1. Research Experience:
Inorganic and Organometallic Chemistery.
Over the six years period of Ph.D. work, a good expertise has been achieved in the field of
organometallic chemistry and catalysis. The central theme of my thesis was the study on bimetallic
cooperative catalysts and aimed at studying if sequential or cooperative participation of two metal
components might lead to enhanced reaction rate, better selectivity and in some cases new types of
reactions. This was in line with the continuing research activity of the group concerning room temperature
cleavage of C-H bonds, formation of the C-C bond and bimetallic water-gas shift chemistry executed on a
di-Ruthenium platform. These stoichiometric reactions have provided valuable insight on fundamental
organometallic processes on a dimetal core.
The challenging task in designing a bimetallic catalyst is the selection of ligand capable of
accommodating geometrical and electronic reorganization of the dimetal unit during the course of the
catalytic cycle. The demonstrated ability of 1,8-naphthyridine (NP) to stabilize a host of dimetal cores
prompted the utilization of the NP-based ligand. A donor appendage (such as pyridyl, thiazolyl, pyrollyl)
at 2-position of the NP unit enables additional chelate ring formation and allows axial modulation of the
metal-metal bond. I also have incorporated hemilabile amido group with the prospect that the oxygen
atom would open up a site for substrate coordination. Metal-metal singly-bonded dipalladium(I),
diruthenium(I) and dicopper(I) compounds have been synthesized employing amide-linked ferrocene-
naphthyridine hybrid ligand. The study of the catalytic aptitudes of [PdI
-PdI
], [RuI
-RuI
] and [(CuI
···CuI
)/
(CuII
···CuII
)] compounds in a variety of organic transformations constituted the main part of my thesis.
Moreover In collaboration with Prof. Henri Doucet (Institut des Sciences Chimiques de Rennes,
UMR 6226 CNRS-Université de Rennes, France), we have studied "Bimetallic Catalysis Involving
Ruthenium and Palladium: C-H Bond Activation/Functionalization and Beyond".

2. Thesis overview
Name of the student: Raj K. Das Roll No: Y6207067
Degree for which submitted: Ph. D. Department: Chemistry
Thesis supervisor: Prof. Jitendra K. Bera
Month and year of thesis submission: 2nd
April, 2012
Thesis Title: “Syntheses, Structures and Catalytic Evaluation of Binuclear Transition Metal
Complexes”
The central premise of this thesis is that cooperative participation of two metal ions might lead to
enhance reaction rate and improve selectivity for a chemical reaction, and might even offer new
reactivity. Towards this objective, a variety of dinuclear complexes with or without metal–metal bonds
are synthesized and their catalytic properties are evaluated. The prospect of bimetallic reactivity in
promoting catalytic organic transformations is examined in this work. Mechanistic investigations are
carried out to highlight the intermediacy of a bimetallic species in the catalytic cycle. The thesis has been
divided into following four chapters:
Chapter 1: General Introduction
In this introductory chapter, a brief overview has been presented on the recent reports of the dinuclear
transition metal complexes and their catalytic applications for a wide variety of reactions. This chapter
starts with a short summary of metalloenzymes containing dinuclear active sites, followed by a discussion
on the fundamental reactivity aspects involving bimetallic complexes. A short treatise on the substrate
activation to and product elimination from dimetal platforms is presented in this chapter. Finally, several
examples of efficient binuclear organometallic catalysts are discussed.

3. Chapter 2: Dipalladium(I) and Diruthenium(I) Complexes and Their Applications in C-C Bond
Formation and Carbene-Transfer Reactions
Dipalladium(I) and diruthenium(I) compounds incorporating [{(5,7–dimethyl–1,8–naphthyridine–2–
yl)amino}carbonyl]ferrocene (L1
) ligands have been synthesized. X-ray structures of [Pd2L1
2][BF4]2 (1)
and[Ru2L1
2(CO)4][BF4]2 (2) are determined (Figure 1). In both of these structures, the naphthyridine unit
bridges the dimetal core and the site trans to metal-metal bond is occupied by weakly coordinating O
atom of the amido fragment. The Pd–Pd bond length in 1 is the shortest among the dipalladium(I)
compounds reported. The prospect of bimetallic catalysis is examined with these two compounds.
Compound 1 is an excellent catalyst for phosphine-free Suzuki cross-coupling reactions of aryl bromides
with arylboronic acids providing high yields in short reaction time. Compound 1 is also found to be
catalytically active for aryl chlorides although corresponding yields are lower. A bimetallic mechanism is
proposed which involves initial oxidative addition of aryl halide across the Pd–Pd bond and bimetallic
reductive elimination of product. The excellent catalytic activity of 1 is also revealed in the Heck cross-
coupling of aryl bromoides with styrenes. The mechanism of the olefination of aldehyde with ethyl
diazoacetate (EDA) catalyzed by 2 has been fully elucidated. It is concluded that 2 catalyzes the
formation of phosphorane utilizing EDA and PPh3 which subsequently reacts with aldehyde to produce
new olefin and phosphine oxide.
1 2
Figure 1. ORTEP diagrams of the dicationic units of compounds (1) [Pd2L1
2] and
(2) [Ru2L1
2(CO)4].

