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Volume 70 
Part 1 
Pages 37-46  
February 2014  

Received 29 July 2013
Accepted 4 January 2014
Online 16 January 2014

Organosilver(I) framework assembly with trifluoroacetate and enediyne-functionalized alicycles

aDepartment of Chemistry and Center of Novel Functional Molecules, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, People's Republic of China
Correspondence e-mail: tcwmak@cuhk.edu.hk

Eight new silver(I) trifluoroacetate complexes based on a series of designed ligands, each featuring an alicyclic ring with enediyne functionality, have been synthesized and characterized by single-crystal X-ray diffraction. Each ethynide terminal is inserted into an Agn (n = 4-5) basket, leading to the generation of coordination chain or layer structures, but the well shielded ethenyl group does not take part in silver-olefin bonding. Variation in ring size of the alicycles is shown to influence the construction of the organosilver(I) coordination networks, which are consolidated by weak intermolecular interactions in the crystal structures. The effect of adding ancillary N-donor ligands to the reaction system on the coordination and supramolecular network assembly is also investigated.

1. Introduction

Owing to their structural diversity (Braunstein et al., 2004[Braunstein, P., Frison, C., Oberbeckmann-Winter, N., Morise, X., Messaoudi, A., Bénard, M., Rohmer, M. M. & Welter, R. (2004). Angew. Chem. Int. Ed. 43, 6120-6125.]; Ronson et al., 2006[Ronson, T. K., Lazarides, T., Adams, H., Pope, S. J. A., Sykes, D., Faulkner, S., Coles, S. J., Hursthouse, M. B., Clegg, W., Harrington, R. W. & Ward, M. D. (2006). Chem. Eur. J. 12, 9299-9313.]; Salazar-Mendoza et al., 2007[Salazar-Mendoza, D., Baudron, S. A. & Hosseini, M. W. (2007). Chem. Commun. pp. 2252-2254.]; Fernández-Cortabitarte et al., 2007[Fernández-Cortabitarte, C., García, F., Morey, J. V., McPartlin, M., Singh, S., Wheatley, A. E. H. & Wright, D. S. (2007). Angew. Chem. Int. Ed. 46, 5425-5427.]; Bruce, 1991[Bruce, M. I. (1991). Chem. Rev. 91, 197-257.]; Lang et al., 2000[Lang, H., George, D. S. A. & Rheinwald, G. (2000). Coord. Chem. Rev. 206-207, 101-197.]; Long & Williams, 2003[Long, N. J. & Williams, C. K. (2003). Angew. Chem. Int. Ed. 42, 2586-2617.]; Yam, 2004[Yam, V. W. W. (2004). J. Organomet. Chem. 689, 1393-1401.]; Chui et al., 2005[Chui, S. S. Y., Ng, M. F. Y. & Che, C.-M. (2005). Chem. Eur. J. 11, 1739-1749.]; Wong, 2007[Wong, W.-Y. (2007). Coord. Chem. Rev. 251, 2400-2427.]; McArdle et al., 2000[McArdle, C. P., Vittal, J. J. & Puddephatt, R. J. (2000). Angew. Chem. Int. Ed. 39, 3819-3822.], 2001[McArdle, C. P., Jennings, M. C., Vittal, J. J. & Puddephatt, R. J. (2001). Chem. Eur. J. 7, 3572-3583.]; McArdle, Irwin et al., 2002[McArdle, C. P., Irwin, M. J., Jennings, M. C., Vittal, J. J. & Puddephatt, R. J. (2002). Chem. Eur. J. 8, 723-734.]; McArdle, Van et al., 2002[McArdle, C. P., Van, S., Jennings, M. C. & Puddephatt, R. J. (2002). J. Am. Chem. Soc. 124, 3959-3965.]; Mohr et al., 2003[Mohr, F., Jennings, M. C. & Puddephatt, R. J. (2003). Eur. J. Inorg. Chem. pp. 217-233.]; Burchell et al., 2006[Burchell, T. J., Jennings, M. C. & Puddephatt, R. J. (2006). Inorg. Chim. Acta, 359, 2812-2818.]; Habermehl et al., 2006[Habermehl, N. C., Eisler, D. J., Kirby, C. W., Yue, N. L. & Puddephatt, R. J. (2006). Organometallics, 25, 2921-2928.]), transition metal ethynyl complexes are regarded as promising building blocks for constructing designed coordination polymers, which find potential applications as photoluminescent materials (Barlow & O'Hare, 1997[Barlow, S. & O'Hare, D. (1997). Chem. Rev. 97, 637-669.]; Whittal et al., 1998[Whittal, I. R., McDonagh, A. M. & Humphrey, M. G. (1998). Adv. Organomet. Chem. 42, 291-362.]; Cifuentes & Humphrey, 2004[Cifuentes, M. P. & Humphrey, M. G. (2004). J. Organomet. Chem. 689, 3968-3981.]), precursors of non-linear optical materials (Younus et al., 1998[Younus, M., Kohler, A., Cron, S., Chawdhury, N., Al-Madani, M. R. A., Khan, M. S., Long, N. J., Friend, R. H. & Raithby, P. R. (1998). Angew. Chem. Int. Ed. 37, 3036-3039.]; Yam, 2002[Yam, V. W. W. (2002). Acc. Chem. Res. 35, 555-563.]; Wei et al., 2004[Wei, Q. H., Zhang, L. Y., Yin, G. Q., Shi, L. X. & Chen, Z. N. (2004). J. Am. Chem. Soc. 126, 9940-9941.]; Xu et al., 2006[Xu, H.