10.1021/ic0501420.s001
Sachindranath Pal
Sachindranath
Pal
Anil Kumar Barik
Anil Kumar
Barik
Samik Gupta
Samik
Gupta
Arijit Hazra
Arijit
Hazra
Susanta Kumar Kar
Susanta Kumar
Kar
Shie-Ming Peng
Shie-Ming
Peng
Gene-Hsiang Lee
Gene-Hsiang
Lee
Ray J. Butcher
Ray J.
Butcher
M. Salah El Fallah
M.
Salah El Fallah
Joan Ribas
Joan
Ribas
Copper(II) Mediated Anion Dependent Formation of Schiff Base
Complexes<sup>†</sup>
American Chemical Society
2005
BF
terminal copper atoms
N 4 O chromophore
HL
copper atoms
H 2 L 1
MPA
UV
2 equiv amount
N 5 chromophore
2 equiv
N 4 Cl chromophore
N 4 O 2 chromophore
Cu
DAP
Schiff base
IR
1 equiv
center
ClO 4
2005-05-30 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Copper_II_Mediated_Anion_Dependent_Formation_of_Schiff_Base_Complexes_sup_sup_/3284149
A tetranuclear mixed ligand copper(II) complex of a pyrazole containing Schiff base and a hydroxyhexahydropyrimidylpyrazole and copper(II) and nickel(II) complexes of the Schiff base having N-donor atoms have been
investigated. A 2 equiv amount of 5-methyl-3-formylpyrazole (MPA) and 2 equiv of 1,3-diamino-2-propanol (1,3-DAP) on reaction with 1 equiv of copper(II) nitrate produce an unusual tetranuclear mixed ligand complex [Cu<sub>4</sub>(L<sub>1</sub>)<sub>2</sub>(L<sub>2</sub>)<sub>2</sub>(NO<sub>3</sub>)<sub>2</sub>] <b>(1),</b> where H<sub>2</sub>L<sub>1</sub> = 1,3-bis(5-methyl-3-formylpyrazolylmethinimino)propane-2-ol and HL<sub>2</sub> = 5-methyl-3-(5-hydroxyhexahydro-2-pyrimidyl)pyrazole. In contrast, a similar reaction with nickel(II) nitrate leads to the formation
of a hygroscopic intractable material. On the other hand, the reaction involving 2 equiv of MPA and 1 equiv each
of 1,3-DAP and various copper(II) salts gives rise to two types of products, viz. [Cu(T3-porphyrinogen)(H<sub>2</sub>O)]X<sub>2</sub> (X
= ClO<sub>4</sub>, NO<sub>3</sub>, BF<sub>4</sub> (<b>2</b>)) (T<sub>3</sub>-porphyrinogen = 1,6,11,16- tetraza-5,10,15,20- tetrahydroxy-2,7,12,17-tetramethylporphyrinogen) and [Cu(H<sub>2</sub>L<sub>1</sub>)X]X·H<sub>2</sub>O (X = Cl (<b>3</b>), Br (<b>4</b>)). The same reaction carried out with nickel(II) salts also
produces two types of compounds [Ni(H<sub>2</sub>L<sub>1</sub>)(H<sub>2</sub>O)<sub>2</sub>]X<sub>2</sub> [X = ClO<sub>4</sub> (<b>5</b>), NO<sub>3</sub> (<b>6</b>), BF<sub>4</sub> (<b>7</b>)] and [Ni(H<sub>2</sub>L<sub>1</sub>)X<sub>2</sub>]·H<sub>2</sub>O [X =
Cl (<b>8</b>), Br (<b>9</b>)]. Among the above species <b>1</b>, <b>3</b>, and <b>5</b> are crystallographically characterized. In <b>1</b>, all four copper
atoms are in distorted square pyramidal geometry with N<sub>4</sub>O chromophore around two terminal copper atoms and
N<sub>5</sub> chromophore around two inner copper atoms. In <b>3</b>, the copper atom is also in distorted square pyramidal
geometry with N<sub>4</sub>Cl chromophore. The nickel atom in <b>5</b> is in a distorted octahedral geometry with N<sub>4</sub>O<sub>2</sub> chromophore,
where the metal atom is slightly pulled toward one of the axial coordinated water molecules. Variable-temperature
(300 to 2 K) magnetic susceptibility measurements have been carried out for complex <b>1. </b>The separations between
the metal centers, viz., Cu(1)···Cu(2), Cu(2)···Cu(2A), and Cu(2A)···Cu(1A) are 3.858, 3.89, and 3.858 Å,
respectively. The overall magnetic behavior is consistent with strong antiferromagnetic interactions between the
spin centers. The exchange coupling constants between Cu(1)···Cu(2) and Cu(2)···Cu(2A) centers have turned
out to be −305.3 and −400.7 cm<sup>-1</sup>, respectively, resulting in a <i>S</i> = 1/2 ground state. The complexes are further
characterized by UV−vis, IR, electron paramagnetic resonance, and electrochemical studies.