Amidinatokomplexe von Bor, Aluminium, Gallium, Indium und Zinn Die Kristallstrukturen von Ph-C(NSiMe₃)₂AICI₂ und Ph-C(NSiMe₃)₂SnCl₃ / Amidinato Complexes of Boron, Aluminium, Gallium, Indium, and Tin The Crystal Structures of Ph-C(NSiMe₃)₂AlCl₂ and Ph-C(NSiMe₃)₂SnCl₃

Abstract

<jats:title>Abstract</jats:title><jats:p> The trichlorides of aluminium, gallium, and indium, as well as boron tribromide and tin tetra-chloride react with N,N,N'-tris(trimethylsilyl)benzamidine to form the monomeric N.N'-bis-(trimethylsilyl)benzamidinato complexes Ph-C(NSiMe<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>MX<jats:sub>2</jats:sub>(M = B, Al. Ga, In; X = Cl, Br) and Ph -C(NSiMe<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>SnCl<jats:sub>3</jats:sub> , respectively. All compounds have been characterized by their IR spectra, two of them by X-ray diffraction studies. </jats:p><jats:p>Ph - C(NSiMei)<jats:sub>2</jats:sub>AlCl<jats:sub>2</jats:sub> : Space group C2/c, Z = 4, 1152 independent observed reflexions, R = 0.052. Lattice dimensions (19 °C): a = 1558.6(1), b = 1116.6(1), c = 1307.0(1) pm, β = 115.17(1)°. The compound forms monomeric molecules, in which the aluminium atom is tetra-hedrally coordinated by two chlorine atoms and by the two nitrogen atoms of the benzamidinato chelate. Bond length A1N = 188.2 pm. </jats:p><jats:p>Ph - C(NSiMe<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>SnCU: Space group P1̄, Z = 2, 3293 independent observed reflexions, R = 0.034. Lattice dimensions (19 °C): a = 980.1(1), b = 1025.9(1), c = 1230.5(2) pm. a = 68.40(1)°, β = 87.71(1)°, y - 68.92(1)°. The compound forms monomeric molecules, in which the tin atom is five-coordinated by three chlorine atoms and by the two nitrogen atoms of the benzamidinato chelate. Bond lengths SnN = 213.5 and 215.2 pm.</jats:p>

Synthetic and structural chemistry of amidinate-substituted boron halides

“…Curiously, in the same report, it was mentioned that attempts to prepare 6 resulted in the isolation of an uncharacterized yellow oil. 6 However, we found that crystalline 6 is indefinitely stable under an inert atmosphere and shows no sign of reverting to an oil, even upon gentle heating.…”

“…1 2 volume) under reduced pressure followed by storage at −30 • C resulted in a crop of colourless crystals which was isolated by filtration. A second crop of crystals formed upon cooling of the filtrate to −30 • C (3.9 g, 90% yield, mp 127-128 (6). Colourless crystalline 6 (mp 129-131 • C) was prepared in 84% yield from BCl 3 (10 mmol, 10 mL 1.0 M solution in CH 2 Cl 2 ) and N,N,N -tris(trimethylsilyl)benzamidine (3.4 g, 10 mmol) using the procedure described for 1.…”

“…5 Considering the rich chemistry displayed by these group 13 species and their relative ease of synthesis, it is remarkable that the coordination chemistry of amidinate ligands with boron substrates remains undeveloped. In fact, examples of such compounds obtained by rational synthetic routes are confined to the dibromo compound 1, 6 and the chloro-phenyl derivative 2. 7 A related example is the vinylidene-amidinate compound 3, which was obtained serendipitously via the in situ generation of an amidinate fragment, followed by displacement of Cl − from BCl 4 − , during reaction of the propylidyne complex [Cp(CO) 2 Mn≡CEt][BCl 4 ] with t BuN=C=NBu t and NEt 3 .…”

N-functionalized amino-aluminium and -boron complexes: intramolecular aromatic nitrogen-assisted formation of aminoboranes

“…Results of the X-ray structure determinations$ are presented in Figures 1 and 2. Molecules of (3) lie on crystallographic mirror planes; key structural features include a strained four-membered chelate ring with similar B-N distances within the ring, some 16% longer than the exocyclic B-N bond distance, which is short [1.371 (8) implying N = B bonding, in contrast to only a 2.5% difference between the B-Cl distances for the two boron centres. The asymmetric unit in (5b) consists of discrete molecules.…”

Aluminum (I, II, III) Compounds with Multidentate Ligands: Syntheses, Reactivity, and Structures

“…obtained from the reaction of L′H (L′ = {HC[(CMe)(NAr′)] 2 }, Ar′ = 2,6-Me 2 C 6 H 3 ) with equivalent amount of AlMe 3 at room temperature followed by reaction with two equivalents of I 2 in refluxing toluene afforded the aluminum diiodide L′AlI 2(40) in high yield. The L′GaCl 2(41) was prepared by the reaction of LiL′ with GaCl 3 in diethyl ether.…”