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A new 3-D neutral framework coordination polymer constructed via square pyramidal binuclear Cu(II) and nicotinato ligand
Inorganic Chemistry Communications 4 (2001) 716±718 www.elsevier.com/locate/inoche
A new 3-D neutral framework coordination polymer constructed via square pyramidal binuclear Cu(II) and nicotinato ligand Jack Y. Lu *, Amy M. Babb Department of Chemistry, University of Houston-Clear Lake, 2700 Bay Area Blvd., Houston, TX 77058, USA Received 31 August 2001; accepted 18 September 2001
Abstract A new 3-D neutral metal±organic framework polymer, Cu NA2 1, has been synthesized under hydrothermal reaction conditions. The structure of 1 is self-assembled from binuclear square pyramidal copper(II) coordinated by multidentate nicotinato ligands. Ó 2001 Elsevier Science B.V. All rights reserved. Keywords: Coordination polymer; 3-D structure; Hydrothermal reaction; Binuclear copper; Square pyramidal; Copper nicotinate
The synthesis of new metal±organic polymers via molecular recognition directed self-assembly process represents a topical and important subject [1±3]. The metal centers as well as organic building blocks play a key role in molecular recognition process. It has been noticed from our recent studies [2±6] and other reports [7,8] that pyridylcarboxylate ligands tend to bind metal centers with both pyridyl and carboxylate groups to form extended networks, where carboxylate groups balance the metal charges. The metal center display dierent coordination geometries with versatility. For example, the copper(II) atoms display mixed octahedral and square pyramidal geometry in open-framework structures [2,3], square pyramidal coordination in 2-D and 3-D framework [4,5], and trigonal bipyramidal centers in a mixed-bonding 3-D network [6]. Dierent copper oxidation states have also been observed such as +1 [9], +2 [2,3,5,6,10], mixed-valence state [4,11,12] and/ or with Cu±Cu bonds [4,9,11,12]. While the utilization of mononuclear copper metal centers and mixed valent copper pairs for building coordination polymers has been documented, the binuclear copper(II) pairs with square pyramidal geometry construction motif has not *
Corresponding author. Tel.: +1-281-283-3780; fax: +1-281-2833707. E-mail address: [email protected] (J.Y. Lu).
been reported. Here we present such a result: Cu NA2 (NA nicotinato) 1, in which binuclear Cu2 NA4 unit is utilized to build a new 3-D framework coordination polymer. The compound 1 was synthesized by reacting Cu NO3 2 2:5H2 O with nicotinic acid in the mole ratio of 2:1 for three days at 170 °C under hydrothermal conditions. The yield is 66%. The blue crystals of 1 are suitable for single crystal X-ray diraction analysis [13]. The structure of 1 consists of distorted square pyramidal copper centers coordinated by two independent nicotinato ligands (Fig. 1). One nicotinato ligand is tridentate, and the other one is bidentate to copper metal centers. Every two copper atoms are bridged by two carboxylato groups of the tridentate nicotinato ligands through O(2) and O(4) atoms to form a binuclear copper(II) unit: Cu2 NA4 . The O(4) atom is at the apical site while the two pyridyl groups and the other two oxygen atoms are at the equatorial positions (Fig. 1). The formation of the binuclear units created 8-member rings (Fig. 1), which are then linked by nicotinato ligands to result in large 24-member rings (Fig. 2). There are four 8-member rings on each 24-member ring: two 8-member rings at transposition to each other are perpendicular to the other two 8-member rings. There are four 24-member rings connecting each 8-member ring, via covalent bonding to the binuclear copper centers: two 24-member rings are
1387-7003/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 1 3 8 7 - 7 0 0 3 ( 0 1 ) 0 0 3 2 0 - 3
J.Y. Lu, A.M. Babb / Inorganic Chemistry Communications 4 (2001) 716±718
717
Fig. 4. View of the 3-D framework structure down to the a-axis. Fig. 1. View of the binuclear copper(II) square pyramidal coordination with atom numbering scheme.
It is interesting to note that the square pyramidal binuclear unit is more complicated than those mononuclear building blocks, which may give more potential in constructing non-interpenetrating open-framework metal±organic polymers.
Acknowledgements
Fig. 2. View of the 8-member and 24-member rings.
The authors thank the ®nancial support from the Welch Foundation and ISSO. This work made use of MRSEC/TCSUH Shared Experimental Facilities supported by the National Science Foundation under Award DMR-9632667 and the Texas Center for Superconductivity at the University of Houston. References
Fig. 3. View of the perpendicular 24-member rings. One parallel 24member ring is omitted for clarity.
perpendicular to the other two 24-member rings (Fig. 3). The propagation of the 24-member rings and 8-member rings extends into three directions to result in a (3-D) framework structure (Fig. 4).
