Bis(tri­ethanol­amine)­bis­(μ₂-trimesato)dicobalt(II): a Co^II dimer with an unreported two-dimensional supra­molecular topology formed from tri­ethanol­amine and trimesic acid ligands

Supra­molecular networks are an important subset in the field of coordination polymer (CP) frameworks and are widely encountered in crystal engineering research. The search for novel topologies continues to be a significant goal in CP chemistry. The dimeric compound bis­(μ-5-carb­oxy­benzene-1,3-di­carboxyl­ato-κ²O¹:O³)bis­[(tri­ethanol­amine-κ⁴N,O,O′,O′′)cobalt(II)], [Co₂(C₉H₄O₆)₂(C₆H₁₅NO₃)₂], formed from the coligands 5-carb­oxy­benzene-1,3-di­carboxyl­ate (tmaH²⁻) and tri­ethanol­amine (teaH₃), namely [Co(μ₂-tmaH)(teaH₃)]₂, was synthesized and characterized by single-crystal and powder X-ray diffraction analyses, IR spectroscopy, thermogravimetric analysis (TGA) and magnetic measurements. The crystal structure features a zero-dimensional mol­ecular structure consisting of centrosymmetric macrocyclic dinuclear complexes. Four classical hydrogen bonds between carboxyl­ate groups and hy­droxy­ethyl arms stabilize and extend the mol­ecules into a two-dimensional supra­molecular network. The topological analysis indicates that an unreported (3,5)-binodal supra­molecular topology with a short Schläfli symbol of (4.5.6)(4.5⁵.6³.7) can be achieved by means of inter­molecular hydrogen bonds. The crystal structure accounts for the potential to obtain unique topological types from two excellent hydrogen-bonding candidates, i.e. tmaH₃ and teaH₃. A variable-temperature magnetic study shows the existence of anti­ferromagnetic behaviour in the complex.

S1. Introduction

Supra­molecular networks are an important subset in the field of coordination polymer (CP) frameworks and are widely encountered in crystal engineering research (Kumar et al., 2007; Dias et al., 2014; Alexandrov et al., 2011). It is now well established that hydrogen bonds, in particular, have provided a fertile ground for the supra­molecular networks of CPs. For the CP family, one of the most fascinating aspects is their topological aesthetics (Yang et al., 2012). Although a large number of topological networks have been found, the search for novel topologies continues to be a significant object in CP chemistry. In this regard, hydrogen-bonding inter­actions represent considerable potential for achieving unique topological types (Zolotarev et al., 2014). A challenging issue for producing the desired supra­molecular network is to select suitable hydrogen-bond donors and acceptors. Trimesic acid (tmaH₃; systematic name: benzene-1,3,5-tri­carb­oxy­lic acid), which possesses three symmetric exo-carboxyl groups around the benzene ring, has attracted considerable inter­est as an excellent organic spacer to construct coordination polymer frameworks (Du et al., 2006). The three carb­oxy­lic acid groups of tmaH₃ can be deprotonated and behave as proton donors to play an important role in the formation of a hydrogen-bonded supra­molecular network. Tri­ethano­lamine (teaH₃) is a versatile ligand containing one amine group and three ethanol arms. Similar to tmaH₃, teaH₃ can also act as a trianionic, dianionic, monoanionic or neutral ligand to coordinate to metal centres according to its degree of deprotonation (Xu et al., 2013, 2015). On the other hand, the three hy­droxy arms make teaH₃ an excellent candidate for hydrogen-bond donation. In this work, we focus on extending our previous work on supra­molecular networks based on the strategy of combining polyalcohol amines with organic carboxyl­ates. As a follow-up to that research, we chose tmaH₃ and teaH₃ to explore their contributions to the formation of special supra­molecular networks. A new dimer, [Co(teaH₃)(µ₂-tmaH)]₂, (I), with a unique two-dimensional supra­molecular topology has been isolated and characterized by single-crystal and powder X-ray diffraction analyses. The novel supra­molecular topology was analysed, and the solid-state IR spectrum of (I) was also investigated, together with its thermal stability and magnetic properties.

S2. Experimental

S2.1. Synthesis and crystallization

A mixture of CoSO₄.7H₂O (0.0360 g, 0.13 mmol) and trimesic acid (tmaH₃) (0.0273 g, 0.13 mmol) in ethanol (12 ml) was stirred for 10 min, and then teaH₃ (0.18 ml) was added and the mixture stirred for a further 20 min. The resulting solution was transferred into a 17 ml Teflon-lined stainless steel container and heated at 393 K for 48 h. After cooling to room temperature, pink block-shaped crystals of (I) were collected in 86.5% yield based on the added amounts of CoSO₄.7H₂O. Analysis, calculated for C₁₅H₁₉CoNO₉: C 43.28, H 4.60, N 3.37%; found: C 43.23, H 4.62, N 3.40%. Selected IR data (KBr pellet, ν, cm^-1): 461 (m), 563 (m), 719 (s), 906 (w), 1030 (w), 1100 (w), 1370 (s), 1430 (s), 1520 (s), 1610 (s), 3150 (w), 3360 (w).

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. All C-bound H atoms were refined using a riding model, with C—H = 0.93 Å for aromatic and C—H = 0.97 Å for CH₂ H atoms, both with U_iso(H) = 1.2U_eq(C). The hy­droxy H atoms were located in a difference Fourier map and their positions were refined under the application of an O—H bond-length restraint of 0.90 (1) Å, with U_iso(H) = 1.5U_eq(O).

