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![(a) The coordination environment around CdIJII) ions in 6 (hydrogen atoms are omitted for clarity). [O3* and O4* are at equivalent positions 3/2 − x, 1/2 + y, 1/2 − z]. (b) Tetrameric 28-membered macrocyclic ring of 6. (c) Fish scale pattern of 2D CP 6. (d) Topological representation of 4-connected nodes in 6. (e) 3D supramolecular structure of 6.](profile/Sarita-Tripathi-5/publication/272423347/figure/fig6/AS:615943348711428@1523863746777/a-The-coordination-environment-around-CdIJII-ions-in-6-hydrogen-atoms-are-omitted-for.png)
(a) The coordination environment around CdIJII) ions in 6 (hydrogen atoms are omitted for clarity). [O3* and O4* are at equivalent positions 3/2 − x, 1/2 + y, 1/2 − z]. (b) Tetrameric 28-membered macrocyclic ring of 6. (c) Fish scale pattern of 2D CP 6. (d) Topological representation of 4-connected nodes in 6. (e) 3D supramolecular structure of 6.
Source publication
A rigid imidazolium dicarboxylate ligand 4,5-dicarboxy-1,3-dimethyl-1H-imidazolium iodide (H2DDII) was synthesized and employed in the construction of metal complexes or coordination polymer (CPs) comprising of anionic zwitter ion (DDI-), [Zn(Cl)(H2O)2(DDI)]∙(H2O) (2), {[Zn2(DDI)3(H2O)2]∙I}n (3), [Zn2(DDI)2I]∙2H2O (4), [Zn(DDI)2(H2O)3]∙(H2O)2 (5) a...
Contexts in source publication
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... carboxylate unit has a free oxygen-donor site. Hence, the charge is balanced since one of the carboxylate groups remains uncoordinated. Thus, 2 can be described as an anionic zwitterion zinc complex as it was also observed in N-carboxy imidazolium metal dicarboxylates. 14 The Zn-O bond distance of carboxylate oxygen to zinc in 2 is found to be 2.009(4) Å (Zn-O1), comparable to the bond lengths reported with such a ligand system, 9h whereas those for the water molecules coordinated to the ZnIJII) ion are nearly the same [av. 2.001(3) Å], while the bond distance of Zn-Cl is 2.274(11) Å (Table 2). The asymmetric unit of 2 extends further through the H-bonding existing between the chloride ion and H7C* (from N-CH 3 ) and H66# (from H 2 O) (Fig. 2b, Table 3) to form a 2D rectangular sheet ( Fig. 2c and d). Each rectangular sheet comprises four monomeric units of 2 in which the two DDI − units are involved in facilitating the extended structure formation. The orientation of DDI − (along a-axis) within the rectangular sheet and in the 2D layers is anti-parallel to each other. The chloride ions are oriented in opposite directions between two layers, but are in the same direction to the ones adjacent to it. The orienta- tions of DDI − and Cl − ions play a significant role in extending the monomer through H-bonding. The distances between ZnIJII) ions in such a rectangular sheet were found to be 4.410(9) Å and 11.481(3) Å for the stacked up and adjacent one, respectively (Fig. S5). The 2D rectangular sheets are fur- ther connected via the lattice water molecules which tend to act as a bridge through CH⋯O interactions, (Table 3, Fig. S6), leading to the formation of a 3D supramolecular architecture (Fig. ...
