Heterocyclic arsinocarbynes via tandem transmetallation

Abstract

Gold(I)-catalysed tandem transmetallation (Sn–Au–As) of the stannylcarbyne [W(≡CSnnBu3)(CO)2(Tp*)] (Tp* = hydrotris-(dimethylpyrazolyl)borate) with haloarsines gives direct access to a range of novel arsinocarbyne complexes, LnM≡CAsR2, including unusual heterocyclic phenarsazininyl and arsolyl...

Heterobimetallic μ2-halocarbyne complexes

“…As with other carbyne complexes of the form [M(CR)(CO) 2 (Tp)] (M = Mo, W) for which computational data are available, 32,33 the HOMOs of [Mo(CX)(CO) 2 (Tp)] are primarily associated with metal-carbonyl retrodonation. Being orthogonal to the M–CR vector, variations in the nature of ‘R’ do not impact significantly beyond what may be surmised experimentally from infrared data.…”

“…The implications of this approximation upon derived data have been quantified in closely related systems and found to be acceptable. 32 Sadly, Lalor has reported that the halocarbyne synthesis in practice fails for this simpler borate.…”

“…Whilst the computational economy afforded by pruning the Tp* ligand to Tp has been found to have a negligible effect on the electronic features and the resulting MuC bond lengths for related complexes, 32 it is expected to impact to some degree on inter-ligand angles. Firstly, Table 6 reveals that quite generally, oxidation of the tungsten centre results in a substantial shift in the carbyne resonance to low-frequency (35-50 ppm), with the effect being least pronounced for amino derivatives bearing positively mesomeric (M + ) trigonal nitrogen substituents.…”

Transition Metal Carbide Complexes

“…Another example of cross-coupling reactivity of [(Tp′)­(OC) 2 WC–SnBu 3 ] involves haloarsines. Here, initial transmetalation with [AuCl­(SMe 2 )] generates {WC–Au} intermediates, which, for instance, react further with AsBrPh 2 to generate [(Tp′)­(OC) 2 WC–AsPh 2 ] . With more exotic arsenic fragments such as ClAs­(C 6 H 4 ) 2 NH and ClAsC 4 Ph 4 , dihydrophenarsazininyl and tetraphenylarsolyl carbynes, [(Tp′)­(OC) 2 WC–As­(C 6 H 4 ) 2 NH] and [(Tp′)­(OC) 2 WC–AsC 4 Ph 4 ], can be prepared (Figure ).…”

Thiocarbonylphosphorane and arsorane ligands

“…19 Taken together, these indicate that both valence bond forms (Chart 1) contribute to the overall description, with perhaps the metallathiirene being particularly apt. This is borne out by computational interrogation of the model complex 20 [W(η 2 -SCPMe 3 )(CO) 2 (Tp)] + ( 2 S : Tp = hydrotris(pyrazolyl)borate, DFT:ωB97X-V/LANL2D ζ /gas phase, Fig. 2) which provides Löwdin bond orders of 1.037, 1.23 and 1.61 for the W–S, C–S and W–C bonds, respectively.…”