Construction of five dicyanamide based coordination polymers with diverse dimensionality: Synthesis, characterization and photoluminescence study

Article abstract of DOI:10.1016/j.poly.2016.06.046

A family of dicyanamide bridged compounds namely {[Co(dca)₄(2-abim)₂]}_n(1), {[Ni(dca)₄(2-abim)₂]}_n(2), {[Cd(dca)₄(2-abim)₂]}_n(3), {[Zn(N(CN)₂)₂(4-bpdb)]}_n(4) and {[Cd(N(CN)₂)₂(4-bpdb)]}_n(5); [where dca?=?dicyanamide, 2-abim?=?2-aminobenzimidazole and 4-bpdb?=?1,4-bis-(4-pyridyl)-2,3-diaza-1,3-butadiene] have been synthesized by stirring at room temperature. These compounds have been characterized by single crystal diffraction analysis, infrared spectroscopy (IR) and powder X-ray diffraction (PXRD). Complexes 1–3 are isostructural and exhibit two-dimensional (2D) metal-dca sheet with pendant 2-abim ligand. Compound 4 forms [Zn(N(CN)₂)]_nchains with a pendent dca and a bridging dca linker, which are further connected by bridging 4-bpdb ligands extending into a 2D layer structure. In case of compound 5 each Cd(II) centers connect with four bridging dca linkers to form [Cd(N(CN)₂)]_ndouble chains, which are further connected by bridging 4-bpdb ligands extending into a 2D layer structure. Here [Cd₂(N(CN)₂)] and 4-bpdb spacer are interpenetrated to each other and resemble polyrotaxane-type structures. Photoluminescent properties of compounds 3–5 were also studied and they exhibit nice ligands based photoluminescence properties at room temperature.

Full text of DOI:10.1016/j.poly.2016.06.046

Accepted Manuscript
Construction of five dicyanamide based coordination polymers with diverse di-
mensionality: synthesis, characterization and photoluminescence study
Anamika Das, Biswajit Bhattacharya, Dilip Kumar Maity, Arijit Halder,
Debajyoti Ghoshal
PII:
S0277-5387(16)30280-7
DOI:
http://dx.doi.org/10.1016/j.poly.2016.06.046
POLY 12087
Reference:
Polyhedron
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Accepted Date:
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25 June 2016
Please cite this article as: A. Das, B. Bhattacharya, D.K. Maity, A. Halder, D. Ghoshal, Construction of five
dicyanamide based coordination polymers with diverse dimensionality: synthesis, characterization and
photoluminescence study, Polyhedron (2016), doi: http://dx.doi.org/10.1016/j.poly.2016.06.046
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Construction of five dicyanamide based coordination polymers with diverse
dimensionality: synthesis, characterization and photoluminescence study
Anamika Das, Biswajit Bhattacharya, Dilip Kumar Maity, Arijit Halder and Debajyoti Ghoshal*
Department of Chemistry, Jadavpur University, Jadavpur, Kolkata, 700 032, India
E-mail: dghoshal@chemistry.jdvu.ac.in
Department of Chemistry, Jadavpur University, Jadavpur, Kolkata, 700 032, India
E-mail: dghoshal@chemistry.jdvu.ac.in
___________________________________________________________________________
Abstract
A family of dicyanamido bridged compounds namely {[Co(dca)4(2-abim)2]}n(1),{[Ni(dca)4(2-
abim)2]}n(2),{[Cd(dca)4(2-abim)2]}n(3), {[Zn(N(CN)2)2(4-bpdb)]}n(4) and {[Cd(N(CN)2)2(4-
bpdb)]}n(5); [where dca = dicyanamide, 2-abim = 2 amino-benzimidazole and 4-bpdb = 1,4-
bis(4-pyridyl)-2,3-diaza-1,3-butadiene] have been synthesized by stirring at room temperature.
These compounds have been characterized by single crystal diffraction analysis, infrared
spectroscopy (IR) and powder X-ray diffraction (PXRD). Complexes 1-3 are isostructural and
exhibit two-dimensional (2D) metal-dca sheet with pendant 2-abim ligand. Compound 4 forms
[Zn(N(CN)2)]n chains with a pendent dca and a bridging dca linker, which are further connected
by bridging 4-bpdb ligands extending into a 2D layer structure. In case of compound 5 each
Cd(II) centers connect with four bridging dca linkers to form [Cd(N(CN)2)]n double chains,
which are further connected by bridging 4-bpdb ligands extending into a 2D layer structure. Here
[Cd2(N(CN)2)] and 4-bpdb spacer are interpenetrated to each other and resemble polyrotaxane-
type structures. Photoluminescent properties of compounds 3–5 were also studied and they
exhibit nice ligands based photoluminescence properties at room temperature.
___________________________________________________________________________
Keywords: Coordination polymers, Single crystal X-ray structures, Network analysis
Dicyanamide, Photoluminescence study.
______________________________________________________________________________

