3934-10-9Relevant academic research and scientific papers
Metal-size influence of alkali metal complexes for polymerization of rac-lactide
Xiong, Jiao,Sun, Yangyang,Jiang, Jitao,Chen, Changjuan,Pan, Xiaobo,Wang, Cheng,Wu, Jincai
, p. 118 - 124 (2018)
A series of alkali metal complexes with 2,2′-ethylidenebis(4,6-di-tert-butylphenol) (EDBP-H2) as a ligand have been synthesized. In the presence of benzyl alcohol as an initiator, all complexes exhibit good catalytic behaviors for the ring-opening polymerization (ROP) of rac-lactide, giving desirable molecular weights and narrow molecular weight distributions. The relative order of activities for this series of complexes is Li > Na > K > Rb, which is related to metallic ion radius; and Lewis acidity of these metal ions is also an important factor for the kinetics of the ROP. The relative order of stereoselectivities for this series of complexes is Rb ≈ K > Na ? Li in this system. The first example of Rb complex in the ROP of rac-lactide in this paper was also described, showing a modest activity and a nice polymerization control, even with a certain isoselectivity.
Rubidium containing thin films by atomic layer deposition
S?nsteby, Henrik H.,Weibye, Kristian,Bratvold, Jon E.,Nilsen, Ola
, p. 16139 - 16144 (2017)
The application range for atomic layer deposition (ALD) has now been extended to include the deposition of rubidium-containing films, enabling the deposition of new and exploratory types of compounds by ALD. The properties of rubidium t-butoxide as an ALD precursor are promising, revealing similar behavior as its lithium, sodium and potassium counterparts. The deposition of rubidium containing films is reported as proof of concept through the Rb-Ti-O and Rb-Nb-O systems. Rubidium content in the doping level range of Rb is controllably achieved in Rb:TiOx up to 20%, whereas Rb can be introduced as a major component in Rb:NbOx. Perovskite RbNbO3, otherwise unattainable in bulk systems under ambient conditions, is shown to be stabilized on SrTiO3 (100) substrates. This report opens up the investigation of thin films of new and unexplored systems, not only in the world of ALD, but in materials chemistry in general.
Organoelement complexes of a dinucleating double β-diiminato ligand - Precedent cases from groups 1, 2, and 13
Falkenhagen, Jan P.,Haack, Peter,Limberg, Christian,Braun, Beatrice
experimental part, p. 1741 - 1749 (2012/01/04)
Main group chemistry of dinucleating ligands based on a xanthene backbone and two parallel diiminato binding sites (Xanthdim) has been investigated. To complement studies concerning the coordination modes adopted by Xanthdim in combination with alkali metal ions a di-rubidium complex with toluene co-ligands has been prepared. Its structural parameters lie in between those previously observed for corresponding K+ and Cs+ complexes. Furthermore, the complexes [ Me 2C 6H 3Xanthdim](MgMe(thf))2 (2) and [ Me 2C 6H 3Xanthdim](MgBr(thf))2 (3) were synthesised by reaction of [ Me 2C 6H 3Xanthdim](K(thf)2)2 and [ Me 2C 6H 3Xanthdim]H2, respectively, with MeMgBr. Both compounds proved stable against ligand exchange according to the Schlenk equilibrium. After reaction of [ Me 2C 6H 3Xanthdim]H2 and [ F 2C 6H 3Xanthdim]H2, respectively, with AlMe3 the complexes [ Me 2C 6H 3Xanthdim](AlMe2)2 (4) and [ F 2C 6H 3Xanthdim](AlMe 2)2 (5) were isolated and fully characterised. They were found to be dynamic in solution and Al-CH3...F-aryl interactions were detected in case of 5. The solid-state structures and NMR spectroscopic properties of all compounds were determined and analysed. Copyright