[1] See, for example: M. O'Keee, M. Eddaoudi, H. Li, T. Reineke, O.M. Yaghi, J. Solid State Chem. 152 (2000) 3; M.J. Zaworotko, Chem. Commun. (2001) 1; S.W. Keller, S. Lopez, J. Am. Chem. Soc. 121 (1999) 6306; J.Y. Lu, C. Norman, K.A. Abboud, A. Ison, Inorg. Chem. Commun. 4 (2001) 459; J.Y. Lu, A. Babb, Inorg. Chim. Acta 318 (2001) 186. [2] J.Y. Lu, A.M. Babb, Chem. Commun. (2001) 821. [3] J.Y. Lu, A.M. Babb, Inorg. Chem. 40 (2001) 3261. [4] J.Y. Lu, K.A. Runnels, Inorg. Chem. Commun. (accepted). [5] J.Y. Lu, A.M. Babb, Angew. Chem. Int. Ed. (submitted). [6] J.Y. Lu, V. Schauss, Cryst. Eng. Comm. (2001) 26. [7] L. Ma, O.R. Evans, B.M. Foxman, W. Lin, Inorg. Chem. 38 (1999) 5837. [8] W. Lin, O.R. Evans, R. Xiong, Z. Wang, J. Am. Chem. Soc. 120 (1998) 13272. [9] P.C. Ford, E. Cariati, J. Bourassa, Chem. Rev. 99 (1999) 3625; CM. Che, Z. Mao, V.M. Miskowski, M-C. Tse, C-K. Chan, K-K. Cheung, D.L. Phillips, K-H. Leung, Angew. Chem. Int. Ed. 39 (2000) 4084. [10] S.S-Y. Chui, S.M-F. Lo, C.A.G. Orpen, I.D. Williams, Science 283 (1999) 1148.
718
J.Y. Lu, A.M. Babb / Inorganic Chemistry Communications 4 (2001) 716±718
[11] S.M-F. Lo, S.S-Y. Chui, L-Y. Shek, Z. Lin, X. Zhang, G. Wen, D. Williams, J. Am. Chem. Soc. 122 (2000) 6293. [12] S. Iwata, C. Ostermeier, B. Ludwig, H. Michel, Nature 376 (1995) 660; S. Ferguson-Miller, G.T. Babcock, Chem. Rev. 96 (1996) 2889. [13] Crystal data for 1: FW, 307.74; monoclinic, space group, p21 =n; cell dimensions a 10:780 2, b 9:447 2, c 12:604 3 A,
3 , Z 4, Dcalc 1:722 g cm 3 , b 112:38 3°, U 1186:9 4 A 1 l 1:851 mm , T 223 2 K. Re¯ections collected: 6195; independent re¯ections: 2210 [R(int) 0.0274]. Final R indices I > 2r I: R1 0:0234; wR2 0:0604 (R for all data: R1 0:0275; wR2 0:0622. All measurements were made with a Siemens SMART platform diractometer equipped with a 1 K CCD area detector.
A new 3-D neutral framework coordination polymer constructed via square pyramidal binuclear Cu(II) and nicotinato ligand Jack Y. Lu *, Amy M. Babb Department of Chemistry, University of Houston-Clear Lake, 2700 Bay Area Blvd., Houston, TX 77058, USA Received 31 August 2001; accepted 18 September 2001
Abstract A new 3-D neutral metal±organic framework polymer, Cu NA2 1, has been synthesized under hydrothermal reaction conditions. The structure of 1 is self-assembled from binuclear square pyramidal copper(II) coordinated by multidentate nicotinato ligands. Ó 2001 Elsevier Science B.V. All rights reserved. Keywords: Coordination polymer; 3-D structure; Hydrothermal reaction; Binuclear copper; Square pyramidal; Copper nicotinate
The synthesis of new metal±organic polymers via molecular recognition directed self-assembly process represents a topical and important subject [1±3]. The metal centers as well as organic building blocks play a key role in molecular recognition process. It has been noticed from our recent studies [2±6] and other reports [7,8] that pyridylcarboxylate ligands tend to bind metal centers with both pyridyl and carboxylate groups to form extended networks, where carboxylate groups balance the metal charges. The metal center display dierent coordination geometries with versatility. For example, the copper(II) atoms display mixed octahedral and square pyramidal geometry in open-framework structures [2,3], square pyramidal coordination in 2-D and 3-D framework [4,5], and trigonal bipyramidal centers in a mixed-bonding 3-D network [6]. Dierent copper oxidation states have also been observed such as +1 [9], +2 [2,3,5,6,10], mixed-valence state [4,11,12] and/ or with Cu±Cu bonds [4,9,11,12]. While the utilization of mononuclear copper metal centers and mixed valent copper pairs for building coordination polymers has been documented, the binuclear copper(II) pairs with square pyramidal geometry construction motif has not *
Corresponding author. Tel.: +1-281-283-3780; fax: +1-281-2833707. E-mail address: [email protected] (J.Y. Lu).