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... OIJ1)-ZnIJ1)-ClIJ1) 104.20 (7) OIJ2)#3-ZnIJ1)-OIJ1W) 108.08 (17) OIJ1)-ZnIJ1)-IIJ1) 103.03(12) OIJ2W)-ZnIJ1)-OIJ1) 100.08 (13) OIJ1)#3-CdIJ1)-OIJ4) 157.57(13) IIJ2)-ZnIJ1)-IIJ1) 110.74 (5) OIJ3W)-ZnIJ1)-OIJ1) 90.36(13) OIJ3)#3-CdIJ1)-OIJ4) 89.03(11) OIJ5)-ZnIJ1)-OIJ1W) 86.43(13) OIJ2W)-ZnIJ1)-OIJ1W) 92.09(13) OIJ3W)-ZnIJ1)-OIJ1W) 170.70(13) OIJ1)-ZnIJ1)-OIJ1W) 86.41 (12) a Symmetry codes for Table 3 Hydrogen bonding interaction parameters in 1-6 interactions and H-bonds (Table 3, Fig. 5c) and result in a 2D supramolecular network. ijCdIJDDI) 2 ] n (6). In order to evaluate the metal ion effect, the reaction was carried out using cadmium nitrate and NEt 3 under similar conditions to those of 5. The same synthetic procedure as that for 2-4 was not fruitful in this case and performing the same reaction by using CdCl 2 was not suc- cessful. Single crystal X-ray diffraction shows that 6 crystal- lizes in the monoclinic space group C2/c (Table 1). In 6, each CdIJII) ion lies in a twofold axis and is in a distorted octahe- dron environment coordinated by six donor O-atoms pro- vided by four anionic DDI − units (Fig. 6a). Similar to 5, in 6 two coordination modes of DDI − , i.e. monodentate terminal and bidentate chelate, were observed. Two of the DDI − units are coordinated to the CdIJII) ion in bidentate chelate mode, while the remaining two DDI − units are coordinated in mono- dentate terminal mode (III; Scheme 3). The Cd-O bond dis- tance in 6 falls in the range of 2.417(3) Å to 2.248(3) Å, all of which are comparable to those reported for other imidazole- based dicarboxylate CdIJII) complexes (Table 2). 9h,i The DDI − units, which are coordinated to one CdIJII) ion in bidentate chelate mode, are further coordinated to another CdIJII) ion in monodentate terminal mode and vice versa. Thus, there exists a tetrameric 28-membered macrocyclic ring (Fig. 6b). Each macrocycle consists of four CdIJII) ions which are coordi- nated to four DDI − units and the distance between two CdIJII) centers was found to be 8.025(6) Å. The four DDI − units are oriented perpendicular to each other. Further, each of these tetramer units in 6 extends through the remaining carboxylate oxygen atoms forming another tetramer and results in a 2D anionic zwitterion cadmium CP showing an interesting "fish scale pattern" (Fig. 6c). Through topological analysis, 6 can be represented as a 4 4 6 2 sql topology with the Cd centre as a 4-connected uninodal net (Fig. 6d). The 2D CP is further connected through the intermolecular CH⋯O interactions existing between carboxylate oxygen with different H-donor carbon atoms, to form a 3D supramolecular network (Fig. 6e). The 3D supramolecular network shows packing in an ABAB fashion with the adjacent layer (Table 3, Fig. S11 and ...
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... OIJ1)-ZnIJ1)-ClIJ1) 104.20 (7) OIJ2)#3-ZnIJ1)-OIJ1W) 108.08 (17) OIJ1)-ZnIJ1)-IIJ1) 103.03(12) OIJ2W)-ZnIJ1)-OIJ1) 100.08 (13) OIJ1)#3-CdIJ1)-OIJ4) 157.57(13) IIJ2)-ZnIJ1)-IIJ1) 110.74 (5) OIJ3W)-ZnIJ1)-OIJ1) 90.36(13) OIJ3)#3-CdIJ1)-OIJ4) 89.03(11) OIJ5)-ZnIJ1)-OIJ1W) 86.43(13) OIJ2W)-ZnIJ1)-OIJ1W) 92.09(13) OIJ3W)-ZnIJ1)-OIJ1W) 170.70(13) OIJ1)-ZnIJ1)-OIJ1W) 86.41 (12) a Symmetry codes for Table 3 Hydrogen bonding interaction parameters in 1-6 interactions and H-bonds (Table 3, Fig. 5c) and result in a 2D supramolecular network. ijCdIJDDI) 2 ] n (6). In order to evaluate the metal ion effect, the reaction was carried out using cadmium nitrate and NEt 3 under similar conditions to those of 5. The same synthetic procedure as that for 2-4 was not fruitful in this case and performing the same reaction by using CdCl 2 was not suc- cessful. Single crystal X-ray diffraction shows that 6 crystal- lizes in the monoclinic space group C2/c (Table 1). In 6, each CdIJII) ion lies in a twofold axis and is in a distorted octahe- dron environment coordinated by six donor O-atoms pro- vided by four anionic DDI − units (Fig. 6a). Similar to 5, in 6 two coordination modes of DDI − , i.e. monodentate terminal and bidentate chelate, were observed. Two of the DDI − units are coordinated to the CdIJII) ion in bidentate chelate mode, while the remaining two DDI − units are coordinated in mono- dentate terminal mode (III; Scheme 3). The Cd-O bond dis- tance in 6 falls in the range of 2.417(3) Å to 2.248(3) Å, all of which are comparable to those reported for other imidazole- based dicarboxylate CdIJII) complexes (Table 2). 