Quintuple Bond Reactivity toward Group 16 and 17 Elements: Addition vs Insertion

Abstract

The low valent, coordinatively unsaturated, and formally quintuply bonded bimetallic aminopyridinato chromium complex 1 was investigated regarding its reactivity toward group 16 and 17 elements. Reaction of 1 with O(2) yielded a dimeric Cr oxo complex 2, a compound with a high formal oxidation state carrying both bridging and terminal oxo ligands. Reactions with the higher homologues of the group lead to the formation of dimeric Cr(II) complexes in which E(2)(2-) ligands were formed [E = S (3), Se (4), and Te (5)]. Here the quintuply bonded dichromium unit formally undergoes an addition reaction. Reaction of 1 with the homo diatomic molecules of the group 17 elements leads to products in which the Cr-Cr quintuple bond is inserted into the corresponding X(2) molecule [X = Cl (6), Br (7), and I (8)]. Complex 1 was also found to insert into the S-S and Se-Se bonds of 1,2-diphenyldisulfane or the corresponding selenium compound (complexes 9 and 10, respectively). All the compounds have been characterized by NMR and elemental analysis. Additionally, eight of the complexes have been characterized by X-ray analysis. The bimetallic Cr(II) complexes feature metal-metal distances between 1.8369(18) and 1.918(12) Å.

Chromium to chromium quintuple bonds in a trigonal lantern configuration

“…X-ray crystallographic analysis on 12a and 12b revealed the temperature-dependent molecular motion. In light of the remarkable reactivity of the type II quintuplebonded compounds, [33,[51][52][53][54][55][56][57][58][59][60][61][62][63][64] the characterization of 5-11 bodes well for a systematic reactivity study of these medium-coordinate univalent dichromium complexes. Selected bond lengths (Å) and angles ( ): 12a: Cr(1)-Cr (2), 1.8261 (5); N(1)-Cr(1)-N(4), 127.26 (10); N(5)-Cr(1)-N(1), 119.65 (10); N(4)-Cr (1)-N(5), 109.26 (10); N(2)-Cr(2)-N (3), 127.85 (10); N(3)-Cr(2)-N(6), 110.46 (10); N(2)-Cr(2)-N(6), 118.21 (10).…”

Solvothermal and ionothermal syntheses and structures of amine- and/or (poly-)chalcogenide coordinated metal complexes

“…Some of these compounds, such as [18] or {R 2 Cr(μ-η 2 ) (Ch 2 )CrR 2 } (R 2 = substituted terphenyle) [19], include amines that appear to be too bulky for further reactions.…”

Haloacylation of the Quintuple‐Bonded Group VI Metal Amidinate Dimers and Disproportionation of Acyl Groups to Form Carbynes

“…[7] These low-coordinate quintuple-bonded species not only have interesting metal-metal bonding, but also show remarkable reaction chemistry. [8][9][10][11][12][13][14][15][16] Recent studies have indicated that there are strong analogies between the d component of the metal-metal quintuple bonds and the p component of the carbon-carbon multiple bonds. For example, the quintuple bonded molybdenum amidinate dimers [Mo 2 {m-k 2 -RC(N-2,6-iPr 2 C 6 H 3 ) 2 } 2 ] (R = H (1), Ph) [17] react with two equivalents of terminal alkynes to give the first aromatics containing two multiple-bonded dimetal units by a [2+2+2] cycloaddition process, [14] while its chromium analogue [Cr 2 {m-k 2 -HC(N-2,6-iPr 2 C 6 H 3 ) 2 } 2 ] (2) [18] reacts with alkynes to afford [2+2] adducts.…”

“…In addition, four septet signals corresponding to the four methine hydrogen atoms of eight iPr substituents suggest that the benzylidynes 8-10 feature an unsymmetrical molecular conformation. The 13 C NMR spec- troscopy show strongly deshielded resonance signals at d = 409.6 (8), 406.9 (9), and 398.8 ppm (10) corresponding to the bridgehead carbon atoms of the carbyne ligands. Such aroyl disproportionation also occurs to an alkyl acyl group.…”

“…To answer this question, we performed two reactions. An ethereal solution of 1 was first treated with 1 equivalent of benzoyl chloride, and then 1 equivalent of o-toluoyl chloride after 10 …”