The use of liquid-liquid interface (biphasic) for the preparation of benzenetricarboxylate complexes of cobalt and nickel

FULL PAPER

DOI: 10.1002/ejic.200800152

The Use of Liquid–Liquid Interface (Biphasic) for the Preparation of

Benzenetricarboxylate Complexes of Cobalt and Nickel

Abhishek Banerjee,^[a]Partha Mahata,^[a]and Srinivasan Natarajan*^[a]

Keywords: Metal–organic frameworks / Cobalt / Nickel/ Biphasic synthesis method

New metal–organic frameworks (MOFs) [Ni(C₁₂N₂H₁₀)-

(H₂O)][C₆H₃(COO)₂(COOH)] (I), [Co₂(H₂O)₆][C₆H₃(COO)₃]₂·

(C₄N₂H₁₂)(H₂O)₂(II), [Ni₂(H₂O)₆][C₆H₃(COO)₃]₂·(C₄N₂H₁₂)-

(H₂O)₂(III), [Ni(C₁₃N₂H₁₄)(H₂O)][C₆H₃(COO)₂(COOH)] (IV),

[Ni₃(H₂O)₈][C₆H₃(COO)₃] (V) and [Co(C₄N₂H₄)(H₂O)][C₆H₃-

nitrogen atoms of the ligand amines and the carboxylate

units to form a variety of structures of different dimensional-

ity. Strong hydrogen bonds of the type O–H···O are present

in all the compounds, which give rise to supramolecularly

organized higher-dimensional structures. In some cases π···π

interactions are also observed. Magnetic studies indicate

weak ferromagnetic interactions in I, IV and V and weak

antiferromagnetic interactions in the other compounds (II, III

(COO)₃] (VI) {C₆H₃(COOH)₃= trimesic acid, C₁₂N₂H₁₀

1,10-phenanthroline, C₄N₂H₁₂piperazine dication,

₁₃N₂H₁₄1,3-bis(4-pyridyl)propane and C₄N₂H₄=

=

C

=

pyrazine} have been synthesized by using an interface be- and VI). All the compounds have been characterized by a

tween two immiscible solvents, water and cyclohexanol. The

compounds are constructed from the connectivity between

the octahedral M²⁺(M = Ni, Co) ions coordinated by oxygen

atoms of carboxylate groups and water molecules and/or by

variety of techniques.

Germany, 2008)

zene-1,3,5-tricarboxylic acid, H₃tma) form the largest

number of high-symmetry structures.^[10]Most of these com-

pounds are prepared by using a mild hydrothermal reaction

between a metal salt, trimesic acid and a base.^{[10a,10b,10d]}

Recently, there have been many attempts to modify the syn-

thesis conditions, which has given rise to newer approaches,

such as the biphasic solvothermal method^[12]and those that

use ionic liquids,^[11]etc. Of these, the biphasic approach ap-

pears to have distinct advantages. In biphasic reactions, the

metal salt is generally in aqueous medium and the organic

acid is in an organic solvent, which is usually immiscible

with water (cyclohexanol). The formation of the product

phase is usually at or near the interface between the two

liquids. This approach has been employed profitably for the

preparation of many inorganic–organic hybrid compounds

by Cheetham and co-workers.^[12]Recently, the liquid–liquid

interface has also been employed for the synthesis of nano-

particles, nanocrystals, etc.^[13]

The biphasic synthesis is advantageous while working

with metals that have low reduction potentials, i.e. metals

that are easily reducible – as is the case for Cu²⁺ions.^[12b]

It also offers the possibility to work with organic solvents

that may be unstable under hydrothermal conditions. Yaghi

and co-workers employed a modified approach for the

preparation of MOFs of aromatic dicarboxylates by em-

ploying two different solvents. Thus, Zn(NO₃)₂·6H₂O and

naphthalene-2,6-dicarboxylic acid were dissolved in a mix-

Introduction

Metal–organic frameworks (MOFs) have been in the

forefront of research for their applications in the areas of

adsorption,^[1]separation and catalysis.^[2]Additionally, the

ability to incorporate almost all the elements of the periodic

table along with the possibility of introducing functionality

through the organic linkers provide the added impetus for

the continuing interest.^[3]Of the many MOFs that have

been synthesized,^[4]those with transition metals are impor-

tant.^[5]The transition elements, with their varied oxidation

states and coordination preferences, present an excellent op-

portunity to correlate magnetic, spectroscopic and related

properties with the framework structure.^[6]The organic lin-

kers, with varying lengths and functionalities, can form

MOFs with adjustable channels and impart chemical reac-

tivity and in some cases chirality.^[7]

A detailed study of the available literature clearly reveals

that the number of metal–organic framework compounds

formed by aromatic carboxylates is far more than that

formed by aliphatic ones.^[4e,8]Of the many aromatic carb-

oxylic acid based MOFs, those of trimesic acid^[9,10](ben-

[a] Framework Solids Laboratory, Solid State and Structural

Chemistry Unit, Indian Institute of Science,

Bangalore 560 012, India

E-mail: snatarajan@sscu.iisc.ernet.in

Supporting information for this article is available on the

WWW under http://ww w .eurjic.org or from the author.

Eur. J. Inorg. Chem. 2008, 3501–3514

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A. Banerjee, P. Mahata, S. Natarajan

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ture of diethyl formamide (def) and chlorobenzene (ClBz), Table 1. Selected bond lengths in compounds I–IV and VI.^[a]

and the solution was kept at room temperature without

Bond

Distance [Å]

Bond

Distance [Å]

contact in a vessel containing def and triethylamine (tea).

This approach resulted in isolating a new framework struc-

ture, Zn₂[C₁₀H₈(COO)₂]·[(Htea)(def)(ClBz)]₂.^[14]In ad-

I

Ni(1)–O(1)

Ni(1)–O(2)

2.021(3)

2.046(3)

2.093(3)

Ni(1)–O(3)#1 2.148(3)

Ni(1)–N(1)

Ni(1)–N(2)

2.063(3)

2.093(3)

dition, they used a mixture of miscible solvents to crys- Ni(1)–O(3)

tallize related metal–organic frameworks.^[14]This approach,

II

Co(1)–O(1)#1

although it uses a variety of organic solvents, cannot truly

Co(1)–O(1)

2.0788(15)

2.0927(16)

2.1205(16)

Co(2)–O(4)

Co(2)–O(4)#2 2.041(2)

Co(2)–O(5)#2 2.1161(16)

Co(2)–O(5)

Co(2)–O(6)#2 2.1776(16)

Co(2)–O(6)

Ni(2)–O(4)

Ni(2)–O(4)#2 2.046(4)

Ni(2)–O(5)#2 2.076(3)

Ni(2)–O(5)

Ni(2)–O(6)#2 2.129(3)

2.041(2)

be considered a biphasic method, since the solvents em-

Co(1)–O(2)#1

ployed are generally miscible.

Co(1)–O(2)

Co(1)–O(3)#1

Co(1)–O(3)

III

Ni(1)–O(1)#1

Ni(1)–O(1)

2.1161(16)

Though the biphasic method is seemingly advantageous,

this approach for the preparation of inorganic–organic hy-

brid compounds has not caught the imagination of rese-

arches. We sought to use this technique, in an exploratory

2.1776(16)

2.046(4)

2.043(3)

2.057(3)

2.085(3)

way, for the preparation of benzenecarboxylates of cobalt Ni(1)–O(2)#1

Ni(1)–O(2)

2.076(3)

and nickel. Our studies have been successful, and we have

Ni(1)–O(3)#1

prepared six new compounds: [Ni(C₁₂N₂H₁₀)(H₂O)][C₆H₃-

Ni(1)–O(3)

Ni(2)–O(5)

2.129(3)

(COO)₂(COOH)] (I), [M₂(H₂O)₆][C₆H₃(COO)₃]₂·(C₄N₂H₁₂)-

IV

(H₂O)₂{M = Co^II(II), Ni^II(III)}, [Ni(H₂O)(C₁₃N₂H₁₄)]-

Ni(1)–O(1)

1.997(2)

2.072(2)

2.120(2)

Ni(1)–O(4)

Ni(1)–N(1)

Ni(1)–N(2)

2.137(2)

2.065(3)

2.103(3)

Ni(1)–O(2)

Ni(1)–O(3)

VI

Co(1)–O(1)

Co(1)–O(2)

[C₆H₃(COO)₂(COOH)] (IV), [Ni₃(H₂O)₈][C₆H₃(COO)₃]₂(V)

and [Co(C₄N₂H₄)(H₂O)][C₆H₃(COO)₂(COOH)] (VI). 1,10-

Phenanthroline was used for I, piperazine for II and III,

1,3-bis(4-pyridyl)propane for IV and pyrazine for VI,

2.009(4)

2.026(4)

2.136(4)

Co(1)–O(4)

Co(1)–N(1)

Co(1)–N(2)

2.243(4)

2.182(5)

2.185(5)

whereas V was synthesized without any N-containing li- Co(1)–O(3)

gand. The compounds have 1D (I, II, III and IV) and 2D

(V and VI) extended structures. In this paper, the synthesis,

structure and properties of the compounds are presented.

