Carbon dioxide insertion and deinsertion processes involving metal-carbon bonds: solid-state structure of [PPN][W(CO)5CH2CN]

Abstract

The synthesis and X-ray structure of [PP-N] [W(CO)&H,CN] are reported. The complex crystallizes in the triclinic space group PT, with unit cell dimensions a = 12.771 (4) A, b = 13.410 (4) A, c = 13.850 (5) A, CY = 54.41 (3)O, @ = 68.65 (3)O, y = 83.98 (3)O, V = 1988 (2) A3, Z = 2, and RF = 4.13%. The W-C-H,CN bond distance was found to be 2.330 (8) A, a value quite similar to that found in the W-CH3 analogue. Unlike W(CO),CH,-, the W(CO),CH,CN-anion does not react with carbon dioxide even under very high pressure. Furthermore, the cyanoacetate derivative, W(CO),O,CC-H,CN-, prepared from cyanoacetate and W(CO),THF, does not undergo decarboxylation either in solution or in the solid state. On the other hand, the W(CO),O,CCH,C-N-complex is a catalyst for the homogeneous decarboxylation of cyanoacetic acid.In general, the carboxylation reaction of transition-metal alkyl compounds is not readily reversible. However, in selected instances, thermal decomposition of carboxylate complexes occurs with formation of metal-carbon bonds (eq l).I This is evident in those metal carboxylates involving coordinatively unsaturated metal centers, e.g., the reactions listed below (eqs 2 and 3).2v3(1) ~~uFM-R~(O,CR)(CO)(PP~~)~ - trur~s-Rh(R)(CO)(PPh~)~ + C02 (3)In particular, for copper(1) carboxylates possessing functional groups other than the 4 2 0 , moiety capable of interacting with the metal center, facile decarboxylation reactions For example, there are several reports of decarboxylation processes involving the cyanoacetate ligand (eq 4),1a*5 where interactions of the type depicted in A are thought to be of importance. AThe investigation presented herein was designed to probe the nature of electron-withdrawing groups on the alkyl carbon atom in the C02 insertion reaction involving [RW(CO)6]-.6 Additionally, the generality of the facile decarboxylation process previously noted for the cyano-

Amino-Substituted Butatrienes: Unusual η1 Ligands Formed by an Unusual Reaction

“…The W−CO(trans) distance is significantly longer than the average of the W−CO(cis) distances, confirming the pronounced donor capacity of the butatriene ligand already deduced from the IR spectra. The W−C6 bond (2.318(5) Å) is considerably longer than in the starting complex 1 (2.185(8) Å) but is significantly shorter than the corresponding W−C bonds in [(CO) 5 W(olefin)] complexes (2.37−2.53 Å) and slightly shorter than in anionic alkyl pentacarbonyl complexes (2.31−2.40 Å) or neutral dipolar [(CO) 5 W−L] complexes with an W−C(sp 3 ) bond (2.32−2.40 Å) . The W1···C7 and W1···C13 distances are 3.241 and 3.233 Å, respectively.…”

[Li(THF)][Zn3(CH2CN)3(LiBr)(NPMe3)4] — ein funktionalisierter Phosphaniminato-Komplex von Zink mit supramolekularer Struktur

“…Es handelt sich um Derivate von Molybdän [13] und Wolfram [14], Osmium [15], Cobalt [16], Rhodium [17], Iridium [18], Palladium [19], Platin [20] und Gold [21]. Von den Elementen der 12.…”