-B., Shi, L.-X., Ma, E., Zhang, L.-Y., Wei, Q.-H. & Chen, Z.-N. (2006). Chem. Commun. pp. 1601-1603.], 2009[Xu, H.-B., Zhang, L.-Y., Chen, X.-M., Li, X.-L. & Chen, Z.-N. (2009). Cryst. Growth Des. 9, 569-576.]; Xu, Ni et al., 2008[Xu, H.-B., Ni, J., Chen, K.-J., Zhang, L.-Y. & Chen, Z.-N. (2008). Organometallics, 27, 5665-5671.]; Xu, Zhang et al., 2008[Xu, H.-B., Zhang, L.-Y., Ni, J., Chao, H. Y. & Chen, Z.-N. (2008). Inorg. Chem. 47, 10744-10752.]) and rigid-rod molecular wires (Paul & Lapinte, 1998[Paul, F. & Lapinte, C. (1998). Coord. Chem. Rev. 178-180, 431-509.]; Yam & Wong, 2005[Yam, V. W. W. & Wong, K. M. (2005). Top. Curr. Chem. 257, 1-32.]; Rigaut et al., 2006[Rigaut, S., Olivier, C., Costuas, K., Choua, S., Fadhel, O., Massue, J., Turek, P., Saillard, J. Y., Dixneuf, P. H. & Touchard, D. (2006). J. Am. Chem. Soc. 128, 5859-5876.]; Koutsantonis et al., 2009[Koutsantonis, G. A., Jenkins, G. I., Schauer, P. A., Szczepaniak, B., Skelton, B. W., Tan, C. & White, A. H. (2009). Organometallics, 28, 2195-2205.]; Kilpin et al., 2011[Kilpin, K. J., Gower, M. L., Telfer, S. G., Jameson, G. B. & Crowley, J. D. (2011). Inorg. Chem. 50, 1123-1134.]). For over a decade, the multinuclear silver(I) ethynide1 supramolecular synthon (Desiraju, 1995[Desiraju, G. R. (1995). Angew. Chem. Int. Ed. 34, 2311-2327.]; Nangia & Desiraju, 1998[Nangia, A. & Desiraju, G. R. (1998). Top. Curr. Chem. 198, 57-95.]; Desiraju, 2007[Desiraju, G. R. (2007). Angew. Chem. Int. Ed. 46, 8342-8356.]; Cheng et al., 2012[Cheng, P.-S, Marivel, S., Zang, S.-Q, Gao, G.-G. & Mak, T. C. W. (2012). Cryst. Growth Des. 12, 4519-4529.]) R-C[triple bond]C[\supset]Agn (R = alkyl, phenyl, heteroaryl, n = 3-5) has been widely employed by our group and others as a robust and versatile building unit in the designed construction of a wide variety of high-nuclearity clusters (McArdle et al., 2000[McArdle, C. P., Vittal, J. J. & Puddephatt, R. J. (2000). Angew. Chem. Int. Ed. 39, 3819-3822.]; Pyykkö, 1988[Pyykkö, P. (1988). Chem. Rev. 88, 563-594.], 1997[Pyykkö, P. (1997). Chem. Rev. 97, 597-636.], 2008[Pyykkö, P. (2008). Chem. Soc. Rev. 37, 1967-1997.]; Grimme & Djukic, 2010[Grimme, S. & Djukic, J. P. (2010). Inorg. Chem. 49, 2911-2919.]; Muñiz et al., 2011[Muñiz, J., Wang, C. & Pyykkö, P. (2011). Chem. Eur. J. 17, 368-377.]; Yam et al., 1996[Yam, V. W. W., Fung, W. K.-M. & Cheung, K.-K. (1996). Angew. Chem. Int. Ed. 35, 1100-1102.]; Hau et al., 2012[Hau, S. C. K., Cheng, P.-S. & Mak, T. C. W. (2012). J. Am. Chem. Soc. 134, 2922-2925.]; Xie & Mak, 2012[Xie, Y.-P. & Mak, T. C. W. (2012). Angew. Chem. Int. Ed. 51, 8783-8786.]) and multi-dimensional coordination networks (Mak & Zhao, 2007[Mak, T. C. W. & Zhao, L. (2007). Chem. Asian J. 2, 456-467.]; Mak et al., 2012[Mak, T. C. W., Zhao, L. & Zhao, X.-L. (2012). The Importance of Pi-Interactions in Crystal Engineering, edited by E. R. T. Tiekink & J. Zukerman-Schpector, pp. 323-366. Chichester: Wiley.]; Zhang et al., 2008[Zhang, T., Kong, J., Hu, Y., Meng, X., Yin, H., Hu, D. & Ji, C. (2008). Inorg. Chem. 47, 3144-3149.], 2009[Zhang, T., Song, H., Dai, X. & Meng, X. (2009). Dalton Trans. 38, 7688-7694.], 2010[Zhang, T., Hu, Y., Kong, J., Meng, X., Dai, X. & Song, H. (2010). CrystEngComm, 12, 3027-3032.]; Zhao et al., 2011[Zhao, Y., Zhang, P., Li, B., Meng, X. & Zhang, T. (2011). Inorg. Chem. 50, 9097-9105.]).