[a] Symmetry transformations used to generate equivalent atoms –

I: #1 –x + 1, –y + 2, –z + 1; II and III: #1 –x + 1, –y + 1, –z + 1;

#2 –x + 1, –y, –z.

Results and Discussion

[M₂(H₂O)₆][C₆H₃(COO)₃]₂·(C₄N₂H₁₂)(H₂O)₂(M =

Co^II, Ni^II)

Structures Description

The compounds II (Co) and III (Ni) are isostructural

and have 24 non-hydrogen atoms in the asymmetric unit.

There are two crystallographically independent M²⁺ions,

[Ni(C₁₂N₂H₁₀)(H₂O)][C₆H₃(COO)₂(COOH)]

The asymmetric unit of I consists of 35 non-hydrogen both of them are octahedrally coordinated and occupy spe-

atoms with one Ni²⁺ion that is crystallographically inde- cial positions [M(1) at site 1b and M(2) at site 1c with a

pendent. The Ni²⁺ion has a distorted octahedral geometry, site multiplicity of 0.5], and one complete trimesate anion.

which is formed by three carboxylate oxygen atoms, two M(1) has two carboxylate oxygen atoms [O(1)] and four

nitrogen atoms of the phenanthroline ring and a bound water molecules [O(2), O(3)], and M(2) has two water mole-

water molecule. The Ni–O/N bonds have lengths in the cules [O(6)] and four carboxylate oxygen atoms [O(4), O(5)]

range 2.021–2.148 Å (av. 2.08 Å) and the O/N–Ni–O/N completing the octahedral coordination. The M–O bonds

bond angles are in the range 77.9(1)–173.0(1)° (Table 1). have lengths in the range 2.041(2)–2.178(2) Å (av. 2.105 Å

The structure consists of two NiO₃N₂(H₂O) octahedra con- for II and 2.072 Å for III), and the O–M–O bond angles

nected through two µ₃carboxylate oxygen atoms [O(3)] (µ₃- are in the range 61.3(6)–180.0° (Table 1). Although the ma-

O connected to two Ni⁺²ions and one carbon atom) to jority of the planar angles are close to 90° (ideal value for

form an edge-shared dimer. The dimers are connected by the octahedral coordination), the angle O(5)–M(2)–O(6) is

[Htma]^2–ligands to form a ladderlike one-dimensional 61.3(6)°, which leads to distortions. The M(2)–O(5) and

structure (Figure 1a). The structure is stabilized by hydro- M(2)–O(6) bonds are also relatively longer (Table 1). The

gen-bond interactions and π···π interactions between single-crystal structures of both compounds have been re-

[Htma]^2–and 1,10-phenanthroline molecules. Strong O– ported earlier without any detailed description.^[16]Here, we

H···O hydrogen-bond interactions between the bonded describe the structures and also provide a detailed dis-

water molecules and the carboxylate oxygen atoms give rise cussion of the weak interactions, such as hydrogen bond

to a supramolecularly organized two-dimensional structure and π···π interactions. The trianionic trimesate units link

along the c axis (Figure 1b). The important hydrogen-bond the M²⁺ions, which gives rise to an anionic one-dimen-

interactions are given in Table 2. This structure is closely sional structure (Figure 2a). The one-dimensional chains

related to the cobalt compound [Co(C₁₂N₂H₁₀)- are arranged in an orthogonal fashion, which leads to a

(H₂O)][C₆H₃(COO)₂(COOH)] reported previously.^[15]

layerlike arrangement with void spaces (Figure 2b). The

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Liquid–Liquid Interface for Benzenetricarboxylate Complexes of Co and Ni

Figure 1. (a) The one-dimensional ladder in [Ni(C₁₂N₂H₁₀)(H₂O)][C₆H₃(COO)₂(COOH)] (I). (b) Hydrogen-bond interactions between

the coordinated water and the carboxylate oxygen atoms in I. The 1,10-phenanthroline molecules, bonded to the Ni²⁺ions, have been

omitted for clarity.

Table 2. Important H-bonding interactions present in compounds

One of the notable features in the structure of II and III

is the presence of cyclic water tetramer units. Hydrogen-

bond interactions between the bound water [O(4)] and lat-

tice water [O(100)] lead to a tetramer with an average O–O

distance of 2.78 Å (Figure 3a, b). Formation of water clus-

ters of different shapes and sizes has been an important

feature in many MOF compounds.^[17]The study of water

clusters, especially the energies involved, are expected to

provide valuable information regarding the role of the hy-

drogen-bond interactions in bulk water (ice) and in some

MOF compounds and their role in the structural stability.

Since the present compounds have low-dimensional charac-

ter, such a study would be important to understand the role

of hydrogen bonds in stabilizing such structures. To this

end, we have performed some preliminary calculations on

the stability of the water cluster using the Gaussian98 pack-

age.^[18]A single-point energy calculation was performed

without symmetry constraints. A value of 27.41 kcalmol^–1

for the water tetramer was obtained, which is comparable

with the values generally obtained for O–H···O hydrogen

bonds.^[19]Since the water tetramer is formed from the

bound as well as the lattice water, this energy may be impor-

tant for the structural stability.

I, II and VI.^[a]

D–H···A

D–H [Å] H···A [Å] D···A [Å]

D–H···A [°]

I

O(2)–H(2a)···O(4)^[b]

O(2)–H(2a)···O(6)#1^[c]

II, III

0.94(5)

0.94(4)

1.73(4)

1.90(4)

2.625(5)

2.778(5)

158(6)

153(4)

O(2)–H(2a)···O(6)#1

O(2)–H(2b)···O(8)#2

O(3)–H(3a)···O(7)

O(3)–H(3b)···O(8)#3

O(4)–H(4a)···O(7)#4

O(100)–H(102)···O(4)#5

C(12)–H(12a)···O(3)

C(12)–H(12b)···O(9)#6

VI

0.95(5)

0.95(4)

0.95(5)

0.94(5)

0.96(3)

0.89(3)

0.97

1.81(6)

1.71(4)

1.75(5)

1.81(6)

1.75(3)

1.97(3)

1.99

2.742(5)

2.654(4)

2.628(5)

2.716(4)

2.692(5)

2.809(8)

2.892(5)

2.728(6)

165(7)

170(4)

152(7)

162(6)

169(6)

157(4)

154

0.97

1.78

165

O2···H2A···O6#1

O2···H2B···O4#2

0.95(8)

0.95(9)

1.77(7)

1.77(9)

2.697(7)

2.695(6)

165(7)

164(11)

[a] Symmetry transformations used to generate equivalent atoms –

I: #1 –1 + x, –1 + y, z; II: #1 1 – x, –y, 1 – z; #2 1 + x, 1 + y, z;

#3 x, 1 + y, z; #4 x, y, 1 + z; #5 –x, –y, 2 – z; #6 1 + x, 1 + y, z;

VI: #1 x, 1 + y, z; #2 –x, 1 – y, –z. [b] Intramolecular. [c] Intermo-

lecular.

void is occupied by charge compensating protonated piper-

azine and water molecules (Figure 2b). The presence of

bonded and lattice water molecules in close proximity gives

rise to O–H···O type hydrogen bonds (Figure 3a, Table 2).