S3. Results and discussion

Single-crystal X-ray diffraction reveals that one independent Co^II cation, one tmaH^2- dianionic ligand and one neutral teaH₃ ligand are present in the asymmetric unit of (I). As shown in Figs. 1 and 2, compound (I) features a zero-dimensional molecular structure in which a dimer can be formed through an inversion centre symmetry. The inversion centre occurs at the centroid of the dimer. Atom Co1 shows a six-coordinated {CoO₅N} o­cta­hedral geometry which is completed by two O atoms from a tmaH^2- ligand and its inversion-related counterpart, and by four coordinating atoms (N1, O7, O8 and O9) of a neutral teaH₃ ligand. In the dimer, each Co^II cation is double-bridged to its inversion-related Co^II cation through two tmaH^2- ligands, resulting in a square four-membered window with a Co···Co separation of 8.086 Å. However, the two Co^II centres are terminated by chelating teaH₃ molecules so that no available position is set aside for providing opportunities for structure extension (Fig. 2). The Co—O and Co—N bond lengths are comparable with the corresponding values found in other Co^II complexes (Xu et al., 2015). The heavy distortion of the o­cta­hedral environment around the Co^II centre is manifested by three trans angles, which range from 156.26 (6) to 176.43 (6)°. Key bond lengths and angles are listed in Table 2.

No hy­droxy arm of the teaH₃ ligand is deprotonated, so that teaH₃ ligand serves as an N,O,O',O''-tetra­dentate neutral species chelating one metal centre. The tmaH^2- ligand uses its two deprotonated COO^- groups to build up a µ₂-κ¹,κ¹ connection towards two Co^II cations from one dimer. Each deprotonated COO^- group adopts a monodentate coordination mode to coordinate with different Co^II cations. The protonated –COOH group points out towards the `window' of the adjacent dimer. It is noteworthy that the dihedral angle [0.8 (2)°] between the –COOH plane and the attached benzene ring in the tmaH^2- ligand is significantly less than those values observed for the deprotonated COO^- groups [12.2 (2) and 37.8 (3)°]. This indicates the different rotations around the C—C axes (C6—C9, C1—C2 and C4—C8) in response to the steric requirements for forming the dimer.

The noteworthy feature for (I) is the supra­molecular assembly of dimers into a two-dimensional network. Both the neutral teaH₃ ligand and the doubly deprotonated tmaH^2- dianionic ligand are engaged in hydrogen-bonding inter­actions. There are four classical hydrogen bonds between tmaH^2- carboxyl­ate groups and the hy­droxy­ethyl arms of teaH₃ ligands (Table 3). According to their different orientations, these hydrogen bonds can be divided into two types, namely intra- and inter­molecular. Within the dimer, each deprotonated COO^- group forms strong intra­molecular hydrogen bonds (O7—H01···O4ⁱ and O9—H03···O1; see Table 3 for details and symmetry codes) which further consolidate the dimer framework (Fig. 2). However, the –COOH group is hydrogen-bonded to the deprotonated COO^- group of an adjacent dimer (O6—H04···O2ⁱⁱ). In addition, another hydrogen bond (O8—H02···O4ⁱⁱⁱ) is observed between a COO^- group and a hy­droxy­ethyl arm of a neighbouring dimer. Therefore, each dimer is linked to four other dimers through two hydrogen bonds and symmetry-related counterparts (eight hydrogen bonds in total). The two inter­molecular hydrogen bonds extend each dimer into an open two-dimensional framework in an inter­crossed manner (Fig. 3). However, despite all these hydrogen bonds, the final unique supra­molecular structure is packed through van der Waals forces instead of hydrogen bonds. [Text added to emphasise this point - OK?]

For a better insight into the supra­molecular assembly of (I), we carried out a topological analysis (see the supporting information) using the TOPOS program (Blatov et al., 2014). The topological method involves simplifying intricate structures into node-and-linker nets (Batten et al., 2009). The dimer of (I) can be simplified into a square skeleton if the [Co^II(COO)₂(teaH₃)] unit and the trimesate benzene ring are regarded as nodes. Taking the inter­molecular hydrogen bonds into account, the [Co^II(COO)₂(teaH₃)] unit can be regarded as a five-connected node, while the central benzene ring can be regarded as a three-connected node. The square skeleton is crosslinked into a (3,5)-binodal two-dimensional supra­molecular topology with a short Schläfli symbol of (4.5.6)(4.5⁵.6³.7) (Fig. 4). To the best of our knowledge, this supra­molecular topology is unknown and significantly enriches the pool of topological aesthetics.

The match between simulated and experimental X-ray powder diffraction (XRPD) patterns for the as-synthesized sample of (I) is good, indicating the phase purity of the product (Fig. 5). The IR spectrum is depicted in Fig. 6 and the main adsorption peaks are listed in the Experimental section. Thermogravimetric analysis (TGA) was performed using a Pyris Diamond thermal analyser. Approximately 10 mg samples were heated under an N₂ atmosphere in the temperature range from room temperature to 1073 K, at a heating rate of 10 K min^-1. As shown in Fig. 7, the TGA curve indicates that the host framework is stable up to 393 K and is finally converted into crystalline cobalt oxide in agreement with the overall mass loss (observed 79.5 wt%, calculated 81.9 wt%). The TGA trace shows that the thermal decomposition takes place in two stages. The first stage is a process to eliminate teaH₃ ligands in the range 423—573 K (observed 30.1 wt%, calculated 35.7 wt%). The obvious difference between the observed and calculated values might be due to the requirement for O atoms to satisfy the coordination geometry of the Co^II cations, so that it is not necessary to lose the total weight of the teaH₃ ligands. The second decomposition stage corresponds to loss of the tmaH^2- linker above 573 K (observed 49.4 wt%, calculated 50.0 wt%). The release of polyalcohol amines prior to organic carboxyl­ate linkers has been documented (Yeşilel & Ölmez, 2007).

