(12)─Course in Materials Science I 1
December 13, 2018
(12)─Course in Materials Science I 2
reaction of ammonia with proton
Q アンモニアにプロトンがちかづいたときに何が起こるか.What happens when a proton is approaching to ammonia?
(12)─Course in Materials Science I 3
reaction of ammonia with proton
Q アンモニアにプロトンがちかづいたときに何が起こるか. What happenswhen a proton isapproaching toammonia?
2個の電子が入った1つのsp3混成軌道にプロトンがちかづくと他のN-H結合とおなじ結合が生じる=4つのN-H結合は等価になる proton approaching lonepair electrons: 4 equivalent N-Hbondings = coordination bond
complex compounds
(12)─Course in Materials Science I 4
BF3-NH3 complex
■ 5Bは3個の2s+2p電子がsp2混成軌道に入り,フッ素と結合.2pz軌道がのこっている=平面構造 boron with 3 electrons in sp2 orbitals (flat plane) with vacant 2pz
■ これにアンモニアのsp3の孤立電子対がちかづくと配位結合(σ結合)が形成される lone pair in an sp3 orbital approaching to boron 2pz orbital
■ BF3はsp2からsp3に変化したと考えられる boron: changed from sp2 to sp3
smaller side of sp3
(12)─Course in Materials Science I 5
charge in NH4+/BF3-NH3
Q アンモニウムイオンや三フッ化ホウ素-アンモニア錯体の電荷はどこ に あ り ま す か Where is a charge in ammonium ion andtrifluoroboron-ammonia complex?
(12)─Course in Materials Science I 6
charge in NH4+/BF3-NH3
Q アンモニウムイオンや三フッ化ホウ素-アンモニア錯体の電荷はどこ に あ り ま す か Where is a charge in ammonium ion andtrifluoroboron-ammonia complex?
■ NH4+では,あらたなN-H結合ができても1個分の電子が水素側にうつったわ
けではない(電気陰性度の差による).窒素は1個分の正電荷はもっていない. One electron in nitrogen is not completely moved to hydrogen dueto higher electronegativity of nitrogen = nitrogen incompletely charged
■ BF3-NH3 でも1個分の負電荷がホウ素側にうつったわけではない.Oneelectron in nitrogen is not completely moved to boron due to higherelectronegativity of nitrogen = nitrogen incompletely charged
(12)─Course in Materials Science I 7
金属錯体(metal complex)
■ 金属カチオンの空の軌道と,「配位子」とよばれる分子の孤立電子対が配位結合を形成 coordination bond formation with vacant metal cation orbitals and lone-pair electrons in "ligand" molecules
■ 遷移金属は空のd軌道(方向性あり)をもつ=配位結合には方向性があり,錯体の「かたち」がきまる directionality due to d-orbitals in transitionmetals = directional coordination bonds to give "shape" of metalcomplexes
■ 金属錯体の構造の考え方(近似法) approximation for understandingstructure of metal complexes・原子価結合法:金属イオンの混成軌道(光吸収の説明に難がある)valence-bond method: use of hybrid orbitals of metal ions/not suitable forinterpretation of photoabsorption・結晶場/配位子場理論:金属のd軌道と配位子の負電荷 crystal/ligandfield theory: interaction of d-orbitals and negative charge of ligands・ 分 子 軌 道 法 : 金 属 イ オ ン と 配 位 子 の 分 子 軌 道 molecular orbitaltheory: molecular orbitals of a metal ion and ligands
(12)─Course in Materials Science I 8
配位子(ligand)
■ 基本的には孤立電子対(:)をもつ having lone pair(s)■ エチレンのようにπ電子により配位するものもある some
exception like ethylene making coordination with π electrons
(12)─Course in Materials Science I 9
valence-bond method for cobalt complex
■ 金属イオンは,配位子の孤立電子対によって配位結合をつくるので,空の軌道をつかう必要がある=電子が収容されている軌道と配位子は相互作用しない no interaction of occupied orbitals withligand since coordination happens to vacant orbitals
■ 正八面体型混成軌道octahedral hybrid orbitals・sp3d2=4s+4p×3+4d×2・d2sp3=3d×2+ 4s+4p×3
Q 2つのd軌道は5種類のうちのどれがつかわれますか Which two d-orbitals are used for thesehybridization?
(12)─Course in Materials Science I 10
hybridization = overlapping orbitals
■ p軌道はx,y,zの各軸上.これと重なるのは,dx2-y2とdz2だけ three p-orbitals on x, y and z axes = overlapping only with dx2-y2 and dz2
■ p3+d2でx,y,z軸の各方向に等価な混成軌道が形成 hybridization of p3+d2: equivalent 6 orbitals on x, y and z axes
■ sp3d2・d2sp3は,のこりの3種類のd軌道とは重ならない no overlapping of sp3d2 and d2sp3 with remaining 3 d-orbitals
(12)─Course in Materials Science I 11
two kinds of hybrid orbitals for cobalt
■ コバルト(III)(=3d電子6個)の2種類の錯体 cobalt(III): six 3d electrons[CoF6]3-: sp3d2=4s+4p×3+4d×2(外軌道錯体)outer orbital complex[Co(NH3)6]3+: d2sp3=3d×2+4s+4p×3(内軌道錯体)inner orbital complex
Q 2つの錯体の磁性について説明してください Explain the magnetism for two kinds of cobalt(III) complexes.