[Ni(H₂O)(C₁₃N₂H₁₄)][C₆H₃(COO)₂(COOH)]

Compound IV has 35 non-hydrogen atoms in the asym-

In addition π···π interactions between the benzene rings are metric unit. The crystallographically independent Ni²⁺ion

also observed.

is surrounded by three carboxylate oxygen atoms, two nitro-

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Figure 2. (a) The one-dimensional zig-zag chain in [Ni₂(H₂O)₆][C₆H₃(COO)₃]₂·(C₄N₂H₁₂)(H₂O)₂(III). (b) Packing diagram of III showing

the open apertures occupied by the piperazine and water molecules. H atoms have been omitted for clarity.

Figure 3. (a) View of hydrogen-bond interactions between the lattice water, the coordinated water and the C–O group of the carboxylate

in III. Note the formation of a cyclic water tetramer by bonded and lattice water molecules (encircled). (b) View of the water tetramer.

gen atoms of 1,3-bis(4-pyridyl)propane (bpp) and a water trimesate anions and one bpp unit to give rise to a one-

molecule and has a distorted octahedral environment dimensional ladderlike structure that resembles a column.

[Ni(H₂O)O₃N₂]. There is one trimesate unit in the structure, The dianionic trimesate groups can be classified into two

which is dianionic, and one bis(pyridyl)propane unit. The different types on the basis of their coordination with metal

Ni–O/N bonds have lengths in the range 1.997(2)– ions; in acid-1, two carboxylate groups are bidentately con-

2.138(2) Å (av. 2.083 Å), and the O/N–Ni–O/N bond angles nected to Ni²⁺, and in acid-2, two carboxylate groups are

are in the range 61.8(7)–178.9(1)° (Table 1). The structure is monodentately connected. The NiO₄N₂octahedra are con-

composed of linkages between the Ni²⁺ions, two dianionic nected to two bpp units to form a dimer, which is connected

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Liquid–Liquid Interface for Benzenetricarboxylate Complexes of Co and Ni

by acid-1 and acid-2 alternatively to form a columnlike ar- around the Ni²⁺ions is similar to that observed in com-

rangement as shown in Figure 4a. The columns are supra- pound III. The Ni–O bonds have lengths in the range

molecularly organized through strong O–H···O hydrogen 2.029(2)–2.139(2) Å (av. 2.068 Å), and the O–Ni–O bond

bonds involving the free –COOH group of the trimesate angles are in the range 81.1(1)–180.0°. Two sets of Ni spe-

dianion, with average O–O contact distances of 2.6 Å (Fig- cies [Ni(1) and Ni(3), and Ni(2) and Ni(4)] are connected

ure 4b). Although –COOH dimers have been well estab- through µ₂-OH₂and carboxylate bridges to form a trinu-

lished in supramolecularly organized organic com- clear unit, which are linked by the trimesate anions to give

pounds,^[20]this is the first example of such interactions rise to a two-dimensional layer (Figure 5). This compound

forming a three-dimensional structure through columns in has recently been isolated through a complex synthesis pro-

a metal–organic framework system.

cedure,^[21]and hence no further discussion will be provided

here.

Figure 5. View of the two-dimensional structure formed through

the connectivity between the Ni²⁺trimeric unit and the tma ligands

in [Ni₃(H₂O)₈][C₆H₃(COO)₃] (V).

[Co(C₄N₂H₄)(H₂O)][C₆H₃(COO)₂(COOH)]

Compound VI has 23 non-hydrogen atoms in the asym-

metric unit. The crystallographically independent Co²⁺ion

is surrounded by three carboxylate oxygen atoms, two nitro-

gen atoms of pyrazine and a water molecule, which forms

a distorted octahedral environment, [Co(H₂O)O₃N₂]. The

coordination environment around the Co²⁺ions is similar

to that observed around the Ni²⁺ions in IV. The Co–

O/N bonds have lengths in the range 2.009(4)–2.243(4) Å

(av. 2.13 Å) (Table 1), and the O/N–Co–O/N bond angles

are in the range 59.8(2)–178.2(2)° (Table S6). The small

O(1)–Co–O(2) bond angle is due to the bidentate nature

Figure 4. (a) The one-dimensional columnlike structure in

[Ni(C₁₃N₂H₁₄)(H₂O)][C₆H₃(COO)₂(COOH)] (IV). Note the pres-

ence of two different types of carboxylic acid groups. (b) Schematic

diagram showing the arrangements of four different columns of one the carboxylate groups towards the Co²⁺ion. The

connectivity between the Co²⁺ions and the trimesate

around a single column, with all possible hydrogen-bonding inter-

actions shown.

[Htma]^2–units leads to one-dimensional chains, which are

connected by pyrazine ligands to form the two-dimensional

structure with a 4,4-net topology (Figure 6a). The adjacent

layers are turned 180° relative to the first layer and results

[Ni₃(H₂O)₈][C₆H₃(COO)₃]₂

in an ABAB-type layer arrangement (Figure 6b). The layers

This compound has 42 non-hydrogen atoms in the asym- are supramolecularly connected through hydrogen-bond in-

metric unit, with four crystallographically independent Ni²⁺teractions to form a pseudo-three-dimensional structure

ions and two trimesate anions. The coordination geometry (Figure S1, Table 2).

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A. Banerjee, P. Mahata, S. Natarajan

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iour. In this compound, the metal and the trianionic trimes-

ate units are in the ratio 3:2, and their connectivity gives

rise to a neutral one-dimensional chain structure, stabilized

by O–H···O hydrogen bonds. In II and III, the metal and

the trimesate units are in the ratio 1:1, and their connectiv-

ity results in a one-dimensional structure, which is anionic.

Charge balance is achieved by the incorporation of proton-

ated piperazine molecules, which lead to additional hydro-

gen-bond interactions, which are absent in [M₃(H₂O)₁₂]-

[C₆H₃(COO)₃]₂(M = Co, Ni, Zn).^[23]

The structure of IV appears to have a close resemblance

to [Cd(C₁₃N₂H₁₄)₂][CH₃(COO)₂(COOH)] (Figure 7b).^[24]In

both the structures, we have [Htma]^2–and one free –COOH

group. The one-dimensional chains formed by Cd²⁺and the

[Htma]^–2–ions are similar to those observed in IV (Fig-

ure 7b). In IV, the bpp ligands connect two chains to form

a unique one-dimensional columnlike structure (Figure 4a),

whereas in the Cd compound, the bpp ligands are bonded

along the opposite side of each chain to form a simple two-

dimensional layer structure (Figure 7b). The structure of VI

is similar to [Ni₂(C₁₀N₂H₈)(H₂O)][C₆H₃(COO)₂(COOH)]

reported earlier (Figure 7c).^[25]A gridlike structure con-

sisting of two Ni–tma chains connected by 4,4Ј-bipyridine

has been observed in [Ni₂(C₁₀N₂H₈)(H₂O)][C₆H₃(COO)₂-

(COOH)], whereas the pyrazine molecule connects the Co

centres in VI. The smaller linker pyrazine gives rise to a

shorter Co–Co distance (7.14 Å) than the Ni–Ni distance

in the nickel compound [Ni₂(C₁₀N₂H₈)(H₂O)][C₆H₃(COO)₂-

(COOH)] (11.25 Å) (Figure 7c).

Figure 6. (a) The two-dimensional structure of [Co(C₄N₂H₄)-

(H₂O)][C₆H₃(COO)₂(COOH)] (VI). Note the (4,4) nets. (b) The

stacking of the layers in the bc plane. Note that the layers are ar-

ranged in an ABAB... fashion.