A temperature-dependent magnetic measurement was performed on a single-crystalline sample of (I) (0.0159 g) in the range 2–300 K under a field of 1 kOe. For a detailed structure analysis of the Co dimer, the magnetic topology can be treated as a Co₂ system. The curves are plotted as the form of χ_MT and 1/χ_M versus T (Fig. 8). The χ_MT value at 300 K is 5.80 cm³ K mol^-1, which is much larger than the expected value (3.75 cm³ K mol^-1) for two isolated HS [high-spin?] Co^II centres with S = 3/2 and g = 2.0 state (Liu et al., 2007). This can be attributed to the significant orbital contribution of the o­cta­hedral Co^II cations (Konar et al., 2003). As the temperature decreases, the χ_MT value gradually decreases and reaches a minimum of 3.48 cm³ K mol^-1 at 2 K, which is possibly ascribed to inter­ionic anti­ferromagnetic inter­action or spin-orbit coupling effects (Tao et al., 2013). The magnetic susceptibility above 30 K obeys the Curie–Weiss law, with the Weiss constant Θ = -11.94 K and the Curie constant C = 6.00 cm³ mol^-1 K. The negative Θ value reveals the presence of an anti­ferromagnetic inter­action in (I) (Chen et al., 2009).

In summary, the crystal structure of (I) clearly illustrates that the combination of tri­ethano­lamine and trimesic acid provides the hydrogen-bonding opportunity to explore novel supra­molecular topologies. This strategy towards supra­molecular topological aesthetics is still a work in progress in our laboratory.

Structure description

Supra­molecular networks are an important subset in the field of coordination polymer (CP) frameworks and are widely encountered in crystal engineering research (Kumar et al., 2007; Dias et al., 2014; Alexandrov et al., 2011). It is now well established that hydrogen bonds, in particular, have provided a fertile ground for the supra­molecular networks of CPs. For the CP family, one of the most fascinating aspects is their topological aesthetics (Yang et al., 2012). Although a large number of topological networks have been found, the search for novel topologies continues to be a significant object in CP chemistry. In this regard, hydrogen-bonding inter­actions represent considerable potential for achieving unique topological types (Zolotarev et al., 2014). A challenging issue for producing the desired supra­molecular network is to select suitable hydrogen-bond donors and acceptors. Trimesic acid (tmaH₃; systematic name: benzene-1,3,5-tri­carb­oxy­lic acid), which possesses three symmetric exo-carboxyl groups around the benzene ring, has attracted considerable inter­est as an excellent organic spacer to construct coordination polymer frameworks (Du et al., 2006). The three carb­oxy­lic acid groups of tmaH₃ can be deprotonated and behave as proton donors to play an important role in the formation of a hydrogen-bonded supra­molecular network. Tri­ethano­lamine (teaH₃) is a versatile ligand containing one amine group and three ethanol arms. Similar to tmaH₃, teaH₃ can also act as a trianionic, dianionic, monoanionic or neutral ligand to coordinate to metal centres according to its degree of deprotonation (Xu et al., 2013, 2015). On the other hand, the three hy­droxy arms make teaH₃ an excellent candidate for hydrogen-bond donation. In this work, we focus on extending our previous work on supra­molecular networks based on the strategy of combining polyalcohol amines with organic carboxyl­ates. As a follow-up to that research, we chose tmaH₃ and teaH₃ to explore their contributions to the formation of special supra­molecular networks. A new dimer, [Co(teaH₃)(µ₂-tmaH)]₂, (I), with a unique two-dimensional supra­molecular topology has been isolated and characterized by single-crystal and powder X-ray diffraction analyses. The novel supra­molecular topology was analysed, and the solid-state IR spectrum of (I) was also investigated, together with its thermal stability and magnetic properties.

Single-crystal X-ray diffraction reveals that one independent Co^II cation, one tmaH^2- dianionic ligand and one neutral teaH₃ ligand are present in the asymmetric unit of (I). As shown in Figs. 1 and 2, compound (I) features a zero-dimensional molecular structure in which a dimer can be formed through an inversion centre symmetry. The inversion centre occurs at the centroid of the dimer. Atom Co1 shows a six-coordinated {CoO₅N} o­cta­hedral geometry which is completed by two O atoms from a tmaH^2- ligand and its inversion-related counterpart, and by four coordinating atoms (N1, O7, O8 and O9) of a neutral teaH₃ ligand. In the dimer, each Co^II cation is double-bridged to its inversion-related Co^II cation through two tmaH^2- ligands, resulting in a square four-membered window with a Co···Co separation of 8.086 Å. However, the two Co^II centres are terminated by chelating teaH₃ molecules so that no available position is set aside for providing opportunities for structure extension (Fig. 2). The Co—O and Co—N bond lengths are comparable with the corresponding values found in other Co^II complexes (Xu et al., 2015). The heavy distortion of the o­cta­hedral environment around the Co^II centre is manifested by three trans angles, which range from 156.26 (6) to 176.43 (6)°. Key bond lengths and angles are listed in Table 2.

No hy­droxy arm of the teaH₃ ligand is deprotonated, so that teaH₃ ligand serves as an N,O,O',O''-tetra­dentate neutral species chelating one metal centre. The tmaH^2- ligand uses its two deprotonated COO^- groups to build up a µ₂-κ¹,κ¹ connection towards two Co^II cations from one dimer. Each deprotonated COO^- group adopts a monodentate coordination mode to coordinate with different Co^II cations. The protonated –COOH group points out towards the `window' of the adjacent dimer. It is noteworthy that the dihedral angle [0.8 (2)°] between the –COOH plane and the attached benzene ring in the tmaH^2- ligand is significantly less than those values observed for the deprotonated COO^- groups [12.2 (2) and 37.8 (3)°]. This indicates the different rotations around the C—C axes (C6—C9, C1—C2 and C4—C8) in response to the steric requirements for forming the dimer.