9h,i The DDI − units, which are coordinated to one CdIJII) ion in bidentate chelate mode, are further coordinated to another CdIJII) ion in monodentate terminal mode and vice versa. Thus, there exists a tetrameric 28-membered macrocyclic ring (Fig. 6b). Each macrocycle consists of four CdIJII) ions which are coordi- nated to four DDI − units and the distance between two CdIJII) centers was found to be 8.025(6) Å. The four DDI − units are oriented perpendicular to each other. Further, each of these tetramer units in 6 extends through the remaining carboxylate oxygen atoms forming another tetramer and results in a 2D anionic zwitterion cadmium CP showing an interesting "fish scale pattern" (Fig. 6c). Through topological analysis, 6 can be represented as a 4 4 6 2 sql topology with the Cd centre as a 4-connected uninodal net (Fig. 6d). The 2D CP is further connected through the intermolecular CH⋯O interactions existing between carboxylate oxygen with different H-donor carbon atoms, to form a 3D supramolecular network (Fig. 6e). The 3D supramolecular network shows packing in an ABAB fashion with the adjacent layer (Table 3, Fig. S11 and ...
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... OIJ1)-ZnIJ1)-ClIJ1) 104.20 (7) OIJ2)#3-ZnIJ1)-OIJ1W) 108.08 (17) OIJ1)-ZnIJ1)-IIJ1) 103.03(12) OIJ2W)-ZnIJ1)-OIJ1) 100.08 (13) OIJ1)#3-CdIJ1)-OIJ4) 157.57(13) IIJ2)-ZnIJ1)-IIJ1) 110.74 (5) OIJ3W)-ZnIJ1)-OIJ1) 90.36(13) OIJ3)#3-CdIJ1)-OIJ4) 89.03(11) OIJ5)-ZnIJ1)-OIJ1W) 86.43(13) OIJ2W)-ZnIJ1)-OIJ1W) 92.09(13) OIJ3W)-ZnIJ1)-OIJ1W) 170.70(13) OIJ1)-ZnIJ1)-OIJ1W) 86.41 (12) a Symmetry codes for Table 3 Hydrogen bonding interaction parameters in 1-6 interactions and H-bonds (Table 3, Fig. 5c) and result in a 2D supramolecular network. ijCdIJDDI) 2 ] n (6). In order to evaluate the metal ion effect, the reaction was carried out using cadmium nitrate and NEt 3 under similar conditions to those of 5. The same synthetic procedure as that for 2-4 was not fruitful in this case and performing the same reaction by using CdCl 2 was not suc- cessful. Single crystal X-ray diffraction shows that 6 crystal- lizes in the monoclinic space group C2/c (Table 1). In 6, each CdIJII) ion lies in a twofold axis and is in a distorted octahe- dron environment coordinated by six donor O-atoms pro- vided by four anionic DDI − units (Fig. 6a). Similar to 5, in 6 two coordination modes of DDI − , i.e. monodentate terminal and bidentate chelate, were observed. Two of the DDI − units are coordinated to the CdIJII) ion in bidentate chelate mode, while the remaining two DDI − units are coordinated in mono- dentate terminal mode (III; Scheme 3). The Cd-O bond dis- tance in 6 falls in the range of 2.417(3) Å to 2.248(3) Å, all of which are comparable to those reported for other imidazole- based dicarboxylate CdIJII) complexes (Table 2). 9h,i The DDI − units, which are coordinated to one CdIJII) ion in bidentate chelate mode, are further coordinated to another CdIJII) ion in monodentate terminal mode and vice versa. Thus, there exists a tetrameric 28-membered macrocyclic ring (Fig. 6b). Each macrocycle consists of four CdIJII) ions which are coordi- nated to four DDI − units and the distance between two CdIJII) centers was found to be 8.025(6) Å. The four DDI − units are oriented perpendicular to each other. Further, each of these tetramer units in 6 extends through the remaining carboxylate oxygen atoms forming another tetramer and results in a 2D anionic zwitterion cadmium CP showing an interesting "fish scale pattern" (Fig. 6c). Through topological analysis, 6 can be represented as a 4 4 6 2 sql topology with the Cd centre as a 4-connected uninodal net (Fig. 6d). The 2D CP is further connected through the intermolecular CH⋯O interactions existing between carboxylate oxygen with different H-donor carbon atoms, to form a 3D supramolecular network (Fig. 6e). The 3D supramolecular network shows packing in an ABAB fashion with the adjacent layer (Table 3, Fig. S11 and ...
