Tetraedrische Gold(I)‐Cluster mit Carba‐closo‐dodecaboranylethinido‐Liganden: [{12‐(R₃PAu)₂CC‐closo‐1‐CB₁₁H₁₁}₂]

Abstract

Im Festkörper und in Lösung dimerisieren die neutralen zweikernigen Gold(I)‐Komplexe [12‐(R3PAu)2CC‐closo‐1‐CB11H11] (R=Me, Et) zu vierkernigen Gold(I)‐Clustern. Für den Et3P‐Komplex wird in Lösung bei 25 °C ein Dimer‐Monomer‐Gleichgewicht beobachtet, während der Me3P‐Komplex auch bei 75 °C als Tetragold(I)‐Cluster vorliegt (siehe Struktur: C schwarz, B braun, P rosa, Au gelb).

Difunctionalized {closo‐1‐CB11} Clusters: 1‐ and 2‐Amino‐12‐ethynylcarba‐closo‐dodecaborates

“…[7,9] More recently, {closo-1-CB 11 } derivatives with one or more functional groups that are connected to the cage atom(s) have gained interest because of the aforementioned interesting properties of the cluster, which result in an unusual behavior of the functional group, as well. [1,10] Selected examples for applications of these functionalized carba-closo-dodecaboron species are the stabilization of unusual {Au I } 4 clusters with carba-closo-dodecaboranylethynyl ligands, [11] the application of gold(I) complexes with the [1-iPr 2 P-closo-1-CB 11 Cl 11 ] À ligand in catalysis, [12] the preparation of pharmacophores/biological active molecules and ionic liquid crystals (ILCs) that contain {closo-1-CB 11 } clusters as key components, [13][14][15] and the synthesis of new polymers that have covalently bonded {closo-1-CB 11 } units. [16] The further development of the substitution chemistry of the carba-closo-dodecaboron cluster, especially the preparation of clusters with functional groups that can easily be modified and that are bonded to atoms of the cage, provides the basis for its wider application.…”

“…[8,12,13,[17][18][19] In contrast, the selective introduction of a functional, reactive substituent to one of the cluster boron vertices is less developed. [1,2] In most examples the reactive substituent is bonded to the antipodal boron atom, for example, in [12-R-closo-1-CB 11 H 11 ] À (R = OH, [20] SMe 2 , [21] NH 2 , [22] CCH [23,24] ) and in [12-HO-closo-1-CB 11 Me 11 ] À (Scheme 1). [25] The most versatile, selective functionalization at the antipodal boron atom and at a single boron atom of the lower B 5 belt is electrophilic iodination [18,21,[26][27][28][29][30] followed by a cross-coupling reaction.…”

“…Carba-closo-dodecaborate anions with two functional groups have been synthesized via a simple two-step procedure starting from monoaminofunctionalized {closo-1-CB 11 } clusters. Iodination at the antipodal boron atom provided access to [1-H 2 N-12-I-closo-1-CB 11 H 10 ] À (1 a) and [2-H 2 N-12-I-closo-1-CB 11 H 10 ] À (2 a), which have been transformed into the anions [1-H 2 N-12-RCC-closo-1-CB 11 Keywords: alkynes · amines · carba-closo-dodecaborates · cluster compounds · cross-coupling reactions…”

Carba‐closo‐dodecaborate Anions with Cluster Carbon–Phosphorous Bonds

“…The analogous reaction using LiH as hydride source but without Et 3 B required a much longer reaction time of 1 week at a slightly higher temperature of 40°C. nBu 3 SnH was found to react with 1a at 40°C to the phosphine 1b, too. However, the reaction was slow and required 1 week to complete.…”

“…[1,2] For example {closo-1-CB 11 } clusters with ethynyl groups have been used for the stabilization of unusual {Au I } 4 clusters. [3] Especially for the cluster carbon atom the selective functionalization is well developed and a number of different substituents have been introduced. [1,[4][5][6] This includes the synthesis of derivatives with different substituents at the boron atoms, e.g.…”