Synthesis and structure of sterically overloaded tetra-coordinated yttrium and lanthanum disiloxides

Abstract

Synthesis and structure of sterically overloaded tetra-coordinated yttrium and lanthanum disiloxides, Inorganic Chemistry Communications (2016Communications ( ), doi: 10.1016Communications ( /j.inoche.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Synthesis and Structure of Sterically Overloaded Tetra-coordinated Yttrium and Lanthanum DisiloxidesBrian McNerney [a] , Suresh Mummadi [a] , Fernando Hung-Low [a] , David B. Cordes [b] , Daniel K.Unruh [a] , Clemens Krempner* [a] [a] Department of Chemistry & Biochemistry, Texas Tech University, Box 1061, Lubbock, Texas, 79409-1061 In the past half century, rare earth metal siloxides [1] have gained some popularity primarily due to their potential as homogeneous catalysts in polymerization catalysis [2][3][4] , as precursors for the formation of metal oxides and silicates [5][6][7] , and as models for silica-supported lanthanide metal heterogeneous catalysts. [8][9][10][11][12][13] In particular work by the Edelmann group has resulted in significant advancements in the synthesis of rare earth metal complexes supported by the. [12][13][14][15][16][17][18][19][20] Our group recently synthesized a sterically overloaded silanediol of formula (CH 2 SiR 2 OH) 2 (1),where R = Si(SiMe 3 ) 2 Me, and demonstrated that its deprotonated form serves as a dianionic chelating spectator ligand for aluminum alkyls, hydroxides and alkoxides. [21] One of these complexes, a monomeric aluminum isopropoxide (Scheme 1) proved to be one of the most active MPV A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTcatalyst for the reduction of ketones and aldehydes reported so far. [22] Key to its high activty was its monomeric nature enforced by the bulkiness of the supporting disiloxide ligand. Based on these results, we reasoned that sterically overloaded disilanol 1 might be the ideal ligand for the synthesis of heteroleptic and salt-and adduct-free rare earth siloxide complexes, the latter potentially useful as Lewis acid catalysts.Scheme 1. Synthesis of sterically overloaded aluminum disiloxides.We first attempted to prepare the heteroleptic yttrium and lanthanum disiloxides of formula [(CH 2 R 2 SiO) 2 MN(SiMe 3 ) 2 ] (M = Ln, Y; R = SiMe(SiMe 3 ) 2 ) (2), respectively, as illustrated in Scheme 2. Initially, one equivalent of disilanol 1 was reacted with one equivalent of La(N(SiMe 3 ) 2 ) 3 in toluene as solvent. The reaction, however, did not give 2 but instead yielded the spirocyclic lanthanum disiloxide 3 as the main product irrespective whether toluene, THF or hexanes were used as solvents. Best yield...

Synthesis and Characterization of Solvated Lanthanide Tris(trimethylsilyl)siloxides

“…), we were interested in the production of LnSiO x materials for radiation shielding applications. While a number of lanthanide siloxides ([Ln­(OSiR 3 ) 3 ]) have been reported, − all attempts in our hands to exploit these types of precursors for production of LnSiO x materials yielded only LnO x products; therefore, alternative Ln–O–Si-bearing precursors attracted interest.…”

Crystal structure of poly[tetraaqua-(μ4-oxalato-κ4 O,O′:O′′,O′′′)-(μ8-benzene-1,2,4,5-tetracarboxylato-κ8 O 1:O 2:O 3:O 4:O 5:O 6:O 7:O

“…In this group, four O atoms come from carboxylate groups from four different btec 4− ligands, two O atoms belongs to a two carboxylate groups of one C 2 O4 2− ligand, and two O atoms are coordinated water molecules. The Y-O bond distances fall in the range of 2.296(5)-2.429(5) Å, which is the common value comparing with other Y 3+ compounds [10]. Moreover, the rationality of eight Y-O bonds can be evaluated by bond valance sum (BVS) calculation.…”