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... OIJ1)-ZnIJ1)-ClIJ1) 104.20 (7) OIJ2)#3-ZnIJ1)-OIJ1W) 108.08 (17) OIJ1)-ZnIJ1)-IIJ1) 103.03(12) OIJ2W)-ZnIJ1)-OIJ1) 100.08 (13) OIJ1)#3-CdIJ1)-OIJ4) 157.57(13) IIJ2)-ZnIJ1)-IIJ1) 110.74 (5) OIJ3W)-ZnIJ1)-OIJ1) 90.36(13) OIJ3)#3-CdIJ1)-OIJ4) 89.03(11) OIJ5)-ZnIJ1)-OIJ1W) 86.43(13) OIJ2W)-ZnIJ1)-OIJ1W) 92.09(13) OIJ3W)-ZnIJ1)-OIJ1W) 170.70(13) OIJ1)-ZnIJ1)-OIJ1W) 86.41 (12) a Symmetry codes for Table 3 Hydrogen bonding interaction parameters in 1-6 interactions and H-bonds (Table 3, Fig. 5c) and result in a 2D supramolecular network. ijCdIJDDI) 2 ] n (6). In order to evaluate the metal ion effect, the reaction was carried out using cadmium nitrate and NEt 3 under similar conditions to those of 5. The same synthetic procedure as that for 2-4 was not fruitful in this case and performing the same reaction by using CdCl 2 was not suc- cessful. Single crystal X-ray diffraction shows that 6 crystal- lizes in the monoclinic space group C2/c (Table 1). In 6, each CdIJII) ion lies in a twofold axis and is in a distorted octahe- dron environment coordinated by six donor O-atoms pro- vided by four anionic DDI − units (Fig. 6a). Similar to 5, in 6 two coordination modes of DDI − , i.e. monodentate terminal and bidentate chelate, were observed. Two of the DDI − units are coordinated to the CdIJII) ion in bidentate chelate mode, while the remaining two DDI − units are coordinated in mono- dentate terminal mode (III; Scheme 3). The Cd-O bond dis- tance in 6 falls in the range of 2.417(3) Å to 2.248(3) Å, all of which are comparable to those reported for other imidazole- based dicarboxylate CdIJII) complexes (Table 2). 9h,i The DDI − units, which are coordinated to one CdIJII) ion in bidentate chelate mode, are further coordinated to another CdIJII) ion in monodentate terminal mode and vice versa. Thus, there exists a tetrameric 28-membered macrocyclic ring (Fig. 6b). Each macrocycle consists of four CdIJII) ions which are coordi- nated to four DDI − units and the distance between two CdIJII) centers was found to be 8.025(6) Å. The four DDI − units are oriented perpendicular to each other. Further, each of these tetramer units in 6 extends through the remaining carboxylate oxygen atoms forming another tetramer and results in a 2D anionic zwitterion cadmium CP showing an interesting "fish scale pattern" (Fig. 6c). Through topological analysis, 6 can be represented as a 4 4 6 2 sql topology with the Cd centre as a 4-connected uninodal net (Fig. 6d). The 2D CP is further connected through the intermolecular CH⋯O interactions existing between carboxylate oxygen with different H-donor carbon atoms, to form a 3D supramolecular network (Fig. 6e). The 3D supramolecular network shows packing in an ABAB fashion with the adjacent layer (Table 3, Fig. S11 and ...
