Four homo- and hetero-bismetallic 3d/3d-2s complexes constructed from a naphthalenediol-based acyclic bis(salamo)-type tetraoxime ligand

Article abstract of DOI:10.1016/j.poly.2017.05.060

The homo/heterotrinuclear metal(II) complexes [Zn₃(L)(OAc)₂(CH₃OH)₂]·3CHCl₃ (1), [Zn₂(L)Ca(OAc)₂]·CHCl₃ (2), [Zn₂(L)Sr(OAc)₂] (3) and [Zn₂Ba(L)(OAc)₂(CH₃OH)]·CH₃OH·CHCl₃ (4), with a novel acyclic bis(salamo)-type tetraoxime ligand H₄L, were synthesized and characterized by elemental analyses, IR, UV–vis and fluorescence spectra. UV–vis titrations clearly show that complexation of H₄L with Zn(II) ions affords a stoichiometric ratio of 3:1 (M:L) in a cooperative fashion. Complexes 2, 3 and 4 can acquire by the substitution reactions of complex 1 with 1 equivalent of M(OAc)₂ (M²⁺?=?Ca²⁺, Sr²⁺ or Ba²⁺). The crystal structures of complexes 1–4 have been determined by single-crystal X-ray diffraction. The coordinating ability of the [Zn₃(L)]²⁺ units may be utilized as a cation recognition phenomenon.

Full text of DOI:10.1016/j.poly.2017.05.060

Accepted Manuscript
Four homo- and hetero-bismetallic 3d/3d-2s complexes constructed from a
naphthalenediol-based acyclic bis(salamo)-type tetraoxime ligand
Jing Hao, Li-Long Li, Jin-Tong Zhang, Sunday Folaranmi Akogun, Li Wang,
Wen-Kui Dong
PII:
S0277-5387(17)30418-7
DOI:
http://dx.doi.org/10.1016/j.poly.2017.05.060
POLY 12681
Reference:
To appear in:
Polyhedron
Received Date:
Revised Date:
Accepted Date:
25 March 2017
16 May 2017
18 May 2017
Please cite this article as: J. Hao, L-L. Li, J-T. Zhang, S. Folaranmi Akogun, L. Wang, W-K. Dong, Four homo-
and hetero-bismetallic 3d/3d-2s complexes constructed from a naphthalenediol-based acyclic bis(salamo)-type
tetraoxime ligand, Polyhedron (2017), doi: http://dx.doi.org/10.1016/j.poly.2017.05.060
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Four homo- and hetero-bismetallic 3d/3d-2s complexes constructed from
a naphthalenediol-based acyclic bis(salamo)-type tetraoxime ligand
*
Jing Hao, Li-Long Li, Jin-Tong Zhang, Sunday Folaranmi Akogun, Li Wang, Wen-Kui Dong
School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, Gansu
7
30070, PR China
ABSTRACT
The homo/heterotrinuclear metal(II) complexes [Zn
3
(L)(OAc)
2
(CH
3
OH)
2
]∙3CHCl
3
(1),
[
[
Zn
2
(L)Ca(OAc)
Ba(L)(OAc)
2
2
]·CHCl
3
(2),
OH∙CHCl
[Zn
2
(L)Sr(OAc)
2
]
(3)
and
Zn
2
(CH OH)]∙CH
3
3
3
(4), with a novel acyclic bis(salamo)-type tetraoxime
ligand H
fluorescence spectra. UV-Vis titrations clearly show that complexation of H
affords a stoichiometric ratio of 3:1 (M:L) in a cooperative fashion. Complexes 2, 3 and 4 can
4
L, were synthesized and characterized by elemental analyses, IR, UV-Vis and
4
L with Zn(II) ions
2
+
2+
acquire by the substitution reactions of complex 1 with 1 equivalent of M(OAc)
2
(M = Ca ,
2
+
2+
Sr or Ba ). The crystal structures of complexes 1-4 have been determined by single-crystal
2
+
X-ray diffraction. The coordinating ability of the [Zn
recognition phenomenon.
3
(L)] units may be utilized as a cation
Keywords: Acyclic bis(salamo) ligand; Heterobismetallic 3d-2s complex; UV-Vis titration;
Crystal structure; Fluorescence property
1. Introduction
Various kinds of salen-type ligands, used for synthesizing functional metal complexe,s
have been synthesized by chemical modification of aldehydes or diamines, which are
versatile and important compounds [1-3]. Many salen-type metal complexes have already
been developed to study their structures, reactivities or fundamental physical properties
[
4,5]. Polynuclear metal complexes with a variety of interesting structures, such as
*
Corresponding authors.
E-mail: dongwk@126.com; Tel: +86 931 4938703
†
CCDC reference numbers 1424752 (for 1), 1424753 (for 2), 1424754 (for 3) and 1424755 (for 4).
1

metallamacrocycles [6], have unique properties and functions like magnetic properties [7],
catalytic activity [8], guest recognition [9] and so on. In particular, heteronuclear
complexes bearing 3d and 4f transition metals are interesting and important because
magnetic superexchange interactions between the bridged metal atoms may exist in the
complexes, which can also be used in guest recognition [10]. Simultaneous and synergistic
non-covalent interactions result in strong and specific host-guest binding phenomena,
except some which are weak [11]. Such a metal-containing ionophore is expected to show
an interaction between the guest cations and the metal complex moieties, leading to
various kinds of functional host-guest systems [12]. In this paper, using the recognition of
metal atoms by the ligand H
4
L, on the basis of complex 1, complexes 2, 3 and 4 were
subjected to UV-Vis titration and fluorescence titration experiments.
A variety of acyclic and cyclic ligands with two kinds of sites have also been
designed to synthesize such a heteronuclear complex [13]. At the beginning, preparing the
complexes was mostly restricted by the stepwise reactions using a readily available
mononuclear complex, which can be regarded as an “addition reaction”. However, the
preparation of heteronuclear complexes has now been developed, for instance, the metal
that initially bonds to one site of some ligands migrates to another site during the second
metalation step [14]. Furthermore, metal exchange between two “coordination-position
isomers” has also been reported [15,16]. In this context, we used a new method to
synthesize (3d)
reaction”. A (3d)
bis(salamo) ligand H
2
(2s) trinuclear complexes, which could be regarded as a “substitution
homotrinuclear complex prepared with three Zn(II) ions and the acyclic
L, having two salen-type chelating moieties [17], undergoes
3
4
exclusive and quantitative transmetalation of the central 3d metal ion with a 2s metal ion.
Herein, following our previous studies on the synthesis, structural characterization and
optical properties of 3d or 3d4f salamo-type complexes [18], we report the cooperative
formation of trinuclear complexes by the metalation of the bis(salamo) ligand H L. The
4
homotrinuclear complex with the central cavity surrounded by six oxygen atoms is expected to
have a high affinity toward metal cations, since the donor atoms are arranged in a cyclic fashion
and are negatively charged. Through the “substitution reaction”, the homotrinuclear complex 1
could be effectively transformed into the heterotrinuclear complexes 2, 3 and 4.
2

