- Email: [email protected]
Two new coordination polymers differentiated by CH⋯O hydrogen bonding — synthesis and crystal structure of [(oxa)M(DPA)]
Polyhedron 20 (2001) 2445– 2449 www.elsevier.com/locate/poly
Two new coordination polymers differentiated by CH···O hydrogen bonding — synthesis and crystal structure of [(oxa)M(DPA)] Jack Y. Lu a,*, Timothy J. Schroeder a, Amy M. Babb a, Marilyn Olmstead b a
Department of Chemistry, Uni6ersity of Houston — Clear Lake, Houston, TX 77058, USA b Department of Chemistry, Uni6ersity of California at Da6is, Da6is, CA 95616, USA Received 28 December 2000; accepted 1 May 2001
Abstract Two new coordination polymers, [(oxa)Fe(DPA)] (1) (DPA= 2,2-dipyridylamine; oxa = oxalate) and [(oxa)Ni(DPA)] (2), were synthesized through a self-assembly chemical process under hydrothermal conditions, and characterized by single crystal structures. The CH···O hydrogen bonds in 1 and 2 play important roles in the crystal packing of the two new compounds. © 2001 Elsevier Science Ltd. All rights reserved. Keywords: Coordination polymers; Oxalate; 2,2-Dipyridylamine; Cobalt; Nickel; Hydrogen bonds
1. Introduction Crystal engineering of metal – organic polymers with functional building blocks may produce framework polymers with tunable properties [1 – 5]. The directionality of the covalent bonds resulting from metal –organic ligand interactions has been extensively exploited for the synthesis of framework coordination polymers [5 – 9]. Compared to the crystal engineering of organic and supramolecular design, the directionality of hydrogen bonds and their influence on crystal packing in coordination polymers are less developed [10 – 13]. In tuning the network structures and properties of metal – organic polymers, many subtle interactions such as weaker hydrogen bonds need to be considered. The detailed information regarding such interactions and their reproducibility in constructing networks is essential and constitutes extremely challenging subjects [10]. While hydrogen bonds are widely used in building supramolecular structures, the new findings of such interactions in coordination polymers for rational design and construction of new framework structures are * Corresponding author. Tel.: + 1-281-283-3780; fax: +1-281-2833707. E-mail address: [email protected] (J.Y. Lu).
apparently important. Here, we wish to report the synthesis and crystal structures of two new metal –organic polymers, [(oxa)Fe(DPA)] (1) (DPA =2,2dipyridylamine; oxa= oxalate) and [(oxa)Ni(DPA)] (2), with both NH···O and CH···O hydrogen bonds that play a key role in the crystal packing of the two new structures.
2. Experimental
2.1. Materials and methods All chemicals were purchased from Aldrich and used without further purification. Thermal gravimetric analysis and differential thermal analysis were performed on a TGA 2050 thermal gravimetric analyzer with a heating rate of 10 °C min − 1.
2.2. Synthesis Both compounds 1 and 2 were synthesized by reacting FeBr2 (0.2157 g, 0.0010 mol) or NiBr2 (0.2185 g, 0.0010 mol) with oxalic acid (0.1261 g, 0.0010 mol) and 2,2-dipyridylamine (0.1712 g, 0.0010 mol) in the molar ratio 1:1:1 in 6 ml water. The reactions were carried out
0277-5387/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 2 7 7 - 5 3 8 7 ( 0 1 ) 0 0 8 5 9 - 2
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
2446
in a 23 ml acid digestion bomb at 180 °C for 3 days. The products, orange– yellow crystals of 1 and blue crystals of 2, were washed with water and acetone and dried in air. The yields are 76% for 1 and 85% for 2. Both 1 and 2 are insoluble in DMF, THF, CH3CN, Table 1 Crystal data and structure refinement parameters for [(oxa)Fe(DPA)] and [(oxa)Ni(DPA)] Empirical formula Formula weight Temperature (°C) Crystal system Space group a (A, ) b (A, ) c (A, ) i (°) V (A, 3) Z v cm−1 R1 (observed data) wR2 (all data)
