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A new uranyl triphosphonate constructed from semi-rigid triphosphonate ligand: New method for the construction of higher dimensional uranyl phosponates
Accepted Manuscript A new uranyl triphosphonate constructed from semi-rigid triphosphonate ligand: New method for the construction of higher dimensional uranyl phosponates Xiaomin Hou, Si-Fu Tang PII:
S0022-2860(17)30744-5
DOI:
10.1016/j.molstruc.2017.05.125
Reference:
MOLSTR 23866
To appear in:
Journal of Molecular Structure
Received Date: 15 April 2017 Revised Date:
24 May 2017
Accepted Date: 27 May 2017
Please cite this article as: X. Hou, S.-F. Tang, A new uranyl triphosphonate constructed from semi-rigid triphosphonate ligand: New method for the construction of higher dimensional uranyl phosponates, Journal of Molecular Structure (2017), doi: 10.1016/j.molstruc.2017.05.125. 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.
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A new three-dimensional uranyl triphosphonate has been synthesized, suggesting that semi-rigid tritopic triphosphonate ligands can be used to construct higher dimensional uranyl phosphonates.
ACCEPTED MANUSCRIPT A New Uranyl Triphosphonate Constructed from Semi-rigid Triphosphonate Ligand: New Method for the Construction of Higher Dimensional Uranyl Phosponates Xiaomin Hou,b and Si-Fu Tanga,c,* College of Chemistry and Pharmaceutical Sciences, Qingdao Agriculture University,
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a
Changcheng Road 700, Chengyang District, Qingdao 266109, China. E-mail: [email protected].
College of Life Science, Qingdao Agriculture University, Changcheng Road 700,
Chengyang District, Qingdao 266109, China.
Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of
Sciences, Qingdao 266101, China.
ABSTRACT
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b
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A new uranyl triphosphonate with three-dimensional crystal structure has been synthesized from a semi-rigid triphosphonate ligand using hydrothermal method. The employment of triphosphonate ligand may provide a new strategy for the construction of higher dimensional uranyl phosphonates. The thermal and luminescent properties
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were also investigated.
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Keywords: Uranyl; Phosphontes; Semi-rigid; Luminescence; Three-dimensional
Uranyl phosphonates have been of great interest in the past two decades due to their fantastic architectures [1] and potential applications in the field of nuclear waste processing as well as in the fields including ion-exchange [2], ionic conductivity [3], intercalation chemistry [4], photochemistry [5], non-linear optical materials [6], and catalysis [7]. Comparing with carboxylic acid group, phosphonic acid group possesses an additional oxygen atom which endows it with more coordination modes, leading to rich structural diversity including
ACCEPTED MANUSCRIPT one-dimensional chain [8] or tubule [9], two-dimensional layer [10] and three-dimensional network [11]. By surveying into the Cambridge Structural Database [12], one can find that most of the reported uranyl phosphonates exhibit one-dimensional and structures.
The
number
of
three-dimensional
uranyl
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two-dimensional
phosphonates is still limited but very desirable because many applications are dependent on it, such as ion-exchange and ionic conductivity, catalysis, and so on. One reason should be that uranyl compounds prefer to form
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low-dimensional crystal structures due to the terminal nature of actinyl unit [13]. To overcome this problem, a few of effective strategies have been
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developed. The first one is the decoration of the phosphonate ligand with additional functional group, such as carboxylic group [14]. With this method employed, two-dimensional and three-dimensional luminescent pillar layered uranyl diphosphonates can be constructed. The second one is the inclusion of alkali [15] and transition [16] metals in the system. These introduced metal ions
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can serve as new connecting nodes and allow the lower dimensional networks to connect into three-dimensional frameworks. The third one is the introduction of a second ligand, such as 1,3,5-tri(1H-imidazol-1-yl)benzene [17] and
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2,2-bipyrimidine [18]. Another reason is that most of the exploited ligands are, to date, simple mono or diphosphonate ligands. Simple mono or diphosphonate ligands are easy to synthesize and comparative apt to crystallize but may limit
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the formation of higher dimensional crystal structures. Therefore, it could be possible to assemble three-dimensional uranyl phosphonates by increasing the phosphonate groups, viz. triphosphonate or tetraphosphonate ligands, which may start a new strategy for the construction of higher dimensional uranyl phosphonates. As far as we know, to date there is only one report on the employment of triphosphonate ligand for the construction of uranyl phosphonates [19]. In our recent work, a triphosphonate ligand, benzene-1,3,5-triyltris(methylene)triphosphonic acid (H6L), has been employed for the construction of metal
ACCEPTED MANUSCRIPT phosphonates [20]. This ligand is semi-rigid which endows it with enough coordination flexibility while retaining enough rigidity. The three arms on the benzene ring could adopt up-up-down conformation to coordinate with metal centers and extend into higher dimensional structures. Herein, we report on the
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synthesis, structure and luminescent property of a new three-dimensional uranyl triphosphonate.
