Synthesis and crystal structures of two new tin bis(carboranylamidinate) complexes

Abstract

Tin forms mononuclear chelate complexes with κC,κN-coordinated carboranylamidinate ligands, in which the Sn atom exhibits a trigonal–bipyramidal (SnIV) or pseudo-trigonal–bipyramidal (SnII) coordination.

Synthesis and Structural Characterization of Two New Main Group Element Carboranylamidinates

“…In both compounds, the C-N bond to the metal-attached nitrogen (N1) is shorter than the C-N bond to the protonated nitrogen (N2), which is in agreement with the presence of a formal double bond between C1 and N1. The observed C-N distances resemble those observed in previously described complexes with [HL] − ligands [21,22].…”

“…Rather untypical for carboranylamidinates, the molecules in 3 are assembled through weak N-H· · · Cl hydrogen bonds to infinite supramolecular chains (Figure 2). In the previously reported complexes with [HL] --type ligands, no hydrogen bonding with participation of the amidine NH moiety has been observed [21,22].…”

“…In the resulting lithium ortho-carboranylamidinates Li[(o-C 2 B 10 H 10 )C(NR)(NHR)] (= Li[HL]; 2a: R = i Pr, 2b: R = Cy (cyclohexyl)), a proton is formally shifted from a carboranyl carbon atom to the amidinate unit, resulting in an amidine moiety acting as a monodentate N-donor functionality (Scheme 1a). The lithium derivatives were further treated with various metal and non-metal chloride precursors to yield carboranylamidinates of e.g., Sn(II) and Cr(II) [8], Rh(I) and Ir(I) [13][14][15][16], Fe(II) and Fe(III) [17,18], Mo(II), Mn(II), Co(II), Ni(II), Cu(II) [18,19], Ti(IV), Zr(IV), Si(IV), Ge(IV), Sn(IV), Pb(IV), and P [20][21][22]. In the case of reactions with Cp 2 TiCl 2 , Cp 2 ZrCl 2 , PhPCl 2 , and various dichlorosilanes R 2 SiCl 2 , formal dehydrochlorination led to complexes with dianionic [(o-C 2 B 10 H 10 )C(NR) 2 ] 2− (= [L] 2− ) ligands having a deprotonated amidine group [20,22].…”