Enediynes are well known for their highly rigid skeleton and conjugated properties, and hence they are widely chosen as building blocks for the construction of a wide range of macrocyclic molecular systems and natural products. In a recent study, our group has reported new silver(I) complexes containing (2-ethynylbut-1-en-3-yne-1,1-diyl)dibenzene and 9-(penta-1,4-diyn-3-ylidene)-9H-fluorene (Hau & Mak, 2013[Hau, S. C. K. & Mak, T. C. W. (2013). Polyhedron, 64, 63-72.]), yielding crystal structures that are composed of a chain of multinuclear metallocycles, which is favourably generated with the assistance of silver-aromatic interactions. Such chains are further interconnected to form two- or three-dimensional networks. As an extension of this line of investigation, we aim to study the coordination behaviour of alicycles bearing an enediyne substituent. A series of enediyne-functionalized alicycles, H2L1, H2L2 (Datta et al., 2005[Datta, S., Odedra, A. & Liu, R. S. (2005). J. Am. Chem. Soc. 127, 11606-11607.]), H2L3, H2L4, H2L5 (Lenz et al., 2005[Lenz, C., Haubmann, C., Hübner, H., Boeckler, F. & Gmeiner, P. (2005). Bioorg. Med. Chem. 13, 185-191.]) and H2L6 (Eisler et al., 2005[Eisler, S., Slepkov, A. D., Elliott, E., Luu, T., McDonald, R., Hegmann, F. A. & Tykwinski, R. R. (2005). J. Am. Chem. Soc. 127, 2666-2676.]), is synthesized as precursors for the generation of new metal-organic frameworks (MOFs) in combination with silver(I) trifluoro­acetate, various ancillary N-donor ligands and co-crystallized solvent molecules.