C12H9FeN3O4 315.07 −183(2) monoclinic P21/c 8.0213(5) 17.0822(11) 9.7929(14) 112.0560(10) 1243.64(14) 4 12.29 0.0341 0.0835
C12H9NiN3O4 317.93 −183(2) monoclinic C2/c 12.0929(6) 12.1868(6) 17.2851(9) 96.4060(10) 2531.5(2) 8 15.49 0.0329 0.0834
Table 2 Selected bond lengths (A, ) and bond angles (°) for [(oxa)Fe(DPA)] Bond lengths (A, ) Fe(1)O(4) Fe(1)O(1) Fe(1)N(1) Fe(1)N(3) Fe(1)O(3)
2.0616(12) 2.1066(12) 2.1417(14) 2.1422(14) 2.2232(12)
Fe(1)O(2) O(1)C(11) O(2)C(11) O(3)C(12)
2.2235(12) 1.2699(19) 1.239(2) 1.246(2)
Bond angles ( °) O(4)Fe(1)O(1) O(4)Fe(1)N(1) O(1)Fe(1)N(1) O(4)Fe(1)N(3) O(1)Fe(1)N(3) N(1)Fe(1)N(3) O(4)Fe(1)O(3) O(3)Fe(1)O(2)
155.86(5) 105.31(5) 91.55(5) 99.30(5) 98.65(5) 87.22(5) 77.69(5) 81.87(5)
O(1)Fe(1)O(3) N(1)Fe(1)O(3) N(3)Fe(1)O(3) O(4)Fe(1)O(2) O(1)Fe(1)O(2) N(1)Fe(1)O(2) N(3)Fe(1)O(2)
83.24(5) 97.13(5) 175.22(5) 86.00(5) 76.68(4) 168.23(5) 94.26(5)
Table 3 Selected bond lengths (A, ) and bond angles (°) for [(oxa)Ni(DPA)] Bond lengths (A, ) Ni(1)N(1) 2.0288(15) Ni(1)O(1) 2.0362(13) Ni(1)N(3) 2.0618(16) Bond angles ( °) N(1)Ni(1)O(1) N(1)Ni(1)N(3) O(1)Ni(1)N(3) N(1)Ni(1)O(2) O(1)Ni(1)O(2) N(3)Ni(1)O(2) N(1)Ni(1)O(4) O(1)Ni(1)O(4)
91.97(6) 88.82(6) 98.88(6) 173.59(6) 81.75(5) 93.41(6) 96.43(6) 167.86(5)
Ni(1)O(2) Ni(1)O(4) Ni(1)O(3)
2.0694(13) 2.0739(13) 2.0906(14)
N(3)Ni(1)O(4) O(2)Ni(1)O(4) N(1)Ni(1)O(3) O(1)Ni(1)O(3) N(3)Ni(1)O(3) O(2)Ni(1)O(3) O(4)Ni(1)O(3)
90.07(6) 89.58(5) 94.07(6) 90.14(5) 170.44(6) 84.70(5) 80.56(5)
Table 4 Hydrogen bonds for [(oxa)Fe(DPA)] in (A, ) and (°) D−H···A
d(DH)
N(2)−H(2)···O(1)c3 0.88 C(7)−H(7)···O(1)c 3 0.95 C(9)−H(9)···O(4)c4 0.95
d(H···A) d(D···A)
Ú(DHA)
2.01 2.49 2.49
159.9 137.2 161.4
2.853(2) 3.249(2) 3.403(2)
Symmetry transformations used to generate equivalent atoms: c 1 −x+1,−y+2,−z+1; c 2 −x+2,−y+2,−z+1; c 3 x,−y+3/ 2,z−1/2; c 4 −x+1,−y+2,−z.
CH2Cl2, benzene, toluene, or water. Elemental analysis: Compound 1: Anal. Found: Fe, 17.93; C, 45.36; N, 13.17; H, 3.00. Calc. Fe, 17.73; O, 20.32; C, 45.71; N, 13.30; H, 2.86%. Compound 2: Anal. Found: Ni, 18.19; C, 45.06; N, 12.96; H, 2.92. Calc. Ni, 18.46; O, 20.13; C, 45.29; N, 13.21; H, 2.83%.
2.3. Single-crystal structure determination 2.3.1. X-ray structure determination of [(oxa)Fe(DPA)] An orange–yellow block of dimensions 0.14× 0.18× 0.30 mm was mounted in the 90 K nitrogen cold stream provided by a CRYO Industries low-temperature apparatus on the goniometer head of a Bruker SMART 1000 diffractometer. Diffraction data were collected with graphite-monochromated Mo Ka radiation employing a 0.3° scan and approximately a full sphere of data to a maximum 2[ of 63°. An empirical correction for absorption was applied using the program SADABS 2.0. A total of 17007 reflections were collected, of which 3972 were unique (Rint = 0.046) and 3099 were observed (I\ 2|(I)). The structure was solved by direct methods (SHELXS-97) and refined by full-matrix least-squares on F 2. All non-hydrogen atoms were refined with anisotropic thermal parameters. Hydrogen atoms were refined using a riding model. The maximum and minimum peaks in the final difference Fourier map corresponded to 0.513 and −0.294 e A, − 3. Crystal data and additional details are provided in Table 1. Selected bond distances and angles are listed in Table 2. Hydrogen-bond distances and angles are listed in Table 4. 2.3.2. X-ray structure determination of [(oxa)Ni(DPA)] A blue plate of dimensions 0.07× 0.16× 0.19 mm was selected for data collection and handled in the same manner as for the Fe compound. A total of 33405 reflections were collected, of which 4016 were unique (Rint = 0.038) and 3141 were observed. The structure was solved and refined as above. The maximum and minimum peaks in the final difference Fourier map corresponded to 0.605 and −0.537 e A, − 3. Crystal data and additional details are provided in Table 1. Selected bond distances and angles are listed in Table 3. Hydrogen-bond distances and angles are listed in Table 5.
