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Part I. Synthesis of metal hydrobora...

University of Illinois at Urbana-Champaign.

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Part I. Synthesis of metal hydroborates as potential chemical vapor deposition precursors. Part II. Chemical vapor deposition of titanium-doped magnesium diboride thin films.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Part I. Synthesis of metal hydroborates as potential chemical vapor deposition precursors. Part II. Chemical vapor deposition of titanium-doped magnesium diboride thin films./
Author:	Kim, Do Young.
Description:	209 p.
Notes:	Adviser: Gregory S. Girolami.
Contained By:	Dissertation Abstracts International68-06B.
Subject:	Chemistry, Inorganic. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoeng/servlet/advanced?query=3269943
ISBN:	9780549096139

Part I. Synthesis of metal hydroborates as potential chemical vapor deposition precursors. Part II. Chemical vapor deposition of titanium-doped magnesium diboride thin films.
Kim, Do Young.

Part I. Synthesis of metal hydroborates as potential chemical vapor deposition precursors. Part II. Chemical vapor deposition of titanium-doped magnesium diboride thin films. - 209 p.

Adviser: Gregory S. Girolami.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.

New compounds Cp*V(B3H8)2, Cp*Cr(B 3H8)2, and Cp*2Co2(B 6H14) have been synthesized by treating the pentamethylcyclopentadienyl complexes [Cp*VCl2]3, [Cp*CrCl2]2, and [Cp*CoCl]2 with NaB3H8. Cp*V(B3 H8)2 and Cp*Cr(B3H8) 2 have the same ligand sets but different molecular structures: the vanadium compound contains two bidentate B3H8 ligands whereas the chromium compound has one bidentate B3H8 ligand and one B3H8 ligand bound in an unprecedented fashion via two geminal hydrogen atoms. The different binding modes of the B3H8- group in these compounds are consequences of the number of available empty valence orbitals on the metal centers. The dinuclear complex Cp*2Co2(B 6H14) can be viewed as a "bi-borallyl" complex or as an eight-vertex hypho cluster.

ISBN: 9780549096139Subjects--Topical Terms:

517253
Chemistry, Inorganic.

Part I. Synthesis of metal hydroborates as potential chemical vapor deposition precursors. Part II. Chemical vapor deposition of titanium-doped magnesium diboride thin films.
LDR:05728nam 2200337 a 45 001 861457
005 20100719
008 100719s2007 ||||||||||||||||| ||eng d
020 $a 9780549096139
035 $a (UMI)AAI3269943
035 $a AAI3269943
040 $a UMI $c UMI
100 1 $a Kim, Do Young. $3 1029171
245 1 0 $a Part I. Synthesis of metal hydroborates as potential chemical vapor deposition precursors. Part II. Chemical vapor deposition of titanium-doped magnesium diboride thin films.
300 $a 209 p.
500 $a Adviser: Gregory S. Girolami.
500 $a Source: Dissertation Abstracts International, Volume: 68-06, Section: B, page: 3782.
502 $a Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.
520 $a New compounds Cp*V(B3H8)2, Cp*Cr(B 3H8)2, and Cp*2Co2(B 6H14) have been synthesized by treating the pentamethylcyclopentadienyl complexes [Cp*VCl2]3, [Cp*CrCl2]2, and [Cp*CoCl]2 with NaB3H8. Cp*V(B3 H8)2 and Cp*Cr(B3H8) 2 have the same ligand sets but different molecular structures: the vanadium compound contains two bidentate B3H8 ligands whereas the chromium compound has one bidentate B3H8 ligand and one B3H8 ligand bound in an unprecedented fashion via two geminal hydrogen atoms. The different binding modes of the B3H8- group in these compounds are consequences of the number of available empty valence orbitals on the metal centers. The dinuclear complex Cp*2Co2(B 6H14) can be viewed as a "bi-borallyl" complex or as an eight-vertex hypho cluster.
520 $a The solid state reaction of MgBr2 and NaB3H 8 at 20°C, followed by sublimation at 80°C and 0.05 Torr, affords Mg(B3H8)2, as a white solid. Similar reactions with MgBr2·Et2O and MgBr2(Me 2O)1.5 afford the crystalline ether adducts Mg(B3H 8)2(Et2O)2 and Mg(B3H 8)2(Me2O)2, respectively. In the solution state reactions of MgBr2 with NaB3H8, the presence of excess solvent results in the formation of non-volatile, probably ionic, magnesium compounds of the type [MgLx][B3H 8]2. Mg(B3H8)2(Et2 O)2 and Mg(B3H8)2(Me 2O)2 are the first crystallographically characterized magnesium complex of the B3H8- ligand. Owing to their volatility, Mg(B3H8)2(Et2O) 2 and Mg(B3H8)2(Me2O) 2 are potential precursors for the deposition of MgB2 thin films, although preliminary efforts to grow thin films from them under CVD conditions, have not yet produced stoichiometric MgB2 films.
520 $a Treatment of MCl3(thf)3 (M = Ti, Cr, or Mo) or MnCl2 with the sodium salt of N,N-dimethyldiboranamide, Na(H3BNMe2BH3), in diethyl ether, followed by sublimation at 45-70°C, affords crystals of the new divalent complexes M(H3BNMe2BH3)2, where M is Ti, Cr, Mn, or Mo, all of which have been characterized by single crystal X-ray diffraction. In all four compounds, the metal center is coordinated to two chelating [H3BNMe2BH3]-ligands. Each BH3 group binds to the metal center by means of two hydrogen bridges, leaving one terminal hydrogen atom on each BH3 group; the H atoms that bridge to the metal center form slightly longer B-H bonds than the terminal H atoms on the same boron centers, as expected. The metal center in each compound forms eight M-H contacts, whose M-H distances are equal within experimental error. The Ti, Cr, and Mo compounds adopt square-planar geometries in which the dihedral angle between ligand planes is 0°. In contrast, in the Mn compound, which adopts a structure intermediate between a tetrahedron and a square plane, the two ligand planes define a dihedral angle of 46.5(2)°; this unusual dihedral angle maximizes interligand H···H distances.
520 $a The solid state reaction of MgBr2 with Na(H3BNMe 2BH3) yields the monomeric, magnesium complex Mg(H3 BNMe2BH3)2. Its ether adducts Mg(H 3BNMe2BH3)2(thf) and Mg(H3BNMe 2BH3)2(dme), and the mixed ligand complex Cp*Mg(H 3BNMe2BH3)(thf), have also been prepared. Significantly, the binary complex Mg(H3BNMe2BH3)2 has a vapor pressure of 800 mTorr at 25°C, which makes it the most volatile magnesium complex known.
520 $a The solid state reaction of MCl3 and Na(H3BNMe 2BH3) and subsequent sublimation in vacuum affords the dinuclear complexes, M2(H3BNMe2BH3) 6 (M = Y or Dy). X-ray crystallographic studies show that, in both compounds, two metal centers are connected by two bridging H3BNMe2BH 3 ligands; each metal center also bears two terminal diboranamide groups, which are chelating. Similar reactions conducted in thf solution yield the monomeric thf adducts M(H3BNMe2BH3) 3(thf) (M = Y or Dy). These molecules, which possess a boron-to-metal ratio of 6, are readily volatile below 100°C and are potential CVD precursors for the low-temperature growth of LnB6 thin films.
520 $a The first low-temperature chemical vapor depositions of doped MgB 2 phases have been achieved by passing the precursor Mg(H3BNMe 2BH3)2 over a surface in the presence of a catalyst that accelerates the rate of the CVD growth reaction. Transition metal hydroborates can serve as effective catalysts, of which Ti(H3BNMe2BH 3)2 is the most attractive so far because it leads to the lowest level of Mg site substitution; the resulting film stoichiometry is Mg0.8Ti0.2B2. Although the metal substitution renders the films non-superconducting above 4 K, the results clearly point the way to the development of technologically-attractive CVD processes to grow superconducting MgB2 thin films at temperatures below 400°C.
590 $a School code: 0090.
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Engineering, Materials Science. $3 1017759
690 $a 0488
690 $a 0794
710 2 $a University of Illinois at Urbana-Champaign. $3 626646
773 0 $t Dissertation Abstracts International $g 68-06B.
790 $a 0090
790 1 0 $a Girolami, Gregory S., $e advisor
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoeng/servlet/advanced?query=3269943