Context 6
... OIJ1)-ZnIJ1)-ClIJ1) 104.20 (7) OIJ2)#3-ZnIJ1)-OIJ1W) 108.08 (17) OIJ1)-ZnIJ1)-IIJ1) 103.03(12) OIJ2W)-ZnIJ1)-OIJ1) 100.08 (13) OIJ1)#3-CdIJ1)-OIJ4) 157.57(13) IIJ2)-ZnIJ1)-IIJ1) 110.74 (5) OIJ3W)-ZnIJ1)-OIJ1) 90.36(13) OIJ3)#3-CdIJ1)-OIJ4) 89.03(11) OIJ5)-ZnIJ1)-OIJ1W) 86.43(13) OIJ2W)-ZnIJ1)-OIJ1W) 92.09(13) OIJ3W)-ZnIJ1)-OIJ1W) 170.70(13) OIJ1)-ZnIJ1)-OIJ1W) 86.41 (12) a Symmetry codes for Table 3 Hydrogen bonding interaction parameters in 1-6 interactions and H-bonds (Table 3, Fig. 5c) and result in a 2D supramolecular network. ijCdIJDDI) 2 ] n (6). In order to evaluate the metal ion effect, the reaction was carried out using cadmium nitrate and NEt 3 under similar conditions to those of 5. The same synthetic procedure as that for 2-4 was not fruitful in this case and performing the same reaction by using CdCl 2 was not suc- cessful. Single crystal X-ray diffraction shows that 6 crystal- lizes in the monoclinic space group C2/c (Table 1). In 6, each CdIJII) ion lies in a twofold axis and is in a distorted octahe- dron environment coordinated by six donor O-atoms pro- vided by four anionic DDI − units (Fig. 6a). Similar to 5, in 6 two coordination modes of DDI − , i.e. monodentate terminal and bidentate chelate, were observed. Two of the DDI − units are coordinated to the CdIJII) ion in bidentate chelate mode, while the remaining two DDI − units are coordinated in mono- dentate terminal mode (III; Scheme 3). The Cd-O bond dis- tance in 6 falls in the range of 2.417(3) Å to 2.248(3) Å, all of which are comparable to those reported for other imidazole- based dicarboxylate CdIJII) complexes (Table 2). 9h,i The DDI − units, which are coordinated to one CdIJII) ion in bidentate chelate mode, are further coordinated to another CdIJII) ion in monodentate terminal mode and vice versa. Thus, there exists a tetrameric 28-membered macrocyclic ring (Fig. 6b). Each macrocycle consists of four CdIJII) ions which are coordi- nated to four DDI − units and the distance between two CdIJII) centers was found to be 8.025(6) Å. The four DDI − units are oriented perpendicular to each other. Further, each of these tetramer units in 6 extends through the remaining carboxylate oxygen atoms forming another tetramer and results in a 2D anionic zwitterion cadmium CP showing an interesting "fish scale pattern" (Fig. 6c). Through topological analysis, 6 can be represented as a 4 4 6 2 sql topology with the Cd centre as a 4-connected uninodal net (Fig. 6d). The 2D CP is further connected through the intermolecular CH⋯O interactions existing between carboxylate oxygen with different H-donor carbon atoms, to form a 3D supramolecular network (Fig. 6e). The 3D supramolecular network shows packing in an ABAB fashion with the adjacent layer (Table 3, Fig. S11 and ...
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Hydrogen sulfide (H2S) is a smelly, colorless, and hazardous gas even at sub-ppm level, produced predominantly from natural and anthropogenic sources. It is also called a ‘knock-down gas’ as its inhalation at higher concentrations can cause death. Therefore, several researchers are working on designing sensors with high stability and robustness for the real-time detection of H2S gas. Apart from many other materials, metal–organic framework (MOF)-based fluorescent probes are of high interest for the detection of H2S. Herein, we present a cost-effective acryl-amide functionalized 2D Zn-bdc MOF, which was shown to function as an excellent probe for the real-time detection of H2S in liquid as well as in the gaseous form through a nucleophilic addition mechanism to olefinic bonds of the MOFs. Interestingly, in the aqueous phase, Zn-bdc was found to exhibit turn-off and subsequent turn-on fluorescence spectra with the gradual addition of H2S. Furthermore, the realistic sensing of H2S by the MOF was investigated by preparing a mixed-matrix membrane of MOF with PVDF as a binder. Notably, the membrane with 60% loading of Zn-bdc increased the probe's sensitivity by two-fold. Furthermore, we note that this is the first example of an essential metal based mixed-matrix membrane for H2S detection with the LOD value as low as 5.3 μM. In vitro cell imaging of Zn-bdc in the presence of H2S displays a vibrant bright red fluorescence signal of LN-18 glioblastoma cells.