1. Introduction
Coordination polymer is one of the most pursed areas of synthetic inorganic chemistry because
of their significant role for different functionality likes luminescence, magnetism, non linear
optics, gas adsorption and catalysis [1-9]. Apart from the functionality these classes of
compounds are intensely studied for their intriguing architectures and fascinating topologies [10-
14]. One of the key operators to design the coordination polymers with an exciting structure is
the thoughtful combination of mixed organic linkers and metal ion and in this way the use of
pseudohalide ligands found pretty effective in combination with the other organic ligand. This
variety of coordination polymers have long being studied for their interesting coordination,
physical and magnetic properties [15-16]. Among the pseudohalides, comparatively larger sized
and versatile dicyanamide (dca) ligand found very interesting bridging ligand with its three
potential donor sites which allow the ligand to act as a monodentate up to a pentadentate donor
[16]. Construction of diverse dimensionality like mononuclear, dinuclear, 1D chains, 2D (4,4) or
(6,3) nets, and 3D network topologies could be possible with the use of dca by introducing
auxiliary co-ligands or other bridging ligand [17-24]. Moreover, the dca can either act as
terminal non-bridging ligands whose main function is to occupy certain portions of the metal-
coordination sphere, or they may act as bridges with other metal ion. Beside their structural
diversity, dca bridged coordination polymer display ferromagnetism, spin-canted
antiferromagnetism and recently metal-organic nanotubes are also formed by
[Mn3(propandiolato)2] building blocks and dca linkers [23].
On the other hand, N,N′-donor auxiliary neutral linkers have long been used as a bridging
ligand to control structural assemblies in combination with dicraboxylate and divalent metal ions
[25-28]. The conformational rigidness, configurations and substituent on N,N′-donor linkers
have further impact on the overall network structures, dimensionality which also reflects in their
property. In addition to that architecture of higher dimensionality can also be generated by
polycatenation of the constituent structures of lower dimensionality [29-30]. Pyridyl based azine
linkers namely-(3-pyridyl)-2,3-diaza-1,3-butadiene (3-bpdb) have strong fluorescence properties
due to a π conjugation effect and not been used for the construction of CPs in combination with
dca ligand.
Taking into account the above-mentioned aspects, five compounds of general formula
[M(dca)4(2-abim)2] [where M is the divalent transition metal cation: Co(1), Ni (2), Cd (3)] and

M(4-bpdb)(N(CN)2)2 M= Zn(4), Cd (5) have been synthesized and characterized structurally,
spectroscopically (Scheme 1). Compounds 1-3 are isostructural and connected with four nitrile
nitrogen atoms of dca ligand and formed a 2-D sheet structure. Compound 4 exhibits a 2D sheet
with the help of 4-bpdb and bridging dca ligands containing the pendent dca ligand also. Finally,
compound 5 exhibits a 2D→3D polycatenated framework due to the mutual interpenetration of
2D sheets constructed through the bridging of 4-bpdb ligand with [Cd2(N(CN)2)] chain.
Moreover, the complexes 3-5 show ligand based photoluminescence in solid state.
Scheme 1
2. Experimental
2.1. Materials
High-purity 2 amino-benzimidazole (2-abim) and sodium dicyanamide were purchased from the
Aldrich Chemical Co. Inc. and used without further purification. 1,4-bis-(4-pyridyl)-2,3-diaza-
1,3-butadiene (4-bpdb) were prepared according to literature procedure [31]. The starting
material for the above synthesis such as, 4-pyridine carboxaldehyde and hydrazine hydrate were
purchased from Sigma-Aldrich Chemical Co. Inc. and used as received. All other chemicals and
solvents were AR grade and were used as received.