2. Experimental
2
.1. Materials and instruments
-Hydroxy-3-methoxybenzaldehyde (99%), methyl trioctyl ammonium chloride
90%), pyridiniumchlorochromate (98%) and borontribromide (99.9%) were purchased
2
(
from Alfa Aesar. Hydrobromic acid 33wt% solution in acetic acid was purchased from
J&K Scientific Ltd. The other reagents and solvents were purchased from Shanghai Darui
Chemical Fine Chemicals Company. All chemicals were of analytical grade and used
without further purification. C, H and N analyses were obtained using a GmbH VarioEL
V3.00 automatic elemental analysis instrument. Elemental analyses for the metals were
detected with an IRIS ER/S-WP–1 ICP atomic emission spectrometer. IR spectra were
recorded on a VERTEX70 FT-IR spectrophotometer, with the samples prepared as KBr
-
1
(
500–4000 cm ) pellets. UV-Vis absorption spectra were recorded on a Shimadzu
1
UV-2550 spectrometer. H NMR spectra were determined with a German Bruker
AVANCE DRX-400 spectrometer. Fluorescent spectra were taken on a LS-55 fluorescence
photometer. X-ray single crystal structure determinations were carried out on a Bruker
Smart Apex CCD diffractometer. Melting points were obtained with the use of an X4
microscopic melting point apparatus made from the Beijing Taike Instrument Limited
Company and were uncorrected.
2
.2. Synthesis of the ligand H
The ligand
,3-dihydroxynaph-thalene-1,4-dicarbaldehyde
4
L
H
4
L
was
obtained
by
the
reaction
of
2
2
with
1
-[O-(1-ethyloxyamide)]oxime-6-methoxyphenol, according to the literature [19]. The H NMR
spectrum in CDCl (Fig. 1) showed signals at δ 11.03 and 9.82 ppm, which could be assigned to
3
the OH protons. However, there were obvious signals at δ 9.14 and 8.29 ppm for the
salicylaldimine CH=N protons. The δ 6.68-7.97 ppm peaks could be assigned to the H protons of
the naphthalene and benzene rings.
The ligand H
4
L is remarkably soluble in chloroform, DMF and DMSO, but only slightly
soluble in methanol, ethanol, acetone and ethyl acetate. Its corresponding complexes are stable in
air. The reaction steps involved in the synthesis of the bis(salamo)-type tetraoxime ligand (H
are shown in Scheme 1.
4
L)
3

Scheme 1
.
Synthetic route to the bis(salamo)-type tetraoxime ligand H L.
4
2
.3. Synthesis of complexes 1, 2, 3 and 4
.3.1. Synthesis of complex 1
A solution of Zn(OAc)
solution of the ligand H L (6.32 mg, 0.01 mmol) in chloroform (3 mL) at room temperature. The
2
2
∙2H O (6.58 mg, 0.03 mmol) in methanol (3 mL) was added to a
2
4
color of the solution immediately turned yellow. The mixture was filtered and the filtrate was
allowed to stand at room temperature for about four weeks. The solvent was partially evaporated
and several yellow prismatic single crystals were obtained. Yield: 5.62 mg (41.2%). Anal. Calc.
for C41
H
45
C
l9
N
4
O
16Zn
3
: C, 36.07; H, 3.32; N, 4.10. Found: C, 35.96; H, 3.40; N, 3.97%. IR (KBr;
-1
cm ): 1604 [ν(C=N)], 1245 [ν(Ar-O)], 3392 [ν(OH)]. UV-Vis [in chloroform/methanol (1:1)],
5
λ
max (nm) [3.3  10 M]: 280, 370, 396, 416.
2
.3.2. Syntheses of the heterotrinuclear complexes
A solution of Zn(OAc)
2
∙2H
2
O (6.58 mg, 0.03 mmol) in methanol (1 mL) and Ca(OAc)
2
(1.58
mg, 0.01 mmol) in water/methanol (1:3, 2 mL) were added to a solution of H
4
L (6.32 mg, 0.01
mmol) in chloroform (3 mL), and the resulting solution was concentrated to dryness. The solid
was redissolved in chloroform/methanol (1:1, 6 mL). The mixture was filtered and the filtrate
was allowed to stand at room temperature for several weeks, giving yellow crystals of complex 2.
Complexes 3 and 4 were prepared by a similar procedure as for complex 2.
Complex 2, yellow crystals, Yield: 4.73 mg (45.6%). Anal. Calc. for C37
H
35CaCl
3
N
4
O
14Zn :
2
-
1
C, 42.86; H, 3.40; N, 5.40. Found: C, 42.79; H, 3.23; N, 5.27%. IR (KBr; cm ): 1610 [ν(C=N)],
5
1
238 [ν(ArO)]. UV-Vis [in chloroform/methanol (1:1)], λmax (nm) [3.3  10 M)]: 280, 370,
3
96, 416.
Complex 3, yellow crystals, Yield: 3.31 mg (34.3%). Anal. Calc. for C36
H
34
N
4
O
14SrZn : C,
2
-
1
4
1
4
4.80; H, 3.55; N, 5.81. Found: C, 44.73; H, 3.62; N, 5.75%. IR (KBr; cm ): 1610 [ν(C=N)],

5
235 [ν(Ar-O)]. UV-Vis [in chloroform/methanol (1:1)], λmax (nm) [3.3  10 M)]: 280, 370, 396,
16.
Complex 4, yellow crystals, Yield: 3.01 mg (25.1%). Anal. Calc. for C39
H
43BaCl
3
N
4
O
16Zn :
2
-
1
C, 39.09; H, 3.62; N, 4.68. Found: C, 39.21; H, 3.72; N, 4.62%. IR (KBr; cm ): 1610 [ν(C=N)],
4