4. Chapter 3: Binuclear Copper Complexes and Their Catalytic Evaluation
Two dinuclear copper complexes [{CuI
(L1
)}2][OTf]2 (3) and [{CuII
(L2
)Cl}2] (4) have been synthesized
and structurally characterized. Reaction of [{(5,7–dimethyl–1,8–naphthyridine–2–
yl)amino}carbonyl]ferrocene (L1
) with [Cu(CH3CN)4][OTf] in dichloromethane affords complex 3 in
high yield. The dicopper(II) complex 4 is obtained by the overnight treatment of N–(5,7–dimethyl–1,8–
naphthyridine–2–yl)–1–methylpyrrolidine-2-carboxamide (L2
H) and [Cu(CH3CN)4][BF4] in
Scheme 1. Metal–metal singly bonded [PdI
–PdI
] and [RuI
–RuI
] complexes
catalyze C–C bond-coupling and aldehyde-olefination reactions,
respectively
3 4
Figure 2. ORTEP diagrams of the compounds (3) [{CuI
(L1
)}2][OTf]2 and (4)
[{CuII
(L2
)Cl}2]

5. dichloromethane. Two copper atoms are bridged by two trans
oriented L1
ligands in complex 3; the naphthyridine nitrogens
bridge two copper centers and the carbonyl oxygen occupies a
site trans to the Cu···Cu vector. The two copper metals are
separated by 2.4594(6) Å. On the contrary, each of the two L2
ligands utilize one naphthyridine, deprotonated amide and
proline nitrogens to bind two copper atoms forming an open-
book geometry for complex 4. Both dicopper complexes are
shown to be excellent cyclopropanation catalysts for various
olefins with ethyl diazoacetate (EDA) although catalyst 3 is
found to be marginally superior than 4 (Scheme 2). This chapter
also contains novel chiral dipalladium(II) complexes 5 derived
from anionic L2
ligand bearing weakly coordinating chlorides
has been synthesized and its structure has been characterized by
X-ray crystallography. Complex 5 is shown to be an efficient catalyst for the allylation of aldehydes to
furnish the corresponding allylated products in good to high yields under mild conditions (Scheme 3).
Scheme 2. Cyclopropanation reaction catalyzed by dinuclear compounds 3 and 4
Scheme 3. Allaylation of aldehydes reaction catalyzed by dinuclear
compound 5
Figure 3. ORTEP diagram of
the compound (5)
[{PdII
(L2
)Cl}2]
5

6. Chapter 4: Syntheses of Fluoro-Bridged Binuclear Nickel(II) and Thiolate-Bridged Tetranuclear
Palladium(II) Compounds
Chapter 4 describes the formation of fluoro and thiolate bridged complexes of Group 10 metals. Reaction
of [Ni(CH3CN)6][BF4]2 with [{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene (L1
) in
acetonitrile affords [NiII
2(μ-F)2(L1
)4][BF4]2 (6). X-ray
structure reveals a fluoro-bridged Ni2F2 core and each Ni
is additionally coordinated to four N atoms from two
chelating ligands. The molecular mass peak is observed at
m/z (z=2) 848 in the ESI-MS. It is believed that the
bimetallic activation of BF4

, followed by the
trifluoroborane exclusion aided by the ligand L1
, results in
the formation of 6. The NH···F interactions play an
important role in the formation and stabilization of
compound 6. A novel tetranuclear Pd(II) complex 7
bearing a [Pd2I2(μ–SMe)2]2 core supported by bis-
carbenes ligand has been synthesized and structurally
characterized. It is proposed that the source of –SMe group in the final product is the solvent DMSO.
Figure 4. ORTEP diagram of
the dicationic unit of compound
(6) [NiII
2(μ-F)2(L1
)4]
6
Scheme 4. Proposed bimetallic
activation of the tetrafluoroborate
anion
7
Figure 5. ORTEP diagram of 7
containing the [Pd2I2(μ–SMe)2]2
core.