2.2. Physical Measurements
Elemental analyses (carbon, hydrogen and nitrogen) were performed using a Heraeus CHNS
analyzer. Infrared spectra (4000–400 cm−1) were taken on KBr pellets, using a PerkinElmer
Spectrum BX-II IR spectrometer. X-ray powder diffraction (PXRD) patterns of the bulk sample
were recorded in Bruker D8 Discover instrument using Cu-Kα radiation. UV-vis spectra were
recorded on a Perkin Elmer Lambda 35 UV-vis spectrophotometer. Emission spectra were
recorded on a HORIBA Jobin Yvon (Fluoromax-3) fluorescence spectrophotometer.
2.3. Syntheses
2.3.1. {[Co(dca)4(2-abim)2]}n (1). An aqueous solution (5 mL) of Co(NO3)2·6H2O (1 mmol,
0.291g) was mixed with an ethanolic solution (5 mL) of 2-abim (1 mmol, 0.133g) with constant
stirring. Then an aqueous solution (5 mL) of sodium dicyanamide (2 mmol, 0.178g) was added
to the mixture with continuous stirring. The pink colored solution was filtered and kept
undisturbed in a CaCl2 desiccator and after three days pink colored block shaped crystals suitable
for X-ray diffraction were obtained from the filtrate. Yield 90%. Anal. Calc. for C18H14CoN12: C,
47.26; H, 3.06; N, 36.74. Found: C, 47.96; H, 3.92; N, 36.10 %. IR spectra (in cm-1): ν(N(CN)2)-1
2243, 2230, 2279; ν(N-H), 3104; and ν(C=C), 1530.
2.3.2. {[Ni(dca)4(2-abim)2]}n (2). The similar procedure has been adopted as that of 1 using
Ni(NO3)·6H2O (1mmol, 0.290g) instead of Co(NO3)2·6H2O. Here the greenish block shaped
crystals suitable for X-ray diffraction were obtained from the filtrate after three days. Yield 87%.
Anal. calcd. for 2 C18H14NiN12: C, 47.50; H, 2.63; N, 31.66. Found: C, 47.53; H, 2.65; N, 31.76
%. IR spectra (in cm-1): ν(N(CN)2)-1 2250, 2283, 2177; ν(N-H), 3376; and ν(C=C), 1640.
.
2.3.3. {[Cd(dca)4(2-abim)2]}n (3). The similar procedure as that of 1 taking Cd(NO3)2 4H2O (1
mmol, 0.308 g) in place of Co(NO3)2·6H2O results the formation of yellowish block shaped
crystals suitable for X-ray diffraction after three days. Yield 84%. Anal. calcd. for 3 C18H14Cd
N12: C, 42.32; H, 2.74; N, 32.90. Found: C, 42.35; H, 2.79; N, 32.95%.IR spectra (in cm-1)
ν(N(CN)2)-1 2254, 2230, 2183; ν(N-H), 3376; and ν(C=C), 1640.
2.3.4. {[Zn(4-bpdb)(N(CN)2)2]}n (4) An aqueous solution (5 mL) of Zn(NO3)·6H2O (1mmol,
0.297g) and sodium dicyanamide (2 mmol, 0.17g) was mixed with constant stirring. Then
methanolic solution of 4-bpdb (1 mmol, 0.210 g) was added to the solution and stirred for about
30 mins at room temperature. After three days, yellowish block shaped crystals suitable for X-

