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In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains. www.rsc.org/crystengcomm Page 1 of 14 CrystEngComm Table of Contents ‘Honeycomb’ nanotube assembly based on thiacalix[4]arene derivatives by weak interactions Wei Wang a, Weiping Yang a,b , Rong Guo a and Shuling Gong a, * a College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China b Key Laboratory of Tobacco Flavor Basic Research, Zhengzhou Tobacco Research Institute of CNTC, No. 2, Fengyang Street, High-Tech Zone, 450001 Zhengzhou, China *Corresponding Author: E-mail: [email protected]; Fax: +86 27 68754067; Tel: +86 27 68752701. Crystallisation of six thiacalix[4]arene derivatives from hexane-chloroform leads to ‘honeycomb’ nanotube architectures and each tubular stack is sounded by six close Manuscript neighbours tubular via weak interactions, such as S···π interaction, C-H···π interactions, and so on. Accepted CrystEngComm Journal Name CrystEngComm Dynamic Article Links Page► 2 of 14 Cite this: DOI: 10.1039/c0xx00000x www.rsc.org/xxxxxx ARTICLE TYPE ‘Honeycomb’ nanotube assembly based on thiacalix[4]arene derivatives by weak interactions Wei Wang, a Weiping Yang,a,b Rong Guo a and Shuling Gong a, * Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX 5 DOI: 10.1039/b000000x The crystal structures of di-O-Propoxy-mono-Formyl-thiacalix[4]arene·chloroform ( 7·CHCl 3), di-O- Propoxy-di-Formyl-thiacalix[4]arene ( 8), di-O-Propoxy-tri-Formyl-thiacalix[4]arene ( 9), di-O-Benzyol- di-Formyl-thiacalix[4]arene·water ( 10·H2O), mono-O-Propoxy-tri-Formyl-thiacalix[4]arene ( 11), di-O- Propoxy-di-Cyano-thiacalix[4]arene·chloroform ( 12·CHCl 3) in the same crystallisation medium have 10 been investigated. These crystals form similar ‘honeycomb’ nanotubes architectures and display different assemblies in the solid state. 7·CHCl 3, 8, 9 and 11 assemble to ‘classical’ head-to-head dimer via interdigitation of aromatic rings with π···π stacking interactions, while 12·CHCl 3 form a novel head-to- head dimer motif and infinite network structures are stabilised by Cl···Cl, Cl···π and CN···Cl Manuscript interactions. Although 10·H2O does not form head-to-head dimer, it has taken in a new cubic closest 15 packing (ccp), forming a water channel nanotube. X-ray single-crystal diffraction studies reveal that the weak interactions, including C-H···O, halogen···halogen, C-H···π, lone pair (lp)···π and π···π interactions are contributing to the supramolecular assembly. Introduction interactions (Fig. 1B) and the six molecules form a specific hexameric disc through parallel back-to-back packing almost Hollow tubular architectures of ring-shaped organic molecules, 1 2 3 50 situated in the same plane (Fig 1C and 1D). The extend structure 20 such as cyclopeptide, crown ethers, pyrogallol[4]arenes, C- 4 5 show that these dimers act as bridges form a ‘cog-like’ or alkylresorcin[4]arenes and calix[4]arene, have attracted wide Accepted ‘honeycomb’ architecture. The whole molecular crystallisation is attention of chemists due to their great prospects in stabilised by N-H···O, C-H···O, C-H···π and π···π interactions. nanomaterials, selective guest encapsulation, biological channels The ‘honeycomb’ architecture gives rise to two channels: endo - and drug delivery. But it is difficult to control the self-assembly 55 channel (triply helical nanotubes) and exo -channel (interstitial 25 of macrocyclic molecules to form an infinite network structure, space was created between adjacent nanotubes). because that is often a compromise between the geometrical Thiacalixarenes, 17 the presences of four sulfur atoms instead of constraints of the building blocks and the competing weak CH groups, has many novel features compared with ‘classical’ intermolecular interactions. 4, 6 2 calixarenes, which also can be used to form a range of structural Hydrogen bonding often play a key role in the self-assembly of 5a, 7 60 motifs. Compared with a large number of ‘honeycomb’ nanotube 30 molecules into an organised supramolecular structures. On the studies available for ‘classical’ calixarenes, only a few number of other hand, a set of somewhat weaker interactions, including C- thiacalixarenes, including di-propyl-thiacalix[4]arenes ( 2), 18 1,3- H···O, 8 C-H···S, 9 C-H···π, 10 cyano···halogen,11 alt -tetrabromo-tetrapropoxy-thiacalix[4]arene ( 3)19 and 1,3-alt - halogen···halogen, 12 lone pair (lp)···π, 13 and π···π interactions,4, tetrabromo-tetrabutoxy-thiacalix[4]arene ( 4)20 could form such 14 not more than a few Kcal/mol also play an crucial role in 65 ‘cog-like’ architecture nanotube. Compound 2 can be assembled 35 supramolecular structures when stronger hydrogen bonding is into a head-to-head dimer via interdigitation of aromatic rings absent. 