scholarly journals From an Al4-Cluster to Al+ Complexes: Lessons on Metalloidal Clustering

Author(s):  
Philipp Dabringhaus ◽  
Julie Willrett ◽  
Ingo Krossing

Abstract Low-valent aluminium compounds are among the most reactive and widely researched main-group compounds. Since the isolation of [(AlCp*)4] in 1991 as the first stable, molecular AlI compound, a variety of highly reactive neutral or anionic low-valent aluminium complexes were developed. In particular, the strongly basic aluminyl anions allowed for nucleophilic activation of a large variety of small molecules and formation of elusive transition-metal complexes. By contrast, an accessible cationic, low-valent aluminium compound combining the nucleophilicity of low-valent compounds with the electrophilicity of aluminium is hitherto unknown. Here, we report the synthesis of [Al(AlCp*)3]+[Al(ORF)4]– (RF = C(CF3)3) via a simple metathesis route. Unexpectedly, the complex ion forms a dimer in the solid state and in concentrated solutions. Addition of Lewis bases results in monomerization and coordination to the unique formal Al+ atom giving [(L)xAl(AlCp*)3]+ salts with L = hexaphenylcarbodiphosporane (cdp; x = 1), tetramethylethylenediamine (tmeda; x = 1) and 4-dimethylamino-pyridine (dmap; x = 3). Depending on the donor strength of the ligand added, the Al+–AlCp* bonds in the [(L)xAl(AlCp*)3]+ cluster cations can be finely tuned between very strong (L = nothing) to very weak and approaching isolated [Al(L)3]+ ions (L = dmap). We anticipate our easily accessible low-valent aluminium cation salts to be the starting point for investigation and potential application of this unusual compound class. In particular, the ambiphilic reactivity of the cationic, low-valent compounds will be studied. Moreover, knowledge gained from the stabilization of the reported complex salts is expected to facilitate the isolation and application of novel cationic, low-valent Al complexes.

2021 ◽  
Vol 11 (7) ◽  
pp. 3038
Author(s):  
Maria Letizia Di Pietro ◽  
Giuseppina La Ganga ◽  
Francesco Nastasi ◽  
Fausto Puntoriero

Transition metal complexes with dppz-type ligands (dppz = dipyrido[3,2-a:2′,3′-c]phenazine) are extensively studied and attract a considerable amount of attention, becoming, from the very beginning and increasingly over time, a powerful tool for investigating the structure of the DNA helix. In particular, [Ru(bpy)2(dppz)]2+ and [Ru(phen)2(dppz)]2+ and their derivatives were extensively investigated as DNA light-switches. The purpose of this mini-review, which is not and could not be exhaustive, was to first introduce DNA and its importance at a biological level and research in the field of small molecules that are capable of interacting with it, in all its forms. A brief overview is given of the results obtained on the Ru-dppz complexes that bind to DNA. The mechanism of the light-switch active in this type of species is also briefly introduced along with its effects on structural modifications on both the dppz ligand and the ancillary ligands. Finally, a brief mention is made of biological applications and the developments obtained due to new spectroscopic techniques, both for understanding the mechanism of action and for cellular imaging applications.


Synthesis ◽  
2020 ◽  
Vol 52 (21) ◽  
pp. 3140-3152
Author(s):  
Kamal Kumar ◽  
Mohammad Rehan ◽  
Jana Flegel ◽  
Franziska Heitkamp ◽  
Jorgelina L. Pergomet ◽  
...  

An enantioselective hetero-Diels–Alder reaction of alkylidene­ oxindoles and 2-aza-3-silyloxy-1,3-butadienes, catalyzed by divalent transition metal complexes with N,N′-dioxide ligands offered an efficient access to natural-product-based 3,3′-piperidinoyl spiroox­indole class of small molecules. exo-Cycloadducts formed via stereospecific cycloaddition with Z-olefin displayed potent activity in modulation of hedgehog pathway.


Author(s):  
Niklas Gessner ◽  
Anna Karina Bäck ◽  
Johannes Knorr ◽  
Christoph Nagel ◽  
Philipp Marquetand ◽  
...  

Transition metal complexes capable of releasing small molecules such as carbon monoxide and nitric oxide upon photoactivation are versatile tools in various fields of chemistry and biology. In this work,...


Author(s):  
Wolfgang Beck ◽  
Wolfram Rieber ◽  
Sergio Cenini ◽  
Francesca Porta ◽  
Girolamo La Monica

2011 ◽  
Vol 45 (2) ◽  
pp. 298-307 ◽  
Author(s):  
Swadhin K. Mandal ◽  
Herbert W. Roesky
Keyword(s):  
Group 14 ◽  

1982 ◽  
Vol 21 (4) ◽  
pp. 1667-1668 ◽  
Author(s):  
Wynand J. Louw ◽  
Dirk J. A. De Waal ◽  
Thomas I. A. Gerber ◽  
Christian M. Demanet ◽  
Richard G. Copperthwaite

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