ray diffraction were obtained from the filtrate. Yield 85%. Anal. calcd. for 4 C16H10N10Zn : C,
47.13; H, 2.45; N, 34.35. Found: C, 47.35; H, 2.59; N, 34.86%.IR spectra (in cm-1) ν(N(CN)2)-1
2298, 2235, 2159; ν(C=C), 1607; ν(C=N) 1423.
2.3.5. {[Cd(4-bpdb)(N(CN)2)2]}n (5) This has been synthesized by following the similar
.
procedure as stated in case of 4 but here Cd(NO3)2 6H2O (1 mmol, 0.308 g) is used instead of
Zn(NO3)·6H2O. After five days, yellowish block shaped crystals suitable for X-ray diffraction
were obtained from the filtrate. Yield 82%. Anal. calcd. for 5 C16H10CdN10: C, 42.25; H, 2.19; N,
30.80. Found: C, 42.35; H, 2.37; N, 31.95%. IR spectra (in cm-1) ν(N(CN)2)-1 2374, 2291, 2274;
ν(C=C), 1606; ν(C=N) 1411.
2.4. Crystallographic Data Collection and Refinement
Suitable single crystals of compounds 1-5 were mounted on the tip of thin glass fibers with
commercially available super glue. X-ray single crystal data collection of all five crystals were
performed at room temperature using Bruker APEX II diffractometer, equipped with a normal
focus, sealed tube X-ray source with graphite monochromated Mo-Kα radiation (λ= 0.71073Å).
The data were integrated using SAINT [32] program and the absorption corrections were made
with SADABS [33]. All the structures were solved by SHELXS 97 [34] using Patterson method
and followed by successive Fourier and difference Fourier synthesis. Full matrix least-squares
refinements were performed on F2 using SHELXL-97 [34] with anisotropic displacement
parameters for all non-hydrogen atoms. All the hydrogen atoms were fixed geometrically by
HFIX command and placed in ideal positions. All calculations were carried out using SHELXS
97, SHELXL 97, PLATON v1.15 [35], ORTEP-3v2 [36], and WinGX system Ver-1.80 [37] and
TOPOS [38-39]. Data collection and structure refinement parameters and crystallographic data
for all complexes are given in Table 1.
3. Results and discussion
3.1. IR spectra
The IR spectra of the complexes 1-5 exhibit strong absorption bands in the 2374-
2159ꢀcm−1 region attributed to the νs+as (C≡N), νas (C≡N), and νs (C≡N) vibrational modes of
mono/di bridging dca ligand. The appearance of two new characteristic bands at ~ 434ꢀcm−1 and
~ 560ꢀcm−1 in the spectrum of the complexes, which are not generally observed in the spectra of

the free dca ligand; can clearly indicates the presence of M-N bonding between the metal and the
nitrogen atoms of the nitrile group of the dca ligand. This observation is confirmed by the X-ray
structure of the complexes which show that metals are bonded to dca ligand through N-atoms.
3.2. X-ray structure description of the compounds
3.2.1. {[M(dca)4(2-abim)2]}n [M=Co for 1, Ni for 2 and Cd for 3]. Single-crystal X-ray
structural analysis revealed that compounds 1-3 are isostructural and all of them are crystallizes
in monoclinic P21/n space group with Z value of 2. All the compounds exhibit two-dimensional
(2D) structure of M(II) [M= Co for 1, Ni for 2 and Cd for 3] ions linked by bridging dca ligand
and the monodentate 2-abim ligand. The M(II) in all three structures shows distorted octahedral
geometry with MN6 coordination environment (Fig. 1a for 1, S1a for 2 and S2a for 3). Here,
each metal center is connected to four nitrile nitrogen atoms (N4, N4a N6b, N6c) from four
different bridging dca ligands to create the equatorial plane of the octahedral coordination
enviroment. Two epical sites are occupied by the two symmetry related nitrogen (N1 and N1a)
atoms from two monodented 2-abim ligand. In compounds 1-3, the M(II)-N bond length varies
from 2.1171(11)-2.1591(15) Å (Co-N for 1), 2.096(2)-2.110(2) Å (Ni-N for 2) and 2.3045(12)-
2.3997(14) Å (Cd-N for 3), respectively (Table S1-S3) which is commensurated with the
covalent radii of the metal atoms used. Each M(II) ion (Fig. 1b for Co, S1b for Ni and S2b for
Cd) links four neighboring metal ions via four µ1,5-dca ligands to form the 2D sheet structure in
the crystallographic ab plane. The M-M distance through dca bridges are 8.186 A° for 1, 8.134
A° for 2 and 8.052 A° for 3 respectively. The topological analysis using TOPOS [38-39] also
reveals that all three structures can be represented as a 4-connected uninodal net with a point
symbol {44.62}. The simplified diagram of the 4-connected net has been represented in Fig. 2c,
Fig. S1c and Fig. S2c for the respective three structures.
3.2.2. {[Zn(4-bpdb)(N(CN)2)2]}n (4) Compound 4 also crystallizes in P21/n space group and the
single-crystal X-ray structure analysis reveals the formation of a two dimensional (2D) sheet
structure with Zn(II) metal ions bridged by both 4-bpdb and dca linkers. But unlike the previous
three structures here one dca is acting as a bridging ligand whereas another dca acts as pendent
monodentate ligand. Hence the asymmetric unit of 4 contains one Zn(II) ion, one bridging 4-
bpdb ligand, one monodentate pendant dca linker and one bridging dca linker which makes the
central metal ion Zn(II), penta-cordinated. Here each penta-coordinated Zn(II) ion shows

