Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten

Silyl-, Germyl-, and Stannyl-Substituted Group 6 Pentacarbonyl Metalates

“…The respective values for the tungsten ( 1 ), molybdenum ( 2 ), and chromium ( 3 ) compounds are −149.8, −140.1, and −122.6 ppm, respectively. A very similar spectral behavior was observed for the analogous tris(trimethylstannyl)silylated compounds 6 and also the undecamethylcyclohexasilanyl derivatives …”

“…Observed W−Si distances range from 2.389 to 2.708 Å with typical values being around 2.56 Å . Compared to related complexes ([W(CO) 5 SiMe 3 ] - , 2.614 Å; [W(CO) 5 Si 6 Me 11 ] - , 2.670 Å;8a [W(CO) 5 Si(SnMe 3 ) 3 ] - , 2.653 Å 6 ), 1a has the longest bond (2.685 Å). The W−Ge distance of 7a (2.724 Å) is the longest found.…”

“…Our continuing program on the synthesis of transition metal silicon compounds 1 employing oligosilyl anions has led us to study derivatives of group 6 pentacarbonyl metalates. For the preparation of the latter electrophilic metalates are required. ,,8c Using tetraalkylammonium group 6 pentacarbonyl chlorometalates triphenylsilyl, -germyl, and -stannyl derivatives have been obtained and reaction with tris(trimethylstannyl)silyllithium afforded the respective chromium, molybdenum, and tungsten adducts . The introduction of the DIME (diethylene glycol dimethyl ether) coordinated lithium salts of the iodopentacarbonyl metalates of tungsten and molybdenum and the use of undecamethylcyclohexasilanylpotassium allowed for the synthesis of undecamethylcyclohexasilanyl derivatives .…”

“…For the preparation of the latter electrophilic metalates are required. ,,8c Using tetraalkylammonium group 6 pentacarbonyl chlorometalates triphenylsilyl, -germyl, and -stannyl derivatives have been obtained and reaction with tris(trimethylstannyl)silyllithium afforded the respective chromium, molybdenum, and tungsten adducts . The introduction of the DIME (diethylene glycol dimethyl ether) coordinated lithium salts of the iodopentacarbonyl metalates of tungsten and molybdenum and the use of undecamethylcyclohexasilanylpotassium allowed for the synthesis of undecamethylcyclohexasilanyl derivatives . Besides salt elimination, also direct carbonyl substitution reactions of group 14 anions with group 6 metal hexacarbonyl compounds are known.…”

Zwitterionic Alkali-Metal Silanides of Tripodal Ligand Geometry: Synthesis, Structure, and Lewis Acid–Base Chemistry

“…Each sodium cation is coordinated by the three ethoxy donors and additionally by either two CO molecules one CO and one THF molecule, which gives rise to two different sodium cations, both having distorted-trigonal-bipyramidal coordination environments. The W−Si distances (2.68 and 2.69 Å) of Na-6b are close to those of (CO) 5 WSi[Si(CH 3 ) 2 (3-Bu t -pz)] 3 K(18-crown-6) (2.68 Å), 6i [Me 11 Si 6 W(CO) 5 ]Li(DIME) 2 , (2.67 Å), 28 [(Me 3 Sn) 3 SiW-(CO) 5 ]NEt 4 (2.66 Å), 29 and [Me 3 Si) 3 SiW(CO) 5 ]NEt 4 (2.67 Å). 30…”