北京化工大学中级化学年非金属原子簇

1、第5章 非金属原子簇化合物 离子 足电子 富电子缺电子12LiNH2BH3 and NaNH2BH3nature materials VOL 7 FEBRUARY 20083B(s) + Ca(l) CaB6CaB6的结构，B62- 原子簇金属硼化物 MB6, MB12 存在硼原子簇（cluster)4一. 硼烷和碳硼烷 二. 富勒烯, 碳纳米管, 石墨烯, 石墨炔固体单质 硼的结构单元，B12 Ih点群（20面体）30条边 价电子数 = 123 = 36 成键缺电子！5William Lipscomb (1919-)1976年Nobel 化学奖the structure of boranes

2、 illuminating problems of chemical bonding 6 BnHn+m B2H6, B4H10, B5H9, B5H11, B6H10, B10H14 缺电子的硼氢簇合物 B2H6 和 C2H4 为等电子体B和桥H的化学键是什么键？桥H的原子轨道？一. 硼烷(Borane)的组成7闭式BnHn2 巢式(开式) BnHn+4 蛛网式 BnHn+6 8B4H10 四硼烷(10) B4H4+6B5H9 五硼烷(9) B5H5+4B5H11 五硼烷(11) B5H5+6B6H10 六硼烷(10) B6H6+4 B6H12 六硼烷(12) B6H6+6B12H122 十二

3、硼烷阴离子 ( B12H12+2 )m = 2 闭式（closo)m = 4 巢（开）式 (nido)m = 6 （蛛）网式 (arachno)通式：BnHn+m9二. 硼烷中的化学键 (定域)Lipscomb用单晶X衍射得出硼烷结构，提出: 3c-2e (三中心两电子)键 3c-2e BBB键 3c-2e BHB键 10nido BnHn+44个BHB 8e1个BBB 2e2个BB 4e0 个BH2 0e5个BH 10e总电子: 24eB5H9 （4120）styx 表示 s BHB 键个数t BBB 键个数y BB 键个数x BH2 键个数11arachno BnHn+63个BHB 6e2

4、个BBB 4e0个BB 03个BH2 6e5个BH 10e总电子: 26estyx表示: (3203)12三种硼烷之间的关系 BH +4H BH +2H B6H62- B5H9 B4H10 m=2 m=4 m=6BnHn+m13斜线方向: BH, +2H水平方向: +2H垂直方向： BH14n+1 n+2 n+3 (Wade 规则）15三. 硼烷的骨架电子对规则(Wades rule)Wade规则: 骨架电子数, 化学式和分子形状之间的关系.把硼烷中的所有化学键作为整体处理骨架电子对数 = 成键分子轨道数由英国化学家Kenneth Wade 在1970s提出. 主要用于三角形多面体(delta

5、hedra)类型的化合物中. 骨架电子: 除每个B-H键以外的所有电子B4H10 4个(B-H)键2 4 = 8个电子为非骨架电子, 其余电子为骨架电子 4 2 + 6 = 1416例如: B6H62 18+6+2=26e 6个 B-H 12e剩余 6 2 + 2=14e , 骨架电子数为14骨架电子对 = 6+1 = 7 （n+1, n为硼原子数）B5H9 即 B5H5+4 骨架电子数= 5 2 +4 = 14骨架电子对 = 5+2 = 7 （n+2, n为硼原子数）B5H11 即 B5H5+6 骨架电子数= 5 2 +6 = 16骨架电子对 = 5+3 = 8 （n+3, n为硼原子数）1

6、7结构化学式骨架电子对实例闭式(closo)BnHn2n +1B12H122巢式(nido)BnHn+4n +2B5H9蛛网式(arachno)BnHn+6n +3B5H11敞网式(hypho)BnHn+8n +4无简单硼烷硼烷结构和骨架电子对数的关系18Wade 规则的应用： 骨架电子对 分子构形 B2H6 B2H2+4 2 + 2 巢式 B4H10 B4H4+6 4 + 3 蛛网 B5H9 B5H5+4 5 + 2 巢式 B5H11 B5H5+6 5 + 3 蛛网 B6H10 B6H6+4 6 + 2 巢式 B10H14 B10H10+4 10 + 2 巢式 B12H122 B12H12+

7、2 12 +1 闭式19B11H14- 的11B-NMR谱 BnHn+4 (nido结构), （缺顶二十面体）5KB9H14+ 2B5H9 5KB11H14 + 9H220硼烷的性质 热稳定性差, fGm和 fHm为正值, 吸热化合物化学稳定性差(自燃, 水解)燃烧值大(G小) BnHm+O2 B2O3+H2O Hf (B2O3)= -1273 kJ.mol-1毒性大四. 硼烷的性质和制备Alfred Stock (July 16, 1876 August 12, 1946) was a German inorganic chemist. He did pioneering research

8、on the hydrides of boron and silicon, coordination chemistry, mercury, and mercury poisoning.Due to their extreme reactivity and flammability in air, boron hydrides could not be purified until his development of methods for separation using high-vacuum manifolds around 1912.21硼烷的制备: BF3+ NaBH4 B2H6B