distorted trigonal bipyramidal geometry with ZnN5 coordination environment having 0.89
Addison parameter (tau) value [40]. The coordination environment is furnished by five nitrogen
atoms from two distinct 4-bpdb ligands (N1 and N4a), one pendant dca (N6) and two different
bridging dca ligands (N5 and N7b) (Fig. 2a). The Zn–N bond lengths are in the range of
1.979(2)–2.3020(17) Å and the angles around central atom (Zn1) lies in the range of 87.13(7)-
177.80(7)° (Table 3). Here each Zn(II) centers connect with a bridging dca linker to form
[Zn(N(CN)2)]n chains, which are further connected by bridging 4-bpdb ligands extending into a
2D layer structure (Fig. 2b) in bc plane. The network analysis by TOPOS [38-39] also reveals
that the structure can be represented as a 4-connected uninodal net (Fig. 2c) with point symbol
{44.62}.
3.2.3. {[Cd(4-bpdb)(N(CN)2)2]}n (5) To explore the effect of the metal ion on the overall
structures of the CPs, Zn(II) of 4 has been replaced by Cd(II), to synthesize compound 5. It
crystallizes in the monoclinic system with slightly different space group P21/c and the structure
analysis revealed that a 2D network structure is formed by dca and 4-bpdb linkers. Here each
Cd(II) centers are connected by two doubly bridged dca and bridging 4-bpdb linkers. In
comparison to 4 the coordination number here increased from five to six; and with the effect of
doubly bridged dca and larger sized Cd(II); is possibly responsible for the completely different
structure of 5 in spite of its similar formula with 4. Each asymmetric unit in 5 contains one
Cd(II) ion located in a special position (0,0,0), half bridging 4-bpdb and one dca linker forming a
distorted octahedral geometry with CdN6 coordination environment (Fig. 3). Here each Cd(II)
ions are ligated to six nitrogen atoms of two different 4-bpdb ligands (N1 and N1a) and four
nitrogen atoms of four different dca linkers (N3, N3a, N5b and N5c). The Cd–N bond lengths are
in the range of 2.310(12)–2.363(9) Å and the angles around central atom (Cd1) lies in the range
of 87.94-180° (Table 4). Here each Cd(II) centers connect with four bridging dca linkers to form
[Cd(N(CN)2)]n doubly bridged chains, which are further connected by bridging 4-bpdb ligands
extending into a 2D layer structure (Fig. 3b). The network analysis by TOPOS [38-39] suggests
that the structure of 5 can be represented as a 4-connected uninodal net and the corresponding
Schläfli symbol is {44.62} (Fig. 3c). The network structures are found interpenetrated to each
other due to the organization of the network structure with two different spacer lengths. Here
[Cd2(N(CN)2)] square acts as a wheel whereas the long 4-bpdb spacer acts as an axle and these
units are got interpenetrated with each other and resemble rotaxane-type structures (Fig. 4a),

which are further connected to form the overall 2D network. These 2D networks are
interpenetrated among each other to form a 2D→3D polycatenated framework (Fig. 4b) structure
in the solid state.
3.3. Powder X-ray diffraction (PXRD)
Powder X-ray diffraction (PXRD) analysis was carried out to confirm the phase purity of the
bulk materials for all the compounds at room temperature. The experimental PXRD patterns of
complexes 1−5 show good agreement with the simulated PXRD patterns from their
corresponding single crystal X-ray structure (Figs. S8-S12). The matching of all major peaks in
experimental as well as simulated pattern confirms the phase purity of the complexes.
3.4. Luminescent Properties
Luminescent properties of CPs with d10 metal centres have drawn an immense interest due to
their potential applications in chemical sensors, photo-switching diodes, non linear optical
(NLO) materials and electroluminescence display. The photo luminescent spectra of the
complexes 3-5 and the free ligands (2-abim and 4-bpdb) in the solid state were recorded at room
temperature, which are shown in Figure 5. All three complexes show ligand based emission
spectra which are found commonly in case of coordination polymers or metal organic
frameworks [41]. The solid-state fluorescence maximum of the 2-abim and N,N′-donor 4-bpdb
ligands show the emission peak at 320 nm (λex = 285 nm) and 394 nm (λex = 250 nm)
respectively. The emission peaks for both the ligands may be attributed to the π*–n or π*–π
transition [41]. Compound 3 gives an emission maxima at 389 nm upon excitation at 385 nm
which indicates a slight red shift as compared to the free ligand 2-abim in case of 3. On the other
hand, the photoluminescence spectra of both the complexes 4 and 5 exhibit slightly blue shifted
emission maxima at around 400 nm (λex = 394 nm) compared to free N,N′-donor 4-bpdb ligand
which also be assigned to ligand-centered electronic transition. Generally, for the d10 complexes,
no emission originates from metal-centered MLCT/LMCT excited states, since the d10 metal ions
are difficult to be reduced or oxidized [42-43]. So, it can be confirmed that the emission spectra
of complexes 3-5 has been originated due to the intra-ligand π*–n or π*–π electron transfer; in
which the emission intensity can be tuned through the ligand coordination with the metal centers.