Hydrothermal method is an efficient technique for the synthesis of coordination polymer [21]. Compound 1 was synthesized hydrothermally as yellow prism crystals
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by reacting H6L with hydrate uranyl acetate (UO2(OAc)2·2H2O) with hydrothermal method (for Experimental details, see ESI). Single-crystal structural analysis reveals
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that compound 1 crystallizes in monoclinic space group P21/c with four molecules in each lattice [22]. The asymmetric unit is composed of two uranyl cations, one fully deprotonated triphosphonate ligand (L6-), one double-protonated 2,2’-bipy and one coordinating aqua ligand, indicating a formula of [2,2’-H2bipy][(UO2)2(H2O)(L)]. The U=O bond lengths are found in the range of 1.761(8)-1.797(7) Å and the bond angles
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of O(10)=U1=O(11) and O(12)=U1=O(13) are 178.1(3)o and 178.1(4)o, respectively (Table S1 and S2). It is found that the two uranyl cations adopt different coordination modes. In U1, the uranyl cation is five-coordinated at the equatorial positions by four
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phosphonate oxygen atoms from four triphosphonate ligands and one aqua ligand, showing a pentagonal bipyramid coordination geometry. In U2, the uranyl cation is four-coordinated by four phosphonate oxygen atoms from four triphosphonate ligands,
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showing an octahedral coordination geometry. The U-Oequatorial distances are in the range of 2.306(7)-2.512(8) Å which are comparable to those found in other uranyl phosphonates [23]. The three phosphonate groups in the triphosphonate ligand (L) are fully deprotonated and adopt an up-up-down conformation. The coordination mode of the triphosphonate ligand can be denoted as µ8:η1:η1:η1:η1:η1:η1:η1:η1:η0, which means that it binds to eight uranyl (II) cations with its eight phosphonate oxygen atoms (see Scheme 1(a) and Fig. 1). These triphosphonate ligands connect the uranyl cations into an anionic three-dimensional framework crystal structure containing drum like channels running along c-direction (see Fig. 2a). The channel size is about 8.3×7.6 Å2.
ACCEPTED MANUSCRIPT The 2,2’-bipy are not involved in the coordination to the uranyl cation and the two nitrogen atoms are protonated based on charge balance requirement. These protonated 2,2’-bipy molecules serve as organic templates and are accommodated in the channels of anionic framework. The large amount of hydrogen donors, available phosphonate
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(O4 and O7) and terminal (O10, O12 and O13) oxygen atoms in the guest and host and suitable distances allow the formation of plenty of either inter or inner C-H···O and N-H···O interactions (see Fig. 2b and Table S3). It can be found that the strength of the N-H···O interactions is comparable to those of O-H···O interactions but
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stronger than those of C-H···O interactions from the donor···acceptor distances. The π···π interactions between the host and guest are very weak, however, obvious π···π
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interactions can be found between the pyridine rings or between the benzene rings (see Table S4).
Thermogravimetric analysis was performed to investigate the thermal stability of compound 1 (see Fig. 3). From the TGA curve, it can be seen that there are two steps of weight losses in the temperature range of 25-800 oC. The
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first one (about 1.8 %), found in the range of 190-340 oC, could be ascribed to the removal of lattice water, matching well with the theoretic value (1.7 %) of one water in each formula. With the temperature increased to 400 oC, it started
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to lose weight dramatically and reached a value of about 27.5 % at 800 oC, indicating the decomposition of the framework. The photoluminescent spectrum of compound 1 was recorded at room
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temperature as shown in Fig. 4. By exciting at 350 nm, five characteristic emission peaks of UO22+ can be observed at 482, 496, 517, 541, and 566 nm, corresponding to the electronic and vibronic transitions of S11−S00 and S10−S0v (ν = 0−4), which are related to the symmetric and antisymmetric vibrational modes of the uranyl cation. Compared to the benchmark compound UO2(NO3)2·6H2O [17], a red shift about 7 nm is observed. The red shift may originate from the coordination of the triphosphonate ligand and the influence of 2,2’-bipy.