5
1
235 [ν(Ar-O)], 3434 [ν(O-H)]. UV-Vis [chloroform/methanol (1:1)], [3.3  10 M)] λmax (nm):
2
80, 370, 396, 416.
2
.4. X-ray crystal structure determination
Intensity data for complexes 1, 2 and 3 were collected on a SuperNova (Dual, Cu at zero,
Eos) diffractometer with Mo K
K, respectively, while intensity data for complex 4 was collected on a Bruker Smart 1000 CCD
area detector with Mo K radiation (λ = 0.71073 Å) at 291.73(10) K. Reflection data were
α
radiation (λ = 0.71073 Å) at 173.00(10), 293(2) and 294.29(10)
α
corrected for Lorentz and polarization factors and for absorption using the multi-scan method.
The structures were solved by using the program SHELXL-97 and Fourier difference techniques,
2
and refined by the full-matrix least-squares method on F . All hydrogen atoms were added in
calculated positions. The crystallographic data are summarized in Table 1.
Table 1 Crystallographic data and refinement parameters for the complexes 1, 2, 3 and 4.
3. Results and discussion
3
.1. Crystal structures
2
+
Complex 1 was synthesized by the reaction of the ligand H L with 3 equivalents of the Zn ion.
4
Complexes 2, 3 and 4 were prepared by the reactions of complex 1 with 1 equivalent of M(OAc)
2
2
+
2+
2+
2+
(
M = Ca , Sr or Ba ). Complex 1 dissolves in DMF and chloroform, but is only slightly
soluble in methanol. Complexes 2, 3 and 4 have similar solubility. The heterotrinuclear
2
+
2+
2+
2+
complexes 2-4 were synthesized by using Ca , Sr and Ba ions to replace the central Zn ion
2
+
of complex 1, [Zn
3
(L)] (Scheme 2). All the structures of the complexes were determined by
single-crystal X-ray diffraction. Selected bond lengths and bond angles are listed in Table S1.
Scheme 2. Formation of the trinuclear complexes L·M
3
from the bis(salamo) ligand H L and ion
4
recognition based on metal exchange.
3
.1.1. Structure of complex 1
The crystal structure and atom numbering of complex 1 are shown in Fig. 2. Complex 1
crystallizes in the monoclinic system, space group P2 /n. X-ray crystallography clearly shows the
1
formation of complex 1, which was isolated as yellow crystals. Interestingly, the formation
5

process of complex 1 was highly cooperative. In the crystal structure of complex 1, two acetate
2
+
ions bridge the trinuclear Zn ions in a µ
formation of complex 1. The Zn1 and Zn2 atoms are both five-coordinated with distorted trigonal
bipyramidal geometries, which were deduced by calculating the τ values, where τ = 0.8227 and
= 0.6943 [20]. The Zn3 atom is six-coordinated, with a distorted octahedral geometry. The
2
-fashion, which probably contributes to the cooperative
1
τ
2
distances between the Zn3 atom and the coordinated oxygen atoms range from 2.02 to 2.19 Å.
The Zn3 atom is located in the cavity that consists of six oxygen atoms, where four oxygen atoms
are phenoxy oxygen atoms and the other two oxygen atoms are from the methoxy groups.
Fig. 2. X-ray crystal structure of complex 1.
In the crystal structure of complex 1, there is a significant intermolecular hydrogen bond
(
C10-H10A∙∙∙O12) between the complex 1 units, which links the units together efficiently to form
a 1D chain supra-molecular structure along the b axis (Fig. S1).
As a result, metalation of the bis(salamo) ligand H L affords the trinuclear complex
(L)]. Complex 1 was not the desired product
4
2
+
[
Zn
3
(L)] instead of the dinuclear complex [Zn
2
2
+
because its cavity is occupied by an additional Zn ion,as is evident from the crystal structure.
2
+
However, the size of the cavity seems to be too large to fit in the central Zn ion because only
2
+
two donor atoms coordinate to the central Zn ion in the crystal structure. Thus, this structure
2
+
suggests that the central Zn ion should be replaced by a metal ion with a suitable size for the
cavity. Thus the 2s ions having a suitable radius are utilized in a “substitution reaction” to prepare
heteronuclear complexes.
3
.1.2. Structure of complex
The crystal structure and atom numbering of complex
Complex crystallizes in the triclinic, space group P1. In complex
atoms are located in the N salamo moieties, two acetate ions bridge the Zn ions and
-fashion. The Zn1 and Zn2 atoms are both five-coordinated with
tetragonal pyramidal geometries, which were deduced by calculating the τ values, where
.3335 and τ = 0.2287, for the Zn1 and Zn2 atoms, respectively [20]. The Ca1 atom is
2
2
is shown in Fig. 3(a).
, The Zn1 and Zn2
2

2
2+
2
O
2
2
+
the Ca ion in a µ
2
3
τ =
0
4
2+
eight-coordinated with the a square antiprismatic geometry, replacing the central Zn ion
6

of complex
1. Here, all the six oxygen atoms of the [LZn
2
] moiety coordinate nicely to the
Ca1 atom. Complex
2
has weak coordination with the methoxy groups, deduced by
analyzing the distance between the Ca1 atom and the oxygen atoms of the methoxy
groups. The distances between the Ca1 atom and the four phenoxy oxygen atoms of the
salamo moieties range from 2.365(4) to 2.432(3) Å, which are obviously shorter than the
bond distances to the methoxy groups (Ca1-O1 2.678(3) Å, Ca1-O10 2.643(3) Å). This
fact clearly shows that the coordination bonds of the former are stronger than those of the
later. Intermolecular hydrogen bonds (C7-H7∙∙∙O11, C24-H24∙∙∙O13) between complex 2 units
obviously link the units together efficiently, and the interlinked units eventually form a 1D chain
supra-molecular structure, which is very similar to complex 1 (Fig. S2).
2
+
In summary, the stable complex 2 is obtained by the substitution reaction of the Ca ion with
complex 1, where the space group and geometries of the Zn1 and Zn2 atoms are all different
from that of complex 1. Compared with the oxygen atoms of the methoxy groups, Ca1 has a
strong coordination with the phenoxy oxygen atoms, which probably results from the electrostatic
interaction.
Fig. 3. X-ray crystal structures of the heterotrinuclear complexes: (a) complex 2, (b) complex 3, (c)
complex 4.
3
.1.3. Structure of complex 3
The crystal structure and atom numbering of complex 3 is shown in Fig. 3(b). Complex 3
2
+
crystallizes in the triclinic system, space group

