褶皱Re-C方网：变形与粘合的化学探索

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"褶皱 Re-C 方网中的变形和粘合" 在化学与材料科学领域，这篇学术论文探讨了Sc5Re2C7化合物中的独特结构和性质。文章由Erika F. Merschrod, Aliya Courtney 和 Roald Hoffmann撰写，发表于2002年4月23日，并献给Rudolf Hoppe教授以庆祝其80岁生日。该研究的核心是Re-C（铼-碳）形成的褶皱状"方形"网络，以及其中的孤立C3单元和钪离子。 Sc5Re2C7的电子构型是导致Re-C网络异常扭曲的关键因素。这种扭曲导致Re-C键和Re-Re键在不同方向上的结合强度显著不同。特别值得注意的是，某些Re-C相互作用的强度甚至超过了双键的强度。褶皱的结构允许钪原子在这种网络中发挥独特的结合作用，这是由于其几何形态引起的变形所促成的。论文的作者深入分析了这些变形如何影响分子间的键合性质，特别是Re-C键和Re-Re键的强度和方向性。他们指出，这种特殊的键合模式可能导致材料具有独特的物理和化学性质，可能对催化、电导率或其他材料性能产生重要影响。此外，研究还可能揭示新的设计原则，用于构建具有特定功能的先进材料。论文的引言部分引入了问题背景和研究动机，正文则详细讨论了实验方法、结构分析、理论计算以及所得结果的解释。作者可能使用X射线晶体学、光谱学和其他表征技术来解析和理解这种结构。论文的结论部分可能总结了他们的发现，并提出了未来研究的方向，以进一步探索这种新颖的Re-C网络在材料科学中的应用潜力。这篇论文为理解Re-C网络的变形和结合提供了新的见解，对材料科学家和化学家来说是宝贵的资源，有助于推动相关领域的研究进展。通过深入研究这些复杂的相互作用，研究人员可以设计出更高效、更具特性的新型材料。

Deformation and Bonding in a Puckered ReⴚC Square Net

Erika F. Merschrod S.

, Aliya Courtney

and Roald Hoffmann*

Ithaca, New York/U.S.A., Cornell University, Department of Chemistry and Chemical Biology and Cornell Center for Materials

Research

Received April 23

, 2002.

Dedicated to Professor Rudolf Hoppe on the Occasion of his 80th Birthday

Abstract. Sc

contains unusual Re⫺C puckered “square”

nets, isolated C

units, and scandium ions.Its electron count drives

the peculiar distortion of the Re⫺C nets, resulting in quite different

Re⫺CandRe⫺Re bonding along each direction. Indeed, some of

the Re⫺C interactions emerge as stronger than double bonds.The

puckering, in turn, enables a bonding role for the scandium atoms

Deformation und Bindung in einem gefalteten quadratischen ReⴚC-Netz

Inhaltsübersicht. Sc

enthält ungewöhnliche „quadratische“

Re⫺C-Netze, isolierte C

-Einheiten und Scandium-Ionen. Die An-

zahl seiner Elektronen bestimmt die besondere Verzerrung der

Re⫺C-Netze, was ganz verschiedene Re⫺C- und Re⫺Re-Bindun-

gen in jeder Richtung zur Folge hat. Tatsächlich erscheinen einige

Introduction

Ternary transition metal carbides exhibit great structural

diversity, containing isolated carbon atoms, C

pairs and

groups. One also finds in them interesting metal-carbon

networks of varying dimensionality. A decade ago, a new

carbide was synthesized by Pöttgen and Jeitschko [1] which

contains both C

groups and individual C atoms. Sc

(shown in three views in 1) has square nets of rhenium and

carbon atoms which are highly distorted through pucker-

ing; the bonds in these nets are indicated with heavier black

lines. The axes in 1 are assigned for convenience during

analysis (placing the nets in the xy plane); our z axis corre-

sponds to the b axis of the original compound.

The Re⫺C sheets have two types of carbon atoms (small

black circle), each bridging two Re atoms (lined circles) in

either a linear or a bent geometry. The linear C

units are

isolated from each other and from the Re⫺C nets by the

scandium atoms (large white circles), which also separate

* Prof. Roald Hoffmann

Baker Laboratory, Department of Chemistry and Chemical

Biology, Cornell University

Ithaca, NY 14853-1301/U.S.A.

Present address: Department of Chemistry, University of

Toronto, Toronto, Ontario, M5S 3H6, Canada

Present address: Johns Hopkins University School of Medicine,

Baltimore, Maryland, 21205-2196, U.S.A.

Z. Anorg. Allg. Chem. 2002, 628, 2757⫺2763  2002 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim 0044⫺2313/02/628/2757⫺2763 $ 20.00⫹.50/0 2757

in addition to their function as electron donors to the nets and the

isolated carbide units.

Keywords: Electronic structure; Extended Hückel theory; Tran-

sition-metal carbide: Scandium bonding; Metal⫺carbon multiple

bond

der Re⫺C-Wechselwirkungen stärker als Doppelbindungen. Die

Faltung erlaubt den Scandium-Atomen andererseits ihre Rolle als

Bindungspartner zusätzlich zu ihrer Funktion als Elektronen-Do-

noren des Netzes und der isolierten Carbid-Einheiten.

the two-dimensional Re⫺C networks from each other. The

unusual Re⫺C square nets attracted our interest, leading to

the investigation of the electronic structure of the com-

pound reported in this paper.

Assigning electrons

We begin by dissecting the three-dimensional structure of

into its chemically meaningful components and

distributing the electrons accordingly. Based on the results

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褶皱Re-C方网：变形与粘合的化学探索

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