives has been effected by a Wurtz-type reaction between anionic and cationic carbonyl species. l5' A bidentate gold ligand, Ph,P*AuC,H4C6H4Au*PPh2, has been used to prepare the first chelate complex containing metal-metal bonds, by interaction of the ligand with the anion l?e(CO),2-.158 Cationic complexes in which mercury is bonded to iron,lS9 ruthenium, and osmium l60 carbonyl phosphine derivatives have been reported.…”