9、2O3+H2+Al B2H6B2H6作起始物 (用BF3制备 B2H6 ) B2H6(g) 2BH3(g) B2H6(g) + BH3(g) B3H7(g)+H2(g)B3H7(g)+ BH3(g) B4H10(g)稳定的B化合物和氢化物或者与还原剂反应Herbert Charles Brown (May 22, 1912 December 19, 2004) was a chemist and Nobel Prize in Chemistry (1979)laureate for his work with organoboranes.22五. 碳硼烷及金属硼烷衍生物B5H9 1,5- C2

10、B3H51,6- C2B4H62,4- C2B5H7C BH 等电子, 分子结构中C 取代 BH C BH， P BH (或BH2), S BH2 (或BH3) 231,2- C2B10H12 ( B12H122 )1-SB9H9 （B10H102）1-SB11H11 （B12H122）1,2-CPB10H11 （B12H122）结构？24Closo-B11H11AlCH32的金属硼烷阴离子结构B11H132-+Al2(CH3)6 2B11H11AlCH32+4CH425Arachno和nido金属取代硼烷Closo的C衍生物取代硼烷26C2B10H12 C2B9H112-盆状二碳硼烷金属配合

11、物27Inorganic Chemistry2001, coverSalute to Fred HawthorneIcosahedral B12H12240 years28Sn94-骨架电子对= 9+2Pb52-骨架电子对=5+129Bi42-，Se42+骨架电子对= 4+3C8H8（立方烷）非三角面结构不符合wade规则B4H4+630Tetrasulfur tetranitride, S4N4, P4其他重要的无机原子簇作为Lewis碱的反应S4N4 + SbCl5 S4N4.SbCl5 S4N4 + SO3 S4N4.SO331六. 富勒烯(Fullerenes)化学 C60 Ih C7

12、0 D5d如何确认C60 的结构？32 13C NMR spectrum of the purified C60 , reported by Kroto et al. (Taylor, 1990). The NMR spectrum contained a single peak at 142.7, as expected for the highly symmetrical truncated icosahedron structure in which all carbons are identical 33Using mass spectrometry, discrete peaks a

13、ppeared corresponding to molecules with the exact mass of sixty or seventy or more carbon atoms. In 1985, Harold Kroto (then of the University of Sussex), James R. Heath, Sean OBrien, Robert Curl and Richard Smalley, from Rice University, discovered C60, and shortly thereafter came to discover the f

14、ullerenes. Kroto, Curl, and Smalley were awarded the 1996 Nobel Prize in Chemistry for their roles in the discovery of this class of molecules. C60 and other fullerenes were later noticed occurring outside the laboratory (e.g., in normal candle soot). 34 Definitive proof for the structure of C60 cam

15、e in 1991 when Joel Hawkins (Univ. of California-Berkeley) synthesized and crystallized an osmium derivative of (C60)OsO4 (4-tert-butylpyridine)2. Single crystal X-ray analysis of this compound yielded the first atomic-resolution picture of the carbon framework of C60 (C 60 )OsO4 (4-叔丁基吡啶)235s0.9p2.

16、28杂化，30个6/6双键，截顶20面体（B12）热力学稳定性比石墨差可被还原和自由基、亲核试剂加成和化学修饰3637制备富勒烯的电弧炉38不同条件下合成的富勒烯的质谱图(He的压力不同和反应时间不同）39富勒烯及碳纳米管的主要研究方面1. 制备和分离理论计算化学修饰 a. 富勒烯的超导化合物 b. 环加成反应(有机反应), C60与氨基酸酯的加成 c. 富勒烯配合物 d. 富勒烯包合物的研究4. 碳纳米管的制备40153 K. C60 crystallizes in a face centered cubic， space group Pa3. 41富勒烯的金属化合物, K3C60 , Rb

17、3C60, Cs3C60 , KxC60 超导温度18KC60以面心立方密堆积, K, Rb, Cs 填充全部八面体和四面体空隙富勒烯的衍生物42Polymeric fullerene chains in RbC60 432. 金属富勒烯包合物（EMF, endohedral metallofullerenes)单金属: La82双金属: Sc282三金属: Sc382杂原子: Sc3N80443. 富勒烯的金属配合物 Os(O)4(py)2(C60)45(eta2-C70-Fullerene)-carbonyl-chloro-bis(triphenylphosphine)-iridium (

18、2-C70)-Ir(CO)Cl(PPh3)246七. 碳纳米管( carbon nanotube)单层碳纳米管 SWCN(Single-wall carbon nanotube)多层碳纳米管 MWCN(Multi- wall carbon nanotube)石墨卷曲成长度: 几十m直径: 1100nm47The smallest carbon nanotube High-resolution electron microscope image of a 4 tubule (side walls are marked by lines) confined inside an 18-shell carbon nanotubeSumio Iijima et alNature 408, 50 (2000) 48Coalescence of C60 Molecules Assisted by Doped Iodine Inside Carbon NanotubesLunhui Guan, Kazu Su