Natural and anthropogenic activities leading to excessive toxic biological anions in water have warranted the development of anion sensors, especially for cyanide (CN-) and fluoride (F-) ions in aqueous media. Herein, a contemporary synthetic route to embed organochalcogen compounds (-SPh and -SePh) in a boron-functionalized imidazole scaffold via metal halogen exchange is reported. Upon methylation, fluorogenic compounds 5-dimesitylboryl-2-phenylthio-1-methylimidazole (7) and 5-dimesitylboryl-2-phenylselone-1-methylimidazole (8) form the corresponding imidazolium salts, 5-dimesitylboryl-2-phenylthio-1-methylimidazolium iodide (9) and 5-dimesitylboryl-2-phenylselone-1-methylimidazolium iodide (10), which are non-luminescent. All of the compounds are thoroughly characterized, and their utility in sensing F-, CN-, and various other biologically relevant halides has been studied through UV-vis and fluorescence spectroscopy. The substrates and products of 1 : 1 binding of anions (F-/CN-) with the compounds have been established by spectroscopy, spectrometry, single-crystal X-ray crystallography, and first principles quantum mechanical theoretical calculations. The superior binding ability and micromolar sensitivity towards CN- ions over other anions in aqueous media were elucidated. The reversibility of compound 7 was also tested and it was found that fluoride binding was reversible while cyanide binding was not.
In this work, we report the chemistry of an unexplored flexible polyether based dicarboxylic acid (3,6,9-trioxaundecanedioic acid, H2toua) with four different cadmium salts. With CdCl2.H2O or Cd(ClO4)2.H2O in a 1:1 ratio, it remarkably forms a discrete compound [Cd(H2toua)Cl2].H2O (1) and a polymeric ionic compound, {[Cd(Htoua)(H2O)](ClO4)}n (2), respectively, as determined by the single crystal X-ray diffraction. In both cases, for the heptacoordinated Cd(II) all basal donor atoms are from the ligand (three ether oxygen and two oxygen atoms from the fully intact or mono-deprotonated carboxylic acid groups, respectively) but with a major difference in axial (trans to each other) coordinated atom types - two chlorines in 1 while one water molecule and a bridging carboxylate oxygen in 2. Unlike 1, the carboxylate group of Htoua bridges between the Cd(II) centers for the formation of a 1D polymeric chain in 2. Furthermore, Hirshfeld surface analysis of the various intermolecular interactions enables quantifiable contributions to crystal packing, revealing the key differences in the interactions encountered by 1 and 2. Using Cd(OAc)2.6H2O as the metal salt, it is possible to make [Cd(toua)].H2O (3), due to the formation of easily removable volatile acetic acid by-product. On the other hand, a nitrate analogue of 2, i.e., {[Cd(Htoua)(H2O)](NO3)}n (4) is isolated if Cd(NO3)2.4H2O is used. All these compounds were characterized by a number of spectroscopic and microscopic methods. Their thermal behaviour and luminescence properties were also determined.
A robust and multifunctional cuboctahedral [In36(μ-OH)24(NO3)8(Imtb)24] MOF (In(Imtb)-MOF) with an atypical pyramidal nitrate ion-containing hitherto unknown SBU core [In9(μ-OH)6(NO3)] is reported. The intra- and interlayer nitrate ions adopt pyramidal and inverted pyramidal shapes, which separates the active indium site [(In3(μ-OH)2)NO3-(In3(μ-OH)2)] and linear In3(μ-OH)2 by 0.5 and 0.9 nm, respectively. Additionally, the high density of active metal sites shows remarkable catalytic activity with higher TOF even for sterically hindered substrates in Strecker synthesis and CO2 cycloaddition. Moreover, the luminescence behavior of In(Imtb)-MOF and the presence of uncoordinated nitrogen atoms are exploited for selective sensing of explosive trinitrophenol (TNP) with a detection limit (LOD) of 2.3 ppb.