[Scheme BI5014]

Herein, we report the synthesis and structural studies of eight new silver organic complexes, denoted (I)-(VIII). Based on our previous experience, we anticipated that the reaction of crude polymeric starting materials [Ag2L1]n, [Ag2L2]n, [Ag2L3]n, [Ag2L4]n, [Ag2L5]n and [Ag2L6]n with water-soluble AgI salts would generate new MOFs consolidated by argentophilic and multinuclear silver(I)-ethynide bonding. Furthermore, the ethenyl group and the N-donor ancillary ligands are potentially capable of participating in silver(I)-olefin and [pi]-[pi] stacking interactions.

2. Experimental

2.1. Synthesis

Reaction schemes and experimental procedures for the synthesis of ligands H2L1-H2L6 are given in the supporting information.2

2.1.1. Preparation of polymeric silver ethynides as synthetic precursors

CAUTION. Silver ethynides are potentially explosive and should be handled in small amounts with extreme care!

Trimethylsilyl-protected ligand (TMS)2L1 (1 mmol) was first dissolved in methanol (10 ml). Silver nitrate (1 mmol) and triethylamine (1 mmol) were subsequently added with vigorous stirring, and the mixture was allowed to stir for 2 h in darkness. The resulting pale yellow slurry was diluted with methanol (20 ml) and filtered by suction filtration to collect a pale yellow precipitate of polymeric [Ag2L1]n, which was washed thoroughly with methanol (3 × 10 ml) and then stored in wet form at 263 K in a refrigerator. Silver complexes of H2L2-H2L6 were prepared in the same manner. Yields and below-red absorption data are as follows: [Ag2L1]n 95%, [nu] = 2010 cm-1 (w, [nu]C[triple bond]C); [Ag2L2]n 93%, [nu] = 2006 cm-1; [Ag2L3]n 97%, [nu] = 2014 cm-1; [Ag2L4]n 91%, [nu] = 2010 cm-1; [Ag2L5]n 95%, [nu] = 2004 cm-1; [Ag2L6]n 97%, [nu] = 2009 cm-1.

2.1.2. Synthesis of silver ethynide complexes

1.5(Ag2L1)·8AgCF3CO2·6DMSO (I): AgCF3CO2 (440 mg, 2 mmol) was first dissolved in DMSO (1 ml), and the polymeric complex [Ag2L1]n (20 mg) was subsequently added to the solution. After stirring until all solids had dissolved, the solution was filtered and the filtrate transferred to a test tube. Yellow block crystals of (I) were obtained after standing in the dark for 1 week by slow liquid diffusion of deionized water into the filtrate. Yield ca 60%. IR (KBr): [nu] = 2033 (C[triple bond]C, w) cm-1. Anal.: calc. for C86H96Ag22F48O44S12: C 18.77, H 1.76; found: C 18.92, H 1.63.

1.5(Ag2L2)·8AgCF3CO2·6DMSO (II): The above preparation was repeated using 20 mg of polymeric [Ag2L2]n to yield yellow block crystals of (II) in ca 65% yield. IR (KBr): [nu] = 2035 (C[triple bond]C, w) cm-1. Anal.: calc. (%) for C89H102Ag22F48O44S12: C 19.27, H 1.85; found: C 19.55, H 1.92.

(Ag2L3)·5AgCF3CO2·5DMSO (III): The preparation procedure was repeated using 100 mg of polymeric [Ag2L3]n to yield yellow block crystals of (III) in ca 63% yield. IR (KBr): [nu] = 2038 (C[triple bond]C, w) cm-1. Anal.: calc. (%) for C32H42Ag7F15O15S5: C 20.58, H 2.27; found: C 20.43, H 2.13.

(Ag2L4)·5AgCF3CO2·4DMSO (IV): The preparation procedure was repeated using 60 mg of polymeric [Ag2L4]n to yield yellow block crystals of (IV) in ca 55% yield. IR (KBr): [nu] = 2034 (C[triple bond]C, w) cm-1. Anal.: calc. (%) for C31H38Ag7F15O14S4: C 20.65, H 2.12; found: C 20.70, H 2.16.