The noteworthy feature for (I) is the supra­molecular assembly of dimers into a two-dimensional network. Both the neutral teaH₃ ligand and the doubly deprotonated tmaH^2- dianionic ligand are engaged in hydrogen-bonding inter­actions. There are four classical hydrogen bonds between tmaH^2- carboxyl­ate groups and the hy­droxy­ethyl arms of teaH₃ ligands (Table 3). According to their different orientations, these hydrogen bonds can be divided into two types, namely intra- and inter­molecular. Within the dimer, each deprotonated COO^- group forms strong intra­molecular hydrogen bonds (O7—H01···O4ⁱ and O9—H03···O1; see Table 3 for details and symmetry codes) which further consolidate the dimer framework (Fig. 2). However, the –COOH group is hydrogen-bonded to the deprotonated COO^- group of an adjacent dimer (O6—H04···O2ⁱⁱ). In addition, another hydrogen bond (O8—H02···O4ⁱⁱⁱ) is observed between a COO^- group and a hy­droxy­ethyl arm of a neighbouring dimer. Therefore, each dimer is linked to four other dimers through two hydrogen bonds and symmetry-related counterparts (eight hydrogen bonds in total). The two inter­molecular hydrogen bonds extend each dimer into an open two-dimensional framework in an inter­crossed manner (Fig. 3). However, despite all these hydrogen bonds, the final unique supra­molecular structure is packed through van der Waals forces instead of hydrogen bonds. [Text added to emphasise this point - OK?]

For a better insight into the supra­molecular assembly of (I), we carried out a topological analysis (see the supporting information) using the TOPOS program (Blatov et al., 2014). The topological method involves simplifying intricate structures into node-and-linker nets (Batten et al., 2009). The dimer of (I) can be simplified into a square skeleton if the [Co^II(COO)₂(teaH₃)] unit and the trimesate benzene ring are regarded as nodes. Taking the inter­molecular hydrogen bonds into account, the [Co^II(COO)₂(teaH₃)] unit can be regarded as a five-connected node, while the central benzene ring can be regarded as a three-connected node. The square skeleton is crosslinked into a (3,5)-binodal two-dimensional supra­molecular topology with a short Schläfli symbol of (4.5.6)(4.5⁵.6³.7) (Fig. 4). To the best of our knowledge, this supra­molecular topology is unknown and significantly enriches the pool of topological aesthetics.

The match between simulated and experimental X-ray powder diffraction (XRPD) patterns for the as-synthesized sample of (I) is good, indicating the phase purity of the product (Fig. 5). The IR spectrum is depicted in Fig. 6 and the main adsorption peaks are listed in the Experimental section. Thermogravimetric analysis (TGA) was performed using a Pyris Diamond thermal analyser. Approximately 10 mg samples were heated under an N₂ atmosphere in the temperature range from room temperature to 1073 K, at a heating rate of 10 K min^-1. As shown in Fig. 7, the TGA curve indicates that the host framework is stable up to 393 K and is finally converted into crystalline cobalt oxide in agreement with the overall mass loss (observed 79.5 wt%, calculated 81.9 wt%). The TGA trace shows that the thermal decomposition takes place in two stages. The first stage is a process to eliminate teaH₃ ligands in the range 423—573 K (observed 30.1 wt%, calculated 35.7 wt%). The obvious difference between the observed and calculated values might be due to the requirement for O atoms to satisfy the coordination geometry of the Co^II cations, so that it is not necessary to lose the total weight of the teaH₃ ligands. The second decomposition stage corresponds to loss of the tmaH^2- linker above 573 K (observed 49.4 wt%, calculated 50.0 wt%). The release of polyalcohol amines prior to organic carboxyl­ate linkers has been documented (Yeşilel & Ölmez, 2007).

A temperature-dependent magnetic measurement was performed on a single-crystalline sample of (I) (0.0159 g) in the range 2–300 K under a field of 1 kOe. For a detailed structure analysis of the Co dimer, the magnetic topology can be treated as a Co₂ system. The curves are plotted as the form of χ_MT and 1/χ_M versus T (Fig. 8). The χ_MT value at 300 K is 5.80 cm³ K mol^-1, which is much larger than the expected value (3.75 cm³ K mol^-1) for two isolated HS [high-spin?] Co^II centres with S = 3/2 and g = 2.0 state (Liu et al., 2007). This can be attributed to the significant orbital contribution of the o­cta­hedral Co^II cations (Konar et al., 2003). As the temperature decreases, the χ_MT value gradually decreases and reaches a minimum of 3.48 cm³ K mol^-1 at 2 K, which is possibly ascribed to inter­ionic anti­ferromagnetic inter­action or spin-orbit coupling effects (Tao et al., 2013). The magnetic susceptibility above 30 K obeys the Curie–Weiss law, with the Weiss constant Θ = -11.94 K and the Curie constant C = 6.00 cm³ mol^-1 K. The negative Θ value reveals the presence of an anti­ferromagnetic inter­action in (I) (Chen et al., 2009).

In summary, the crystal structure of (I) clearly illustrates that the combination of tri­ethano­lamine and trimesic acid provides the hydrogen-bonding opportunity to explore novel supra­molecular topologies. This strategy towards supra­molecular topological aesthetics is still a work in progress in our laboratory.