Among the recent developments in metal-organic frameworks (MOFs), porous layered coordination polymers (CPs) have garnered attention due to their modular nature and tunable structures. These factors enable a number of properties and applications, including gas and guest sorption, storage and separation of gases and small molecules, catalysis, luminescence, sensing, magnetism, and energy storage and conversion. Among MOFs, two-dimensional (2D) compounds are also known as 2D CPs or 2D MOFs. Since the discovery of graphene in 2004, 2D materials have also been widely studied. Several 2D MOFs are suitable for exfoliation as ultrathin nanosheets similar to graphene and other 2D materials, making these layered structures useful and unique for various technological applications. Furthermore, these layered structures have fascinating topological networks and entanglements. This review provides an overview of different aspects of 2D MOF layered architectures such as topology, interpenetration, structural transformations, properties, and applications.
Incorporation of a Lewis acidic BMes2 (Mes = mesityl) moiety at the backbone of the imidazole ring was achieved by metal-halogen exchange procedure. Among them, two isomeric boron-phosphine functionalized imidazoles (3 and 6), monoboron-functionalized imidazoles (4 and 5), and its corresponding imidazolium salts were synthesized and thoroughly characterized. The solid-state structure of 3 reveals a dimeric B-N adduct that possesses six-membered [C-B-N]2 ring, and 5 crystallizes as tetrameric B-N adduct that forms an interesting 16-membered macrocycle, whereas 4 and 6 were obtained as monomeric BMes2-substituted imidazoles. 6 behaves as a P^N-type ligand upon the coordination with CuI to afford luminescent L2Cu4I4-type metal complexes (10 and 11) whose photophysical properties were also studied. The presence (in 10) and the absence (in 11) of BMes2 made a remarkable impact on fluorescence emission causing shift from the green (10) to orange (11) region. The fluoride sensing properties of BMes2-containing imidazoles (4 to 9) were studied using UV-vis and fluorescence spectroscopy.
Backbone dihalofunctionalized imidazol-2-ylidene/imidazolyl-metal complexes (5−13) of group–10 metal ions were synthesized through a proficient and single step oxidative addition method using 2,4,5-trihaloimidazolium salts or imidazoles respectively. The donor property of 4,5-diiodofunctionalized imidazol-2-ylidene was described for the first time. The catalytic activity of palladium complexes containing imidazol-2-ylidene (6 and 7)/imidazolyl (10 and 11) groups towards Suzuki-Miyaura coupling reaction of aryl bromides was evaluated and compared with its unsubstituted counterpart. Besides, the investigation of reaction pathway in catalysis was carried out.
5-(6-Carboxypyridin-3-yl)isophthalic acid (H3L) was utilized as an almost unexplored multifunctional ligand to construct, under hydrothermal conditions, ten new coordination compounds, namely, [Cd(μ2-H2L)2]n (1), [Ni(HL)(H2biim)2] (2), [Mn(μ2-HL) (phen)(H2O)]2·2H2O (3), {[Mn3(μ4-L)2(H2O)6]·3H2O}n (4), {[Co3(μ5-L)2(H2O)6]·2H2O}n (5), {[Ni3(μ4-L)2(H2O)6]·2H2O}n (6), {[Zn3(μ5-L)2(H2O)4]·2H2O}n (7), {[Mn3(μ5-L)2(H2O)6]·4H2O}n (8), {[Co3(μ4-L)2(μ2-4,4′-bipy)(H2O)6]·2H2O}n (9), and {[Ni3(μ5-L)2(H2O)6]·2H2O}n (10), also using an optional auxiliary ligand selected from 2,2′-biimidazole (H2biim), 1,10-phenanthroline (phen), or 4,4′-bipyridine (4,4′-bipy). The obtained compounds 1-10 were analyzed by IR spectroscopy, thermogravimetric and elemental analysis, and single-crystal and powder X-ray diffraction. The structures of the products vary from 3D MOFs (metal-organic frameworks 5 and 7-10) to 2D CPs (coordination polymers 1, 4, and 6) as well as to a discrete 0D monomer 2 and a dimer 3. The latter two are extended by multiple hydrogen bonds into complex 3D supramolecular networks. This structural difference in 1-10 is directed by the kind of metal(II) center, the deprotonation degree of the principal H3L building block, and/or the kind of auxiliary ligand. Notably, an addition of 4,4′-bipy can tune the structures of MOFs 8-10 by the coordination or template effect. Topological classification of metal-organic and H-bonded underlying networks was performed, disclosing a variety of topological nets: sql (in 1), 3,10T3 (in 3), 3,4L83 (in 4 and 6), tcs (in 5, 8, and 10), 3,4,5T95 (in 7), and sra (in 9), as well as a topologically unique network in 2. The magnetic properties (for compounds 3-6, 8-10) and luminescent properties (for compounds 1, 7) were also investigated and discussed. In fact, compound 7 exhibits an intense violet emission in the solid state. Measurements of the magnetic susceptibility indicate interactions of an antiferromagnetic nature between the adjacent metal(II) centers in the compounds 3-6 and 8-10. The obtained products represent the first series of metal-organic compounds assembled from the H3L precursor, thus opening up its application as a new pyridine-tricarboxylate organic block for designing CPs or MOFs.
