Brendan F Abrahams, Christopher J Commons, Timothy A Hudson, Robin Sanchez-Arlt
{"title":"Supramolecular hydrogen-bonded networks formed from copper(II) carboxylate dimers.","authors":"Brendan F Abrahams, Christopher J Commons, Timothy A Hudson, Robin Sanchez-Arlt","doi":"10.1107/S2053229624004534","DOIUrl":null,"url":null,"abstract":"<p><p>The well-known copper carboxylate dimer, with four carboxylate ligands extending outwards towards the corners of a square, has been employed to generate a series of crystalline compounds. In particular, this work centres on the use of the 4-hydroxybenzoate anion (Hhba<sup>-</sup>) and its deprotonated phenolate form 4-oxidobenzoate (hba<sup>2-</sup>) to obtain complexes with the general formula [Cu<sub>2</sub>(Hhba)<sub>4-x</sub>(hba)<sub>x</sub>L<sub>2-y</sub>]<sup>x-</sup>, where L is an axial coligand (including solvent molecules), x = 0, 1 or 2, and y = 0 or 1. In some cases, short hydrogen bonds result in complexes which may be represented as [Cu<sub>2</sub>(Hhba)<sub>2</sub>(H<sub>0.5</sub>hba)<sub>2</sub>L<sub>2</sub>]<sup>-</sup>. The main focus of the investigation is on the formation of a variety of extended networks through hydrogen bonding and, in some crystals, coordinate bonds when bridging coligands (L) are employed. Crystals of [Cu<sub>2</sub>(Hhba)<sub>4</sub>(dioxane)<sub>2</sub>]·4(dioxane) consist of the expected Cu dimer with the Hhba<sup>-</sup> anions forming hydrogen bonds to 1,4-dioxane molecules which block network formation. In the case of crystals of composition [Et<sub>4</sub>N][Cu<sub>2</sub>(Hhba)<sub>2</sub>(H<sub>0.5</sub>hba)<sub>2</sub>(CH<sub>3</sub>OH)(H<sub>2</sub>O)]·2(dioxane), Li[Cu<sub>2</sub>(Hhba)<sub>2</sub>(H<sub>0.5</sub>hba)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]·3(dioxane)·4H<sub>2</sub>O and [Cu<sub>2</sub>(Hhba)<sub>2</sub>(H<sub>0.5</sub>hba)<sub>2</sub>(H<sub>0.5</sub>DABCO)<sub>2</sub>]·3CH<sub>3</sub>OH (DABCO is 1,4-diazabicyclo[2.2.2]octane), square-grid hydrogen-bonded networks are generated in which the complex serves as one type of 4-connecting node, whilst a second 4-connecting node is a hydrogen-bonding motif assembled from four phenol/phenolate groups. Another two-dimensional (2D) network based upon a related square-grid structure is formed in the case of [Et<sub>4</sub>N]<sub>2</sub>[Cu<sub>2</sub>(Hhba)<sub>2</sub>(hba)<sub>2</sub>(dioxane)<sub>2</sub>][Cu<sub>2</sub>(Hhba)<sub>4</sub>(dioxane)(H<sub>2</sub>O)]·CH<sub>3</sub>OH. In [Cu<sub>2</sub>(Hhba)<sub>4</sub>(H<sub>2</sub>O)<sub>2</sub>]·2(Et<sub>4</sub>NNO<sub>3</sub>), a square-grid structure is again apparent, but, in this case, a pair of nitrate anions, along with four phenolic groups and a pair of water molecules, combine to form a second type of 4-connecting node. When 1,8-bis(dimethylamino)naphthalene (bdn, `proton sponge') is used as a base, another square-grid network is generated, i.e. [Hbdn]<sub>2</sub>[Cu<sub>2</sub>(Hhba)<sub>2</sub>(hba)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]·3(dioxane)·H<sub>2</sub>O, but with only the copper dimer complex serving as a 4-connecting node. Complex three-dimensional networks are formed in [Cu<sub>2</sub>(Hhba)<sub>4</sub>(O-bipy)]·H<sub>2</sub>O and [Cu<sub>2</sub>(Hhba)<sub>4</sub>(O-bipy)<sub>2</sub>]·2(dioxane), where the potentially bridging 4,4'-bipyridine N,N'-dioxide (O-bipy) ligand is employed. Rare cases of mixed carboxylate copper dimer complexes were obtained in the cases of [Cu<sub>2</sub>(Hhba)<sub>3</sub>(OAc)(dioxane)]·3.5(dioxane) and [Cu<sub>2</sub>(Hhba)<sub>2</sub>(OAc)<sub>2</sub>(DABCO)<sub>2</sub>]·10(dioxane), with each structure possessing a 2D network structure. The final compound reported is a simple hydrogen-bonded chain of composition (H<sub>0.5</sub>DABCO)(H<sub>1.5</sub>hba), formed from the reaction of H<sub>2</sub>hba and DABCO.