Alkaline Earth Catalysis of Alkynyl Alcohol Hydroalkoxylation/Cyclization
摘要:
Heavier alkaline earth bis(trimethylsilyl)amides [Ae{N(SiMe3)(2)}(2)](2) (Ae = Ca, Sr, Ba) are shown to act as effective precatalysts for the regioselective intramolecular hydroalkoxylation/cyclization of a wide range of alkynyl and allenyl alcohols. In the majority of cases, cyclization of alkynyl alcohols produces mixtures of the possible endo- and exocyclic enol ether products, rationalized as a consequence of alkynylalkoxide isomerization to the corresponding allene derivatives. Cyclization rates for terminal alkynyl alcohols were found to be significantly higher than for substrates bearing internal alkynyl substituents, while the efficacy of cyclization was in general found to be determined by a combination of stereoelectronic influences and the thermochemical viability of the specific alkaline earth metal catalysis, which we suggest is determined by the individual M-O bond strengths. Kinetic studies have provided a rate law pertaining to a pronounced catalyst inhibition with increasing [substrate], indicating that turnover-limiting insertion of C-C unsaturation into the M-O bond requires the dissociation of substrate molecules away from the Lewis acidic alkaline earth center.
Alkaline Earth Metallocenes Coordinated with Ester Pendants: Synthesis, Structural Characterization, and Application in Metathesis Reactions
作者:Heng Li、Wen-Xiong Zhang、Zhenfeng Xi
DOI:10.1002/chem.201301618
日期:2013.9.16
chlorides. Direct deprotonation of the ester‐substituted cyclopentadienes with Ae[N(SiMe3)2]2 (Ae=Ca, Sr, Ba) efficiently generated members of a new class of heavier alkalineearth (Ca, Sr, Ba) metallocenes in good to excellent yields. Single‐crystal X‐ray structural analysis demonstrated that these heavier alkalineearth metallocenes incorporated two intramolecularly coordinated ester pendants and multiply‐substituted
Volatile Imidazoles and Group 2 Imidazole Based Metal Precursors
申请人:Norman John Anthony Thomas
公开号:US20120035351A1
公开(公告)日:2012-02-09
Sterically hindered imidazole ligands are described, along with their synthesis, which are capable of coordinating to Group 2 metals, such as: calcium, magnesium, strontium, in an eta-5 coordination mode which permits the formation of monomeric or dimeric volatile complexes.
A compound comprising one or more polysubstituted imidazolate anions coordinated to a metal selected from the group consisting of barium, strontium, magnesium, radium or calcium or mixtures thereof. Alternatively, one anion can be substituted with and a second non-imidazolate anion.
Synthesis of the novel compounds and their use to form BST films is also contemplated
High Coordination Sphere Group 2 Metal B-Diketiminate Precursors
申请人:Norman John Anthony Thomas
公开号:US20100173075A1
公开(公告)日:2010-07-08
The present invention is directed to high coordination sphere Group 2 metal β-diketiminate compositions, such as bis(N-(2,2-methoxyethyl)-4-(2,2-methoxyethylimino)-2-penten-2-aminato) barium; and the deposition of the metals of such metal ligand compositions by chemical vapor deposition, pulsed chemical vapor deposition, molecular layer deposition or atomic layer deposition to produce Group 2 metal containing films, such as barium strontium titanate films or strontium titanate films or barium doped lanthanate as high k materials for electronic device manufacturing.
Cyclooctatetraenyl calcium and strontium amido complexes
作者:Farid M. Sroor、Laure Vendier、Michel Etienne
DOI:10.1039/c8dt02257g
日期:——
cyclooctatetraenyl (C8H8) complexes of calcium and strontium, most of them containing the bis(trimethylsilyl)amido ligand. Mixing MI2 (M = Ca, Sr), KN(SiMe3)2 and K2(C8H8) in thf in a 2 : 2 : 1 ratio gave the inverse sandwich amido complexes [[(Me3Si)2N}M(thf)x]2(μ-C8H8)] (M = Ca, x = 1; M = Sr, x = 2) (1-Ca, 1-Sr) in fair to good yields. From a 1 : 1 : 1 ratio, the mixedpotassium calcium complex [[(Me3Si)2N}Ca(thf)](μ-C8H8)K]
本文报道了一系列钙和锶的环辛酸酯基(C 8 H 8)配合物的合成和结构表征,其中大多数都含有双(三甲基甲硅烷基)酰胺基配体。以2:2:1的比例混合MI 2(M = Ca,Sr),KN(SiMe 3)2和K 2(C 8 H 8),得到反三明治酰胺复合物[[(Me 3 Si)2 N} M(THF)X ] 2(μ-C 8 H ^ 8)](M =钙,X = 1; M = SR,X = 2)(1-的Ca,1-Sr)处于中等至良好的收益率。从1:1:1分的比例,混合钾钙络合物[[(ME 3 Si)的2 N}的Ca(THF)](μ-C 8 H ^ 8)K](2以良好的收率获得)。的反应2与1:彩1混合物2和KN(森达3)2,得到1-钙确认反应可以逐步进行。从2与Sr N(SiMe 3)2 } 2的反应制备异双金属钙锶酰胺基配合物的尝试导致这提供钾锶络合物[[K (ME再分配反应3 Si)的2 N}
Highly Fluorinated Tris(indazolyl)borate Silylamido Complexes of the Heavier Alkaline Earth Metals: Synthesis, Characterization, and Efficient Catalytic Intramolecular Hydroamination
Heteroleptic silylamido complexes of the heavier alkaline earth elements calcium and strontium containing the highly fluorinated 3‐phenyl hydrotris(indazolyl)borate F12‐Tp4Bo, 3Ph}− ligand have been synthesized by using salt metathesis reactions. The homoleptic precursors [AeN(SiMe3)2}2] (Ae=Ca, Sr) were treated with [Tl(F12‐Tp4Bo, 3Ph)] in pentane to form the corresponding heteroleptic complexes