P1. The Zn ions of complex 3 have similar
= 0.4233 (Zn1) and
= 0.5087 (Zn2) [20]. Both zinc atoms are five-coordinated with tetragonal pyramidal (Zn1) and
coordination environments and coordination geometries, with the τ values τ
5
τ
6
trigonal bipyramidal (Zn2) geometries. The Sr1 atom is eight-coordinated with a square
antiprismatic geometry, which is similar to the Ca1 atom in complex 2. The distances between the
Sr1 atom and the four phenoxy oxygen atoms of the coordinated salamo moieties range from
2
.501(4) to 2.569(5) Å, which are obviously shorter than the bond distances to the methoxy
groups (Sr1-O1 2.645(5) Å, Sr1-O10 2.735(4) Å). The Sr-O bonds in complex 3 experience the
same coordination environment as the Ca-O bonds in complex 2, however, these bonds are
obviously longer than the corresponding Ca-O bond lengths found in complex 2.
7

In the crystal structure of complex 3 there are significant intermolecular hydrogen bonds
C16-H16∙∙∙O3, C24-H24∙∙∙O11) and C-H∙∙∙π interactions (C8-H8B∙∙∙Cg6 (C1-C6),
(
C22-H22A∙∙∙Cg5 (C11-C20)). Here, complex 3 units are interlinked by the intermolecular
hydrogen bonds and C-H∙∙∙π interactions into a 2D supra-molecular structure (Fig. S3).
3
.1.4. Structure of complex 4
The crystal structure and atom numbering of complex 4 is shown in Fig. 3(c). Complex 4
crystallizes in the triclinic system, space groupP1, which is the same as complexes 2 and 3. The
2
+
Zn ions of complex 4 are both five-coordinated with tetragonal pyramidal geometries, derived
from the τ values of τ = 0.4688 (Zn1) and τ = 0.4263 (Zn2) [20]. In this complex the Ba1 atom
7
8
is nine-coordinated with a single square antiprismatic geometry, which is different from the Ca1
and Sr1 atoms in complexes 2 and 3 because of the coordination of a methanol molecule. The
distances between the Ba1 atom and the four phenoxy oxygen atoms of the salamo moieties range
from 2.706(4) to 2.814(4) Å, which are obviously shorter than the bond distances to the methoxy
groups (Ba1-O1 2.973(5) Å, Ba1-O10 2.955(4) Å). The same situation was also observed in
complexes 2 and 3.
In the crystal structure of complex 4, because of the presence of methanol molecules, there
are more significant intermolecular hydrogen bonds (C23-H23A∙∙∙O14, O15-H15∙∙∙O16 and O16-
H16A∙∙∙O13) and C-H∙∙∙π interactions (C21-H21∙∙∙Cg6 (C11-C12-C17-C18-C19-C20) and
C14-H14∙∙∙Cg8 (C25-C30)). Here, complex 4 units are interlinked by the intermolecular
hydrogen bond and C-H∙∙∙π interactions into a 2D supra-molecular structure along the bc plane
(
Fig. S4).
Therefore, the final formed geometries of the Zn1 and Zn2 atoms are both square pyramids,
whilst the Ca1 and Sr1 atoms both display square antiprismatic geometries. The Ba1 atom is
larger than the Ca1 and Sr1 atoms, so the coordination of the Ba1 atom with a methanol molecule
makes the structure more stable. The resulting geometry of the Ba1 atom is a single square
antiprism. The coordination bonds of the Ca1 atom with the phenoxy oxygen atoms are obviously
shorter than the Ca1 atom with methoxy groups in complex 2, with complexes 3 and 4 showing
the same experimental phenomena. It can be seen that with the increase of the cation radius, the
coordination bonds of the central cation are stronger. This fact suggests that the charge of the
central cation and the size-fit principle (between the cavity and the central metal cation) are
8

significant factors which affect the cation-binding ability of complex 1.
3
.2. IR spectra
The IR spectra of the ligand H L and its corresponding complexes exhibit various bands in the
4
-1
region 4000-400 cm . The most important bands are given in Table S2. The spectrum of the ligand
1
shows an O-H stretching band at 3172 cm that belongs to phenolic hydroxyl group, whereas
1
complex 1 shows a band at 3392 cm that belongs to the coordinated methanol molecules. The
1
band is shifted by 220 cm in complex 1 compared to ligand H
4
L, probably resulting from the
powerful intramolecular hydrogen bonds in the ligand. The free ligand exhibits characteristic C=N
1
and Ar-O stretching bands at 1607 and 1250 cm , respectively. Those bands are shifted by 3-5
1
cm in complex 1. This lowering of energy results from the Zn-N and Zn-O interactions upon
complexation, which is similar to previously reported Zn(II) complexes [21]. Compared with
complex 1, the C=N and Ar-O stretching bands belonging to the heterotrinuclear complexes are
1
shifted by 3 and 7 cm , respectively. Meanwhile, the O-H stretching band disappeared in
1
complexes 2 and 3. The O-H stretching band at 3434 cm , attributed to the methanol molecules of
-1
2+
complex 4, is shifted by 42 cm . These facts are due to the replacement of the central Zn ion by
2
+
the M ions and the formation of new M-O coordination bond. The above facts are consistent with
the results determined by X-ray diffraction.
3
.3. UV-Vis absorption spectra
In the UV-Vis titration experiment of complex 1, the color of the ligand solution in
chloroform/methanol (1:1) gradually changed from colorless to yellow upon addition of a solution
of Zn(II) acetate. The free ligand H L shows four strong absorption bands at 269, 343, 360 and 378
4
nm. However, complex 1 shows four absorption bands at 280, 370, 396 and 416 nm, which are
shifted by 11, 27, 36 and 38 nm, respectively. The red-shift phenomena is due to the coordination
2
+
of the ligand H
4
L with the Zn ion. In the case of complex 1, although the ligand H L has two
4
salamo chelate moieties, the spectroscopic titration clearly indicates the formation of a 3:1
homotrinuclear Zn(II) complex. The exclusive and cooperative formation of a 3:1 homotrinuclear
Zn(II) complex was indicated by the spectral changes, in which the absorbance of the solution
2
+
hardly changed after Zn was added up to 3 equivalents, and the isosbestic points at 274, 308 and
67 nm were observed (Fig. 4).
3
9