Role of Weak Interactions

The use of hydrogen bonding in inorganic crystal design

has been of much focus recently.^[26]A hydrogen bond of the

type D–H···A can be broadly defined as one that requires

Structural Comparison

All the structures obtained in the present study are a donor (D) that forms a polar σ bond with hydrogen (D–

formed with trimesate anions, which are variably deproton- H) and interacts through the hydrogen atom in an attractive

ated. The structural features of compounds I–VI can be manner with at least one acceptor atom or group (A) by

compared and contrasted with other similar structures virtue of a lone pair of electrons or other accumulation of

formed using trimesic acid. Thus, I has a similar structure electron density on the acceptor (A). Thus, a hydrogen

to that of [Co(C₁₀N₂H₈)(H₂O)][C₆H₃(COO)₂(COOH)].^[22]bond is an interaction between a Lewis acid and a Lewis

In I, the secondary chelation occurs with 1,10-phenan- base, wherein D–H serves as a Lewis acid and A as the

throline and in [Co(C₁₀N₂H₈)(H₂O)][C₆H₃(COO)₂(COOH)] Lewis base. When considering the hydrogen bonds in inor-

with 2,2Ј-bipyridine.^[22]The structures of II and III, al- ganic systems, the strength of the hydrogen-bond interac-

though appear to be unique in their arrangement, can be tions, the reliability of the hydrogen-bonded recognition

correlated with the structure of [M₃(H₂O)₁₂][C₆H₃(COO)₃]₂motifs and the attainability of a particular hydrogen bond

(M = Co, Ni, Zn) reported by Yaghi and co-workers (Fig- may be important. To this end, the definitions for a variety

ure 7a).^[23]The overall connectivity in II and III and in the of hydrogen bonds provided by Desiraju and Steiner^[20]is

structure reported by Yaghi and co-workers are compar- of considerable importance. For a D–H···O hydrogen bond

able; the compounds have one-dimensional structures that (D, A = O or N) to be strong, the energies are likely to be

exhibit strong hydrogen-bonding interactions, which give in the range 4–15 kcalmol^–1. The strong hydrogen bonds

rise to channel structures. Unlike the structure reported by can effectively participate through directed assembly of the

Yaghi and co-workers,^[23]in II and III, the channels are not building units. On the basis of the many structures available

empty but are occupied by piperazinium cations and water in the literature, the participating functional groups can be

molecules. The void space, thus, in II and III are fully occu- carbonyl, amide, oxime, alcohol, amine, etc. and the met-

pied and also gives rise to cyclic water tetramer units. In als.^[26]

the structure of Yaghi and co-workers,^[23]the void space

creates opportunities for the reversible adsorption behav- hydrogen-bond interactions play a key role in the stability

Many of the present structures are low-dimensional, and

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Liquid–Liquid Interface for Benzenetricarboxylate Complexes of Co and Ni

Figure 7. (a) The one-dimensional chain in [M₃(H₂O)₁₂][C₆H₃(COO)₃]₂(M = Co, Ni, Zn) and in III. (b) View of the two-dimensional

structure formed by the linking of Cd–tma chains by bpp ligands in [Cd(C₁₃N₂H₁₄)₂][CH₃(COO)₂(COOH)]. (c) The two-dimensional

gridlike structure of [Ni₂(C₁₀N₂H₈)(H₂O)][C₆H₃(COO)₂(COOH)] and VI. Note the difference between the Ni centres because of the

difference in the linking ligand (see text).

of such structures. Many hydrogen-bonded motifs involving well established and reported in the literature.^[27]Of these,

carboxylate and/or amine/amide-based synthons have been we have observed the classic dimer motif along with a few

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new ones that involve the water molecules. In I and VI, we H···O interactions also give rise to a cyclic water tetramer,

observed an O–H···O interaction between the carboxylate which is noteworthy. The calculated energy of

group and the water molecules (Figure 8), where both the 27.41 kcalmol^–1for the water clusters is within the range

water hydrogen atoms act as the donor and one of the oxy- 15–40 kcalmol^–1observed for very strong hydrogen

gen atoms of the carboxylate groups acts as the acceptor bonds.^[19]The water clusters, formed by involving the lattice

(Figure 8a). In II and III, we observed both O–H···O and water and bound water molecules, give additional structural

C–H···O interactions (Figure 8b–d). The O–H···O interac- stability to II and III.

tions are different from those observed in I (Figure 8b); the

In IV, the free –COOH group of tma is primarily respon-

acceptor oxygen atoms are different – one is a carboxylate sible for the formation of a supramolecularly organized

oxygen atom and the other is a carboxylic acid oxygen three-dimensional structure. The hydrogen atom of the car-

atom. The C–H···O interaction is between the methylene boxylic acid group and the oxygen atom of the other car-

hydrogen atom of the piperazine and the oxygen atom of boxylic acid group interact to form the classical carboxylate

the carboxylic acid group (Figure 8c). In II and III, the O– dimer (Figure 8e). The observed O–O distance of 2.59 and

Figure 8. Representations of the hydrogen-bonding motifs observed in the present structures (a) I and VI, (b), (c), (d) II and III and (e)

IV.

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Liquid–Liquid Interface for Benzenetricarboxylate Complexes of Co and Ni

O–H···O bond angle of 167° can be described as strong hy- teractions (Figure S2). It has been observed that the aro-

drogen bonds. A single column in IV connects through the matic rings in tma in all the structures are parallel to each

carboxylate dimers to neighbouring columns to form the other but are staggered in conformation with respect to the

three-dimensional structure with sinusoidal spaces.

carboxylate group. This staggered arrangement of the aro-

In addition to this, many of the structures are also stabi- matic rings has been commonly observed in systems exhib-

lized by π···π interactions involving the benzene ring of the iting dipolar properties. It is likely that the staggered ar-

carboxylate groups. The role of π···π interactions in the sta- rangement of the tma anions reduces the dipole–dipole re-

bility of supramolecularly engineered crystal structures have pulsion between the two carboxylate groups. The π···π in-

been well documented and in recent years, the role of π···π teraction energy has been calculated by using the

interactions in extended structures has been a topic of much Gaussian98 software package at the [B3LYP/6-31 + G(d,p)]

interest.^[28]In the present compounds, we find significant level of theory.^[18]The net π···π interactions calculated on

intermolecular π···π interactions between two aromatic the basis of the above arrangements of the carboxylate

rings of 1,10-phenanthroline in I and tma in I, II, III and groups give rise to energies of 3.21, 3.94 and 3.45 and

VI. The centroid–centroid distance (d) and the interplanar 3.25 kcalmol^–1between the tma rings for I, II and VI,

angle (θ) between the 1,10-phenanthroline rings of I and respectively, and to an energy of 1.24 kcalmol^–1between

between the tma units of I, II and VI are shown in Fig- the 1,10-phenanthroline rings for I. These are typical values

ure 9a–d, respectively. Favourable π···π interactions have and similar π···π interaction energies have been observed

been observed in these compounds as can be seen from Fig- before.^[29]

ure 9.

Strong π···π interactions are also observed in VI, where

they are seen to act in a parallel direction to the two-dimen-

sional sheet of VI. Most importantly, because of the short

Co–Co distances, the connecting [Htma]^2–ions are close

Physical Properties

UV/Vis Spectroscopic Studies

The diffuse reflectance UV/Vis spectra at room tempera-

(3.683 and 3.805 Å), which results in two different π···π in- ture were recorded for the sodium salt of tma and for the

Figure 9. The possible π···π interaction between the (a) 1,10-phenanthroline ligands in I, (b) tma in I, (c) tma in II and III, and (d) tma

in VI. Note the differences in the conformation of the tma ligands.

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as-synthesized coordination polymers (Figures S3 and S4).

