PAPER Cite this: CrystEngComm, 2013, 15, 9623 Received 3rd June 2013, Accepted 12th August 2013 DOI: 10.1039/c3ce41003j www.rsc.org/crystengcomm Coordination polymers via self-assembly of silver(I) and cis-bis-nitrile-oxa-bowl derivatives† P. Niranjana, a Anita Pati, a Suheel K. Porwal, a Venkatachalam Ramkumar, a Santosh J. Gharpure‡ * ab and Dillip Kumar Chand * a A series of silver(I)-based coordination polymers (AgCPs) have been synthesized using three new nonchelating cis-bis-nitrile derivatives of oxa-bowls, L1–L3, as ligand components. The ligands are designed to provide conformational restrictions as well as semi-rigid directionality to the coordination vectors extended from the nitrile functionalities. The steric bulks around the oxa-bowl spacer moieties are gradually escalated to study their influence on the topologies of the ensuing AgCPs. Two silver salts i.e. AgSbF 6 and AgPF 6 are used to check the influence of anions on the structural architectures. Ziz-zag-sheet type 2-D AgCPs are formed with the ligands L1 and L2 possessing less steric bulk. All the metal centres are found to be tetracoordinated by nitrile-nitrogens of the same sheet giving distorted-bisphenoidal geometries. Additional short interactions of the silver(I) centres of a given sheet with the oxygen of the oxa-bowls belonging to the neighbouring stacked sheets are observed. The bulky ligand L3 behaved differently where the metal centres are tetracoordinated although only two of the ligating units are derived from the nitrile nitrogens and the remaining two are from, depending upon the counter anion, the counter anion/oxygen of oxa-bowls or two water molecules. The overall arrangements in the AgCPs of L3 are of the 2-D carpet type (for SbF 6 − ion) composed of interconnected chains, and 1-D ladder type (for PF 6 − ion) constructed from two chains. Cation–π interactions are found between the aromatic part of L3 of a given chain and the silver(I) of the adjacent chain that are interdigitated. Introduction The design and construction of coordination polymers using designated ligand and metal components have attracted significant contemporary attention from researchers. 1 Above and beyond the aesthetically pleasing topologies of the architectures a wide range of applications of these materials have also been accomplished and reported in the literature. 2 The rational design of suitable ligands is quite important for the reason that minor structural changes at the ligand backbone can potentially alter the architecture of the ensuing coordination polymers. 3 Silver(I) is extensively exploited as a metal component which exhibits a variety of coordination numbers ranging from 2 to 8. Thus the coordination geometries are also as varied as linear, T-shaped, seesaw type, square pyramidal, trigonal bipyramidal, octahedral and other geometries. The overall structural arrangement of the participating components in the silver(I)-based coordination polymers (AgCPs) are influenced by the ligand design, 4 counter anion, 5 metal to ligand ratio 6 and a few other parameters. The properties of AgCPs include photoluminescence, 7 photochromism, 8 catalysis, 9 conduc- tion, 10 and antibiotic activities 11 etc. The ligands employed in the synthesis of AgCPs are usually, pyridyl, 12 pyrazine, 13 pyridazine, 14 phosphinito, 15 thioethers 4,16 etc. Nitrile appended ligands are successfully used for the construction of a variety of AgCPs. A range of nitrile based ligands are exploited that can be typically classified as bis-nitriles, 3b,5b,8,17 tris-nitriles, 18 and tetrakis-nitriles. 5,19 Complexation of the cis-bis-nitrile ligand, cis-1,3-bis(cyano- methyl)cyclopentane, L with AgSbF 6 and AgPF 6 resulted in 1-D chains of binuclear loops and 2-D interpenetrated square grids, respectively. 3b Anion induced structural variations of the coordination polymers have been noticed even though a Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India. E-mail: dillip@iitm.ac.in; Fax: +91-4422574202; Tel: +91-4422574224 b Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. E-mail: sjgharpure@iitb.ac.in; Fax: +91-2225767152; Tel: +91-2225767171 † Electronic supplementary information (ESI) available: The 1 H NMR and 13 C NMR spectra of the dimethyl acetals (acetal-1, acetal-2 and acetal-3), the ligands (L1, L2 and L3) and the complexes (1a, 1b, 2a, 2b, 3a, and 3b) are available. IR spectra of the ligands and the complexes, PXRD patterns of the complexes, ESI- MS and MALDI-MS of 1a are also provided. X-ray crystallographic data in CIF format for the structures reported in this paper (L1, L2, L3, 1a, 1b, 2a, 2b, 3a, and 3b) is deposited with CCDC. The CCDC numbers are 942145–942153. Crystal data and structure refinement parameters for the ligands and complexes, relevant bond lengths and angles of the complexes and a brief description of the structure of 1b and 2b, are available. For ESI and crystallographic data in CIF or other elec- tronic format see DOI: 10.1039/c3ce41003j ‡ Present address of SJG: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. CrystEngComm, 2013, 15, 9623–9633 | 9623 This journal is © The Royal Society of Chemistry 2013 CrystEngComm Published on 12 August 2013. Downloaded by Indian Institute of Technology Chennai on 16/06/2015 07:48:22. View Article Online View Journal | View Issue