5
2
Fig. 4. (a) UV-Vis spectral changes of H
4
L (1.6  10 M) on addition of Zn(OAc) (1.05  10
2
M) (CHCl
3
/CH
3
OH (1:1); (b) UV-Vis spectral changes of complex 1 on addition of Ca(OAc)
2
2
+
5
(
[[Zn
3
(L)] ] = 3.3  10 M) (the amount of metal salt added to the ligand H
4
L each time was 2
μL )
In the UV-Vis titration experiment of complex 2, the color of the solution of complex 1 in
2
+
chloroform/methanol (1:1) changed inconspicuously when a solution of Ca ions was added. In
the titration experiment, there were neither red-shift nor blue-shift phenomena, except for
2
+
changes in absorbance, and the absorbance of the solution hardly changed after the Ca ion was
added up to 1 equivalent. The spectroscopic titration clearly indicates that the ratio of the reaction
stoichiometry is 1:1 (Fig. 4). Similar changes were also observed for complexes 3 and 4 (Fig. S5),
thus giving the same results.
3
.4. Fluorescence tests
The excitation and emission spectra of complex 1 are shown in Fig. 5. The excitation
spectrum (435 nm) in a chloroform and methanol solution (1:1) is detected at the same intensity
as the corresponding emission spectrum (501 nm) at room temperature. The emission spectrum
excited at 435 nm exhibits broad visible luminescence in the range 450 to 650 nm. Since the
conjugate system of a naphthalene ring is larger than that of a benzene ring, their optical
properties are better than the reported Zn(II) complexes with benzene [22].
Fig. 5. The excitation and emission spectra of complex 1 (CHCl
35).
3
/CH
3
OH = 1:1, v/v,
ex
λ =
4
The excitation and emission spectra of complex 2 at room temperature are shown in Fig. 6.
Complex 2 shows an intense photoluminescence with a maximum emission at ca. 500 nm upon
excitation at 429 nm. Upon excitation at 438 and 440 nm, complexes 3 and 4 respectively show
maximum emissions at ca. 502 and 503 nm, the emission spectra are shown in Fig. 7 and Fig. 8.
Compared with complex 1, strong fluorescence intensities of the heterotrinuclear complexes are
observed, indicating that the fluorescent characteristic has been influenced by the introduction of
10

the alkaline earth metal ions. Among the three heterotrinuclear complexes, the fluorescence
intensity of complex 2 is the strongest, while the lowest is observed for complex 4. It is obvious
that enhancement in the fluorescence intensities show declining trend from complex 2 to 4.
Meanwhile, the maximum emissions of the heterotrinuclear complexes have subtle differences,
the maximum wavelength shifts from 500 to 503 nm. Differences in the radii of the alkaline earth
metal ions may be the main reason for the diverse fluorescence enhancement and peak
wavelength variation.

5
Fig. 6
1:1, v/v,
Ca(OAc)
.
(a) The excitation and emission spectra of complex
2
1
(5.0

10 M) (CHCl
3
/CH
3
OH
=
λ
ex = 429 nm). (b) Fluorescence spectral changes of complex
1
by the addition of
3
5
2
(5.0

10 M) (CHCl
3
/CH
3
OH (1:1), [complex
] = 5.0

10 M,
λ
ex = 429) (The
amount of Ca(OAc) added to complex 1 each time was 2 μL).
2
5
Fig. 7
Fluorescence spectral changes of complex
CHCl /CH OH (1:1), [complex ] = 5.0
added to complex 1 each time was 2 μL)
.
(a) The excitation and emission spectra of complex
3
(5.0

10 M). (b)
3
1
by the addition of Sr(OAc)
2
(5.0
 10 M)

5
(
3
3
1

10 M,
λ
ex = 438 nm) (The amount of Sr(OAc)
2
Fluorescence titration experiments of the alkaline earth metal ions with crystals of
complex show the same results in comparison with the UV-Vis titration experiments.
1
The fluorescence intensity of the solution hardly changed after the alkaline earth metal ion
was added up to 1 equivalence. The spectroscopic titration clearly indicated that the ratio
of the reaction stoichiometry was 1:1. The binding constants of complex
1
upon sequential
2
+
2+
2+
5
6
addition of Ca , Sr or Ba ions were estimated to be 4.71 × 10 , 1.92 × 10 and 3.12 ×
6
-1
1
0 M , respectively.
5
Fig. 8. (a) The excitation and emission spectra of complex
Fluorescence spectral changes of complex by the addition of Ba(OAc)
CHCl /CH OH = 1:1, v/v), [complex ] = 5.0
Ba(OAc) added to complex 1 each time was 2 μL).
4 (5.0 
10 M). (b)
3
1
2
(5.0
 10 M)

5
(
3
3
1
 10 M, λex = 440 nm) (The amount of
2
11

Furthermore, complexes 1-4 exhibit strong fluorescence intensities in the solid state at room
temperature, as shown in Fig. S6 (a-b). The emission spectra of complexes 1-4 were measured at
the appropriate excitation wavelengths of 440 and 420 nm. Complexes 1-4 show maximum
emissions at 515.5, 497.5, 490.5 and 532 nm, respectively. The results show that the fluorescence
intensity of complex 2 was the strongest among the complexes, and the fluorescence intensity of
complexes 3 and 4 were weaker than complex 1. The differences in the fluorescence intensities
could be easily observed in the maximum wavelengths of complexes 1-4, especially between
complexes 3 and 4 which are shifted by 41.5 nm.
According to the obtained experimental data, the differences among the three
heterotrinuclear complexes are very obvious and could be utilized in host-guest systems. Also,
the complexes with the naphthalene ring show better optical properties.
4. Conclusion
We have designed and synthesized a novel acyclic bis(salamo)-type ligand, H L, and
4
obtained the corresponding homotrinuclear Zn(II) complex by the reaction of the
2
+
bis(salamo)-type tetraoxime ligand H
4
L with 3 equivalents of the Zn ion. The heterotrinuclear
3
d-2s complexes were acquired by the substitution reaction of the homotrinuclear Zn(II) complex
2
+
2+
2+
2+
with 1 equivalent of M(OAc) (M = Ca , Sr or Ba ). UV-Vis and fluorescence intensity
2
spectral titrations and X-ray crystallography clearly show that the stoichiometry of the
2
+
homotrinuclear Zn(II) complex is 3:1 (Zn / ligand) and those of the heterotrinuclear complexes
2
+
2+
are all 2:1:1 (Zn /M /ligand). The different fluorescence enhancements and maximum
wavelength variations of the heterotrinuclear complexes clearly show the success of the
transformation from homotrinuclear to heteronuclear complexes, which could be used in
host-guest systems. Furthermore, by analyzing the structures of these complexes, the
2
+
metal-chelate function of the phenoxy oxygen atoms with the M ion has stronger coordination
than the oxygen atoms of methoxy groups, which may be affected by the electrostatic interaction.
2
+
2+
The central Zn ion of the complex [Zn (L)] could be replaced by a metal cation that has a
3
suitable size for the cavity. Owing to their electrostatic interaction and size-fit principle,
heteronuclear complexes with rare-earth(III) ions may be prepared by substitution reactions, and
related research is underway.
12