In all cases, the main absorption bands are centred around

296 nm, which can be assigned to the ligand-to-metal

charge-transfer transition. The additional peaks observed

in the compounds I–VI can be assigned to the d–d transi-

tions of the Ni²⁺(d⁸) and Co²⁺(d⁷) ions in an octahedral

environment. Thus, the peaks at 385, 654, and 737 for I, at

384, 653, and 734 for III, at 385, 635, and 760 for IV and

at 404, 678, and 732 for V can be assigned to the d–d transi-

3

tions for Ni²⁺(d⁸), A_2gǞ T_2g, A_2gǞ T_1g(F) and A_2g

3

Ǟ T_1g(P). Similarly, the peaks at 533 and 621 for II and

at 517 and 615 for VI can be assigned to d–d transitions

4

for Co²⁺(d⁷), T_1g(F) Ǟ T_2gand T_1g(F) Ǟ T_1g(P).^[30]

Room-temperature solid-state photoluminescence studies

were carried out on powdered samples (Perkin–Elmer,

U.K.) (Figure 10). The compounds and the sodium salt of

tma were excited at 300 nm. The excitation and emission

intensities were controlled by using a slit width of 10 nm

for both cases. Intense emissions occurring at about 360 nm

and about 420 nm were observed, which may be arise from

the charge transfer from the ligand to the metal (LMCT

band). In addition, bands due to the d–d transitions of the

octahedrally coordinated Ni²⁺(d⁸) and Co²⁺(d⁷) are also

observed. Thus, the bands at 488 and 526 nm for I, 487 and

525 nm for III, 427 and 528 for IV and 487 and 528 nm for

3

V can be assigned to the electronic transitions T_2gǞ A_2g

and ³T_1g(F) Ǟ ³A_2g, respectively, for the Ni²⁺ion. Similarly,

the bands at 486 and 529 nm for II and at 486 and 527 nm

4

for VI can be assigned to the electronic transitions T_2g

Ǟ

⁴T_1g(F) and T_1g(P) Ǟ T_1g(F), respectively, for the Co²⁺

ion.^[30]A study of the literature on the photoluminescence

spectra of related compounds reveals that the observed d–

d transition bands for the compounds correspond well with

those reported for related metal–organic framework com-

pounds.^[29]MOFs based on Co and Ni with 4,4Ј-oxybis-

(benzoic acid) and 4,4Ј-bipyridine, [Co₂(C₁₀H₈N₂)][C₁₂H₈O-

(COO)₂]₂and [Ni₂(C₁₀H₈N₂)₂][C₁₂H₈O(COO)₂]₂·H₂O,

show LMCT bands at about 440 nm with d–d transition

bands at about 480 and about 525 nm, respectively, which

are also observed in I–VI.

4

Figure 10. (a) Solid-state photoluminescence spectra of I, III, IV,

V and Na(tma). (b) Solid-state photoluminescence spectra of II, VI

and Na(tma).

Magnetic Studies

Transition elements possess unpaired electrons and thus

provide a useful opportunity for the investigation and cor-

relation of the structure and magnetic behaviour. Transi-

tion-metal–organic framework compounds based on trim- at room temperature (300 K) are 3.07, 3.01, 3.41 and

esic acid^[31]and organic ligands which mimic the symmetry 2.66 µ_B, respectively, which correspond to the non-inter-

and coordination of trimesic acid^[32]have been prepared acting paramagnetic Ni²⁺ions and are close to the spin-

and exhibit interesting magnetic behaviour. Thus, only magnetic moment of the Ni²⁺ion in octahedral field

[Mn₃{C₆H₃(COO)₃}] shows antiferromagnetic behaviour at (2.83 µ_B). A plot of 1/χ_Mvs. T for compounds III and IV

5 K,^[31a]and [(MnCuL)₃{C₆H₃(COO)₃}](ClO₄)₃·8H₂O in the temperature range 50–300 K can be fitted to the Cu-

[H₂L = macrocyclic Robson proligand] shows ferromag- rie–Weiss behaviour, with a value for C of 1.46 and

netic interaction at 12 K.^[31b]Presently, we have investigated 0.89 emumol^–1and for θ_Pof –0.7 and 1.8 K, respectively

the magnetic susceptibility as a function of temperature for (Figure S5). Similar values have been observed for other

I–VI with a SQUID magnetometer in the range 2–300 K by compounds.^[33]The presence of Ni–O–Ni dimeric and tri-

employing a field of 0.1 T (Figures 11 and S5). The ob- meric units in compounds I and V, respectively, prompted

served magnetic moments for compounds I, III, IV and V us to fit the magnetic susceptibility data with a dimer and

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Liquid–Liquid Interface for Benzenetricarboxylate Complexes of Co and Ni

trimer model, respectively (Figure 11). The spin Hamilto-

nian for a Ni²⁺dimer can be written in the form:

H = –J₁₂·(S₁ϫS₂) – J₂₁·(S₂ϫS₁).

(1)

The best fit for the experimentally observed data was ob-

tained with a J value of 11.334 cm^–1, which indicates rea-

sonable ferromagnetic interactions. Similarly, for compound

V, the spin Hamiltonian for the Ni²⁺trimer can be written

as H = –J₁₂·(S₁ϫS₂) – J₂₃·(S₂ϫS₃) – J₁₃·(S₁ϫS₃). If we con-

sider J₁₃to be equal to zero and J₁₂= J₂₃= J, then the

susceptibility equation for the Ni²⁺trimer can be obtained

by a similar substitution, as before, of the values of the Ni²⁺

ion in a trimeric complex into Equation (2),^[36]where x =

J/kT. Here, the best fit for the experimentally observed data

gives a J value of 0.3386 cm^–1, which indicates much weaker

ferromagnetic interactions. The observed magnetic moment

for compounds II and VI at 300 K are 4.78 and 4.57 µ_B,

respectively, which appear to be much larger than the calcu-

lated spin only value of 3.87 µ_Bfor Co²⁺. This indicates

significant orbital contribution. A fit of the 1/χ_Mvs. T plot

to the Curie–Weiss law, in the temperature range 50–300 K,

was linear with a C value of 2.905 and 2.668 emumol^–1and

a θ_Pvalue of –4.99 and –6.45 K, respectively, which indi-

cates weak antiferromagnetic interactions (Figure S5).

(2)

Conclusions

The immiscible liquid–liquid interphase region has been

employed for the preparation of a variety of benzenetricarb-

oxylate coordination polymers of Co and Ni. Most of the

prepared compounds have lower-dimensional structures

and appear to be stabilized by weak intermolecular forces

such as hydrogen bonds or π···π interactions. Magnetic

studies indicate weak ferromagnetic (I, IV and V) as well as

antiferromagnetic (II, III and VI) behaviour in these com-

pounds. The present results indicate that it would be profit-

able to investigate this approach further as it is likely to give

better control of the dimensionality of the product phases.

Figure 11. Temperature variation of the molar susceptibility (χ_M)

for (a) [Ni(C₁₂N₂H₁₀)(H₂O)][C₆H₃(COO)₂(COOH)] (I) and for (b)

[Ni₃(H₂O)₈][C₆H₃(COO)₃] (V). The symbols correspond to the ex-

perimental values, and the theoretical fit is the solid line.

Experimental Section

Synthesis and Initial Characterization: All the compounds were syn-

thesized by employing a biphasic solvothermal reaction involving

water and cyclohexanol. The synthesis conditions employed in the

present study are presented in Table 3. In a typical synthesis, for I,

Ni(CH₃COO)₂·4H₂O (0.2 g, 0.804 m) was dissolved in H₂O

(5 mL), and trimesic acid (0.178 g, 0.804 m) and 1,10-phenan-

throline (0.1602 g, 0.804 m) were dissolved in cyclohexanol

(4 mL) and layered above the aqueous solution. The reaction mix-

ture was placed in a PTFE vessel and sealed in a stainless steel

autoclave, heated at 150 °C for 3 d and cooled to room temperature

in air. The final product contained large quantities of crystals,

which were vacuum filtered, washed with deionized water and dried

The susceptibility equation for the Ni²⁺dimer can be ob-

tained by substituting the values for the Ni²⁺ion in a di-

meric complex^[34]into the Van Vleck Equation (1),^[35]

where, N_A= Avogadro’s number, g = gyromagnetic ratio

(approximated here to 2.0), µ_B= Bohr Magneton, k =

Boltzmann constant, T = temperature, J = J₁₂= J₂₁= the

coupling constant between two neighbouring metal centres

and x = J/kT.

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Table 3. Synthesis conditions for compounds I–VI.

