Transcript Crown Ether Palladacycles as Metalloligands

Crown Ether Palladacycles as Metalloligands:
Suitable Precursors for Tetranuclear Mixed
Transition/Non-Transition Metal Complexes
Organometallics
Received May 13, 2009
Author：Samuel Castro-Juiz,† Alberto Fernandez,† Margarita LopezTorres,†Digna

Vazquez-Garcia,† Antonio J. Suarez,† Jose M. Vila,*,‡ and Jesus J. Fernandez*,
††Departamento de Quimica Fundamental, Universidade da Coruna, E-15071 A
Coruna, Spain （西班牙拉科鲁吉亚大学物理化学系）
‡Departamento de Quimica Inorganica, Universidad de Santiago de Compostela,
E-15782 Santiago de Compostela, Spain（圣地亚哥大学物理化学系）
Contents
Introduction
 Experimental
 Results and discussion

Introduction

The particular ability of crown ethers to complex cations has
been used to study a large number of applications such as the
production of sensors and the selective extraction of cations or
the ionic transport in membranes. We can use them to obtain
photochemical controlled and electrochemical active receptors
or compounds with promising anticancer properties.

They may also provide a novel and interesting route to the
preparation of metalloligands containing a crown ether ring
systems, capable of further coordination to metal cations,
producing mixed transition metal/main group metal species.
Experimental
一、Synthesis of the Ligands.
2,3,4-(MeO)3C6H2C(H)=N-[9,10-(C8H16O5)C6H3] (a):

O
O
O
O
+
CHCl3
O
O
Dean-Stark装置
O
O
O
H2N
ligand a
4‘-aminobenzo-15-crown-5

2,3,4-(MeO)3C6H2C(H)=N[9,10-(C10H20O6)C6H3 (b).
O
O
O
O
O
O
+
CHCl3
Dean-Stark装置
O
O
O
H2N
O
4’-aminobenzo-18-crown-6
ligand b
二、Synthesis of the Complexes.

[Pd{2,3,4-(MeO)3C6HC(H) =N-[9,10
(C8H16O5)C6H3]-C6,N}(μ-O2CMe)]2 (1a).
ligand a
+
Pd(OAc)2
toluene
under argon
1a
4 h ,60 C.

[Pd{2,3,4-(MeO)3C6HC(H) =N-[9,10
(C8H16O5)C6H3]-C6,N}(μ-Cl)]2 (2a).
1a with acetone + tetrabutylammonium chloride
四丁基氯化铵
Stirred 12 h
2a

[Pd{2,3,4-(MeO)3C6HC(H) =N-[9,10
(C8H16O5)C6H3]-C6,N}(μ-O2CMe)]2 (1b).
ligand b
+
Pd(OAc)2
toluene
under argon
1b
4 h ,60 C.

[(1a)Na2(ClO4)2] (3a).
acetonitrile
A solution of compound 1a +
NaClO4
3a
stirred at room temperature
12h

[(1a)K2(ClO4)2] (4a).
acetonitrile
A solution of compound 1a +

KClO4
4a
stirred at room temperature
12h
[(1a)Pb2(SCN)4] (5a).
acetonitrile
A solution of compound 1a + Pb(SCN)2
5a
stirred at room temperature
12h








[(2a)Na2(ClO4)2] (6a).
[(2a)K2(ClO4)2] (7a).
[(2a)(NH4)2(PF6)2] (8a).
[(2a)Pb2(SCN)4] (9a).
[(1b)K2(ClO4)2] (2b).
[(1b)Pb2(SCN)4] (3b).
[(1b)Rb2(ClO4)2] (4b).
[(1b)Ba2(ClO4)4] (5b).
Pd(OAc)2
四丁基氯化铵
Pd(OAc)2
四丁基氯化铵
Results and discussion





Microanalyses（微量分析） were carried out using a Carlo Erba（卡劳尔巴）
elemental analyzer, model 1108.
The FAB（快原子轰击） mass spectra were recorded using a FISONS Quatro
mass spectrometer with a Cs ion gun; 3-nitrobenzyl alcohol was used as
the matrix.
IR spectra were recorded as Nujol mulls or polythene discs Nujol mulls or
KBr discs on a Perkin-Elmer model 1330.
NMRspectra were obtained as CDCl3 solutions and referenced to SiMe4
(1H,13C{1H}) and were recorded on a Bruker AVANCE-300 spectrometer.
Three-dimensional, roomtemperature X-ray data were collected on a
Bruker Smart 1K CCD diffractometer using graphite-monochromated Mo
KR radiation.

Crystal Structure of
Complex 1a.

monoclinic
As a result of Pd(1) and
Pd(2) being bridged by two
mutually cis μ-acetate
ligands, the chelating C,N
bonded Schiff bases are
forced to lie above one
another in the dimeric
molecule.


Each palladium atom is
in a slightly distorted
square-planar
coordination
environment.



Crystal Structure
of Complex 6a.
Dimeric
presents a
crystallographic
inversion center
located at the center
of the Pd(μ-Cl)2Pd
moiety.

the cyclometalated ligands in a relative anti disposition and the
[Na(ClO4-O,O] fragments situated on opposite faces of the
molecule.
Conclusions




We have shown that Schiff base crown ether palladacycles
may be prepared as acetate- or chloride-bridged dimer
compounds in the anti form, with 15-crown-5 or 18-crown-6
rings.
The ensuing complexes may accommodate two non-transition
metals per dimer molecule without substantial changes in the
palladacycle structure to yield mixed transition/non-transition
metal complexes.
Alkaline and alkaline-earth metal cations, as well as lead(II)
and (owing to its size) the ammonium cation, have been tested;
the corresponding counteranion is bonded to the coordinated
metal cation.
The first crystal structure of this type of mixed metal
complexes is reported, as definitive proof of the molecular
arrangement.