Appendix A. Supplementary data
CCDC 1424752, 1424753, 1424754 and 1424755 contain the supplementary
crystallographic data for complexes 1, 2, 3 and 4. These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk.
Acknowledgement
This work was supported by the National Natural Science Foundation of China (21361015),
which is gratefully acknowledged.
13

References
[
1] (a) H.L. Wu, G.L. Pan, Y.C. Bai, Y.H. Zhang, H. Wang, F.R. Shi, X.L. Wang, J. Kong, J.
Photochem. Photobiol. B 135 (2014) 33-43;
(
b) H.L. Wu, Y.C. Bai, Y.H. Zhang, Z. Li, M.C. Wu, C.Y. Chen, J.W. Zhang, J. Coord. Chem.
7 (2014) 3054-3066;
c) H.L. Wu, H. Wang, X.L. Wang, G.L. Pan, F.R. Shi, Y.H. Zhang, Y.C. Bai, J. Kong, New J.
Chem. 38 (2014) 1052-1061;
d) H.L. Wu Y.C., Bai, Y.H. Zhang, G.L. Pan, J. Kong, F.R. Shi, X.L. Wang, Z. Anorg. Allg.
Chem. 640 (2014) 2062-2071;
e) H.L. Wu, G.L. Pan, Y.C. Bai, H. Wang, J. Kong, F.R. Shi, Y.H. Zhang, X.L. Wang, Res.
Chem. Intermed. 41 (2015) 3375-3388;
6
(
(
(
(
(
(
f) H.L. Wu, C.P. Wang, F. Wang, H.P. Peng, H. Zhang, Y.C. Bai, J. Chinese Chem. Soc. 62
2015) 1028-1034;
g) C.Y. Chen, J.W. Zhang, Y.H. Zhang, Z.H. Yang, H.L. Wu, G.L. Pan, Y.C. Bai, J. Coord.
Chem. 68 (2015) 1054-1071;
h) H.L. Wu, G.L. Pan, Y.C. Bai, H. Wang, J. Kong, F.R. Shi, Y.H. Zhang, X.L. Wang, J.
Chem. Res. 38 (2014) 211-217;
i) H.L. Wu, G.L. Pan, Y.C. Bai, H. Wang, J. Kong, F.R. Shi, Y.H. Zhang, X.L. Wang, J.
(
(
Coord. Chem. 66 (2013) 2634-2646.
[
2] (a) Y.X. Sun, W.K. Dong, L. Wang, L. Zhao, Y.H. Yang, Chinese J. Inorg. Chem. 25 (2009)
1
478-1482;
b) Y.X. Sun, L. Xu, T.H. Zhao, S.H. Liu, G.H. Liu, X.T. Dong, Synth. React. Inorg. Met.
Org. Nano Met. Chem. 43 (2013) 509-513;
(
(
(
c) Y.X. Sun, X.H. Gao, Synth. React. Inorg. Met. Org. Nano Met. Chem. 41 (2011) 973-978;
d) Y.X. Sun, S.T. Zhang, Z.L. Ren, X.Y. Dong, L. Wang, Synth. React. Inorg. Met. Org.
Nano Met. Chem. 43 (2013) 995-1000;
e) Y.X. Sun, L. Wang, X.Y. Dong, Z.L. Ren, W.S. Meng, Synth. React. Inorg. Met. Org.
Nano Met. Chem. 43 (2013) 599-603;
(
(
(
(
f) L. Xu, L.C. Zhu, J.C. Ma, Y. Zhang, J. Zhang, W.K. Dong, Z. Anorg, Allg. Chem. 641
2015) 2520-2524;
g) L. Xu, Y.P. Zhang, J.Y. Shi, W.K. Dong, Chinese J. Inorg. Chem. 23 (2007) 1999-2002;
14

(
h) L. Xu, Y.P. Zhang, L. Wang, J.Y. Shi, W.K. Dong, Chinese J. Struct. Chem. 27 (2008)
83-186;
i) L. Wang, J.C. Ma, W.K. Dong, L.C. Zhu, Y. Zhang, Z. Anorg, Allg. Chem. 642 (2016)
34-839;
j) X.Y. Dong, Y.X. Sun, L. Wang, L. Li, J. Chem. Res. 36 (2012) 387-390.
3] (a) X.Q. Song, P.P. Liu, Z.R. Xiao, X. Li, Y.A. Liu, Inorg. Chim. Acta 438 (2015) 232-244;
1
(
8
(
[
(
(
(
(
(
b) P.P. Liu, L. Sheng, X.Q. Song, W.Y. Xu, Y.A. Liu, Inorg. Chim. Acta 434 (2015) 252-257;
c) X.Q. Song, Y.J. Peng, G.Q. Chen, X.R. Wang, P.P. Liu, W.Y. Xu, Inorg. Chim. Acta 427
2015) 13-21;
d) X.Q. Song, P.P. Liu, Y.A. Liu, J.J. Zhou, X.L. Wang, Dalton Trans. 45 (2016) 8154-8163;
e) T.Z. Yu, K. Zhang, Y.L. Zhao, C.H. Yang, H. Zhang, L. Qian, D.W. Fan, W.K. Dong, L.L.
Chen, Y.Q. Qiu, Inorg. Chim. Acta 361 (2008) 233-240;
f) T.Z. Yu, K. Zhang, Y.L. Zhao, C.H. Yang, H. Zhang, D.W. Fan, W.K. Dong, Inorg. Chem.
Commun., 10 (2007) 401-403;
g) T.Z. Yu, W.M. Su, W.L. Li, Z.R. Hong, R.N. Hua, M.T. Li, B. Chu, B. Li, Z.Q. Zhang, Z.
Hu, Inorg. Chim. Acta, 359 (2006) 2246-2251;
h) L.Q. Chai, G. Wang, Y.X. Sun, W.K. Dong, L. Zhao, X.H. Gao, J. Coord. Chem. 65 (2012)
621-1631.
4] (a) W.K. Dong, J.C. Ma, L.C. Zhu, Y. Zhang, X.L. Li, Inorg. Chim. Acta 445 (2016) 140-148;
(
(
(
1
[
(
(
b) W.K. Dong, J.C. Ma, Y.J. Dong, L.C. Zhu, Y. Zhang, Polyhedron 115 (2016) 228-235;
c) W.K. Dong, J.G. Duan, Y.H. Guan, J.Y. Shi, C.Y. Zhao, Inorg. Chim. Acta 362 (2009)
1129-1134;
(
(
(
(
(
d) W.K. Dong, J. Zhang, Y. Zhang, N. Li, Inorg. Chim. Acta 444 (2016) 95-102;
e) W.K. Dong, P.F. Lan, W.M. Zhu, Y. Zhang, J. Coord. Chem. 69 (2016) 1272-1283;
f) W.K. Dong, J.T. Zhang, Y.J. Dong, Y. Zhang, Z.K. Wang, Z. Anorg, Allg. Chem. 642
2016) 189-196;
g) W.K. Dong, F. Zhang, N. Li, L. Xu, Y. Zhang, J. Zhang, L.C. Zhu, Z. Anorg, Allg. Chem.
6
42 (2016) 532-538;
(
(
h) W.K. Dong, Y.X. Sun, C.Y. Zhao, X.Y. Dong, L. Xu, Polyhedron 29 (2010) 2087-2097;
i) W.K. Dong, L.S. Zhang, Y.X. Sun, M.M. Zhao, G. Li, X.Y. Dong, Spectrochim. Acta Part
A 121 (2014) 324-329;
15

