The preparation and characterisation of ruthenium cyanovinylidene complexes

Abstract

Reactions of half-sandwich ruthenium metal acetylide complexes with 1-cyano-4-dimethylaminopyridinium salts afford complexes containing mono- or di-cyanovinylidene ligands; the procedure can be adapted to permit the simple synthesis of a cyanoacetylide complex, via the in situ deprotonation of a primary cyanovinylidene complex.

The synthesis, molecular and electronic structure of cyanovinylidene complexes

“…Reduction to [18]˙ is accompanied by a shift in the (CN) band by -39 cm -1 with an evident shoulder on the high frequency side, although the (C=C) cannot be observed and is likely obscured by residual bands from the supporting electrolyte. Similar behaviour has been noted for the ruthenium complexes [20] + and [20]˙ [46]. In both cases, the limited shift of the (CN) band argues against reduction at the methylene carbon (C (2)).…”

“…[92], and in the cyanation of cysteine residues in proteins to inhibit the activity of cysteine active enzymes [93], and aid in peptide sequencing [94]. Solutions of the hygroscopic bromide salt [9]Br are readily prepared from 4-dimethylaminopyridine and cyanogen bromide [46], whilst the air-stable, crystalline BF 4 -salt, which is also available commercially, has been obtained by anion metathesis of [9]Br with AgBF 4 [93]. We found it to be expeditious to employ a small excess of cyanogen bromide in the preparation of [9] + salts to ensure complete reaction of the dimethylaminopyridine which can be troublesome to remove from the products by crystallisation.…”

Ligand Redox Non‐Innocence in Transition‐Metal σ‐Alkynyl and Related Complexes

“…The reduction of vinylidene complexes is favoured at the C α carbene carbon, even in the presence of strongly electron-withdrawing substituents on the C β R 2 fragment, [100] giving rise to C-localised radicals that can have significant chemical stability due to the steric protection afforded by the L n M fragment. In addition to these steric considerations, the chemistry of oxidised derivatives of vinylidene complexes is directed by the various resonance forms of the resulting radical, which can be stabilised by the supporting metal fragment.…”

Structural and Nonlinear Optical Properties of Aligned Heterotrinuclear [RuII‐(Spacer)‐MII‐(Spacer)‐RuII] Complexes (M=Pd, Pt; spacer=4‐ethynylpyridine)

“…Metal alkynyl complexes have been growing at a phenomenal rate, largely because of their unique structural, electronic, and other functional properties. [1][2][3][4][5][6] For example, the linear dimensionality of the alkynyl moiety and its unsaturated character make it an ideal building block for molecular wires [7][8][9][10][11] and clusters [12][13][14] as well as organometallic oligomers, polymers, and dendrimers. [15][16][17] When the redox ca-pacity of the metal is enhanced by the electron-rich alkyne, and especially if they are conjugated in a structurally aligned network, the resultant materials could have active electronic, [18,19] optical, [20][21][22][23] and magnetic attributes that are unmatched.…”