Synthesis and crystallization

A mixture of CoSO₄.7H₂O (0.0360 g, 0.13 mmol) and trimesic acid (tmaH₃) (0.0273 g, 0.13 mmol) in ethanol (12 ml) was stirred for 10 min, and then teaH₃ (0.18 ml) was added and the mixture stirred for a further 20 min. The resulting solution was transferred into a 17 ml Teflon-lined stainless steel container and heated at 393 K for 48 h. After cooling to room temperature, pink block-shaped crystals of (I) were collected in 86.5% yield based on the added amounts of CoSO₄.7H₂O. Analysis, calculated for C₁₅H₁₉CoNO₉: C 43.28, H 4.60, N 3.37%; found: C 43.23, H 4.62, N 3.40%. Selected IR data (KBr pellet, ν, cm^-1): 461 (m), 563 (m), 719 (s), 906 (w), 1030 (w), 1100 (w), 1370 (s), 1430 (s), 1520 (s), 1610 (s), 3150 (w), 3360 (w).

Refinement details

Crystal data, data collection and structure refinement details are summarized in Table 1. All C-bound H atoms were refined using a riding model, with C—H = 0.93 Å for aromatic and C—H = 0.97 Å for CH₂ H atoms, both with U_iso(H) = 1.2U_eq(C). The hy­droxy H atoms were located in a difference Fourier map and their positions were refined under the application of an O—H bond-length restraint of 0.90 (1) Å, with U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL-Plus (Sheldrick, 1990); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. A view of the local coordination of the Co^II cations in (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. [Symmetry code: (i) -x + 1, -y, -z.]
	Fig. 2. A view of dimer molecule of (I) with a square four-membered window, showing the strong intramolecular O—H···O interactions (dashed green lines) consolidating the dimer framework. H atoms not involved in these interactions have been omitted for clarity. [Symmetry code: (i) -x + 1, -y, -z.]
	Fig. 3. The two-dimensional layer of (I) formed by strong intermolecular O—H···O interactions (dashed green lines). H atoms not involved in these interactions have been omitted for clarity. Two colours are used to highlight the intercrossed arrangement of the dimer molecules. [Symmetry codes: (ii) x + 1/2, -y - 1/2, z + 1/2; (iii) -x + 3/2, y + 1/2, -z + 1/2.]
	Fig. 4. An illustration of the topological analysis for (I). (a) A schematic representation of the connectivities of the [Co^II(COO^-)2(teaH3)] units, showing the detailed hydrogen-bonding interactions (dashed green lines). H atoms not involved in these interactions have been omitted for clarity. (b) The final supramolecular topology constructed from the intercrossed square skeletons (bold parts with two different colours). [Symmetry codes: (iv) -x + 2, -y, -z + 1; (v) -x + 1/2, -y + 1/2, z + 1/2; (vi) x - 1/2, -y - 1/2, z - 1/2; (vii) x - 1/2, -y + 1/2, z - 1/2; (viii) -x + 1/2, y + 1/2, -z - 1/2; (ix) x - 1, y, z - 1; (x) -x, -y, -z - 1.]
	Fig. 5. The simulated and observed powder X-ray diffraction patterns of (I).
	Fig. 6. The IR spectrum of (I).
	Fig. 7. Thermogravimetric analysis (TGA) of (I).
	Fig. 8. Plots of χMT and 1/χM versus T for (I). The solid line shows the Curie–Weiss fitting.

Bis(µ-5-carboxybenzene-1,3-dicarboxylato-κ²O¹:O³)bis[(triethanolamine-κ⁴N,O,O',O'')cobalt(II)]

Crystal data

[Co2(C9H4O6)2(C6H15NO3)2]	F(000) = 860
Mr = 832.48	Dx = 1.636 Mg m^−3
Monoclinic, P21/n	Melting point: not measured K
Hall symbol: -p 2yn	Mo Kα radiation, λ = 0.71069 Å
a = 13.1337 (5) Å	Cell parameters from 293(2) reflections
b = 9.8973 (4) Å	θ = 1.7–27.5°
c = 14.5191 (6) Å	µ = 1.07 mm^−1
β = 116.449 (5)°	T = 293 K
V = 1689.77 (12) Å^3	Block, pink
Z = 2	0.30 × 0.22 × 0.20 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer	3770 independent reflections
Radiation source: fine-focus sealed tube	3183 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ω scans	θmax = 27.5°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −17→16
Tmin = 0.740, Tmax = 0.815	k = −12→12
10803 measured reflections	l = −18→18