ACCEPTED MANUSCRIPT In conclusion, a new three-dimensional uranyl phosphonate has been synthesized from one tritopic semi-rigid triphosphonate ligand. Semi-rigid phosphonate ligand with three arms may adopt an up-up-down conformation and exhibit flexible coordination modes. The increasing of coordination groups
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can offset the coordination limitation of uranyl cation and provide a new strategy for the construction of higher dimensional uranyl phosphonates.
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Acknowledgment
The authors are grateful to the financial support from Natural Science Foundation of
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China (No. 21171173). Appendix A. Supplementary material
Experimental details, XRD patterns, IR spectrum, selected bond angles and H-bonds can be found in the supporting file. Supplementary data associated with this article can be found online at http://dx.doi.org/10.1016/j.inoche.xxxx.xx.xxx.
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3-Dimensional Bimetallic UO22+/Zn2+ Phosphonoacetates. Eur. J. Inorg. Chem. (2010) 1177−1185; (b) D. Grohol, F. Gingl, A. Clearfield. Syntheses and Crystal Structures of a Linear-Chain Uranyl Phenylphosphinate
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Phosphonoacetate Based Hybrid Compounds of Uranium and Thorium. Inorg. Chem. 49(2010) 7927–7934. [15] P. O. Adelani, A. G. Oliver, T. E. Albrecht-Schmitt. Layered and
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ACCEPTED MANUSCRIPT [17] W. Yang, T. Tian, H. Y. Wu, Q. J. Pan, S. Dang, Z. M. Sun. Syntheses and Structures of a Series of Uranyl Phosphonates and Sulfonates: An Insight into Their Correlations and Discrepancies. Inorg. Chem. 52(2013) 2736–2743. [18] P. O. Adelani, N. D. Cook, P. C. Burns. Use of 2,2-Bipyrimidine for the
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Preparation of UO22+-3d Diphosphonates. Cryst. Growth Des. 14(2014) 5692–5699.
[19] S. S. Bao, G. S. Chen, Y. Wang, Y. Z. Li, L. M. Zheng, Q. H. Luo. Incorporation of Triazacyclononane into the Metal Phosphonate Backbones.
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[20] S. F. Tang, X. B. Pan, X. X. Lv, S. H. Yan, X. R. Xu, L. J. Li X. B. Zhao.
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Fabrication of new metal phosphonates from tritopic trisphosphonic acid containing methyl groups and auxiliary ligands: syntheses, structures and gas adsorption properties. CrystEngComm 15(2013) 1860–1873. [21] (a) B. Ay, E. Yildiz, İ. Kani. Two novel isostructural and heteroleptic Nd(III)
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2,5-pyridinedicarboxylic acid and in situ generated 2-pyridinecarboxylic acid: Hydrothermal synthesis, characterization, photoluminescence properties and heterogeneous catalytic activities. Polyhedron 130 (2017) 165–175. (b) B.
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Ay, E. Yildiz, İ. Kani. Novel heteroleptic lanthanide organic frameworks containing
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luminescent properties. J. Solid State Chem. 233(2016) 44–51.
[22] Crystal Data for 1: C19H21N2O14P3U2, Mr = 1070.35 g mol–1, monoclinic, P21/c, a = 12.498(6), b = 21.561(10), c = 10.037(4) Å, α = 90, β= 109.279(5), γ = 90o, V = 2552.9(19) Å3, Z = 4, T = 293(2) K, ρ = 2.785 g cm–3, µ = 12.935 mm–1, F(000) = 1960. 14200 reflections were collected, of which 4353 were unique (Rint = 0.0718). GOF = 0.0997. R1/R2 = 0.0399/0.0744 [I>2σ(I)]. [23] (a) W. T. Yang, H. Y. Wu, R. X. Wang, Q. J. Pan, Z. M. Sun, H. J. Zhang, From 1D Chain to 3D Framework Uranyl Diphosphonates: Syntheses, Crystal Structures,
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ACCEPTED MANUSCRIPT 11458−11465. (b) T. Zheng, Y. Gao, L. Chen, Z. Liu, J.n Diwu, Z. Chai, T. E. Albrecht-Schmitt, S. Wang. A new chiral uranyl phosphonate framework consisting of achiral building units generated from ionothermal reaction: structure and spectroscopy characterizations. Dalton Trans. 44(2015)
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18158–18166. (c) L. Chen, T. Zheng, S. Bao, L. Zhang, H. K.n Liu, L. Zheng, J. Wang, Y. Wang, J. Diwu, Z. Chai, T. E. Albrecht-Schmitt, S. Wang. A Mixed-Valent Uranium Phosphonate Framework Containing UIV,
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UV, and UVI. Chem. Eur. J. 22(2016) 11954 – 11957.