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
2447
Table 5 Hydrogen bonds for [(oxa)Ni(DPA)] in (A, ) and (°) D−H···A
d(DH)
C(3)−H(3)···O(1)c 3 0.95 N(2)−H(2)···O(4)c 4 0.88
d(H···A) d(D···A)
Ú(DHA)
2.44 2.03
168.2 171.2
3.374(2) 2.906(2)
Symmetry transformations used to generate equivalent atoms: c1 −x+3/2,−y+1/2,−z+1; c2 −x+1,−y,−z+1; c3 −x+3/2, y−1/2,−z+1/2; c4 −x+3/2,−y−1/2,−z+1.
3. Results and discussion Complex 1 consists of octahedral metal centers of the iron atom surrounded by two tetradentate oxalates and one bidentate DPA ligand (Fig. 1) and is extended as twisted zigzag one-dimensional chains (Fig. 2). The twisting of the one-dimensional chains is in such a way that one pair of the N− H···O (N(2) − H(2)···O(1) 2.8534(18) A, ) and C − H···O (C(7) − H(7)···O(1) 3.249(2) A, ) hydrogen bonds from the same DPA molecule can link to the same oxygen atom in the adjacent chain to form a mixed NH···O and CH···O hydrogen bonding linkage (Fig. 2). These mixed NH···O and CH···O hydrogen-bond pairs are not mutually linked between the two adjacent one-dimensional chains; it is only one way and the other C− H···O (C(9)−H(9)···O(4) 3.403(2) A, ) hydrogen bonds are formed between one chain in this pair and another chain (Fig. 3), and this linking pathway propagates to result in a three-dimensional network. Similar to the structure of 1, the structure of 2 also consists of octahedral nickel metal centers coordinated by two oxalate ligands and one DPA ligand (Fig. 4) to form zigzag chains along the [110] direction (Fig. 5). The one-dimensional chains are then linked by NH···O hydrogen bonds (N(2) −H(2)···O(4) 2.906(2) A, ) in one direction (Fig. 5) and CH···O hydrogen bonds (C(3)− H(3)···O(1) 3.374(2) A, ) in another direction (Fig. 6) to result in a three-dimensional structure. The NH···O
Fig. 1. The basic unit in [(oxa)Fe(DPA)] with numbering scheme and the thermal ellipsoids at the 50% probability level.
Fig. 2. View of the NH···O and CH···O hydrogen-bonding pair in [(oxa)Fe(DPA)].
hydrogen bonds in 2 are mutually formed between the two adjacent one-dimensional chains (Fig. 5). Compared with the crystal structure of [(oxa)Co(DPA)] [14] in which only mutual N− H···O (N(H)···O, 2.879(2) A, ) hydrogen bonds are formed between the two adjacent one-dimensional chains, and with the absence of CH···O hydrogen bonds it resulted in a two-dimensional structure. Although the NH···O hydrogen bonds are much weaker relative to the covalent bonds, the directionality of the NH···O hydrogen bonding is strongly shown in these structures. The CH···O hydrogen bonds formed in 1 and 2 are clearly different and they contribute directly to the formation of the threedimensional structures although the real reason for the difference is not completely understood. Hydrogen bonds have now been widely used in the crystal engineering of coordination polymers [15–19], but the CH···O hydrogen bonds found in 1 and 2 and their influence on crystal packing are different. It has been reviewed that in general, the CH···O hydrogen bonds determine crystal packing when stronger hydrogen bonding is absent in supramolecular structures [11]. In the cases of 1 and 2, it is clear that the CH···O
2448
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
hydrogen bonds are strong enough even when the stronger covalent bonding and NH···O hydrogen bonding are present so that the new crystal packing structures are resulted where the different orientations of the oxalate ligands in the chains were formed to comply with the linking requirement. The metaloxygen distances, FeO, in 1 range from 2.062(1) to 2.224(1) A, , and NiO distances in 2 vary from 2.036(1) to 2.091(1) A, , and are comparable with those found in oxalato complexes (FeO, 1.962(2)– 2.039(2) A, ; NiO, 2.10(2)– 2.13(1) A, ) [20a,b] (FeO, 2.116(4) A, ; NiO, 2.048(2) A, ) [20c]. The NiN dis-
Fig. 5. One-dimensional zigzag chains along [110] with mutual NH···O hydrogen bonds in [(oxa)Ni(DPA)].