A novel flexible multifunctional building block (H3L) bearing picolinate and terephthalate functionalities was designed and applied for the hydrothermal self-assembly generation of a series of coordination compounds [Co(H2L)2(H2O)2] (1), [M(HL)(H2O)]n {M = Cd (2) and Mn (3)}, {[Mn1.5(L)(phen)(H2O)2]·H2O}n (4), [Zn3(L)2(H2O)6]n (5), and {[Zn3(L)2(py) (H2O)4]·4H2O}n (6) {wherein H3L = 2-(4-carboxypyridin-3-yl)-terephthalic acid, phen = 1,10-phenanthroline, py = pyridine}. All the obtained products 1-6 were fully characterized by IR spectroscopy, elemental, thermogravimetric, powder and single-crystal X-ray diffraction analyses. By adjusting the molar ratio of NaOH and H3L ligand, the latter becomes partially deprotonated to form the H2L- blocks in 1 and HL2- moieties in 2 and 3, or completely deprotonated to create the L3- units in 4-6. The structures of the obtained compounds range from a discrete 0D monomer 1 and 1D coordination polymers 4 and 5 to 2D coordination polymers 2 and 3, and an intricate 3D metal-organic framework 6; their detailed topological classification was also performed. The structures of 1-5 are further extended [0D → 3D (1), 1D → 3D (4, 5), and 2D → 3D (2, 3)] into supramolecular networks by means of multiple hydrogen bonds. The results reveal that the nature of metal(ii) ion, molar ratio between NaOH and H3L ligand, and the presence (optional) of auxiliary ligand play a significant role in determining dimensionality, topology and other structural features of the obtained products. Magnetic susceptibility measurements indicate that compounds 3 and 4 have dominating antiferromagnetic couplings between metal centers. Furthermore, luminescent properties of 2, 5, and 6 were also investigated.
A series of novel mixed-ligand coordination polymers, namely, {[Cd2(μ4-L)(μ3-OH)(phen)2]·2H2O}n (1), {[Mn3(μ5-L)2(phen)2(H2O)]·H2O}n (2), [Cd2(μ3-L)(H2biim)2(μ2-Hbiim)]n (3), {[Pb2(μ4-L)(μ4-bpdc)0.5(phen)2]·H2O}n (4), [Cd2(μ5-L)(μ2-bpdc)0.5(phen)2]n (5), and [Zn2(μ4-L)(μ2-bpdc)0.5(py)2]n (6), was hydrothermally synthesized using 4-(5-carboxypyridin-2-yl)isophthalic acid (H3L) as a new and virtually unexplored multifunctional pyridine-tricarboxylate building block, along with various auxiliary ligands {phen = 1,10-phenanthroline, H2biim = 2,2′-biimidazole, H2bpdc = 4,4′-biphenyldicarboxylic acid, and py = pyridine}. All the products 1-6 were characterized by IR spectroscopy, elemental, thermogravimetric, and single-crystal X-ray diffraction analyses. Compounds 1, 3, and 5 reveal 2D metal-organic layers with the kgd, fes, and 3,4,5L5 topology, respectively, whereas the metal-organic frameworks (MOFs) 2, 4, and 6 disclose 3D underlying nets with the unique (2, 4) or ins (6) topology. The results indicate that the nature of the metal(ii) ion and type of auxiliary ligand play a significant role in determining the dimensionality, topology and other structural features of the obtained products. Luminescent (for 1 and 3-6) and magnetic (for 2) properties were studied and discussed. This journal is