(
(
(
(
j) W.K. Dong, X.N. He, H.B. Yan, Z.W. Lv, X. Chen, C.Y. Zhao, X.L. Tang, Polyhedron 28
2009) 1419-1428;
k) J.C. Ma, X.Y. Dong, W.K. Dong, Y. Zhang, L.C. Zhu, J.T. Zhang, J. Coord. Chem. 69
2016) 149-159.
[
5] (a) P. Wang, L. Zhao, Spectrochim. Acta, Part A 135 (2015) 342-350;
(
(
b) P. Wang, L. Zhao, Synth. React. Inorg. Met. Org. Nano Met. Chem. 46 (2016) 1095-1101;
c) L. Zhao, L. Wang, Y.X. Sun, W.K. Dong, X.L. Tang, X.H. Gao, Synth. React. Inorg. Met.
Org. Nano Met. Chem. 42 (2012) 1303-1308;
d) L. Zhao, X.T. Dang, Q. Chen, J.X. Zhao, L. Wang, Synth. React. Inorg. Met. Org. Nano
(
Met. Chem. 43 (2013) 1241-1246.
[
[
[
[
6] S. Akine, T. Nabeshima, Dalton Trans. 47 (2009) 10395-10408.
7] S.J. Wezenberg, A.W. Kleij, Angew. Chem. Int. Ed. 47 (2008) 2354-2364.
8] G. Mezei, C.M. Zaleski, V.L. Pecoraro, Chem. Rev. 107 (2007) 4933-5003.
9] (a) S. Akine, T. Taniguchi, T.J. Nabeshima, Am. Chem. Soc. 128 (2006) 15765-15774;
(
(
b) S. Akine, S. Kagiyama, T. Nabeshima, Inorg. Chem. 46 (2007) 9525-9527;
c) T. Ohshima, T.I. Wasaki, Y. Maegawa, A. Yoshiyama, K.J. Mashima, Am. Chem. Soc.
1
30 (2008) 2944-2945.
10] (a) M.M.J. Smulders, S. Zarra, J.R.J. Nitschke, J. Am. Chem. Soc. 135 (2013) 7039-7046;
b) N. Kumari, M.A. Hasan, B.D. Ward, L. Mishra, Ind. Eng. Chem. Res. 52 (2013)
5007-15014;
[
(
1
(
(
(
(
c) J.P. Costes, F. Dahan, A. Dupuis, Inorg. Chem. 39 (2000) 165-168;
d) C. Edder, C. Piguet, J.C.G. Bünzli, G. Hopfgartner, Chem. Eur. J. 7 (2001) 3014-3024;
e) J.C.G. Bünzli, C. Piguet, Chem. Rev. 102 (2002) 1897-1928;
f) W. Chen, X. Tang, W. Dou, Z. Ju, B. Xu, W. Xu, W. Liu, Chem. Commun. 52 (2016)
5
124-5127.
[
[
11] G.W. Gokel, W.M. Leevy, Chem. Rev. 104 (2004) 2723-2750.
12] (a) T. Nabeshima, S. Akine, Chem. Rec. 8 (2008) 240-251;
(
b) T. Nabeshima, Bull. Chem. Soc. Jpn. 83 (2010) 969–991; (c) T. Nabeshima, S. Akine, C.
Ikeda, M. Yamamura, Chem. Lett. 39 (2010) 10-16;
d) G. Lautrette, B. Kauffmann, Y. Ferrand, C. Aube, N. Chandramouli, D. Dubreuil, I. Huc,
Angew. Chem. Int. Ed. 52 (2013) 11517-11520.
(
16

[
13] (a) E. Barreiro, J.S. Casas, M.D. Couce, A. Sánchez, J. Sordo, E. M. Vázquez-López, J.
Inorg. Biochem. 131 (2014) 68-75;
(
b) G. Brewer, L.J. Alvarado, S. Lear, C. Viragh, P.Y. Zavalij, Inorg. Chim. Acta 439 (2016)
11-116;
c) E.S. Bazhina, G.G. Aleksandrov, N.N. Efimov, E.A. Ugolkova, V. Minin, A. Sidorov, V.
Novotortsev, I. Eremenko, Rus. Chem. Bul. 62 (2013) 962-965;
1
(
(
(
d) P. Guerriero, S. Tarnburini, P.A. Vigato, Coord. Chem. Rev. 139 (1995) 17-243;
e) P. Totaro, K.C.M. Westrup, M.E. Boulon, G.G. Nunes, D.F. Back, A. Barison, S. Ciattini,
M. Mannini, L. Sorace, J.F. Soares, Dalton Trans. 42 (2013) 4416-4426.
[
[
[
14] Y. Nakamura, M. Yonemura, K. Arimura, N. Usuki, M. Ohba, H. Okawa, Inorg. Chem. 40
(
2001) 3739-3744.
15] M. Yonemura, K. Arimura, K. Inoue, N. Usuki, M. Ohba, H. Okawa, Inorg. Chem. 41 (2002)
82-589.
16] ꢀ.ꢁ. ꢂas, A. ꢃiswas, C.ꢄ. ꢅꢆmeꢇ-ꢅarcꢈa, M.G. Drew, A. Ghosh, Inorg. Chem. 53 (2013)
34-445.
17] (a) A. Kumar, R. Pandey, R.K. Gupta, V. Mishra, S.M. Mobin, D.S. Pandey, Dalton Trans. 43
5
4
[
(
(
2014) 6365-6376;
b) S. Akine, T. Taniguchi, T. Nabeshima, Chem. Lett 7 (2001) 682-683; (c) S. Ghosh, S.
Biswas, A. Bauzá, M. Barceló-Oliver, A. Frontera, A. Ghosh, Inorg. Chem. 52 (2013)
508-7523.
18] (a) W.K. Dong, J.C. Ma, L.C. Zhu, Y. Zhang, Cryst. Growth Des. 16 (2016) 6903-6914;
b) W.K. Dong, X.L. Li, L. Wang, Y. Zhang, Y.J. Ding, Sens. Actuators. B 229 (2016)
70-378;
c) W.K. Dong, F.A. Sunday, Y. Zhang, Y.X. Sun, X.Y. Dong, Sens. Actuators. B 238 (2017)
27-734;
7
[
(
3
(
7
(
(
d) W.K. Dong, J.C. Ma, L.C. Zhu, Y. Zhang, New J. Chem. 40 (2016) 6998-7010;
e) S.T. Zhang, T.R. Li, B.D. Wang, Z.Y. Yang, J. Liu, Z.Y. Wang, W.K. Dong, Dalton Trans.
4
3 (2014) 2713-2717.
19] (a) S. Akine, S. Sairenji, T. Taniguchi, T. Nabeshima, J. Am. Chem. Soc. 135 (2013)
2948-12951;
b) A.J. Gallant, M. Yun, M. Sauer, C.S. Yeung, M. MacLachlan, J. Org. Lett. 7 (2005)
[
1
(
17