4. Conclusion
Five different coordination polymers (CPs) of transition metals have successfully synthesized
and characterized based on dca linker along with two different ligands, 2-abim and 4-bpdb using
stirring method at room temperature. A systematic study of structural diversities of compounds
1−5 reveals that dca act as an excellent bridging ligand and display versatile coordination
abilities in combination with the monodentate 2-abim and bridging 4-bpdb ligand. Compounds
1-3 exhibit 2D sheet structure containing pendant 2-abim ligand whereas compound 4 displays a
2D layer structure with a pendent dca and a bridging dca linker and 5 results totally different
polycatenated 2D→3D framework through the interpenetration of the nets constructed through
both dca and 4-bpdb ligands. Though the synthetic procedure for compounds 4 and 5 are same
but quite interestingly the difference in structural topology for both may be due to the different
nature of metal ions as well as versatile binding mode of dca linkers.
Acknowledgements
Authors gratefully acknowledge the financial assistance given by UGC for Post Doctoral
Fellowship for Women (AD) and DRDO Govt. of India (Grant to DG). Dr. K. K. Rajak of JU is
gratefully acknowledged for the photoluminescence study.
Appendix A. Supplementary data
CCDC 1471976-1471980 contain the supplementary crystallographic data for complexes 1-5.
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.
The IR, PXRD patterns of complexes 1-5 along with different structural figures and tables
related to the crystal structures reported in this paper are given as supplementary material.
Supplementary data associated with this article and crystallographic data in CIF format can
found online at http://dx.doi.org.
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Figures
Fig. 1. (a) Coordination environment around the Co(II) ions in 1; Co (green), N (blue), C (black).
−
(b) 2D sheet in 1 constructed by N(CN)2 linkers and 2-abim ligand. (c) Topological
representation of 4-connected 2D sheet of 1.

Fig. 2. (a) Coordination environment around the Zn(II) ions in 4; Zn (green), N (blue), C (black).
−
(b) 2D sheet in 4 constructed by both 4-bpdb and N(CN)2 linkers. (c) Topological representation
of 4-connected 2D sheet of 4

Fig. 3. (a) Coordination environment around the Cd(II) ions in 5; Cd (green), N (blue), C (black).
−
(b) 2D sheet in 5 constructed by both 4-bpdb and N(CN)2 linkers. (c) Topological representation
of 4-connected 2D sheet of 5.

Fig. 4. (a) Representation of interpenetration in compound 5. (b) Simplified 3D structural view
of compound 5, which is formed by 2D→3D polycatenation.
Fig. 5. Emission spectra of complex 3-5 with free 2-abim & 4-bpdb ligand.