(12)─Course in Materials Science I 12
配位結合(coordination bond)
■ 2種類のコバルト(III)錯体の電子配置 two kinds of electron configurations in cobalt(III) complexes
■ 配位結合の軌道にはかならず2個の配位子の電子が収容されている=スピンは相殺されている coordination bonds filled by two electrons each = no spins
■ 混成に使われなかった3d軌道の電子の収容状況による magnetism depending on electrons in d-orbitals not hybridized
paramagnetic = high spin
diamagnetic = low spin
(12)─Course in Materials Science I 13
結晶場理論(crystal field theory)
■ 金属イオンのd軌道と配位子の負電荷(孤立電子対)の反発的相互作用を考慮considering REPULSIVE interaction between d-orbitals and negative charges of ligands
■ 例: 金属イオンに対し座標軸に沿っての6個の負電荷が接近 six negative charges approaching to metal ion on x, y, z axes (6 coordination = octahedral complex)(1)ちかづく前は縮退した5個のd軌道 five degenerated d-orbitals before approaching(2)ちかづくと相互作用により縮退したままエネルギー上昇 higher energy due to interaction with negative charges remaining degeneration(3)負電荷と空間的にちかいものと遠いものの2種類に分裂 splitting depending on the spatial distance
(12)─Course in Materials Science I 14
hybridization = overlapping orbitals
■ p軌道はx,y,zの各軸上.これと重なるのは,dx2-y2とdz2だけ three p-orbitals on x, y and z axes = overlapping only with dx2-y2 and dz2
■ p3+d2でx,y,z軸の各方向に等価な混成軌道が形成 hybridization of p3+d2: equivalent 6 orbitals on x, y and z axes
■ sp3d2・d2sp3は,のこりの3種類のd軌道とは重ならない no overlapping of sp3d2 and d2sp3 with remaining 3 d-orbitals
(12)─Course in Materials Science I 15
crystal field splitting of titanium(IV)■ eg(二重に縮重)とt2g(三重に縮重)の2つに分裂 eg (doubly denerated)
and t2g (triply denerated)■ 特定の軌道が配位子と結合するとは考えていない not assuming bonds
between specific orbitals and ligands ■ 金属イオンの正電荷と配位子の負電荷により全体は安定化 stabilization by
positive charge of metal ions and negative charge of ligands
eg
t2g
(12)─Course in Materials Science I 16
結晶場安定化エネルギー
■ 結晶場分裂したエネルギー差=Δo energy difference in crystal field splitting = Δo
■ Ti(H2O)63+では3d電子は1つ(d1錯体)= t2gに入る one d electron in
orbital t2g
■ 八面体構造では,0.4Δoの安定化=結晶場安定化エネルギー crystal field stabilization energy (CFSE) = 0.4 Δo for octahedral coordination
(12)─Course in Materials Science I 17
CFSE for octahedral coordination
Q つぎの■の部分をうめてください Fill up orange parts.
(12)─Course in Materials Science I 18
CFSE for octahedral coordination
■ CFSE=0.4×(t2g electrons)-0.6×(eg electrons)■ 一般的には低スピン型の方が安定 general trend = lower "low
spin" complexes
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various crystal field splittingsCFSE depending on the structure of coordinations
(12)─Course in Materials Science I 20
CFSE depending on ligands
■ CFSEが大きくなるのは larger CFSE・配位子の負電荷が大きい:1価イオンより2価イオン higher negative charge: divalent ions > monovalent ions・小さいイオン:接近できる=F->Cl- smaller ions: approaching closely・1つの軌道に負電荷が集中:相互作用大=NH3>H2O concentrated in one orbital in ligand: stronger interaction
■ 配位子による結晶場安定化の大きさ extent of CFSE・強配位子場(strong):CO>CN->NO2
->phen(フェナントロリンphenanthroline)・中間配位子場(medium):
en(エチレンジアミン)>NH3>NCS->H2O>F-
・弱配位子場(week): RCO2->OH->Cl->Br->I-
(12)─Course in Materials Science I 21
講義日程/schedule
1 Oct 11, 2018 Thu 08:45-10:15 D103 guidance/check test/introduction
2 Oct 18, 2018 Thu 08:45-10:15 D103 wave function/Schroedinger equation
3 Oct 18, 2018 Thu 16:30-18:00 Sosei Hall atomic orbitals and quantum numbers
4 Oct 25, 2018 Thu 08:45-10:15 D103 s, p and d orbitals/monoelectron atom
5 Oct 25, 2018 Thu 13:00-14:30 Sosei Hall multielectron atoms/shielding
6 Oct 25, 2018 Thu 14:45-16:15 Sosei Hall chemical bonds (1)
Nov 1, 2018 Thu [no class]
7 Nov 8, 2018 Thu 09:15-10:15 D103 (interim test 1)
Nov 15, 2018 Thu [no class]
8 Nov 22, 2018 Thu 13:00-14:30 Sosei Hall chemical bonds (2)
9 Nov 22, 2018 Thu 14:45-16:15 Sosei Hall bond ionicity and hybrid orbitals
10 Nov 29, 2018 Thu 08:45-10:15 D103 hybrid orbitals
11 Dec 6, 2018 Thu 08:45-10:15 D103 metal complexes (1)
12 Dec 13, 2018 Thu 08:45-10:15 D103 metal complexes (2)
13 Dec 20, 2018 Thu 09:15-10:15 D103 (interim test 2)
Dec 27, 2018 Thu [no class]
14 Jan 10, 2019 Thu 08:45-10:15 D103 summary
15 Jan 17, 2019 Thu 08:45-10:15 D103 final test
(12)─Course in Materials Science I 22
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