Guanidinate, Amidinate, and Formamidinate Ligands

Synthesis and Structural Characterization of p-Carboranylamidine Derivatives

“…Remarkably, the formation of the lithium carboranylamidiate represents the first incidence of a "normal" reactivity of a lithiated carborane with carbodiimides. This means that 1,12-dilithiocarborane behaves toward carbodiimides like any other organolithium reagents and adds to the central carbon atom of the N=C=N moiety under the formation of regular amidinate anion of the type [RC(NR ) 2 ] − [36][37][38][39][40]. This finding reveals that all three C 2 B 10 H 12 isomers behave differently in their reactivity toward 1,3-diorganocarbodiimides.…”

“…Besides an X-ray structural analysis of 4 (see next paragraph), all analytical and spectroscopic data were in ex- Both bis(anionic) title compounds 2 and 3 were fully characterized through the usual set of elemental analyses and spectroscopic methods. In the IR spectra, strong bands at 1523 cm −1 (2) and 1543 cm −1 (3) are typical for the stretching vibrations of the delocalized amidinate NCN units [36][37][38][39][40]. Medium strong bands in the range of 2590-2620 cm −1 could be assigned to the B-H stretching vibrations, while the ν as (C-O-C) bands of the coordinated solvents appear around 1050 cm −1 as medium or strong bands.…”

“…These were obtained in the form of their lithium derivatives by in situ lithiation of o-carborane using n-butyllithium followed by treatment with one equivalent of 1,3-diorganocarbodiimides, R-N=C=N-R (R = i Pr, Cy (= cyclohexyl)). As illustrated in Scheme 1, the resulting carboranylamidinate anions were quite unique as they combined the highly versatile amidinate ligand system, [RC(NR ) 2 ] − [36][37][38][39][40], with a σ-bond to the carborane cage. Subsequently, the lithium salts served as precursors for a variety of main-group and transition metal complexes comprising carboranylamidinate ligands [41][42][43][44][45].…”

Boron Complexes with Propiolamidinato Ligands: Synthesis, Structure, and Photophysical Properties

“…The most widely used strategy is Pinner’s reaction, although it presents several limitations like nitriles bearing electron-withdrawing groups at the α-position or the synthesis of sterically hindered and aromatic amidines. More recently, with the aim of overcoming those limitations, powerful catalytic methods were developed, where many compounds of transition metals, lanthanoids, and main group elements have been described as catalysts . As previously mentioned, we have made several contributions to this area.…”

Guanidinates as Alternative Ligands for Organometallic Complexes

“…Although the chemistry of guanidinato derivatives (and their amidinato analogues) extends well beyond Organometallic Chemistry and has been covered in excellent reviews [39][40][41][42][43][44][45][46], this work is mainly concerned with systematically and comprehensively reviewing the examples of organometallic complexes, excluding some carbonyl derivatives, highlighting synthetic or structural aspects and the influence of the presence of these guanidinato ligands on their properties. The results reviewed here show a trend towards the search for targeted guanidines with the main goal of obtaining organometallic complexes with a use as potential homogeneous catalysts or as molecular precursors of solid materials.…”