Fig. 3. One-dimensional twisted zigzag chains with C −H···O (C(9)− H(9)···O(4) 3.403(2) A, ) hydrogen bonds in [(oxa)Fe(DPA)].
Fig. 6. View of the CH···O and NH···O hydrogen bonding in the structure of [(oxa)Ni(DPA)].
tances ranging from 2.029(2) to 2.062(2) A, are comparable with those found in Ni3(DPA)4Cl2·THF (1.889(5)–2.099(5) A, ) [21]. The thermal analyses for 1 and 2 indicate that they are very stable and undergo a single-step weight loss. Compound 1 lost both oxalate and dipyridylamine ligands from approximately 280 to 330 °C. The compound 2 is thermally stable up to 377 °C and the decomposition process was completed at 470 °C.
4. Conclusions Fig. 4. The basic unit in [(oxa)Ni(DPA)] with numbering scheme and the thermal ellipsoids at the 50% probability level.
The present study has shown that the CH···O hydrogen bonds play important roles in the crystal pack-
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
ing of the coordination polymers. While we are tuning network structures and properties of metal– organic polymers, detailed information regarding hydrogenbonding interactions and their reproducibility are essential and should be extensively explored.
5. Supplementary material Crystallographic data for the structural analysis have been deposited with the Cambridge Crystallographic Data Centre, CCDC Nos. 154678 and 154679 for compounds 1 and 2, respectively. Copies of this information may be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: +44-1223-336033; e-mail: [email protected]. ac.uk or www: http://www.ccdc.cam.ac.uk).
Acknowledgements The authors thank the Welch Foundation for financial support.
References [1] S. Subramanian, M.J. Zaworotko, Angew. Chem., Int. Ed. Engl. 34 (1995) 2127. [2] B.F. Hoskins, R. Robson, J. Am. Chem. Soc. 112 (1990) 1546.
.
2449
[3] J.Y. Lu, A.M. Babb, Chem. Commun. (2001) 821. [4] J. Lu, G. Crisci, T. Niu, A.J. Jacobson, Inorg. Chem. 36 (1997) 5140. [5] O.M. Yaghi, H. Li, C. Davis, D. Richardson, T.L. Groy, Acc. Chem. Res. 31 (1998) 474. [6] C. Janiak, Angew. Chem., Int. Ed. Engl. 36 (1997) 1431. [7] M. Zaworotko, J. Chem. Soc. Rev. (1994) 283. [8] S.R. Batten, R. Robson, Angew. Chem., Int. Ed. Engl. 37 (1998) 1461. [9] Y.-B. Dong, M.D. Smith, R.C. Layland, H.-C. zur Loye, Chem. Mater. 12 (2000) 1156. [10] D. Braga, F. Grepioni, Acc. Chem. Res. 33 (2000) 601. [11] G.R. Desiraju, Acc. Chem. Res. 29 (1996) 441. [12] O. Fe´ lix, M.W. Hosseini, A. De Cian, J. Fischer, Chem. Commun. (2000) 281. [13] P.V. Bernhardt, Inorg. Chem. 38 (1999) 3481. [14] J.Y. Lu, A. Babb, Inorg. Chim. Acta 318 (2001) 816. [15] J. Lu, T. Paliwala, S.C. Lim, C. Yu, T. Niu, A.J. Jacobson, Inorg. Chem. 36 (1997) 923. [16] R.H. Groeneman, L.R. MacGillivray, J.L. Atwood, Inorg. Chem. 38 (1999) 208. [17] A.J. Blake, S.J. Hill, P. Hubberstey, W. Li, J. Chem. Soc., Dalton Trans. (1997) 913. [18] O.M. Yaghi, H. Li, T.L. Groy, J. Am. Chem. Soc. 118 (1996) 9096. [19] D. Venkataraman, S. Lee, J. Zhang, J.S. Moore, Nature 371 (1994) 591. [20] (a) S. Decurtins, H.W. Schmalle, P. Schneuwly, H.R. Oswald, Inorg. Chem. 32 (1993) 1888; (b) P. Roman, C. Guzman-Miralles, A. Luque, J.I. Beitia, J. Cano, F. Lloret, M. Julve, S. Alvarez, Inorg. Chem. 35 (1996) 3741; (c) J.Y. Lu, M.A. Lawandy, J. Li, Inorg. Chem. 38 (1999) 2695. [21] R. Cle´ rac, F.A. Cotton, K.R. Dunbar, C.A. Murillo, I. Pascual, X. Wang, Inorg. Chem. 38 (1999) 2655.