Table 1. Crystallographic and structural refinement parameters of complexes 1-5.
Complex
Formula
Formula Weight
Crystal System
Space group
a/ Å
b/Å
c/ Å
α/°
1
2
3
4
5
C18H14CoN12 C18H14NiN12 C18H14CdN12 C16H10ZnN10 C16H10CdN10
457.34
Monoclinic
P21/n
455.09
Monoclinic Monoclinic
510.82
407.73
Monoclinic
P21/n
454.75
Monoclinic
P21/c
P21/n
P21/n
9.2368(2)
7.9054(1)
13.1246(2)
90
9.1968(3)
7.9084(3)
13.0855(4)
90
9.3046(2)
10.7334(2)
9.6007(2)
90
15.0013(3)
7.6847(2)
15.8275(4)
90
9.2895(12)
12.9991(16)
7.5531(10)
90
β/°
102.394(1)
90
936.03(3)
2
1.623
0.953
102.891(2)
90
927.75(5)
2
1.629
1.082
101.174(1)
90
940.65(3)
2
1.804
1.197
108.305(1)
90
1732.27(7)
4
1.563
1.442
824
1.6-27.5
27163
3978
3131
93.915(10)
90
910.0(2)
2
1.660
1.223
448
2.7-28.0
13138
2098
1307
γ/°
V/ Å3
Z
Dc/ g cm–3
µ /mm–1
F(000)
θ range/°
466
2.5-27.5
464
508
3.0-27.5
14751
2113
2.8-27.6
15802
2165
Reflections collected 15339
Unique reflections 2146
Reflections I > 2σ(I) 1975
1584
1956
Rint
0.022
1.07
0.0247
0.0679
-0.34, 0.28
0.060
1.03
0.0421
0.1019
-0.57, 0.33
0.019
1.07
0.0168
0.0472
-0.41, 0.27
0.036
1.03
0.0313
0.0816
-0.22, 0.29
0.106
1.25
0.1442
0.3595
-1.62, 8.38
goodness-of-fit(F2)
R1 (I > 2σ(I))[a]
wR2(I > 2σ(I))[a]
∆ρ min/max/e Å3
2
2
½
[a]R1 = ΣFo–Fc/ΣFo, wR2 = [Σ (w (Fo – Fc2 ) 2 )/ Σw (Fo )2] .
Table 2. Selected bond lengths (Å) and angles (°) for 1
Co1-N1
2.1171(13)
2.1520(13)
2.1171(13)
88.50(5)
91.47(5)
92.36(5)
87.64(5)
92.04(6)
87.61(5)
88.50(5)
180.00
Co1-N4
2.1591(15)
2.1520(13)
2.1591(15)
87.95(6)
91.50(5)
92.36(5)
180.00
92.05(6)
180.00
87.95(5)
Co1-N6c
Co1-N6b
Co1-N1a
Co1-N4a
N1 -Co1-N4
N1-Co1-N4a
N1-Co1-N6b
N1-Co1-N6c
N4-Co1-N6c
N1a-Co1-N6b
N1a -Co1-N4a
N1-Co1-N1a
N4-Co1-N6b
N1a-Co1-N4
N1a-Co1-N6c
N4-Co1-N4a
N4a-Co1-N6b
N6b-Co1-N6c
N4a-Co1-N6c
Symmetry code: a = 2-x,-y,-z, b= 3/2-x,-1/2+y,-1/2-z, c= 1/2+x, 1/2-y, 1/2+z

Table 3. Selected bond lengths (Å) and angles (°) for 4
Zn1-N1
Zn1-N6
Zn1-N7b
2.3020(17) Zn1-N5
1.979(2)
Zn1-N4a
2.0002(17)
2.2067(17)
87.13(7)
1.9820(17) N1-Zn1-N6
N1-Zn1-N5 89.51(6)
N4a-Zn1-N7b 91.40(7)
N1-Zn1-N4a 177.80(7) N1-Zn1-N7b
N5-Zn1-N6 124.68(8) N4a-Zn1-N5
N5-Zn1-N7b 113.20(8) N4a-Zn1-N6
N6-Zn1-N7b 122.00(9)
90.02(7)
91.49(7)
90.69(7)
Symmetry code: a = x, y, -1+z; b = x, 1+y, z
Table 4. Selected bond lengths (Å) and angles (°) for 5
Cd1-N1
2.363(9)
Cd1-N3
2.310(12)
2.363(9)
2.339(14)
87.9(4)
89.6(4)
90.0(5)
Cd1-N5b
Cd1-N3a
N1-Cd1-N3
2.339(14) Cd1-N1a
2.310(12) Cd1-N5c
90.4(4)
N1-Cd1-N5b
N1-Cd1-N1a 180.00
N1-Cd1-N5c 92.1(4)
N1a-Cd1-N3 89.6(4)
N3-Cd1-N5c 90.0(5)
N3a-Cd1-N5b 90.0(5)
N1a-Cd1-N3a 90.4(4)
N1-Cd1-N3b
N3-Cd1-N5b
N3-Cd1-N3a
180.00
N1a-Cd1-N5b 92.1(4)
N5b-Cd1-N5c 180.00
N1a-Cd1-N5c 87.9(4)
Symmetry code: b = x, y, -1+z; a = -x, -y, -z; c = -x, -y, 1-z.

Five dicyanamide based coordination polymers of diverse dimensionality have
been synthesized and characterized by X-ray diffraction and photoluminescence
study.