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Monomeric organolithium (LiR) complexes could provide enhanced Li-C bond reactivity and suggest mechanisms for a plethora of LiR-mediated reactions. They are highly sought-after but remain a synthetic challenge for organometallic chemists. In this work, we report the synthesis and characterisation of a monomeric (trimethylsilyl)methyl lithium complex, namely [Li(CH 2 SiMe 3 )(κ 3 - N , N ', N ''-Me 6 Tren)] (1), where Me 6 Tren is a tetradentate neutral amine ligand. The structure of 1 was comprehensively examined by single-crystal X-ray diffraction, variable temperature NMR spectroscopy and electron absorption spectroscopy. Complex 1 decomposes via ligand C-H and C-N activations to produce a Li amide complex 2. Preliminary reactivity studies of 1 reveal CO insertion and C-H activation reaction patterns.

Aromatic amides can be used to construct light‐harvesting materials with valuable optical properties. The amide bond is formed using well‐known coupling agents in near quantitative yield, as illustrated here through the synthesis of two boron dipyrromethene derivatives bearing an amide linkage. The primary concern with acyl amides is rotation around the C−N bond, leading to cis and trans isomers. Using NMR spectroscopy, quantum chemical calculations and critical comparison to simpler benzamides, the stereochemistry of the target compounds has been addressed. The N‐cyclohexyl derivative gave diffraction quality crystals that established a trans geometry for the amide bond. Quantum chemical calculations support the trans geometry as being the lowest‐energy structure in solution but indicate that inversion of the aryl ring is an important structural feature. Indeed, rotation around the C(sp2)−C(aryl) bond has a strong influence on the solution‐phase NMR spectra. The amide connection has minimal effect on the photophysical properties. [ABSTRACT FROM AUTHOR]