Two new coordination polymers differentiated by CH···O hydrogen bonding — synthesis and crystal structure of [(oxa)M(DPA)] Jack Y. Lu a,*, Timothy J. Schroeder a, Amy M. Babb a, Marilyn Olmstead b a
Department of Chemistry, Uni6ersity of Houston — Clear Lake, Houston, TX 77058, USA b Department of Chemistry, Uni6ersity of California at Da6is, Da6is, CA 95616, USA Received 28 December 2000; accepted 1 May 2001
Abstract Two new coordination polymers, [(oxa)Fe(DPA)] (1) (DPA= 2,2-dipyridylamine; oxa = oxalate) and [(oxa)Ni(DPA)] (2), were synthesized through a self-assembly chemical process under hydrothermal conditions, and characterized by single crystal structures. The CH···O hydrogen bonds in 1 and 2 play important roles in the crystal packing of the two new compounds. © 2001 Elsevier Science Ltd. All rights reserved. Keywords: Coordination polymers; Oxalate; 2,2-Dipyridylamine; Cobalt; Nickel; Hydrogen bonds
1. Introduction Crystal engineering of metal – organic polymers with functional building blocks may produce framework polymers with tunable properties [1 – 5]. The directionality of the covalent bonds resulting from metal –organic ligand interactions has been extensively exploited for the synthesis of framework coordination polymers [5 – 9]. Compared to the crystal engineering of organic and supramolecular design, the directionality of hydrogen bonds and their influence on crystal packing in coordination polymers are less developed [10 – 13]. In tuning the network structures and properties of metal – organic polymers, many subtle interactions such as weaker hydrogen bonds need to be considered. The detailed information regarding such interactions and their reproducibility in constructing networks is essential and constitutes extremely challenging subjects [10]. While hydrogen bonds are widely used in building supramolecular structures, the new findings of such interactions in coordination polymers for rational design and construction of new framework structures are * Corresponding author. Tel.: + 1-281-283-3780; fax: +1-281-2833707. E-mail address: [email protected] (J.Y. Lu).
apparently important. Here, we wish to report the synthesis and crystal structures of two new metal –organic polymers, [(oxa)Fe(DPA)] (1) (DPA =2,2dipyridylamine; oxa= oxalate) and [(oxa)Ni(DPA)] (2), with both NH···O and CH···O hydrogen bonds that play a key role in the crystal packing of the two new structures.
2. Experimental
2.1. Materials and methods All chemicals were purchased from Aldrich and used without further purification. Thermal gravimetric analysis and differential thermal analysis were performed on a TGA 2050 thermal gravimetric analyzer with a heating rate of 10 °C min − 1.
2.2. Synthesis Both compounds 1 and 2 were synthesized by reacting FeBr2 (0.2157 g, 0.0010 mol) or NiBr2 (0.2185 g, 0.0010 mol) with oxalic acid (0.1261 g, 0.0010 mol) and 2,2-dipyridylamine (0.1712 g, 0.0010 mol) in the molar ratio 1:1:1 in 6 ml water. The reactions were carried out
0277-5387/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S 0 2 7 7 - 5 3 8 7 ( 0 1 ) 0 0 8 5 9 - 2
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
2446
in a 23 ml acid digestion bomb at 180 °C for 3 days. The products, orange– yellow crystals of 1 and blue crystals of 2, were washed with water and acetone and dried in air. The yields are 76% for 1 and 85% for 2. Both 1 and 2 are insoluble in DMF, THF, CH3CN, Table 1 Crystal data and structure refinement parameters for [(oxa)Fe(DPA)] and [(oxa)Ni(DPA)] Empirical formula Formula weight Temperature (°C) Crystal system Space group a (A, ) b (A, ) c (A, ) i (°) V (A, 3) Z v cm−1 R1 (observed data) wR2 (all data)
C12H9FeN3O4 315.07 −183(2) monoclinic P21/c 8.0213(5) 17.0822(11) 9.7929(14) 112.0560(10) 1243.64(14) 4 12.29 0.0341 0.0835