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.080	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0389P)^2 + 0.6386P] where P = (Fo^2 + 2Fc^2)/3
3770 reflections	(Δ/σ)max < 0.001
247 parameters	Δρmax = 0.51 e Å^−3
4 restraints	Δρmin = −0.38 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2sigma(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.78489 (14)	−0.00799 (18)	0.01621 (13)	0.0261 (4)
C2	0.78316 (14)	−0.11215 (18)	0.09084 (13)	0.0249 (4)
C3	0.68846 (14)	−0.13119 (19)	0.10847 (13)	0.0263 (4)
H3	0.6209	−0.0868	0.0675	0.032*
C4	0.69398 (14)	−0.21621 (18)	0.18700 (13)	0.0257 (4)
C5	0.79462 (14)	−0.28459 (19)	0.24756 (14)	0.0271 (4)
H5	0.7997	−0.3386	0.3018	0.033*
C6	0.88765 (14)	−0.27147 (18)	0.22625 (14)	0.0273 (4)
C7	0.88199 (14)	−0.18547 (19)	0.14914 (14)	0.0278 (4)
H7	0.9447	−0.1763	0.1359	0.033*
C8	0.59172 (14)	−0.23147 (18)	0.20679 (14)	0.0271 (4)
C9	0.99612 (15)	−0.3461 (2)	0.28703 (15)	0.0329 (4)
C10	0.63168 (17)	0.3438 (2)	−0.31119 (16)	0.0438 (5)
H10A	0.5803	0.3540	−0.3837	0.053*
H10B	0.7085	0.3366	−0.3040	0.053*
C11	0.62280 (18)	0.4648 (2)	−0.25312 (17)	0.0450 (5)
H11A	0.6466	0.5451	−0.2767	0.054*
H11B	0.5445	0.4771	−0.2654	0.054*
C12	0.7170 (2)	0.4793 (3)	0.0332 (2)	0.0596 (7)
H12A	0.7963	0.5062	0.0644	0.072*
H12B	0.6810	0.5195	0.0722	0.072*
C13	0.6587 (2)	0.5261 (2)	−0.0766 (2)	0.0556 (6)
H13A	0.5770	0.5176	−0.1023	0.067*
H13B	0.6763	0.6205	−0.0803	0.067*
C14	0.89411 (16)	0.3544 (2)	−0.05159 (18)	0.0440 (5)
H14A	0.9673	0.3573	−0.0530	0.053*
H14B	0.9065	0.3636	0.0191	0.053*
C15	0.81800 (17)	0.4669 (2)	−0.11710 (19)	0.0485 (6)
H15A	0.8433	0.5521	−0.0810	0.058*
H15B	0.8249	0.4729	−0.1808	0.058*
N1	0.69645 (13)	0.44475 (17)	−0.14137 (13)	0.0378 (4)
O1	0.87782 (11)	0.01773 (15)	0.01687 (11)	0.0395 (3)
O2	0.69118 (10)	0.05105 (13)	−0.04060 (10)	0.0300 (3)
O3	0.49657 (10)	−0.23432 (14)	0.13001 (10)	0.0317 (3)
O4	0.60802 (11)	−0.24033 (17)	0.29904 (11)	0.0452 (4)
O5	1.07840 (14)	−0.3334 (2)	0.27251 (16)	0.0784 (7)
O6	0.99421 (11)	−0.42270 (17)	0.35934 (12)	0.0445 (4)
H04	1.0631 (12)	−0.460 (3)	0.3948 (18)	0.067*
O7	0.60338 (11)	0.22324 (15)	−0.27235 (10)	0.0358 (3)
H01	0.5300 (10)	0.225 (3)	−0.2883 (19)	0.054*
O8	0.70820 (12)	0.33482 (17)	0.03388 (11)	0.0425 (4)
H02	0.7635 (17)	0.301 (3)	0.0911 (13)	0.064*
O9	0.83747 (11)	0.23047 (15)	−0.09400 (11)	0.0364 (3)
H03	0.866 (2)	0.1613 (18)	−0.0502 (16)	0.055*
Co1	0.670536 (18)	0.23853 (2)	−0.110248 (18)	0.02479 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0236 (8)	0.0268 (9)	0.0276 (9)	−0.0015 (7)	0.0110 (7)	−0.0007 (7)
C2	0.0224 (8)	0.0244 (9)	0.0271 (9)	−0.0010 (7)	0.0105 (7)	−0.0003 (7)
C3	0.0204 (8)	0.0289 (10)	0.0261 (9)	0.0020 (7)	0.0071 (6)	0.0013 (7)
C4	0.0195 (8)	0.0282 (9)	0.0274 (9)	−0.0006 (7)	0.0086 (7)	0.0005 (7)
C5	0.0235 (8)	0.0284 (10)	0.0282 (9)	0.0007 (7)	0.0103 (7)	0.0036 (7)
C6	0.0221 (8)	0.0257 (9)	0.0320 (9)	0.0029 (7)	0.0101 (7)	0.0014 (7)
C7	0.0219 (8)	0.0277 (9)	0.0349 (10)	−0.0003 (7)	0.0137 (7)	0.0018 (8)
C8	0.0213 (8)	0.0300 (10)	0.0283 (9)	0.0010 (7)	0.0096 (7)	0.0043 (7)
C9	0.0263 (9)	0.0305 (11)	0.0415 (11)	0.0059 (8)	0.0148 (8)	0.0065 (8)
C10	0.0316 (10)	0.0660 (16)	0.0341 (11)	−0.0006 (10)	0.0148 (8)	0.0143 (10)
C11	0.0357 (10)	0.0442 (13)	0.0482 (13)	0.0038 (9)	0.0126 (9)	0.0231 (10)
C12	0.0664 (16)	0.0499 (16)	0.0561 (15)	−0.0037 (13)	0.0216 (13)	−0.0234 (12)
C13	0.0611 (15)	0.0334 (13)	0.0673 (16)	0.0030 (11)	0.0241 (13)	−0.0062 (11)
C14	0.0258 (9)	0.0494 (14)	0.0483 (12)	−0.0106 (9)	0.0089 (9)	0.0045 (10)
C15	0.0351 (11)	0.0416 (13)	0.0603 (14)	−0.0135 (9)	0.0136 (10)	0.0074 (11)
N1	0.0319 (8)	0.0306 (9)	0.0453 (10)	−0.0019 (7)	0.0123 (7)	0.0051 (7)
O1	0.0264 (6)	0.0456 (9)	0.0505 (9)	0.0049 (6)	0.0208 (6)	0.0180 (7)
O2	0.0218 (6)	0.0292 (7)	0.0332 (7)	−0.0025 (5)	0.0072 (5)	0.0067 (5)
O3	0.0190 (6)	0.0463 (8)	0.0282 (7)	−0.0019 (5)	0.0090 (5)	0.0026 (6)
O4	0.0227 (6)	0.0846 (13)	0.0262 (7)	−0.0041 (7)	0.0091 (5)	0.0090 (7)
O5	0.0437 (9)	0.1062 (17)	0.1023 (16)	0.0392 (10)	0.0478 (10)	0.0637 (13)
O6	0.0286 (7)	0.0544 (10)	0.0508 (9)	0.0168 (7)	0.0179 (6)	0.0248 (7)
O7	0.0270 (6)	0.0507 (9)	0.0298 (7)	−0.0029 (6)	0.0127 (6)	0.0005 (6)
O8	0.0401 (8)	0.0508 (10)	0.0283 (7)	−0.0034 (7)	0.0078 (6)	−0.0076 (7)
O9	0.0261 (6)	0.0391 (8)	0.0413 (8)	−0.0016 (6)	0.0127 (6)	0.0090 (6)
Co1	0.01981 (13)	0.02806 (15)	0.02425 (14)	−0.00262 (9)	0.00778 (9)	0.00271 (10)