(Ag2L5)·5AgCF3CO2·2H2O (V): Silver salts AgCF3CO2 (880 mg, 4 mmol) and AgBF4 (382 mg, 2 mmol) were first dissolved in methanol (2 ml) and deionized water (1 ml). Polymeric [Ag2L5]n (~ 23 mg) was then added to the solution. After stirring for about 30 min, the solution was filtered and left to stand in the dark at room temperature. After several days, colourless block crystals of (V) were deposited in ca 73% yield. IR (KBr): [nu] = 2043 (C[triple bond]C, w) cm-1. Anal.: calc. (%) for C20H12Ag7F15O12: C 16.18, H 0.81; found: C 16.33, H 0.75.

(Ag2L5)·7AgCF3CO2·(pyridine)·(CF3CO2-)2·(pyridineH+)2 (VI): The above preparation was repeated with the addition of pyridine (1-2 droplets) to yield yellow block crystals of (VI) in ca 45% yield. IR (KBr): [nu] = 2043 (C[triple bond]C, w) cm-1. Anal.: calc. (%) for C43H25Ag9F27N3O18: C 21.92, H 1.07, N 1.78; found: C 21.75, H 0.95, N 1.73.

(Ag2L5)·5AgCF3CO2·(2,2'-bipyridine)2 (VII): The preparation procedure for (V) was repeated using polymeric [Ag2L5]n (20 mg) with the addition of 2,2'-bipyridine (2-3 mg) to yield yellow block crystals of (VII) in ca 60% yield. IR (KBr): [nu] = 2038 (C[triple bond]C, w) cm-1. Anal.: calc. (%) for C40H24Ag7F15N4O10: C 27.29, H 1.37, N 3.18; found: C 27.33, H 1.41, N 3.16.

(Ag2L6)·9AgCF3CO2·3H2O·CH3CN (VIII): The preparation procedure for (V) was repeated with polymeric [Ag2L6]n replacing [Ag2L5]n, together with the addition of CH3CN (0.1 ml) to yield yellow block crystals of (VIII) in ca 75% yield. IR (KBr): [nu] = 2032 (C[triple bond]C, w) cm-1. Anal.: calc. (%) for C26H9Ag11Br2F27NO21: C 12.34, H 0.36, N 0.55; found: C 12.41, H 0.37, N 0.50.

2.2. X-ray crystallography

Selected crystals were used for data collection on a Bruker Kappa APEX-II Duo diffractometer at 173 K. H atoms were placed in calculated positions and refined as riding. In most cases, the trifluoroacetate anions display rotational disorder of their CF3 group, which was handled by including a single CF3 orientation. The geometry was restrained to be tetrahedral (one refined parameter for all C-F bond lengths, all F...F distances restrained to be 1.633 times that value), and anisotropic displacement parameters were assigned to the F atoms. In most cases, the resulting displacement ellipsoids are prolate, but this is considered to be an acceptable approximation to describe the rotational disorder. Some DMSO molecules are modelled as disordered over two orientations, and in (II) and (III) the ring systems of the organic ligands are also disordered over two orientations. For (VI) the two uncoordinated pyridine molecules must be protonated for charge balance. For one of them (containing N2), the position of the protonated N atom is clearly implied by the hydrogen-bond geometry. For the other (containing N3), there are two positions forming clear hydrogen bonds, and the molecule is therefore modelled as disordered over two orientations, with atoms N3 and N3' each having site occupancy 0.5. For the non-centrosymmetric structures (III), (IV) and (VI), the Flack parameter (Flack, 1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]) differs significantly from zero (Table 1[link]), and the structures were refined as inversion twins. The crystallographic data are summarized in Table 1[link].

Table 1
Experimental details

Experiments were carried out at 173 K with Mo K[alpha] radiation using a Bruker APEX-II CCD diffractometer. Absorption was corrected for by multi-scan methods, SADABS (Bruker, 2003[Bruker (2003). APEX2, SADABS and SAINT. Bruker AXS, Madison, Wisconsin, USA.]). H-atom parameters were constrained