C12H9NiN3O4 317.93 −183(2) monoclinic C2/c 12.0929(6) 12.1868(6) 17.2851(9) 96.4060(10) 2531.5(2) 8 15.49 0.0329 0.0834
Table 2 Selected bond lengths (A, ) and bond angles (°) for [(oxa)Fe(DPA)] Bond lengths (A, ) Fe(1)O(4) Fe(1)O(1) Fe(1)N(1) Fe(1)N(3) Fe(1)O(3)
2.0616(12) 2.1066(12) 2.1417(14) 2.1422(14) 2.2232(12)
Fe(1)O(2) O(1)C(11) O(2)C(11) O(3)C(12)
2.2235(12) 1.2699(19) 1.239(2) 1.246(2)
Bond angles ( °) O(4)Fe(1)O(1) O(4)Fe(1)N(1) O(1)Fe(1)N(1) O(4)Fe(1)N(3) O(1)Fe(1)N(3) N(1)Fe(1)N(3) O(4)Fe(1)O(3) O(3)Fe(1)O(2)
155.86(5) 105.31(5) 91.55(5) 99.30(5) 98.65(5) 87.22(5) 77.69(5) 81.87(5)
O(1)Fe(1)O(3) N(1)Fe(1)O(3) N(3)Fe(1)O(3) O(4)Fe(1)O(2) O(1)Fe(1)O(2) N(1)Fe(1)O(2) N(3)Fe(1)O(2)
83.24(5) 97.13(5) 175.22(5) 86.00(5) 76.68(4) 168.23(5) 94.26(5)
Table 3 Selected bond lengths (A, ) and bond angles (°) for [(oxa)Ni(DPA)] Bond lengths (A, ) Ni(1)N(1) 2.0288(15) Ni(1)O(1) 2.0362(13) Ni(1)N(3) 2.0618(16) Bond angles ( °) N(1)Ni(1)O(1) N(1)Ni(1)N(3) O(1)Ni(1)N(3) N(1)Ni(1)O(2) O(1)Ni(1)O(2) N(3)Ni(1)O(2) N(1)Ni(1)O(4) O(1)Ni(1)O(4)
91.97(6) 88.82(6) 98.88(6) 173.59(6) 81.75(5) 93.41(6) 96.43(6) 167.86(5)
Ni(1)O(2) Ni(1)O(4) Ni(1)O(3)
2.0694(13) 2.0739(13) 2.0906(14)
N(3)Ni(1)O(4) O(2)Ni(1)O(4) N(1)Ni(1)O(3) O(1)Ni(1)O(3) N(3)Ni(1)O(3) O(2)Ni(1)O(3) O(4)Ni(1)O(3)
90.07(6) 89.58(5) 94.07(6) 90.14(5) 170.44(6) 84.70(5) 80.56(5)
Table 4 Hydrogen bonds for [(oxa)Fe(DPA)] in (A, ) and (°) D−H···A
d(DH)
N(2)−H(2)···O(1)c3 0.88 C(7)−H(7)···O(1)c 3 0.95 C(9)−H(9)···O(4)c4 0.95
d(H···A) d(D···A)
Ú(DHA)
2.01 2.49 2.49
159.9 137.2 161.4
2.853(2) 3.249(2) 3.403(2)
Symmetry transformations used to generate equivalent atoms: c 1 −x+1,−y+2,−z+1; c 2 −x+2,−y+2,−z+1; c 3 x,−y+3/ 2,z−1/2; c 4 −x+1,−y+2,−z.
CH2Cl2, benzene, toluene, or water. Elemental analysis: Compound 1: Anal. Found: Fe, 17.93; C, 45.36; N, 13.17; H, 3.00. Calc. Fe, 17.73; O, 20.32; C, 45.71; N, 13.30; H, 2.86%. Compound 2: Anal. Found: Ni, 18.19; C, 45.06; N, 12.96; H, 2.92. Calc. Ni, 18.46; O, 20.13; C, 45.29; N, 13.21; H, 2.83%.
2.3. Single-crystal structure determination 2.3.1. X-ray structure determination of [(oxa)Fe(DPA)] An orange–yellow block of dimensions 0.14× 0.18× 0.30 mm was mounted in the 90 K nitrogen cold stream provided by a CRYO Industries low-temperature apparatus on the goniometer head of a Bruker SMART 1000 diffractometer. Diffraction data were collected with graphite-monochromated Mo Ka radiation employing a 0.3° scan and approximately a full sphere of data to a maximum 2[ of 63°. An empirical correction for absorption was applied using the program SADABS 2.0. A total of 17007 reflections were collected, of which 3972 were unique (Rint = 0.046) and 3099 were observed (I\ 2|(I)). The structure was solved by direct methods (SHELXS-97) and refined by full-matrix least-squares on F 2. All non-hydrogen atoms were refined with anisotropic thermal parameters. Hydrogen atoms were refined using a riding model. The maximum and minimum peaks in the final difference Fourier map corresponded to 0.513 and −0.294 e A, − 3. Crystal data and additional details are provided in Table 1. Selected bond distances and angles are listed in Table 2. Hydrogen-bond distances and angles are listed in Table 4. 2.3.2. X-ray structure determination of [(oxa)Ni(DPA)] A blue plate of dimensions 0.07× 0.16× 0.19 mm was selected for data collection and handled in the same manner as for the Fe compound. A total of 33405 reflections were collected, of which 4016 were unique (Rint = 0.038) and 3141 were observed. The structure was solved and refined as above. The maximum and minimum peaks in the final difference Fourier map corresponded to 0.605 and −0.537 e A, − 3. Crystal data and additional details are provided in Table 1. Selected bond distances and angles are listed in Table 3. Hydrogen-bond distances and angles are listed in Table 5.