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Fig. 1 Coordination environment of the triphosphonate ligand (L)6- in compound 1 with 30% probability. Symmetry transformations used to generate equivalent atoms: A: x, 0.5-y, -0.5+z; B: x, y, -1+z; C: -1+x, y, -1+z; D: -x, 1-y, 3-z; E: 1-x, 1-y, 3-z; F: x, 0.5-y, 0.5+z; G: x, y, z+1; H: 1+x, y, 1+z.
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(a)
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(b)
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Fig. 2 Three-dimensional framework structure of compound 1 without (a) and with (b) the presence of 2,2’-H2bipy.
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70 200
400
600
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75
800
o
Temperature ( C)
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Fig. 3 TGA diagram of compound 1.
450
500 550 Wavelength (nm)
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Relative Intensity
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600
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Fig. 4 Emission spectrum of compound 1 at room temperature.
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(a)
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(b) (c) Scheme 1. Coordination modes of the triphosphonate ligand (a), U1 (b) and U2 (c).
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A new uranyl phosphonate has been synthesized from a triphosphonate ligand. It displays three-dimensional framework structure. 2,2’-Bipy molecules serve as organic templates. The thermal and luminescent properties were also investigated.
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S0022-2860(17)30744-5
DOI:
10.1016/j.molstruc.2017.05.125
Reference:
MOLSTR 23866
To appear in:
Journal of Molecular Structure
Received Date: 15 April 2017 Revised Date:
24 May 2017
Accepted Date: 27 May 2017
Please cite this article as: X. Hou, S.-F. Tang, A new uranyl triphosphonate constructed from semi-rigid triphosphonate ligand: New method for the construction of higher dimensional uranyl phosponates, Journal of Molecular Structure (2017), doi: 10.1016/j.molstruc.2017.05.125. 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.
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ACCEPTED MANUSCRIPT
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A new three-dimensional uranyl triphosphonate has been synthesized, suggesting that semi-rigid tritopic triphosphonate ligands can be used to construct higher dimensional uranyl phosphonates.
ACCEPTED MANUSCRIPT A New Uranyl Triphosphonate Constructed from Semi-rigid Triphosphonate Ligand: New Method for the Construction of Higher Dimensional Uranyl Phosponates Xiaomin Hou,b and Si-Fu Tanga,c,* College of Chemistry and Pharmaceutical Sciences, Qingdao Agriculture University,
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a
Changcheng Road 700, Chengyang District, Qingdao 266109, China. E-mail: [email protected].
College of Life Science, Qingdao Agriculture University, Changcheng Road 700,
Chengyang District, Qingdao 266109, China.
Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of
Sciences, Qingdao 266101, China.
ABSTRACT
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b
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A new uranyl triphosphonate with three-dimensional crystal structure has been synthesized from a semi-rigid triphosphonate ligand using hydrothermal method. The employment of triphosphonate ligand may provide a new strategy for the construction of higher dimensional uranyl phosphonates. The thermal and luminescent properties
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were also investigated.
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Keywords: Uranyl; Phosphontes; Semi-rigid; Luminescence; Three-dimensional
Uranyl phosphonates have been of great interest in the past two decades due to their fantastic architectures [1] and potential applications in the field of nuclear waste processing as well as in the fields including ion-exchange [2], ionic conductivity [3], intercalation chemistry [4], photochemistry [5], non-linear optical materials [6], and catalysis [7]. Comparing with carboxylic acid group, phosphonic acid group possesses an additional oxygen atom which endows it with more coordination modes, leading to rich structural diversity including
ACCEPTED MANUSCRIPT one-dimensional chain [8] or tubule [9], two-dimensional layer [10] and three-dimensional network [11]. By surveying into the Cambridge Structural Database [12], one can find that most of the reported uranyl phosphonates exhibit one-dimensional and structures.