Mol ratio

T [°C]

t [h]

Yield [%] Product

Ni(CH₃COO)₂·4H₂O + H₃tma+ C₁₂N₂H₁₀+ 42 C₆H₁₁OH + 278 H₂O

Co(CH₃COO)₂·4H₂O + H₃tma + 0.54 Piperazine + 42 C₆H₁₁OH + 278 H₂O

Ni(CH₃COO)₂·4H₂O + H₃tma + 0.54 Piperazine + 42 C₆H₁₁OH + 278 H₂O

Ni(CH₃COO)₂·4H₂O + H₃tma + 2 C₁₃N₂H₁₄+ 42 C₆H₁₁OH + 278 H₂O

Ni(CH₃COO)₂·4H₂O + H₃tma + 42 C₆H₁₁OH + 278 H₂O

150

72

78

72

66

78

76

69

[Ni(C₁₂N₂H₁₀)(H₂O)][C₆H₃(COO)₂(COOH)] (I)

[Co₂(H₂O)₆][C₆H₃(COO)₃]₂·(C₄N₂H₁₂)(H₂O)₂(II)

[Ni₂(H₂O)₆][C₆H₃(COO)₃]₂·(C₄N₂H₁₂)(H₂O)₂(III)

[Ni(C₁₃N₂H₁₄)(H₂O)][C₆H₃(COO)₂(COOH)] (IV)

[Ni₃(H₂O)₈][C₆H₃(COO)₃] (V)

Co(CH₃COO)₂·4H₂O + H₃tma + 2 C₄N₂H₄+42 C₆H₁₁OH + 278 H₂O

[Co(C₄N₂H₄)(H₂O)][C₆H₃(COO)₂(COOH)] (VI)

at ambient conditions. In all cases, the products were found to con-

tain large quantities of single crystals. Thus, greenish-blue squares

(I, yield ≈ 78%), pale pink plates (II, yield ≈ 72%), pale green plates

(III, yield ≈ 66%), bluish-green blocks (IV, yield ≈ 78%), green

blocks (V, yield ≈ 75%) and dark pink rods (VI, yield ≈ 69%) crys-

tals were obtained. I: calcd. C 54.20, N 6.02, H 3.01; found C 54.38,

N 6.16, H 2.95%. II, III: calcd. C 34.59, N 3.67, H 4.49; found C

34.21, N 3.82, H 4.20%. IV: calcd. C 54.66, N 5.80, H 4.14; found

C 54.58, N 5.92, H 4.25%. V: calcd. C 29.50, H 3.01; found C

29.62, H 3.14%; VI: calcd. C 42.80, N 7.67, H 2.74; found C 42.74,

N 7.54, H 2.85%. Powder X-ray diffraction (XRD) patterns were

recorded on powdered samples in the 2θ range 5–50° by using Cu-

K_αradiation (Philips XЈPert). The XRD patterns were found to be

entirely consistent with the simulated XRD patterns generated

from the structures determined by single-crystal XRD studies,

which establishes the purity of the phases (Figure S6–S11). The

thermogravimetric analyses were carried out (Metler–Toledo) in an

oxygen atmosphere (flow rate = 20 mLmin^–1) in the temperature

range 30–800 °C (heating rate = 10 °Cmin^–1). In all cases, the total

observed weight loss corresponds well with the loss of the carboxyl-

ate and the water molecules 83% (calcd. 84%), 80% (calcd. 80%),

82% (calcd. 81%), 86.5% (calcd. 84.5%), and 79% (calcd. 79.5%)

for I, II, III IV, V and VI, respectively, (Figure S12). The final cal-

cined product was found to be crystalline by powder XRD and

corresponds to CoO (JCPDS No. 78-0431) and NiO (JCPDS Nos.

78-0643).

cate characteristic sharp lines with comparable bands (Figure S13

and S14). Minor variations between the bands were noticed be-

tween the compounds. The observed bands in compounds I–VI are

listed in Table S1. An additional peak at about 1700 cm^–1in the

case of I, IV and VI, which corresponds to a –C–O–H vibration,

indicates the presence of a free carboxylic acid group in tma; no

such bands were observed in II and III.

Single-Crystal Structure Determination: A suitable single crystal of

each compound was carefully selected under a polarizing micro-

scope and glued to a thin glass fibre. The single crystal data were

collected on a Bruker AXS smart Apex CCD diffractometer at

293(2) K. The X-ray generator was operated at 50 kV and 35 mA

by using Mo-K_α(λ = 0.71073 Å) radiation. Data were collected

with ω scan width of 0.3°. A total of 606 frames were collected in

three different settings of φ (0, 90, 180°) whilst the sample-to-detec-

tor distance was fixed at 6.03 cm and the detector position (2θ)

fixed at –25°. The data were reduced by using SAINTPLUS,^[37]

and an empirical absorption correction was applied by using the

SADABS program.^[38]The structure was solved and refined with

SHELXL97,^[39]present in the WinGx suit of programs (Version

1.63.04a).^[40]All hydrogen atoms of the carboxylic acids were ini-

tially located in the difference Fourier maps, and for the final re-

finement, the hydrogen atoms were placed in geometrically ideal

positions and held in the riding mode. Final refinement included

atomic positions for all the atoms, anisotropic thermal parameters

for all non-hydrogen atoms and isotropic thermal parameters for

all hydrogen atoms. Full-matrix least-squares refinement against

|F²| was carried out with the WinGx package of programs.^[40]De-

Infrared Spectroscopic Studies: The IR spectra were recorded on

KBr pellets (Perkin–Elmer, SPECTRUM 1000). The results indi-

Table 4. Crystal data and structure refinement parameters for compounds I–VI.^[a]

I

II

III

IV

V

VI

Empirical formula

Formula weight

Crystal system

Space group

a [Å]

b [Å]

c [Å]

C₂₁H₁₄O₇N₂Ni

465.04

C₂₂H₃₄O₂₀N₂Co₂C₂₂H₃₄O₂₀N₂Ni₂C₂₂H₂₀O₇N₂Ni

C₁₈H₂₂O₂₀Ni₃

732.41

C₁₃H₁₀N₂O₇Co

365.16

764.37

763.89

483.11

triclinic

orthorhombic

Pnnm (no. 58)

16.390(3)

18.683(4)

20.069(4)

90.0

6145(2)

triclinic

¯

P1 (no. 2)

9.574(5)

7.1517(12)

10.5393(17)

10.5415(18)

110.783(2)

91.417(3)

102.519(2)

720.7(2)

7.157(2)

10.0317(14)

10.0852(14)

13.1549(18)

75.757(2)

68.631(2)

65.408(2)

1119.9(3)

2

7.140(5)

9.244(7)

10.316(7)

78.091(11)

88.694(10)

79.426(11)

654.8(8)

10.823(6)

11.175(6)

97.133(9)

110.790(9)

111.831(8)

960.2(9)

10.466(3)

10.495(3)

110.779(4)

92.232(5)

101.891(4)

713.8(4)

α [°]

β [°]

γ [°]

V [Å³]

Z

2

8

2

T [K]

293(2)

1.609

1.060

0.71073

2.04 to 27.87

R₁= 0.0623

wR₂= 0.1544

R₁= 0.0780

wR₂= 0.1656

293(2)

1.761

1.247

0.71073

2.08 to 28.01

R₁= 0.0360

wR₂= 0.0953

R₁= 0.0413

wR₂= 0.0989

293(2)

1.777

1.415

0.71073

2.09 to 28.00

R₁= 0.0587

wR₂= 0.1500

R₁= 0.0730

wR₂= 0.1588

293(2)

1.044

0.664

0.71073

2.18 to 28.05

R₁= 0.0680

wR₂= 0.1686

R₁= 0.0982

wR₂= 0.1878

293(2)

2.178

2.604

0.71073

1.67 to 28.00

R₁= 0.0398

wR₂= 0.0933

R₁= 0.0489

wR₂= 0.0974

293(2)

1.852

1.354

0.71073

2.02 to 28.11

R₁= 0.0759

wR₂= 0.1761

R₁= 0.1014

wR₂= 0.1936

ρ_calcd.[gcm^–3]

µ [mm^–1]

Wavelength [Å]

θ range [°]

R index [IϾ2σ(I)]

R (all data)

2

[a] R₁= Σ||F_o| – |F_c||/Σ|F_o|; wR₂= {Σ[w(F_o– F_c)]/Σ[w(F_o²)²]}^1/2. w = 1/[ρ²(F_o)²+ (aP)²+ bP]. P = [max(F_o, 0) + 2(F_c)²]/3, where a =

0.1017 and b = 0.0000 for I, a = 0.0517 and b = 0.4579 for II, a = 0.0759 and b = 2.0187 for III, a = 0.0990 and b = 3.2207 for IV, a =

0.0391 and b = 0.7381 for V and a = 0.1140 and b = 1.3649 for VI.