Geometric parameters (Å, º)

C1—O1	1.243 (2)	C12—O8	1.435 (3)
C1—O2	1.278 (2)	C12—C13	1.502 (4)
C1—C2	1.503 (2)	C12—H12A	0.9700
C2—C3	1.390 (2)	C12—H12B	0.9700
C2—C7	1.396 (2)	C13—N1	1.480 (3)
C3—C4	1.393 (2)	C13—H13A	0.9700
C3—H3	0.9300	C13—H13B	0.9700
C4—C5	1.394 (2)	C14—O9	1.424 (3)
C4—C8	1.501 (2)	C14—C15	1.515 (3)
C5—C6	1.394 (2)	C14—H14A	0.9700
C5—H5	0.9300	C14—H14B	0.9700
C6—C7	1.382 (3)	C15—N1	1.490 (2)
C6—C9	1.495 (2)	C15—H15A	0.9700
C7—H7	0.9300	C15—H15B	0.9700
C8—O3	1.251 (2)	N1—Co1	2.1500 (17)
C8—O4	1.262 (2)	O2—Co1	2.0724 (13)
C9—O5	1.196 (2)	O3—Co1^i	2.0833 (12)
C9—O6	1.304 (2)	O6—H04	0.897 (10)
C10—O7	1.437 (3)	O7—Co1	2.1192 (14)
C10—C11	1.499 (3)	O7—H01	0.885 (10)
C10—H10A	0.9700	O8—Co1	2.1470 (14)
C10—H10B	0.9700	O8—H02	0.890 (10)
C11—N1	1.486 (3)	O9—Co1	2.0996 (14)
C11—H11A	0.9700	O9—H03	0.896 (10)
C11—H11B	0.9700	Co1—O3^i	2.0833 (12)
O1—C1—O2	124.87 (17)	N1—C13—H13B	109.5
O1—C1—C2	117.72 (15)	C12—C13—H13B	109.5
O2—C1—C2	117.36 (15)	H13A—C13—H13B	108.1
C3—C2—C7	118.98 (16)	O9—C14—C15	106.84 (16)
C3—C2—C1	121.87 (15)	O9—C14—H14A	110.4
C7—C2—C1	119.01 (15)	C15—C14—H14A	110.4
C2—C3—C4	120.55 (16)	O9—C14—H14B	110.4
C2—C3—H3	119.7	C15—C14—H14B	110.4
C4—C3—H3	119.7	H14A—C14—H14B	108.6
C3—C4—C5	119.92 (16)	N1—C15—C14	112.23 (17)
C3—C4—C8	119.52 (15)	N1—C15—H15A	109.2
C5—C4—C8	120.55 (16)	C14—C15—H15A	109.2
C6—C5—C4	119.57 (17)	N1—C15—H15B	109.2
C6—C5—H5	120.2	C14—C15—H15B	109.2
C4—C5—H5	120.2	H15A—C15—H15B	107.9
C7—C6—C5	120.08 (16)	C13—N1—C11	112.43 (17)
C7—C6—C9	118.42 (16)	C13—N1—C15	113.34 (18)
C5—C6—C9	121.48 (17)	C11—N1—C15	110.26 (17)
C6—C7—C2	120.75 (16)	C13—N1—Co1	104.70 (14)
C6—C7—H7	119.6	C11—N1—Co1	105.60 (13)
C2—C7—H7	119.6	C15—N1—Co1	110.06 (13)
O3—C8—O4	125.05 (16)	C1—O2—Co1	127.13 (11)
O3—C8—C4	117.11 (16)	C8—O3—Co1^i	134.13 (12)
O4—C8—C4	117.84 (15)	C9—O6—H04	108.9 (17)
O5—C9—O6	123.08 (18)	C10—O7—Co1	108.90 (12)
O5—C9—C6	122.83 (18)	C10—O7—H01	108.6 (16)
O6—C9—C6	114.05 (15)	Co1—O7—H01	98.9 (17)
O7—C10—C11	110.12 (16)	C12—O8—Co1	114.84 (14)
O7—C10—H10A	109.6	C12—O8—H02	110.2 (19)
C11—C10—H10A	109.6	Co1—O8—H02	118.8 (18)
O7—C10—H10B	109.6	C14—O9—Co1	109.51 (12)
C11—C10—H10B	109.6	C14—O9—H03	112.1 (16)
H10A—C10—H10B	108.2	Co1—O9—H03	101.6 (16)
N1—C11—C10	109.38 (17)	O2—Co1—O3^i	87.14 (5)
N1—C11—H11A	109.8	O2—Co1—O9	90.46 (5)
C10—C11—H11A	109.8	O3^i—Co1—O9	176.43 (6)
N1—C11—H11B	109.8	O2—Co1—O7	112.16 (5)
C10—C11—H11B	109.8	O3^i—Co1—O7	87.35 (5)
H11A—C11—H11B	108.2	O9—Co1—O7	91.11 (5)
O8—C12—C13	108.06 (19)	O2—Co1—O8	89.92 (6)
O8—C12—H12A	110.1	O3^i—Co1—O8	85.09 (5)