The
number
of
three-dimensional
uranyl
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two-dimensional
phosphonates is still limited but very desirable because many applications are dependent on it, such as ion-exchange and ionic conductivity, catalysis, and so on. One reason should be that uranyl compounds prefer to form
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low-dimensional crystal structures due to the terminal nature of actinyl unit [13]. To overcome this problem, a few of effective strategies have been
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developed. The first one is the decoration of the phosphonate ligand with additional functional group, such as carboxylic group [14]. With this method employed, two-dimensional and three-dimensional luminescent pillar layered uranyl diphosphonates can be constructed. The second one is the inclusion of alkali [15] and transition [16] metals in the system. These introduced metal ions
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can serve as new connecting nodes and allow the lower dimensional networks to connect into three-dimensional frameworks. The third one is the introduction of a second ligand, such as 1,3,5-tri(1H-imidazol-1-yl)benzene [17] and
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2,2-bipyrimidine [18]. Another reason is that most of the exploited ligands are, to date, simple mono or diphosphonate ligands. Simple mono or diphosphonate ligands are easy to synthesize and comparative apt to crystallize but may limit
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the formation of higher dimensional crystal structures. Therefore, it could be possible to assemble three-dimensional uranyl phosphonates by increasing the phosphonate groups, viz. triphosphonate or tetraphosphonate ligands, which may start a new strategy for the construction of higher dimensional uranyl phosphonates. As far as we know, to date there is only one report on the employment of triphosphonate ligand for the construction of uranyl phosphonates [19]. In our recent work, a triphosphonate ligand, benzene-1,3,5-triyltris(methylene)triphosphonic acid (H6L), has been employed for the construction of metal
ACCEPTED MANUSCRIPT phosphonates [20]. This ligand is semi-rigid which endows it with enough coordination flexibility while retaining enough rigidity. The three arms on the benzene ring could adopt up-up-down conformation to coordinate with metal centers and extend into higher dimensional structures. Herein, we report on the
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synthesis, structure and luminescent property of a new three-dimensional uranyl triphosphonate.
Hydrothermal method is an efficient technique for the synthesis of coordination polymer [21]. Compound 1 was synthesized hydrothermally as yellow prism crystals
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by reacting H6L with hydrate uranyl acetate (UO2(OAc)2·2H2O) with hydrothermal method (for Experimental details, see ESI). Single-crystal structural analysis reveals
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that compound 1 crystallizes in monoclinic space group P21/c with four molecules in each lattice [22]. The asymmetric unit is composed of two uranyl cations, one fully deprotonated triphosphonate ligand (L6-), one double-protonated 2,2’-bipy and one coordinating aqua ligand, indicating a formula of [2,2’-H2bipy][(UO2)2(H2O)(L)]. The U=O bond lengths are found in the range of 1.761(8)-1.797(7) Å and the bond angles
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of O(10)=U1=O(11) and O(12)=U1=O(13) are 178.1(3)o and 178.1(4)o, respectively (Table S1 and S2). It is found that the two uranyl cations adopt different coordination modes. In U1, the uranyl cation is five-coordinated at the equatorial positions by four
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phosphonate oxygen atoms from four triphosphonate ligands and one aqua ligand, showing a pentagonal bipyramid coordination geometry. In U2, the uranyl cation is four-coordinated by four phosphonate oxygen atoms from four triphosphonate ligands,
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showing an octahedral coordination geometry. The U-Oequatorial distances are in the range of 2.306(7)-2.512(8) Å which are comparable to those found in other uranyl phosphonates [23]. The three phosphonate groups in the triphosphonate ligand (L) are fully deprotonated and adopt an up-up-down conformation. The coordination mode of the triphosphonate ligand can be denoted as µ8:η1:η1:η1:η1:η1:η1:η1:η1:η0, which means that it binds to eight uranyl (II) cations with its eight phosphonate oxygen atoms (see Scheme 1(a) and Fig. 1). These triphosphonate ligands connect the uranyl cations into an anionic three-dimensional framework crystal structure containing drum like channels running along c-direction (see Fig. 2a). The channel size is about 8.3×7.6 Å2.
ACCEPTED MANUSCRIPT The 2,2’-bipy are not involved in the coordination to the uranyl cation and the two nitrogen atoms are protonated based on charge balance requirement. These protonated 2,2’-bipy molecules serve as organic templates and are accommodated in the channels of anionic framework. The large amount of hydrogen donors, available phosphonate
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(O4 and O7) and terminal (O10, O12 and O13) oxygen atoms in the guest and host and suitable distances allow the formation of plenty of either inter or inner C-H···O and N-H···O interactions (see Fig. 2b and Table S3). It can be found that the strength of the N-H···O interactions is comparable to those of O-H···O interactions but
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stronger than those of C-H···O interactions from the donor···acceptor distances. The π···π interactions between the host and guest are very weak, however, obvious π···π
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interactions can be found between the pyridine rings or between the benzene rings (see Table S4).