</p>","PeriodicalId":7115,"journal":{"name":"Acta Crystallographica Section C Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":0.7000,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11150878/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Crystallographica Section C Structural Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1107/S2053229624004534","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/5/22 0:00:00","PubModel":"Epub","JCR":"Q4","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The well-known copper carboxylate dimer, with four carboxylate ligands extending outwards towards the corners of a square, has been employed to generate a series of crystalline compounds. In particular, this work centres on the use of the 4-hydroxybenzoate anion (Hhba-) and its deprotonated phenolate form 4-oxidobenzoate (hba2-) to obtain complexes with the general formula [Cu2(Hhba)4-x(hba)xL2-y]x-, where L is an axial coligand (including solvent molecules), x = 0, 1 or 2, and y = 0 or 1. In some cases, short hydrogen bonds result in complexes which may be represented as [Cu2(Hhba)2(H0.5hba)2L2]-. The main focus of the investigation is on the formation of a variety of extended networks through hydrogen bonding and, in some crystals, coordinate bonds when bridging coligands (L) are employed. Crystals of [Cu2(Hhba)4(dioxane)2]·4(dioxane) consist of the expected Cu dimer with the Hhba- anions forming hydrogen bonds to 1,4-dioxane molecules which block network formation. In the case of crystals of composition [Et4N][Cu2(Hhba)2(H0.5hba)2(CH3OH)(H2O)]·2(dioxane), Li[Cu2(Hhba)2(H0.5hba)2(H2O)2]·3(dioxane)·4H2O and [Cu2(Hhba)2(H0.5hba)2(H0.5DABCO)2]·3CH3OH (DABCO is 1,4-diazabicyclo[2.2.2]octane), square-grid hydrogen-bonded networks are generated in which the complex serves as one type of 4-connecting node, whilst a second 4-connecting node is a hydrogen-bonding motif assembled from four phenol/phenolate groups. Another two-dimensional (2D) network based upon a related square-grid structure is formed in the case of [Et4N]2[Cu2(Hhba)2(hba)2(dioxane)2][Cu2(Hhba)4(dioxane)(H2O)]·CH3OH. In [Cu2(Hhba)4(H2O)2]·2(Et4NNO3), a square-grid structure is again apparent, but, in this case, a pair of nitrate anions, along with four phenolic groups and a pair of water molecules, combine to form a second type of 4-connecting node. When 1,8-bis(dimethylamino)naphthalene (bdn, `proton sponge') is used as a base, another square-grid network is generated, i.e. [Hbdn]2[Cu2(Hhba)2(hba)2(H2O)2]·3(dioxane)·H2O, but with only the copper dimer complex serving as a 4-connecting node. Complex three-dimensional networks are formed in [Cu2(Hhba)4(O-bipy)]·H2O and [Cu2(Hhba)4(O-bipy)2]·2(dioxane), where the potentially bridging 4,4'-bipyridine N,N'-dioxide (O-bipy) ligand is employed. Rare cases of mixed carboxylate copper dimer complexes were obtained in the cases of [Cu2(Hhba)3(OAc)(dioxane)]·3.5(dioxane) and [Cu2(Hhba)2(OAc)2(DABCO)2]·10(dioxane), with each structure possessing a 2D network structure. The final compound reported is a simple hydrogen-bonded chain of composition (H0.5DABCO)(H1.5hba), formed from the reaction of H2hba and DABCO.
期刊介绍：
Acta Crystallographica Section C: Structural Chemistry is continuing its transition to a journal that publishes exciting science with structural content, in particular, important results relating to the chemical sciences. Section C is the journal of choice for the rapid publication of articles that highlight interesting research facilitated by the determination, calculation or analysis of structures of any type, other than macromolecular structures. Articles that emphasize the science and the outcomes that were enabled by the study are particularly welcomed. Authors are encouraged to include mainstream science in their papers, thereby producing manuscripts that are substantial scientific well-rounded contributions that appeal to a broad community of readers and increase the profile of the authors.
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