Synthesis and crystal structure of Mn(II) and Hg(II) compounds and solution studies of Mn(II), Zn(II), Cd(II) and Hg(II) compounds based on piperazinediium pyridine-2,3-dicarboxylate

• Published in: Journal of the Iranian Chemical Society Vol. 6; no. 3; pp. 620 - 637
• Main Authors: Aghabozorg, H., Daneshvar, S., Motyeian, E., Manteghi, F., Khadivi, R., Ghadermazi, M., Shokrollahi, A., Ghaedi, M., Derki, S., Shamsipur, M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-09-2009
• Subjects: Analytical Chemistry; Biochemistry; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Organic Chemistry; Physical Chemistry; Water cluster; Solution study; Metal complexes; Crystal structure; Supramolecular chemistry
• ISSN: 1735-207X; 1735-2428
• DOI: 10.1007/BF03246542

Novel metal organic frameworks including {(pipzH
2
)[Mn(py-2,3-dc)
2
]·7.75H
2
O}
n
,
1
, {(pipzH
2
)[Zn(py-2,3-dc)
2
]·4H
2
O}
n
,
2
, [Cd(py-2,3-dc)(H
2
O)
3
]
n
,
3
and {(pipzH
2
)[Hg
4
Cl
10
]}
n
,
4
, in which pipz is piperazine and py-2,3-dcH
2
is pyridine-2,3-dicarboxylic acid were synthesized applying a proton transfer ion pair
i.e.
(pipzH
2
)(py-2,3-dcH)
2
and corresponding metallic salts and studied by IR,
1
H NMR,
13
C NMR spectroscopy and single crystal X-ray diffractometry. The space group of compounds
1
and
4
are
P
2
1
/
c
and
C
2/
c
of monoclinic system, respectively. The crystal dimensions are
a
= 20.108(2) Å,
b
= 19.910(2) Å,
c
= 12.997(1) Å, β = 94.354(2)° for
1
and
a
= 15.940(1) Å,
b
= 11.2690(9) Å,
c
= 11.1307(9) Å, β = 90.685(2)° for
4
. The crystal structures of
2
and
3
have been reported previously. However, their solution studies are discussed here. The compounds had all polymeric structures. Although Zn
II
, Cd
II
and Hg
II
were elements of the same group, their behavior against the ion pair was essentially different. Various supramolecular interactions mainly hydrogen bonds of the type O-H⋯O, N-H⋯O, C-H⋯O, N-H…Cl and C-H⋯Cl were observed in the structures. There was an unusual and huge water cluster in the structure of compound
1
. The solution states of compounds
1–4
were studied and reported. The protonation constants of pipz and py-2,3-dc, the py-2,3-dc/pipz proton transfer equilibrium constants and stoichiometry and stability of the system with Mn
2+
, Zn
2+
, Cd
2+
and Hg
2+
ions in aqueous solution were investigated by potentiometric
p
H titrations.