  (I) (II) (III) (IV)
Crystal data
Chemical formula 22Ag+·3C10H82-·16C2F3O2-·12C2H6SO 22Ag+·3C11H102-·16C2F3O2-·12C2H6SO 7Ag+·C12H122-·5C2F3O2-·5C2H6SO 7Ag+·C13H142-·5C2F3O2-·4C2H6SO
Mr 5503.48 5545.56 1867.04 1802.94
Crystal system, space group Monoclinic, C2/c Monoclinic, C2/c Monoclinic, Cc Triclinic, P1
a, b, c (Å) 22.076 (3), 14.7930 (18), 45.863 (6) 21.9927 (13), 14.8488 (13), 45.797 (3) 17.8567 (17), 21.007 (2), 16.044 (3) 13.4350 (15), 13.8806 (15), 16.3609 (18)
[alpha], [beta], [gamma] (°) 90, 93.501 (3), 90 90, 93.937 (2), 90 90, 117.802 (1), 90 110.194 (2), 106.492 (2), 104.003 (2)
V3) 14950 (3) 14920.4 (19) 5323.6 (12) 2542.2 (5)
Z 4 4 4 2
[mu] (mm-1) 3.11 3.11 2.83 2.92
Crystal size (mm) 0.50 × 0.50 × 0.40 0.50 × 0.50 × 0.40 0.50 × 0.40 × 0.40 0.50 × 0.40 × 0.40
 
Data collection
Tmin, Tmax 0.306, 0.370 0.305, 0.369 0.332, 0.398 0.324, 0.389
No. of measured, independent and observed [I > 2[sigma](I)] reflections 102 163, 13 534, 9700 164 822, 13 506, 12 140 19 165, 6449, 5135 31 854, 16 780, 15 708
Rint 0.158 0.131 0.102 0.075
(sin [theta]/[lambda])max-1) 0.600 0.600 0.600 0.600
 
Refinement
R[F2 > 2[sigma](F2)], wR(F2), S 0.076, 0.200, 1.08 0.064, 0.164, 1.14 0.066, 0.165, 1.05 0.087, 0.235, 1.05
No. of reflections 13 534 13 506 6449 16 780
No. of parameters 967 998 668 1276
No. of restraints 606 508 184 615
[Delta][rho]max, [Delta][rho]min (e Å-3) 3.61, -1.64 2.34, -2.24 1.67, -1.38 3.89, -1.66
Absolute structure - - Refined as an inversion twin Refined as an inversion twin
Absolute structure parameter - - 0.48 (12) 0.71 (8)
  (V) (VI) (VII) (VIII)
Crystal data
Chemical formula 7Ag+·C10H82-·5C2F3O2-·2H2O 9Ag+·C10H82-·9C2F3O2-·C5H5N·2C5H6N+ 7Ag+·C10H82-·5C2F3O2-·2C10H8N2 11Ag+·C6Br22-·9C2F3O2-·C2H3N·3H2O
Mr 1484.39 2355.49 1760.72 2530.73
Crystal system, space group Monoclinic, C2/c Monoclinic, P21 Triclinic, P[\overline{1}] Orthorhombic, Pbca
a, b, c (Å) 23.394 (2), 13.9512 (12), 10.7920 (9) 8.9453 (9), 24.902 (3), 14.4248 (16) 12.427 (3), 14.132 (3), 16.384 (6) 16.861 (6), 24.431 (9), 26.723 (10)
[alpha], [beta], [gamma] (°) 90, 102.214 (1), 90 90, 105.016 (2), 90 96.481 (5), 108.935 (5), 115.229 (4) 90, 90, 90
V3) 3442.5 (5) 3103.5 (6) 2353.5 (12) 11008 (7)
Z 4 2 2 8
[mu] (mm-1) 4.03 2.93 2.97 5.43
Crystal size (mm) 0.50 × 0.50 × 0.40 0.50 × 0.50 × 0.40 0.50 × 0.50 × 0.40 0.50 × 0.50 × 0.50
 
Data collection
Tmin, Tmax 0.238, 0.295 0.323, 0.388 0.318, 0.383 0.172, 0.172
No. of measured, independent and observed [I > 2[sigma](I)] reflections 30 572, 3109, 2897 68 475, 11 211, 10 668 18 969, 8486, 6185 179 417, 9961, 7690
Rint 0.087 0.077 0.093 0.135
(sin [theta]/[lambda])max-1) 0.600 0.600 0.600 0.600
 