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Liquid–Liquid Interface for Benzenetricarboxylate Complexes of Co and Ni

S. O. Hill, S. P. Perlepes, G. Christou, J. Am. Chem. Soc. 2007,

129, 9484–9499; c) X. M. Zhang, Z. M. Hao, W. X. Zhang,

X. M. Chen, Angew. Chem. Int. Ed. 2007, 46, 3456–3459; d)

M. Martinho, D. W. Choi, A. A. DiSpirito, W. E. Antholine,

J. D. Semrau, E. Munck, J. Am. Chem. Soc. 2007, 129, 15783–

15785.

a) J. Zhang, S. Chen, H. Valle, M. Wong, C. Austria, M. Cruz,

X. Bu, J. Am. Chem. Soc. 2007, 129, 14168–14169; b) L. Han,

M. C. Hong, R. H. Wang, J. H. Luo, Z. Z. Lin, D. Q. Yuan,

Chem. Commun. 2003, 2580–2581; c) J. S. Seo, D. Whang, H.

Lee, S. I. Jun, J. Oh, Y. J. Jeon, K. Kim, Nature 2000, 404, 982–

986; d) C. J. Kepert, T. J. Prior, M. J. Rosseinsky, J. Am. Chem.

Soc. 2000, 122, 5158–5168.

tails of the structure solution and final refinements for I–VI are

given in Table 4. Selected bond lengths for compounds I–IV and

VI are listed in Table 3. CCDC-648864, -648865, -648866, -648867,

-648868, -648869 for compounds I–VI contain the crystallographic

data for this paper. These data can be obtained free of charge from

The Cambridge Crystallographic Data Centre (CCDC) via

www.ccdc.cam.ac.uk/data_request/cif.

[7]

Supporting Information (see footnote on the first page of this arti-

cle): UV/Vis spectra of I–VI and of the Na salt of tma, magnetic

plots of II, III, IV and VI, simulated and experimental powder X-

ray patterns of I–VI, TGA curves of I–VI, IR spectra and data of

I–VI and bond angles of I–IV and VI are presented. Diagrams

[8]

[9]

G. Férey, Chem. Soc. Rev. 2008, 37, 191–214.

showing the various forms of connectivity of the tma ligand in the

compounds and the interactions in VI are also given.

a) L. Xu, E. Y. Choi, Y. U. Kwon, Inorg. Chem. 2008, 47, 1907–

1909; b) Q. Fang, G. Zhu, M. Xue, Z. Wang, J. Sun, S. Qiu,

Cryst. Growth Des. 2008, 8, 319–329; c) F. Luo, Y. X. Che, J. M.

Zheng, Cryst. Growth Des. 2008, 8, 176–178; d) A. M. Kirillov,

Y. Y. Karabach, M. Haukka, M. F. C. G. da Silva, J. Sanchiz,

M. N. Kopylovich, A. J. L. Pombeiro, Inorg. Chem. 2008, 47,

162–175; e) L. Xu, E. Y. Choi, Y. U. Kwon, Inorg. Chem. 2008,

47, 10670–10680; f) M. Du, X. J. Jiang, X. J. Zhao, Inorg.

Chem. 2006, 45, 3998–4006.

Acknowledgments

SN thanks the Department of Science and Technology (DST),

Government of India, BRNS, DAE, Ramanna fellowship (DST)

and CSIR for the award of a research grant.

[10]

a) S. O. H. Gutschke, M. Molinier, A. K. Powell, R. E. P. Win-

penny, P. T. Wood, Chem. Commun. 1996, 823–824; b) S. S. Y.

Chui, S. M. F. Lo, J. P. H. Charmant, A. G. Orpen, I. D. Wil-

liams, Science 1999, 283, 1148–1150; c) J. Kim, B. Chen, T. M.

Reineke, H. Li, M. Eddaoudi, D. B. Moler, M. O. Keeffe, O. M.

Yaghi, J. Am. Chem. Soc. 2001, 123, 8239–8247; d) M. Pascu,

F. Lloret, N. Avarvari, M. Julve, M. Andruh, Inorg. Chem.

2004, 43, 5189–5191; e) Z. Li, G. Zhu, X. Guo, X. Zhao, Z.

Jin, S. Qiu, Inorg. Chem. 2007, 46, 5174–5178; f) X. Guo, G.

Zhu, Z. Li, Y. Chen, X. Li, S. Qiu, Inorg. Chem. 2007, 46,

4065–4070.

[1] a) A. C. Sudik, A. P. Côté, A. G. Wong-Foy, M. O. Keeffe,

O. M. Yaghi, Angew. Chem. Int. Ed. 2006, 45, 2528–2533; b)

M. Latroche, S. Surblé, C. Serre, C. M. Draznieks, P. L. Llewel-

lyn, J. H. Lee, J. S. Chang, S. H. Jhung, G. Férey, Angew. Chem.

Int. Ed. 2006, 45, 8227–8231; c) S. Ma, H. C. Zhou, J. Am.

Chem. Soc. 2006, 128, 11734–11735; d) X. Lin, A. J. Blake, C.

Wilson, X. Z. Sun, N. R. Champness, M. W. George, P. Hub-

berstey, R. Mokaya, M. Schroéder, J. Am. Chem. Soc. 2006,

128, 10745–10753.

[2] a) Z. T. Yu, Z. L. Liao, Y. S. Jiang, G. H. Li, G. D. Li, J. S.

Chen, Chem. Commun. 2004, 1814; b) Z. T. Yu, Z. L. Liao,

Y. S. Jiang, G. H. Li, J. S. Chen, Chem. Eur. J. 2005, 11, 2642;

c) F. Gandara, A. Garcıa-Cortes, C. Cascales, B. Gomez-Lor,

E. Gutierrez-Puebla, M. Iglesias, A. Monge, N. Snejko, Inorg.

Chem. 2007, 46, 3475–3484.

[11]

a) D. N. Dybtsev, H. Chun, K. Kim, Chem. Commun. 2004,

1594–1595; b) K. Jin, X. Huang, L. Pang, J. Li, A. Appel, S.

Wherland, Chem. Commun. 2002, 2872–2873; c) J. H. Liao,

P. C. Wu, Y. H. Bai, Inorg. Chem. Commun. 2005, 8, 390–393;

d) Z. Lin, D. S. Wragg, R. E. Morris, Chem. Commun. 2006,

2021–2023.

[3] a) J. B. Livramento, A. Sour, A. Borel, A. E. Merbach, É. Tóth,

Chem. Eur. J. 2006, 12, 989–1003; b) R. Vaidhyanathan, D.

Bradshaw, J. N. Rebilly, J. P. Barrio, J. A. Gould, N. G. Berry,

M. J. Rosseinsky, Angew. Chem. Int. Ed. 2006, 45, 6495–6499.

[4] a) G. Ferey, C. M. Draznieks, C. Serre, F. Millange, J. Dutour,

S. Surble, I. Margiolaki, Science 2005, 309, 2040–2042; b) X.

Lin, A. J. Blake, C. Wilson, X. M. Sun, N. R. Champness,

M. W. George, P. Hubberstey, R. Mokaya, M. Schröder, J. Am.

Chem. Soc. 2006, 128, 10745–10753; c) B. D. Chandler, D. T.

Cramb, G. K. H. Shimizu, J. Am. Chem. Soc. 2006, 128, 10403–

10412; d) A. G. Wong-Foy, A. J. Matzger, O. M. Yaghi, J. Am.

Chem. Soc. 2006, 128, 3494–3495; e) C. N. R. Rao, S. Natara-

jan, R. Vaidhyanathan, Angew. Chem. Int. Ed. 2004, 43, 1466–

1496; f) X. H. Bu, M. L. Tong, H. C. Chang, S. Kitagawa, S. R.

Batten, Angew. Chem. Int. Ed. 2004, 43, 192–195; g) R. K.

Feller, C. N. R. Rao, A. K. Cheetham, Chem. Commun. 2006,

4780–4795; h) D. Maspoch, D. Ruiz-Molina, J. Veciana, Chem.

Soc. Rev. 2007, 36, 770–818.