4
827-4830;
(
(
c) H.A. Tran, J. Collins, P.E. Georghiou, New J. Chem. 32 (2008) 1175-1182;
d) S. Akine, T. Tadokoro, T. Nabeshima, Inorg. Chem. 51 (2012) 11478-11486.
[
20] A.W. Addison, T.N. Rao, J. Reedijk, J.V. Rijn, G.C. Verschoor, J. Chem. Soc. Dalton Trans.
(1984) 1349-1356.
21] A. Majumder, G.M. Rosair, A. Mallick, N. Chattopadhyay, S. Mitra, Polyhedron 25 (2006)
753-1762.
22] (a) J. Cheng, X. Ma, Y. Zhang, J. Liu, X. Zhou, H. Xiang, Inorg. Chem. 53 (2014)
210-3219;
b) Q.H. Meng, P. Zhou, F. Song, Y.B. Wang, G.I. Liu, H. Li, Cryst. Eng. Comm. 15 (2013)
786-2790;
c) C.E. Burrow, T.J. Burchell, P.H. Lin, F. Habib, W. Wernsdorfer, R. Clérac, M. Murugesu,
Inorg. Chem. 48 (2009) 8051-8053.
7
[
1
[
3
(
2
(
18

Table 1
Crystallographic data and refinement parameters for the complexes 1, 2, 3 and 4.
Complex
Empirical formula
Formula weight
T (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
α (°)
β (°)
1
C
2
C
3
C
4
C
41
H
45Cl
9
N
4
O
16Zn
3
37
H
35CaCl
3
N
4
O
14Zn
2
36
H
34
N
4
O
14SrZn
2
39 3 4 2
H43BaCl N O16Zn
1364.97
173.00(10)
0.71073
monoclinic
P2
14.0480(4)
16.5494(3)
23.6735(5)
90
100.464(2)
90
5412.2(2)
4
1.675
1036.86
293(2)
0.71073
triclinic
P1
13.4794(7)
13.6682(6)
15.4156(9)
85.483(4)
65.228(5)
65.053(5)
2321.6(2)
2
965.03
1198.20
291.73(10)
0.71073
triclinic
P1
10.6854(5)
14.1383(7)
16.2738(13)
73.657(6)
88.178(5)
78.971(4)
2315.0(2)
2
294.29(10)
0.71073
triclinic
P1
12.6197(14)
13.346(2)
15.6864(18)
114.099(13)
104.696(10)
99.435(11)
2223.2(6)
2
1
/n
γ (°) 3
V (Å )
Z
D
-
3
calc (g cm )
1.483
1.381
3.40-26.02
1056.0
1.442
2.329
3.409-26.020
976.0
1.719
2.115
3.290-26.022
1200
-
1
Absorption coefficient (mm )
θ range for data collection (°)
F(000)
1.831
3.377-26.021
2760.0
h/k/l (minimum, maximum)
Crystal size (mm)
Reflections collected
13, 17/20, 19/29, 23
0.21  0.24  0.32
23279/10650
[Rint = 0.049]
10650
15, 16/16, 16/19, 18
0.25  0.27  0.31
17514/9119
[Rint= 0.043]
9119
14, 15/16, 13/17, 19
0.17  0.18  0.23
15027/8714
[Rint= 0.079]
8714
13, 12/16, 17/17, 20
0.21  0.23  0.25
16597/9101
[Rint= 0.032]
9101
Independent reflection
Completeness to 26.32 (%)
Data/restraints/parameters
Final R indices [I > 2σ (I)]
99.71
10650/0/670
99.76
9119/0/554
99.75
8714/0/518
99.79
9101/0/596
R
1
= 0.0519,
wR =0.1136
= 0.0812,
wR =0.0968
R
1
= 0.0524,
wR =0.1549
= 0.0731,
wR =0.1377
R
1
= 0.0690,
wR =0.0926
= 0.0963,
wR =0.1139
R
1
= 0.0520,
wR =0.1453
= 0.0695,
wR =0.1286
2
2
2
2
R indices (all data)
R
1
R
1
R
1
R
1
2
2
2
2
2
Goodness-of-fit for ( F )
1.032
1.048
1.025
1.050
Largest difference peak and hole
-
3
0.91, 1.10
0.72, 0.65
1.06, 0.61
1.99, 1.08
(e Å )
2
2
c
2
2
2
1/2
2
2
2
-1
2
2
c
2
a. R = Σ‖F
1
2
o
| − |F
c
1/2
‖/Σ|F
o
|; b. wR
2
= [Σw(F
o
- F
) /Σw(F
o
) ] , w = [σ (F
o
) + (0.0784P) + 1.3233P] , where P = (F
o
+ 2F
)/3; c. ꢅOF = [Σw(F
o
-
2
c
F ) /nobs - nparam)] ;
19

Scheme 1
20

Scheme 2
21

Fig. 1.
22

Fig. 2.
23

Fig. 3.
24

Fig. 4.
25

Fig. 5.
26

Fig. 6.
27

Fig. 7.
28

Fig. 8.
.
29