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
2447
Table 5 Hydrogen bonds for [(oxa)Ni(DPA)] in (A, ) and (°) D−H···A
d(DH)
C(3)−H(3)···O(1)c 3 0.95 N(2)−H(2)···O(4)c 4 0.88
d(H···A) d(D···A)
Ú(DHA)
2.44 2.03
168.2 171.2
3.374(2) 2.906(2)
Symmetry transformations used to generate equivalent atoms: c1 −x+3/2,−y+1/2,−z+1; c2 −x+1,−y,−z+1; c3 −x+3/2, y−1/2,−z+1/2; c4 −x+3/2,−y−1/2,−z+1.
3. Results and discussion Complex 1 consists of octahedral metal centers of the iron atom surrounded by two tetradentate oxalates and one bidentate DPA ligand (Fig. 1) and is extended as twisted zigzag one-dimensional chains (Fig. 2). The twisting of the one-dimensional chains is in such a way that one pair of the N− H···O (N(2) − H(2)···O(1) 2.8534(18) A, ) and C − H···O (C(7) − H(7)···O(1) 3.249(2) A, ) hydrogen bonds from the same DPA molecule can link to the same oxygen atom in the adjacent chain to form a mixed NH···O and CH···O hydrogen bonding linkage (Fig. 2). These mixed NH···O and CH···O hydrogen-bond pairs are not mutually linked between the two adjacent one-dimensional chains; it is only one way and the other C− H···O (C(9)−H(9)···O(4) 3.403(2) A, ) hydrogen bonds are formed between one chain in this pair and another chain (Fig. 3), and this linking pathway propagates to result in a three-dimensional network. Similar to the structure of 1, the structure of 2 also consists of octahedral nickel metal centers coordinated by two oxalate ligands and one DPA ligand (Fig. 4) to form zigzag chains along the [110] direction (Fig. 5). The one-dimensional chains are then linked by NH···O hydrogen bonds (N(2) −H(2)···O(4) 2.906(2) A, ) in one direction (Fig. 5) and CH···O hydrogen bonds (C(3)− H(3)···O(1) 3.374(2) A, ) in another direction (Fig. 6) to result in a three-dimensional structure. The NH···O
Fig. 1. The basic unit in [(oxa)Fe(DPA)] with numbering scheme and the thermal ellipsoids at the 50% probability level.
Fig. 2. View of the NH···O and CH···O hydrogen-bonding pair in [(oxa)Fe(DPA)].
hydrogen bonds in 2 are mutually formed between the two adjacent one-dimensional chains (Fig. 5). Compared with the crystal structure of [(oxa)Co(DPA)] [14] in which only mutual N− H···O (N(H)···O, 2.879(2) A, ) hydrogen bonds are formed between the two adjacent one-dimensional chains, and with the absence of CH···O hydrogen bonds it resulted in a two-dimensional structure. Although the NH···O hydrogen bonds are much weaker relative to the covalent bonds, the directionality of the NH···O hydrogen bonding is strongly shown in these structures. The CH···O hydrogen bonds formed in 1 and 2 are clearly different and they contribute directly to the formation of the threedimensional structures although the real reason for the difference is not completely understood. Hydrogen bonds have now been widely used in the crystal engineering of coordination polymers [15–19], but the CH···O hydrogen bonds found in 1 and 2 and their influence on crystal packing are different. It has been reviewed that in general, the CH···O hydrogen bonds determine crystal packing when stronger hydrogen bonding is absent in supramolecular structures [11]. In the cases of 1 and 2, it is clear that the CH···O
2448
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
hydrogen bonds are strong enough even when the stronger covalent bonding and NH···O hydrogen bonding are present so that the new crystal packing structures are resulted where the different orientations of the oxalate ligands in the chains were formed to comply with the linking requirement. The metaloxygen distances, FeO, in 1 range from 2.062(1) to 2.224(1) A, , and NiO distances in 2 vary from 2.036(1) to 2.091(1) A, , and are comparable with those found in oxalato complexes (FeO, 1.962(2)– 2.039(2) A, ; NiO, 2.10(2)– 2.13(1) A, ) [20a,b] (FeO, 2.116(4) A, ; NiO, 2.048(2) A, ) [20c]. The NiN dis-
Fig. 5. One-dimensional zigzag chains along [110] with mutual NH···O hydrogen bonds in [(oxa)Ni(DPA)].