[5] a) J. Zhang, Y. Gen Yao, X. Bu, Chem. Mater. 2007, 19, 5083–

5089; b) M. Dinca, J. R. Long, J. Am. Chem. Soc. 2007, 129,

11172–11176; c) S. R. Halper, L. Do, J. R. Stork, S. M. Cohen,

J. Am. Chem. Soc. 2006, 128, 10745–10753; d) M. Du, Z. H.

Zhang, L. F. Tang, X. G. Wang, X. J. Zhao, S. R. Batten,

Chem. Eur. J. 2007, 13, 2578–2586; e) D. R. Xiao, E. B. Wang,

H. Y. An, Y. G. Li, Z. M. Su, C. Y. Sun, Chem. Eur. J. 2006, 12,

6528–6541; f) P. Mahata, A. Sundaresan, S. Natarajan, Chem.

Commun. 2007, 4471–4473; g) P. Mahata, D. Sen, S. Natarajan,

Chem. Commun. 2008, 1278–1280.

[12]

[13]

a) P. M. Forster, A. K. Cheetham, Angew. Chem. Int. Ed. 2002,

41, 457–459; b) P. M. Forster, P. M. Thomas, A. K. Cheetham,

Chem. Mater. 2002, 14, 17.

a) K. P. Kalyanikutty, U. K. Gautam, C. N. R. Rao, Solid State

Sci. 2006, 8, 296–302; b) M. Ghosh, U. K. Gautam, V. V. Agar-

wal, G. U. Kulkarni, C. N. R. Rao, J. Colloid Interf. Sci. 2005,

289, 305–318; c) U. K. Gautam, M. Ghosh, C. N. R. Rao,

Langmuir 2004, 20, 10775–10778; d) M. K. Sanyal, V. V. Agra-

wal, M. K. Bera, K. P. Kalyanikutty, J. Daillant, C. Blot, S.

Kubowicz, O. Konovalov and C. N. R. Rao, J. Phys. Chem. C.

2008, DOI: 10.1021/jp710635e.

J. Kim, B. Chen, T. M. Reineke, H. Li, M. Eddaoudi, D. B.

Moler, M. O. Keeffe, O. M. Yaghi, J. Am. Chem. Soc. 2001,

123, 8239–8247.

M. J. Plater, M. R. S. J. Foreman, R. A. Howie, J. M. S. Skakle,

E. Coronado, C. J. Gomez-Garcıa, T. Gelbrich, M. B. Hurst-

house, Inorg. Chim. Acta 2001, 319, 159–175.

a) J. Y. Han, W. Y. Wei, Acta Crystallogr., Sect. E 2005, 61,

m2242–m2243; b) W. Wei, Y. Dong, J. Han, H. Chang, Acta

Crystallogr., Sect. E 2006, 62, m26–m27.

a) L. S. Long, Y. R. Wu, R. B. Huang, L. S. Zheng, Inorg.

Chem. 2004, 43, 3798–3800; b) S. K. Ghosh, P. K. Bharadwaj,

Angew. Chem. Int. Ed. 2004, 43, 3577–3580; c) B. Zhao, P.

Cheng, X. Chen, C. Cheng, W. Shi, D. Liao, S. Yan, Z. Jiang,

J. Am. Chem. Soc. 2004, 126, 3012–3013.

Gaussian 98, Revision A. 11, Gaussian Inc., Pittsburgh, PA,

2001.

S. Schneiner, Hydrogen-Bonding: A Theoretical Perspective, Ox-

ford University Press, Oxford, 1997.

[14]

[15]

[16]

[17]

[18]

[19]

[6] a) S. M. Humphrey, P. T. Wood, J. Am. Chem. Soc. 2004, 126,

13236–13237; b) T. C. Stamatatos, D. Foguet-Albiol, S. C. Lee,

C. C. Stoumpos, C. P. Raptopoulou, A. Terzis, W. Wernsdorfer,

Eur. J. Inorg. Chem. 2008, 3501–3514

www.eurjic.org

3513

A. Banerjee, P. Mahata, S. Natarajan

FULL PAPER

[20]

[21]

[22]

[31] a) S. O. H. Gutschke, M. Molinier, A. K. Powell, R. E. P. Win-

pennyb, P. T. Wood, Chem. Commun. 1996, 823–824; b) M. Pa-

scu, F. Lloret, N. Avarvari, M. Julve, M. Andruh, Inorg. Chem.

2004, 43, 5189–5191.

[32] a) D. Maspoch, N. Domingo, D. Ruiz-Molina, K. Wurst, J.

Tejada, C. Rovira, J. Veciana, Chimie 2005, 8, 1213–1225; b) F.

Luo, J. M. Zheng, M. Kurmoo, Inorg. Chem. 2007, 46, 8448–

8450.

G. R. Desiraju, T. Steiner, The Weak Hydrogen Bond, Oxford

University Press, Oxford, 1999.

S. Noro, T. Akutagawa, T. Nakamura, Cryst. Growth Des.

2007, 7, 1205–1208.

M. J. Plater, M. R. S. J. Foreman, E. Coronado, C. J. Gómez-

García, A. M. Z. Slawin, J. Chem. Soc., Dalton Trans. 1999,

4209–4216.

T. L. Groy, H. Li, O. M. Yaghi, J. Am. Chem. Soc. 1996, 118,

9096–9101.

[23]

[24]

[33] J. N. Behera, C. N. R. Rao, J. Am. Chem. Soc. 2006, 128, 9334–

9335.

F. A. P. Paz, J. Klinowski, Inorg. Chem. 2004, 43, 3882–3893.

[34] P. W. Ball, A. B. Blake, J. Chem. Soc. A 1969, 1415–1422.

[35] O. Kahn, Molecular Magnetism, VCH Publishers, Weinheim,

1993.

[36] F. J. Rietmeijer, G. A. Van Albada, R. A. G. De Graff, J. G.

Haasnoot, J. Reedijk, Inorg. Chem. 1985, 24, 3597–3601.

[37] SMART (V 5.628), SAINT (V 6.45a), XPREP, SHELXTL,

Bruker AXS Inc., Madison, Wisconsin, USA, 2004.

[38] G. M. Sheldrick, Siemens Area Correction Absorption Correc-

tion Program, University of Göttingen, Göttingen, Germany,

1994.

[39] G. M. Sheldrick SHELXL-97 Program for Crystal Structure

Solution and Refinement, University of Göttingen, Göttingen,

Germany, 1997.

[40] WinGx Suite for small molecule single-crystal crystallography:

J. L. Farrugia, J. Appl. Crystallogr. 1999, 32, 837–838.

Received: February 9, 2008

[25] E. Y. Choi, K. Young-Uk, Inorg. Chem. 2005, 44, 538–545.

[26] a) W. D. Cheng, D. S. Wu, J. Shen, S. P. Huang, Z. Xie, H.

Zhang, Y. J. Gong, Chem. Eur. J. 2007, 13, 5151–5159; b) C. B.

Aakeroey, N. Schultheiss, J. Desper, Inorg. Chem. 2005, 44,

4983–4991; c) E. Tynan, P. Jensen, A. C. Lees, B. Moubaraki,

K. S. Murray, P. E. Kruger, Cryst. Eng. Commun. 2005, 90–95;

d) T. J. Prior, D. Bradshaw, S. J. Teat, M. J. Rosseinsky, Chem.

Commun. 2003, 500–501.

[27] G. R. Desiraju, Angew. Chem. Int. Ed. Engl. 1995, 34, 2311–

2327.

[28] L. Brammer, J. C. M. Rivas, R. Atencio, S. Fang, F. C. Pigge,

J. Chem. Soc., Dalton Trans. 2000, 3855–3867.

[29] P. Mahata, G. Madras, S. Natarajan, J. Phys. Chem. B 2006,

110, 13759–13768.

[30] A. B. P. Lever, Inorganic Electronic Spectroscopy, Elsevier,

NewYork, 1968.

Published Online: June 25, 2008

3514

www.eurjic.org

Eur. J. Inorg. Chem. 2008, 3501–3514

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The use of liquid-liquid interface (biphasic) for the preparation of benzenetricarboxylate complexes of cobalt and nickel

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