Refinement
R[F2 > 2[sigma](F2)], wR(F2), S 0.047, 0.125, 1.07 0.036, 0.098, 1.03 0.083, 0.214, 1.04 0.055, 0.154, 1.08
No. of reflections 3109 11 211 8486 9961
No. of parameters 264 873 686 794
No. of restraints 78 283 360 216
[Delta][rho]max, [Delta][rho]min (e Å-3) 1.26, -1.77 1.39, -0.71 1.74, -1.62 1.77, -1.33
Absolute structure - Refined as an inversion twin - -
Absolute structure parameter - 0.48 (4) - -
Computer programs: APEX2, SAINT (Bruker, 2003[Bruker (2003). APEX2, SADABS and SAINT. Bruker AXS, Madison, Wisconsin, USA.]) (Bruker, 2003[Bruker (2003). APEX2, SADABS and SAINT. Bruker AXS, Madison, Wisconsin, USA.]), SHELXS97, SHELXL2013 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), DIAMOND (Brandenburg, 2009[Brandenburg, K. (2009). DIAMOND. Crystal Impact GbR, Bonn, Germany.]).

3. Results and discussion

3.1. Crystallization

Complexes (I)-(VIII) were obtained from room-temperature crystallization of the corresponding crude polymeric compounds in a concentrated DMSO solution of AgCF3CO2, or a mixed water/methanol solution of AgCF3CO2/AgBF4 (2:1). AgCF3CO2 and AgBF4 were used to provide the auxiliary CF3CO2- ligand and to increase the AgI ion concentration, respectively. The high concentration of AgI ions and their aggregation through argentophilicity ensure that the ethynide group mostly achieves a high ligation number of 4 or 5 within a butterfly shaped Ag4 or square-pyramidal Ag5 basket, as opposed to most transition-metal alkyl and aryl ethynide complexes with ligation numbers ranging from 1 to 4. Such baskets can be fused to give larger aggregates or mutually connected by bridging trifluoroacetate ligands to yield higher-dimensional MOFs (Guo & Mak, 1999[Guo, G.-C. & Mak, T. C. W. (1999). Chem. Commun. pp. 813-814.]).

3.2. Crystal structures

3.2.1. (Ag2L1)·8AgCF3CO2·6DMSO (I)

Complex (I) contains two crystallographic independent L1 ligands, one of which has its planar molecular skeleton bisected by a crystallographic twofold axis. Accordingly, the three ethynide groups C1[triple bond]C2, C4[triple bond]C5 and C11[triple bond]C12 are each bound to a butterfly-shaped Ag4 basket in [mu]4-[eta]1,[eta]1,[eta]2,[eta]2, [mu]4-[eta]1,[eta]1,[eta]1,[eta]2 and [mu]4-[eta]1,[eta]1,[eta]2,[eta]2 coordination modes, respectively (Fig. 1[link]a). Such silver-ethynide supramolecular synthons come together to yield two different AgI fragments: Type 1, Ag8 aggregate on an inversion centre, containing Ag1; Type 2, Ag7 aggregate sharing the common vertex Ag5 (Fig. S1a in the supporting information ). Adjacent Ag7 and Ag8 segments are interconnected through the linkage of three DMSO ligands (O18, O19 and O20) via the [mu]2 coordination mode; while two Ag7 aggregates are interconnected by two pairs of symmetry-related DMSO ligands (O21 and O21A; O22 and O22A; symmetry code: [-x + 1, y, -z + {1\over 2}]) via [mu]2-[eta]1,[eta]1 and [mu]3-[eta]1,[eta]1,[eta]1 modes, respectively, to generate a one-dimensional silver organic chain along the [101] direction. Cross linkage of such chains by weak C-H...F interactions between ligand L1 and the trifluoroacetate groups (Table 2[link]) generates a supramolecular layer (Fig. S1b in the supporting information ). Such AgI layers are interconnected by additional C-H...F contacts between DMSO ligands and nearby trifluoroacetate groups (Table 2[link]) to yield the three-dimensional supramolecular network (Fig. 1[link]b).