Fig. 3. One-dimensional twisted zigzag chains with C −H···O (C(9)− H(9)···O(4) 3.403(2) A, ) hydrogen bonds in [(oxa)Fe(DPA)].
Fig. 6. View of the CH···O and NH···O hydrogen bonding in the structure of [(oxa)Ni(DPA)].
tances ranging from 2.029(2) to 2.062(2) A, are comparable with those found in Ni3(DPA)4Cl2·THF (1.889(5)–2.099(5) A, ) [21]. The thermal analyses for 1 and 2 indicate that they are very stable and undergo a single-step weight loss. Compound 1 lost both oxalate and dipyridylamine ligands from approximately 280 to 330 °C. The compound 2 is thermally stable up to 377 °C and the decomposition process was completed at 470 °C.
4. Conclusions Fig. 4. The basic unit in [(oxa)Ni(DPA)] with numbering scheme and the thermal ellipsoids at the 50% probability level.
The present study has shown that the CH···O hydrogen bonds play important roles in the crystal pack-
J.Y. Lu et al. / Polyhedron 20 (2001) 2445–2449
ing of the coordination polymers. While we are tuning network structures and properties of metal– organic polymers, detailed information regarding hydrogenbonding interactions and their reproducibility are essential and should be extensively explored.
5. Supplementary material Crystallographic data for the structural analysis have been deposited with the Cambridge Crystallographic Data Centre, CCDC Nos. 154678 and 154679 for compounds 1 and 2, respectively. Copies of this information may be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: +44-1223-336033; e-mail: [email protected]. ac.uk or www: http://www.ccdc.cam.ac.uk).
Acknowledgements The authors thank the Welch Foundation for financial support.
References [1] S. Subramanian, M.J. Zaworotko, Angew. Chem., Int. Ed. Engl. 34 (1995) 2127. [2] B.F. Hoskins, R. Robson, J. Am. Chem. Soc. 112 (1990) 1546.
.
2449
[3] J.Y. Lu, A.M. Babb, Chem. Commun. (2001) 821. [4] J. Lu, G. Crisci, T. Niu, A.J. Jacobson, Inorg. Chem. 36 (1997) 5140. [5] O.M. Yaghi, H. Li, C. Davis, D. Richardson, T.L. Groy, Acc. Chem. Res. 31 (1998) 474. [6] C. Janiak, Angew. Chem., Int. Ed. Engl. 36 (1997) 1431. [7] M. Zaworotko, J. Chem. Soc. Rev. (1994) 283. [8] S.R. Batten, R. Robson, Angew. Chem., Int. Ed. Engl. 37 (1998) 1461. [9] Y.-B. Dong, M.D. Smith, R.C. Layland, H.-C. zur Loye, Chem. Mater. 12 (2000) 1156. [10] D. Braga, F. Grepioni, Acc. Chem. Res. 33 (2000) 601. [11] G.R. Desiraju, Acc. Chem. Res. 29 (1996) 441. [12] O. Fe´ lix, M.W. Hosseini, A. De Cian, J. Fischer, Chem. Commun. (2000) 281. [13] P.V. Bernhardt, Inorg. Chem. 38 (1999) 3481. [14] J.Y. Lu, A. Babb, Inorg. Chim. Acta 318 (2001) 816. [15] J. Lu, T. Paliwala, S.C. Lim, C. Yu, T. Niu, A.J. Jacobson, Inorg. Chem. 36 (1997) 923. [16] R.H. Groeneman, L.R. MacGillivray, J.L. Atwood, Inorg. Chem. 38 (1999) 208. [17] A.J. Blake, S.J. Hill, P. Hubberstey, W. Li, J. Chem. Soc., Dalton Trans. (1997) 913. [18] O.M. Yaghi, H. Li, T.L. Groy, J. Am. Chem. Soc. 118 (1996) 9096. [19] D. Venkataraman, S. Lee, J. Zhang, J.S. Moore, Nature 371 (1994) 591. [20] (a) S. Decurtins, H.W. Schmalle, P. Schneuwly, H.R. Oswald, Inorg. Chem. 32 (1993) 1888; (b) P. Roman, C. Guzman-Miralles, A. Luque, J.I. Beitia, J. Cano, F. Lloret, M. Julve, S. Alvarez, Inorg. Chem. 35 (1996) 3741; (c) J.Y. Lu, M.A. Lawandy, J. Li, Inorg. Chem. 38 (1999) 2695. [21] R. Cle´ rac, F.A. Cotton, K.R. Dunbar, C.A. Murillo, I. Pascual, X. Wang, Inorg. Chem. 38 (1999) 2655.