C13—C12—H12A	110.1	O9—Co1—O8	97.56 (6)
O8—C12—H12B	110.1	O7—Co1—O8	156.26 (6)
C13—C12—H12B	110.1	O2—Co1—N1	162.54 (6)
H12A—C12—H12B	108.4	O3^i—Co1—N1	104.22 (6)
N1—C13—C12	110.5 (2)	O9—Co1—N1	78.73 (6)
N1—C13—H13A	109.5	O7—Co1—N1	82.01 (6)
C12—C13—H13A	109.5	O8—Co1—N1	78.12 (7)
O1—C1—C2—C3	168.72 (17)	C4—C8—O3—Co1^i	−174.51 (12)
O2—C1—C2—C3	−8.8 (3)	C11—C10—O7—Co1	−38.51 (17)
O1—C1—C2—C7	−6.9 (3)	C13—C12—O8—Co1	19.0 (2)
O2—C1—C2—C7	175.61 (16)	C15—C14—O9—Co1	−51.71 (19)
C7—C2—C3—C4	3.6 (3)	C1—O2—Co1—O3^i	−163.30 (15)
C1—C2—C3—C4	−171.97 (16)	C1—O2—Co1—O9	19.35 (15)
C2—C3—C4—C5	−1.0 (3)	C1—O2—Co1—O7	110.73 (15)
C2—C3—C4—C8	177.95 (16)	C1—O2—Co1—O8	−78.21 (15)
C3—C4—C5—C6	−2.6 (3)	C1—O2—Co1—N1	−31.9 (3)
C8—C4—C5—C6	178.47 (17)	C14—O9—Co1—O2	−131.75 (13)
C4—C5—C6—C7	3.5 (3)	C14—O9—Co1—O3^i	−180 (100)
C4—C5—C6—C9	−178.12 (17)	C14—O9—Co1—O7	116.07 (13)
C5—C6—C7—C2	−0.8 (3)	C14—O9—Co1—O8	−41.77 (13)
C9—C6—C7—C2	−179.26 (17)	C14—O9—Co1—N1	34.45 (13)
C3—C2—C7—C6	−2.7 (3)	C10—O7—Co1—O2	−157.91 (11)
C1—C2—C7—C6	173.00 (17)	C10—O7—Co1—O3^i	116.26 (12)
C3—C4—C8—O3	38.3 (3)	C10—O7—Co1—O9	−66.96 (12)
C5—C4—C8—O3	−142.73 (18)	C10—O7—Co1—O8	44.81 (19)
C3—C4—C8—O4	−141.63 (19)	C10—O7—Co1—N1	11.49 (12)
C5—C4—C8—O4	37.3 (3)	C12—O8—Co1—O2	174.10 (15)
C7—C6—C9—O5	0.9 (3)	C12—O8—Co1—O3^i	−98.76 (16)
C5—C6—C9—O5	−177.5 (2)	C12—O8—Co1—O9	83.65 (16)
C7—C6—C9—O6	178.72 (18)	C12—O8—Co1—O7	−26.9 (2)
C5—C6—C9—O6	0.3 (3)	C12—O8—Co1—N1	6.91 (15)
O7—C10—C11—N1	55.9 (2)	C13—N1—Co1—O2	−78.7 (2)
O8—C12—C13—N1	−48.0 (3)	C11—N1—Co1—O2	162.45 (17)
O9—C14—C15—N1	44.1 (3)	C15—N1—Co1—O2	43.4 (3)
C12—C13—N1—C11	166.66 (19)	C13—N1—Co1—O3^i	50.70 (14)
C12—C13—N1—C15	−67.5 (2)	C11—N1—Co1—O3^i	−68.17 (14)
C12—C13—N1—Co1	52.5 (2)	C15—N1—Co1—O3^i	172.83 (14)
C10—C11—N1—C13	−156.06 (18)	C13—N1—Co1—O9	−131.36 (14)
C10—C11—N1—C15	76.4 (2)	C11—N1—Co1—O9	109.77 (14)
C10—C11—N1—Co1	−42.47 (18)	C15—N1—Co1—O9	−9.23 (14)
C14—C15—N1—C13	101.2 (2)	C13—N1—Co1—O7	135.89 (14)
C14—C15—N1—C11	−131.8 (2)	C11—N1—Co1—O7	17.03 (13)
C14—C15—N1—Co1	−15.7 (2)	C15—N1—Co1—O7	−101.97 (14)
O1—C1—O2—Co1	−21.1 (3)	C13—N1—Co1—O8	−31.05 (13)
C2—C1—O2—Co1	156.17 (12)	C11—N1—Co1—O8	−149.91 (14)
O4—C8—O3—Co1^i	5.4 (3)	C15—N1—Co1—O8	91.09 (15)

Symmetry code: (i) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H04···O2^ii	0.90 (1)	1.77 (1)	2.6588 (17)	174 (3)
O7—H01···O4^i	0.89 (1)	1.76 (1)	2.6323 (19)	170 (2)
O8—H02···O4^iii	0.89 (1)	1.78 (1)	2.655 (2)	168 (3)
O9—H03···O1	0.90 (1)	1.69 (1)	2.5584 (19)	162 (2)

Symmetry codes: (i) −x+1, −y, −z; (ii) x+1/2, −y−1/2, z+1/2; (iii) −x+3/2, y+1/2, −z+1/2.