Heterobimetallic μ2-Halocarbyne complexes

The halocarbyne complexes [M(≡CX)(CO)2(Tp*)] (M = Mo, W; X = Cl, Br; Tp* = hydrotris(dimethylpyrazolyl)borate) react with [AuCl(SMe2)], [Pt(-H2C=CH2)(PPh3)2] or [Pt(nbe)3] (nbe = norbornene) to furnish rare examples of μ2-halocarbyne...

Boron-based stepwise dioxygen activation with 1,4,2,5-diazadiborinine

Activation of dioxygen (O2) by 1,4,2,5-diazadiborinine 1 is reported. Two boron centers in 1 undergo a formal [4 + 2] cycloaddition with O2 at room temperature affording a bicyclo[2.2.2] molecule 2 featuring a B-O-O-B unit. Treatment of 2 with an additional equivalent of 1 leads to the cleavage of the O-O bond in 2 concomitant with the formation of two B-O bonds to yield 4 involving the extremely rare B4C2N2O2 ten-membered rings. A series of these reactions demonstrate the stepwise scission of the O[double bond, length as m-dash]O π-bond and the O-O σ-bond of O2.

Alkynylbis(alkylidynyl)phosphines: {LnMC}2PCCR

Synthetic strategies are presented for the formation of alkynylbis(alkylidynyl)phosphines which represent promising building blocks for unsaturated 2- and 3-dimensional assemblies. Parent ethynyl derivatives provide a means for installing further donor functionalities, e.g., AsPh₂ as shown.

Bis(alkylidynyl)arsines

The synthesis and characterization of the first examples of bimetallic bis(alkylidynyl)arsines are described. For the tungsten complexes, these may be prepared by a potentially generalizable route: successive treatment of [W(CBr)(CO)₂(Tp*)] with ⁿBuLi, ACl₃ (A = P, As) and a nucleophilic source of R⁻via the inferred intermediacy of [ClA{CW(CO)₂(Tp*)}₂].

Dual nucleophilic substitution at a W(ii) η(2)-coordinated diiodo acetylene leading to an amidinium carbyne complex

The synthesis and reactivity of a W(ii) C2I2 complex towards various nucleophiles are described. Soft, aprotic nucleophiles like 4-dimethylaminopyridine (DMAP) lead to substitution of one CO at tungsten, whereas reaction with an excess of benzylamine results in a dual nucleophilic substitution at the alkyne moiety involving the rearrangement to a novel cationic amidinium carbyne complex.