Thermogravimetric analysis was performed to investigate the thermal stability of compound 1 (see Fig. 3). From the TGA curve, it can be seen that there are two steps of weight losses in the temperature range of 25-800 oC. The
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first one (about 1.8 %), found in the range of 190-340 oC, could be ascribed to the removal of lattice water, matching well with the theoretic value (1.7 %) of one water in each formula. With the temperature increased to 400 oC, it started
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to lose weight dramatically and reached a value of about 27.5 % at 800 oC, indicating the decomposition of the framework. The photoluminescent spectrum of compound 1 was recorded at room
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temperature as shown in Fig. 4. By exciting at 350 nm, five characteristic emission peaks of UO22+ can be observed at 482, 496, 517, 541, and 566 nm, corresponding to the electronic and vibronic transitions of S11−S00 and S10−S0v (ν = 0−4), which are related to the symmetric and antisymmetric vibrational modes of the uranyl cation. Compared to the benchmark compound UO2(NO3)2·6H2O [17], a red shift about 7 nm is observed. The red shift may originate from the coordination of the triphosphonate ligand and the influence of 2,2’-bipy.
ACCEPTED MANUSCRIPT In conclusion, a new three-dimensional uranyl phosphonate has been synthesized from one tritopic semi-rigid triphosphonate ligand. Semi-rigid phosphonate ligand with three arms may adopt an up-up-down conformation and exhibit flexible coordination modes. The increasing of coordination groups
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can offset the coordination limitation of uranyl cation and provide a new strategy for the construction of higher dimensional uranyl phosphonates.
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Acknowledgment
The authors are grateful to the financial support from Natural Science Foundation of
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China (No. 21171173). Appendix A. Supplementary material
Experimental details, XRD patterns, IR spectrum, selected bond angles and H-bonds can be found in the supporting file. Supplementary data associated with this article can be found online at http://dx.doi.org/10.1016/j.inoche.xxxx.xx.xxx.
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[22] Crystal Data for 1: C19H21N2O14P3U2, Mr = 1070.35 g mol–1, monoclinic, P21/c, a = 12.498(6), b = 21.561(10), c = 10.037(4) Å, α = 90, β= 109.279(5), γ = 90o, V = 2552.9(19) Å3, Z = 4, T = 293(2) K, ρ = 2.785 g cm–3, µ = 12.935 mm–1, F(000) = 1960. 14200 reflections were collected, of which 4353 were unique (Rint = 0.0718). GOF = 0.0997. R1/R2 = 0.0399/0.0744 [I>2σ(I)]. [23] (a) W. T. Yang, H. Y. Wu, R. X. Wang, Q. J. Pan, Z. M. Sun, H. J. Zhang, From 1D Chain to 3D Framework Uranyl Diphosphonates: Syntheses, Crystal Structures,
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18158–18166. (c) L. Chen, T. Zheng, S. Bao, L. Zhang, H. K.n Liu, L. Zheng, J. Wang, Y. Wang, J. Diwu, Z. Chai, T. E. Albrecht-Schmitt, S. Wang. A Mixed-Valent Uranium Phosphonate Framework Containing UIV,
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Fig. 1 Coordination environment of the triphosphonate ligand (L)6- in compound 1 with 30% probability. Symmetry transformations used to generate equivalent atoms: A: x, 0.5-y, -0.5+z; B: x, y, -1+z; C: -1+x, y, -1+z; D: -x, 1-y, 3-z; E: 1-x, 1-y, 3-z; F: x, 0.5-y, 0.5+z; G: x, y, z+1; H: 1+x, y, 1+z.
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Fig. 2 Three-dimensional framework structure of compound 1 without (a) and with (b) the presence of 2,2’-H2bipy.
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Fig. 3 TGA diagram of compound 1.
450
500 550 Wavelength (nm)
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Relative Intensity
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Fig. 4 Emission spectrum of compound 1 at room temperature.
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(b) (c) Scheme 1. Coordination modes of the triphosphonate ligand (a), U1 (b) and U2 (c).
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A new uranyl phosphonate has been synthesized from a triphosphonate ligand. It displays three-dimensional framework structure. 2,2’-Bipy molecules serve as organic templates. The thermal and luminescent properties were also investigated.
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