been reported. Here we present such a result: Cu NA2 (NA nicotinato) 1, in which binuclear Cu2 NA4 unit is utilized to build a new 3-D framework coordination polymer. The compound 1 was synthesized by reacting Cu NO3 2 2:5H2 O with nicotinic acid in the mole ratio of 2:1 for three days at 170 °C under hydrothermal conditions. The yield is 66%. The blue crystals of 1 are suitable for single crystal X-ray diraction analysis [13]. The structure of 1 consists of distorted square pyramidal copper centers coordinated by two independent nicotinato ligands (Fig. 1). One nicotinato ligand is tridentate, and the other one is bidentate to copper metal centers. Every two copper atoms are bridged by two carboxylato groups of the tridentate nicotinato ligands through O(2) and O(4) atoms to form a binuclear copper(II) unit: Cu2 NA4 . The O(4) atom is at the apical site while the two pyridyl groups and the other two oxygen atoms are at the equatorial positions (Fig. 1). The formation of the binuclear units created 8-member rings (Fig. 1), which are then linked by nicotinato ligands to result in large 24-member rings (Fig. 2). There are four 8-member rings on each 24-member ring: two 8-member rings at transposition to each other are perpendicular to the other two 8-member rings. There are four 24-member rings connecting each 8-member ring, via covalent bonding to the binuclear copper centers: two 24-member rings are
1387-7003/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S 1 3 8 7 - 7 0 0 3 ( 0 1 ) 0 0 3 2 0 - 3
J.Y. Lu, A.M. Babb / Inorganic Chemistry Communications 4 (2001) 716±718
717
Fig. 4. View of the 3-D framework structure down to the a-axis. Fig. 1. View of the binuclear copper(II) square pyramidal coordination with atom numbering scheme.
It is interesting to note that the square pyramidal binuclear unit is more complicated than those mononuclear building blocks, which may give more potential in constructing non-interpenetrating open-framework metal±organic polymers.
Acknowledgements
Fig. 2. View of the 8-member and 24-member rings.
The authors thank the ®nancial support from the Welch Foundation and ISSO. This work made use of MRSEC/TCSUH Shared Experimental Facilities supported by the National Science Foundation under Award DMR-9632667 and the Texas Center for Superconductivity at the University of Houston. References
Fig. 3. View of the perpendicular 24-member rings. One parallel 24member ring is omitted for clarity.
perpendicular to the other two 24-member rings (Fig. 3). The propagation of the 24-member rings and 8-member rings extends into three directions to result in a (3-D) framework structure (Fig. 4).
[1] See, for example: M. O'Keee, M. Eddaoudi, H. Li, T. Reineke, O.M. Yaghi, J. Solid State Chem. 152 (2000) 3; M.J. Zaworotko, Chem. Commun. (2001) 1; S.W. Keller, S. Lopez, J. Am. Chem. Soc. 121 (1999) 6306; J.Y. Lu, C. Norman, K.A. Abboud, A. Ison, Inorg. Chem. Commun. 4 (2001) 459; J.Y. Lu, A. Babb, Inorg. Chim. Acta 318 (2001) 186. [2] J.Y. Lu, A.M. Babb, Chem. Commun. (2001) 821. [3] J.Y. Lu, A.M. Babb, Inorg. Chem. 40 (2001) 3261. [4] J.Y. Lu, K.A. Runnels, Inorg. Chem. Commun. (accepted). [5] J.Y. Lu, A.M. Babb, Angew. Chem. Int. Ed. (submitted). [6] J.Y. Lu, V. Schauss, Cryst. Eng. Comm. (2001) 26. [7] L. Ma, O.R. Evans, B.M. Foxman, W. Lin, Inorg. Chem. 38 (1999) 5837. [8] W. Lin, O.R. Evans, R. Xiong, Z. Wang, J. Am. Chem. Soc. 120 (1998) 13272. [9] P.C. Ford, E. Cariati, J. Bourassa, Chem. Rev. 99 (1999) 3625; CM. Che, Z. Mao, V.M. Miskowski, M-C. Tse, C-K. Chan, K-K. Cheung, D.L. Phillips, K-H. Leung, Angew. Chem. Int. Ed. 39 (2000) 4084. [10] S.S-Y. Chui, S.M-F. Lo, C.A.G. Orpen, I.D. Williams, Science 283 (1999) 1148.
718
J.Y. Lu, A.M. Babb / Inorganic Chemistry Communications 4 (2001) 716±718
[11] S.M-F. Lo, S.S-Y. Chui, L-Y. Shek, Z. Lin, X. Zhang, G. Wen, D. Williams, J. Am. Chem. Soc. 122 (2000) 6293. [12] S. Iwata, C. Ostermeier, B. Ludwig, H. Michel, Nature 376 (1995) 660; S. Ferguson-Miller, G.T. Babcock, Chem. Rev. 96 (1996) 2889. [13] Crystal data for 1: FW, 307.74; monoclinic, space group, p21 =n; cell dimensions a 10:780 2, b 9:447 2, c 12:604 3 A,
3 , Z 4, Dcalc 1:722 g cm 3 , b 112:38 3°, U 1186:9 4 A 1 l 1:851 mm , T 223 2 K. Re¯ections collected: 6195; independent re¯ections: 2210 [R(int) 0.0274]. Final R indices I > 2r I: R1 0:0234; wR2 0:0604 (R for all data: R1 0:0275; wR2 0:0622. All measurements were made with a Siemens SMART platform diractometer equipped with a 1 K CCD area detector.