15 with C-H···π and π···π interactions (Fig. 1E). Symmetry Calixarenes, which can be tailored by functionalising either CrystEngComm expansion of the crystal structure of 2 reveals that two trimeric the ‘lower rim’ or ‘upper rim’, has been extensively studied in the units (three molecules of 2 are situated in the same plane) pack as design of hexameric, dimeric capsules, bilayers or nanostructures. 11 70 a hexagonal close–packed (hcp) arrangement and C-H···S and 40 ‘Honeycomb’ nanotube assembly of calixarenes can be S···π interactions assist with the stacking (Fig. 1F, 1G, 1H and obtained by hierarchical self-assembly: 16 first intermolecular Fig. S1, Supporting Information). The common head-to-head aggregates form a closed disk-shaped oligomeric, and then dimer motif is not observed in the crystal structure of 4, and aggregation of multiple disks into rods or cylinders objects examination of the extended array shows that the infinite open through non-covalent interactions. Recently, Dalgarno et al .5i has 75 network structures are stabilised by triangular Br 3 synthon-type 45 reported that in the presence of pyridine (acting as a template), p- halogen···halogen interactions (Fig. 1I)12c and S···π interactions. carboxylatocalix[4]arenes ( 1) has formed a head-to-head In these previous work 5, 18-21 we realised that 1) solvent molecules hydrogen-bonded dimer motif facilitated by host−guest This journal is © The Royal Society of Chemistry [year] [journal] , [year], [vol] , 00–00 | 1 Page 3 of 14 CrystEngComm Scheme 1 Syntheses of the six compounds. interactions and so on. Based upon the above, we have been Manuscript 30 prepared six thiacalix[4]arene derivertives (7-12 ) according to a known literature (Scheme 1). 17b,17c, 23 All compounds are soluble well in chloroform, so we employ hexane-chloroform as a solvent for crystallisation. Slow evaporation over several days at room temperature afford single crystals suitable for X-ray diffraction 35 studies. The results of these crystallisation show that modest changes in the primary structure of thiacalix[4]arene lead to different packing in the solid state, but all compounds form the ‘honeycomb’ architecture which is stabilised by weak Accepted interactions (Fig.2). Fig. 1 (A) Schematic of calix[4]arenes 1-4. (B) Pyridine templated dimerisation of 1. (C) Back-to-back assembly of 1 to form hexameric 40 Results and discussion discs. (D) Interlocked hexameric discs (orthogonal view to (C)) to form 5 infinite nanotubes of 1 shown in alternating colour. (E) Host-to-host Crystal structure of 7· CHCl 3 dimer assembly of 2. (F) Back-to-back assembly of 2 to form hexameric discs. (G) Interlocked hexameric discs (orthogonal view to (F)) to form Single crystals of 7·CHCl 3 are in a trigonal cell, and structure infinite nanotubes of 2 shown in alternating colour. (H) The parameters was performed in the space group R3¯ . The asymmetric unit 13c, 13e defining the geometry of lp···π interactions. (I) The triangular Br 3 consists of one molecule of 7 and one-sixth of the chloroform 10 synthon interaction in 4. 45 molecules which is disordered near the lower-rim propoxy groups. In the solid state, compound 7 adopts a cone and the backbone of calixarenes all play an important part in the conformation is due to O-H···O interactions and O-H···S construction of nanotube, 2) the interdigitated dimer motif is interactions (Table S7, Supporting Information). The aromatic almost omnipresent.5 ring D is highly disordered over two positions, and the non- Our earlier work has reported that a one-dimensional channel 21 50 disordered situation is modelled at 85.9% with refined site 15 formed by 1,2-alt-tetra-acetic acid calix[4]arene and a three- occupation factors (Table S17). This positional disorder might be dimensional network of endo -aquatubes formed by 1,3-alt- 22 related to the interactions with solvent molecular: two weaker C- thiacalix[4]arene derivatives are both stabilised by the strong 13d H···Cl interactions between hydrogen atoms of methyl or CrystEngComm intermolecular hydrogen bonding.