Table Of ContentAROMATICITY and
METAL CLUSTERS
A , M , C
TOMS OLECULES AND LUSTERS
Structure, Reactivity, and Dynamics
Series Editor: Pratim Kumar Chattaraj
Aromaticity and Metal Clusters
Edited by Pratim Kumar Chattaraj
Quantum Trajectories
Edited by Pratim Kumar Chattaraj
A , M , C
TOMS OLECULES AND LUSTERS
Structure, Reactivity, and Dynamics
AROMATICITY and
METAL CLUSTERS
Edited by
Pratim Kumar Chattaraj
Boca Raton London New York
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Contents
Foreword ...................................................................................................................ix
Series Preface ............................................................................................................xi
Preface....................................................................................................................xiii
Editor .......................................................................................................................xv
Contributors ...........................................................................................................xvii
Chapter 1 Aromaticity: From Benzene to Atomic Clusters ..................................1
Sandeep Nigam and Chiranjib Majumder
Chapter 2 On the Measures of Aromaticity ........................................................31
G. Narahari Sastry, P. Venuvanalingam, and P. Kolandaivel
Chapter 3 Aromaticity in Metals: From Clusters to Solids ................................55
Alina P. Sergeeva and Alexander I. Boldyrev
Chapter 4 Computational Studies on Molecules with Unusual
Aromaticity: What to Expect? ............................................................69
Ayan Datta, Sairam S. Mallajosyula, and Swapan K. Pati
Chapter 5 Using the Electron Localization Function to
Measure Aromaticity ..........................................................................95
Patricio Fuentealba, Elizabeth Florez, and Juan C. Santos
Chapter 6 Polarizability of Metal Clusters: A Coarse-Grained Density
Functional Theory Approach ...........................................................103
Swapan K. Ghosh
Chapter 7 Reactivity of Metal Clusters .............................................................119
Julio A. Alonso, Angel Mañanes, and Luis M. Molina
Chapter 8 Electronic Shells and Magnetism in Small Metal Clusters ..............137
Prasenjit Sen
v
vi Contents
Chapter 9 Using Theory in Determining the Properties of Metal
Clusters: Sodium as a Case Study ....................................................161
Violina Tevekeliyska, Yi Dong, Michael Springborg, and
Valeri G. Grigoryan
Chapter 10 The Induced Magnetic Field and Its Application .............................187
Rafael Islas, Gerardo Martínez-Guajardo, Gotthard Seifert,
Thomas Heine, and Gabriel Merino
Chapter 11 A Density Functional Investigation on the Structures,
Energetics, and Properties of Sodium Clusters through
Electrostatic Guidelines and Molecular Tailoring ...........................205
K. V. Jovan Jose, Subodh S. Khire, and Shridhar R. Gadre
Chapter 12 Size and Shape-Dependent Structural and Electronic
Properties of Metal Chalcogenide Nanoclusters ..............................227
Sougata Pal and Pranab Sarkar
Chapter 13 Correlation between Electron Delocalization and Ring Currents
in All Metallic “Aromatic” Compounds ..........................................245
Patrick Bultinck, Stijn Fias, Marcos Mandado, and
Robert Ponec
Chapter 14 Phenomenological Shell Model and Aromaticity in
Metal Clusters ..................................................................................271
Tibor Höltzl, Tamás Veszprémi, Peter Lievens, and
Minh Tho Nguyen
Chapter 15 Rationalizing the Aromaticity Indexes Used to Describe the
Aromatic Behavior of Metal Clusters ..............................................297
Prasenjit Seal and Swapan Chakrabarti
Chapter 16 Aromaticity in All-Metal Rings .......................................................323
Jose M. Mercero, Ivan Infante, and Jesus M. Ugalde
Chapter 17 Synthesis and Structure of Aromatic Alkali Metal Clusters
Supported by Molybdenum Metalloligands .....................................339
Manish Bhattacharjee
Contents vii
Chapter 18 5f Orbital Successive Aromatic and Antiaromatic Zones in
Triangular Uranium Cluster Chemistry ...........................................349
Constantinos A. Tsipis
Chapter 19 Bonding, Aromaticity, and Possible Bond-Stretch Isomerism
in an “All-Metal” Cluster—[Be Zn ]2− ............................................371
6 2
Santanab Giri, R. P. S. Abhijith Kumar, Arindam Chakraborty,
Debesh R. Roy, Soma Duley, Ramakrishnan Parthasarathi,
Munusamy Elango, Ramadoss Vijayaraj, Venkatesan Subramanian,
Gabriel Merino, and Pratim Kumar Chattaraj
Chapter 20 Are Dicationic Chalcogenid Ring Systems Aromatic? ....................387
Patrizia Calaminici, Andreas M. Köster, and
Zeferino Gómez-Sandoval
Chapter 21 Study of Aromaticity in Phosphazenes ............................................409
Prakash Chandra Jha, Y. Anusooya Pati, and S. Ramasesha
Index ......................................................................................................................423
Foreword
Michael Faraday, “the best experimentalist in the history of science,” is responsible
for the many contributions to this book. He is my candidate for its inspirational pio-
neer. Similar to the diverse subject matter of the following chapters, Faraday’s career
spanned both chemistry and physics. He discovered benzene in 1825, recognized its
special properties, and determined the composition of naphthalene. His seminal
involvement with the interrelationship of electricity and magnetism formed the basis
for the later association of unusual magnetic properties with aromaticity. Faraday
observed that an electrical current was induced when a magnet was moved in a coil
of wire. He discovered diamagnetism and paramagnetism and invented the “Faraday
balance” for their measurement. The exaltation of magnetic susceptibility due to the
induced ring currents in aromatic compounds is among the widely employed mag-
netic criteria, and is highly pertinent to the characterization of metal clusters.
Faraday was the first to report what are now described as “nanoparticles.” He
noted in 1847 that properties of gold colloids (clusters!) differed from those of the
bulk metal. This “might be considered to be the birth of nanoscience.” Gold atom
aggregates are prominent among metal clusters of current interest.
Charts of the Periodic Table typically categorize the chemical elements as
“nonmetallic” or “metallic.” The 80 metals among the first 105 elements are “good
conductors of both electricity and heat” in the bulk. They epitomize electron delocal-
ization, the hallmark of aromaticity. However, the typical reactions and chemical
behavior of individual metal atoms (particularly those of the s,p-block) are much like
those of the nonmetallic elements. How many atoms of a metal are needed before the
cluster becomes “metallic”? The onset of “aromaticity” in any kind of system also is
a fuzzy matter of viewpoint and interpretation. Physicists disdain concepts incapable
of precise definition.
Organic chemists, the principal purveyors of aromaticity, were slow to recognize
that elements other than carbon can participate (this realization dates from the isola-
tion of thiophene as an impurity in benzene in 1883). Stock’s “inorganic benzene”
(Borazine, 1926) culminated the quest for main group element examples lacking
carbon completely. Despite their prevalence among the chemical elements, transition
metals were accepted into the panoply of aromaticity even more slowly. Ferrocene
and dibenzenechromium drew attention to the participation of d-block metals, but
the aromaticity of these sandwiches was largely ascribed to their carbon rings.
Replacement of a benzene CH by a metal group was another step forward. Many
well-known complexes with multiple transition metal atoms obviously benefit from
the highly delocalized bonding associated with “aromaticity,” but this sobriquet was
seldom applied until recently.
Progress toward the title of this book is outlined in its chapters. Physicists were
intrigued by the intensity distributions (“magic numbers”) in the mass spectra of
sodium and other metal atom clusters. Chemists discussed the relationship of Li+
3
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