Radical anions of 1,1-azoliumdithiocarboxylates.

The 1,1-azoliumdithiocarboxylate cAAC-CS (1a) was prepared and its redox chemistry was evaluated and compared to NHC based dithiocarboxylates IDipp-CS (1b) and IMes-CS (1c). Radical anions [carbene-CS]˙ were prepared by metallic reduction as the potassium or magnesium ion complexes [K(18-crown-6)(cAAC-CS)] (2a), [K(18-crown-6)(NHC-CS)] (NHC = IDipp: 2b, IMes: 2c), and [Mg(NacNac)(cAAC-CS)] (3) and extensively characterized (SC-XRD, EPR, UV/VIS/NIR, DFT). These complexes represent the first examples of isolated radical anions of 1,1-dithiolenes.

NHC aluminum chemistry on the rise.

This perspective highlights recent developments of the use of -heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (cAACs) in alane and aluminum organyl chemistry. Especially in the last few years this flourishing research field led to some remarkable discoveries including various substitution patterns at the central aluminum atom, different oxidation states, neutral and charged compounds with varying coordination numbers and unique reactivities. Thereby NHCs play a vital role in the stabilization of these otherwise highly reactive compounds, which would not be realizable without the use of this intriguing class of ligands.

Construction of a Boron Chain on a Single Metal by Dehydrocoupling of Borane Ligands.

Borane coordination, B-H borane bond activation, and borane catenation via metal-mediated dehydrocoupling to form electron-precise B-B bonds are reported. The reaction of -[M(IMes)Cl] (M = W, Mo) (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) with borates Li[BHR] (R = Mes, Dur; Mes = 2,4,6-MeCH and Dur = 2,3,5,6-MeCH) afforded the complexes [M(IMes)(η-HBR)(η-HBR)] (M = W: R = Mes , R = Dur ; M = Mo: R = Mes , R = Dur ). Three borane ligands are coordinated in to the group 6 metal atom via five (σ-B-H) bonds.

The tetracyanoborate anion as a building block for the heterocubane cluster cage [Cr{B(CN)}].

The tetracyanoborate anion [B(CN)] (TCB) was utilized as a building block for the synthesis of polynuclear chromium carbonyl compounds upon photolytic reaction with [Cr(CO)]. Up to four κN-coordinated cyano groups of TCB can be involved in binding to chromium, giving mixtures of [B(CN){CN-Cr(CO)}] ( = 1-4; 1-4) and [{Cr(CO)(B(CN))}] (5). The reaction of [B(CN)] with -[Cr(CO)(MeCN)] led to isolation of salts of the tetraanionic heterocubane cage [{Cr(CO)(B(CN))}].

Fluoride Abstraction Induced by Tris(pentafluoroethyl)difluorophosphorane: A Convenient Way to Synthesize Cationic -Heterocyclic Carbene- and Cyclic (Alkyl)(amino)carbene-Ligated Copper Alkyne and Arene Complexes.

We herein report the convenient synthesis of different -heterocyclic carbene (NHC)- and cyclic (alkyl)(amino)carbene (cAAC)-ligated copper cations using the weakly coordinating tris(pentafluoroethyl)trifluorophosphate counterion ( anion, [(CF)PF]). The reaction of the fluorido complexes [(carbene)CuF] (carbene = NHC, cAAC) - and the tris(pentafluoroethyl)difluorophosphorane (CF)PF in the presence of alkynes or arenes led to fluoride transfer from Cu to the phosphorane with formation of the cationic transition metal complexes [(carbene)Cu()] and the weakly coordinating counteranion [(CF)PF] (). Using this method, the complexes [(IDipp)Cu()] (IDipp = 1,3-bis(2,6-di--propylphenyl)-imidazolin-2-ylidene; = PhC≡CPh, ; PhC≡CMe, ), [(cAAC)Cu()] (cAAC = 1-(2,6-di--propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene; PhC≡CPh, ; PhC≡CMe, ), [(SIDipp)Cu(CMe)] (), (SIDipp = 1,3-bis(2,6-di--propylphenyl)-imidazolidine-2-ylidene), and [(cAAC)Cu(CMe)] () have been synthesized and characterized.