Formation of Derivative Carbyne Complexes from Tp‘(CO)₂M⋮CCH₃ (M = Mo, W)

Abstract

Chloride displacement from Tp‘(CO)2M⋮CCl (M = Mo, W (1); Tp‘ = hydridotris(3,5-dimethylpyrazolyl)borate) with LiMe2Cu affords the methylcarbyne complex Tp‘(CO)2M⋮CCH3 (M = Mo (2), W (3)). Deprotonation of this methylcarbyne forms [Tp‘(CO)2M=CCH2]- (M = Mo, W (4)), a nucleophilic vinylidene anion which reacts with a variety of substrates. Reaction of 4 with CH3I yields Tp‘(CO)2W⋮CCH2CH3 (5), while PhC(O)H yields Tp‘(CO)2W⋮CCH2CH(OH)(Ph) (8) and PhC(O)CH3 yields Tp‘(CO)2W⋮CCH2C(OH)(CH3)(Ph) (10). In the presence of base complex 8 undergoes elimination to form a conjugated vinyl carbyne complex Tp‘(CO)2W⋮CCHCH(Ph) (11). Reaction of 4 with PhC(O)Cl and then base forms Tp‘(CO)2W⋮CCH2C(O)Ph (14), which rearranges in solution to a metallafuran complex, (15). Spectroscopic data suggests that a dinuclear intermediate, Tp‘(CO)2W⋮CCH2CPh(OH)CH2C⋮W(CO)2Tp‘ (13), is first formed from 4 and PhC(O)Cl before the addition of base produces the expected monomeric product, Tp‘(CO)2W⋮CCH2C(O)Ph (14).

Metallaaromatic Chemistry: History and Development

“…Another example for the synthesis of metallafurans through rearrangement is shown in Scheme . The Tp Me2 -based tungsten complex 280 was converted to the seven-coordinate complex 281 in solution, via β-H migration into the α-position …”

“…The Tp Me2 -based tungsten complex 280 was converted to the seven-coordinate complex 281 in solution, via β-H migration into the αposition. 314 Some other methods, such as isomerization of metallacyclopropene complexes, 315 reaction of tungsten complexes WCl 2 (NAr)(PX 3 ) 3 with ketalcyclopropene, 316 ether bond cleavage in oxygen-containing five-membered metallacycles, 317 and multiple CX cleavage of CF 2 CFCl, 318 have also been developed.…”

Variable Electronic Coupling through Hydrocarbon Spacers Bridging Metal−Carbon Triple Bonds

“…Syntheses of the monomeric (1 and 6) [59][60][61] and dimeric (2-5, 7-10) 36,37 carbyne complexes were accomplished using literature routes. Electrochemical data were collected using a Princeton Applied Research 273A potentiostat.…”

Deprotonation and Oxidation of the W⋮CCH2−W Bridge To Form a C2-Biscarbyne W⋮C−C⋮W Bridge

“…We have established that the vinylidene anion, [Tp‘(CO) 2 MCCH 2 ] - (M = Mo, W), reacts with a variety of electrophiles. 2h, It is also known that metal halides are susceptible to nucleophilic attack, as observed in the reaction of [W]−I with LiMe 2 Cu to form [W]−CH 3 ([W] = Tp‘(CO)(RC⋮CR)W]) . This work merges these two complementary reagents: the vinylidene anion(s) [Tp‘(CO) 2 MCCH 2 ] - reacts with Tp(CO)(I)W(PhC⋮CPh) to form a bridging ligand with a two-carbon framework.…”