Table 2
Intermolecular interaction geometry (Å, °) for (I)-(VIII)

D-H...A D-H H...A D...A D-H...A
(I)
C16-H16B...F22i 0.99 2.66 3.42 (2) 133
C34-H34B...F13ii 0.98 2.64 3.27 (2) 122
         
(II)
C40-H40C...F8iii 0.98 2.50 3.448 (17) 164
C41-H41B...F9iv 0.98 2.61 3.565 (18) 164
         
(III)
C27-H27C...F10v 0.98 2.62 3.27 (4) 125
C27-H27C...F12v 0.98 2.52 3.47 (4) 164
         
(IV)
C47-H47B...O6vi 0.98 2.68 3.65 (6) 168
C48-H48C...O4vi 0.98 2.55 3.45 (6) 150
C51-H51A...F28vii 0.98 2.63 3.46 (6) 125
C51-H51A...F29vii 0.98 2.57 3.23 (5) 144
C56-H56A...F14viii 0.98 2.60 3.59 (6) 174
         
(V)
O1W-H1W...O1ix 0.85 2.05 2.786 (7) 145
O1W-H2W...O3ix 0.85 2.13 2.808 (7) 136
         
(VI)
N2-H2...O1 0.88 2.63 3.013 (12) 107
N2-H2...O5 0.88 1.97 2.852 (12) 176
N3-H3...O8 0.88 2.53 3.133 (15) 126
N3-H3...O17 0.88 2.35 3.041 (17) 136
N3'-H3'...O6x 0.88 2.39 3.049 (12) 132
N3'-H3'...O15x 0.88 2.21 2.927 (13) 138
C6-H6B...F1xi 0.99 2.54 3.282 (2) 132
C6-H6B...F13xi 0.99 2.46 3.361 (4) 150
         
(VII)
C22-H22A...F14xii 0.95 2.59 3.55 (2) 164
C32-H32A...F15xiii 0.95 2.53 3.31 (2) 140
C33-H33A...O10xiii 0.95 2.52 3.39 (3) 153
C37-H37A...F10xiii 0.95 2.70 3.44 (3) 135
C38-H38A...O1viii 0.95 2.45 3.32 (2) 152
C39-H39A...O6xiv 0.95 2.51 3.45 (2) 170
         
(VIII)
O1W-H2W...O2xv 0.85 1.96 2.783 (11) 164
O1W-H1W...O18xvi 0.85 1.94 2.774 (11) 167
O2W-H4W...O10xvii 0.85 2.06 2.875 (11) 161
O2W-H3W...O1W 0.85 2.02 2.846 (12) 165
O3W-H5W...O16xviii 0.85 2.08 2.851 (13) 150
O3W-H6W...F20 0.85 2.66 3.212 (14) 124
Symmetry codes: (i) x, y + 1, z; (ii) [x + {1\over 2}, y - {1\over 2}, z]; (iii) x, y - 1, z; (iv) [x - {1\over 2}, y - {1\over 2}, z]; (v) [x, -y+1, z - {1\over 2}]; (vi) x + 1, y, z; (vii) x - 1, y, z; (viii) x + 1, y + 1, z; (ix) [x, -y, z - {1\over 2}]; (x) x, y, z + 1; (xi) [-x + 1, y + {1\over 2}, -z + 1]; (xii) x - 1, y - 1, z; (xiii) -x + 1, -y, -z + 1; (xiv) -x + 1, -y + 1, -z + 2; (xv) -x + 1, -y + 1, -z + 1; (xvi) [x + {1\over 2}, y, -z + {1\over 2}]; (xvii) -x, -y + 1, -z + 1; (xviii) [x - {1\over 2}, y, -z + {1\over 2}].
[Figure 1]
Figure 1
(a) Coordination environment of the AgI atoms and ethynide groups in (I). Symmetry code: (A) [ -x + 1, y, -z + {1\over 2}]. The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of the supramolecular network structure in (I), showing notable C-H...F contacts (Table 2[link]). Colour scheme: Ag purple; O orange; F green; broken lines Ag-C bonds; the same colour scheme applies to all figures.
3.2.2. (Ag2L2)·8AgCF3CO2·6DMSO (II)

Complex (II) is found to be virtually isomorphous to complex (I), although the L2 ligand has a larger alicyclic ring. Of the two crystallographically independent L2 ligands, one has its pair of ethynide groups related by crystallographic twofold symmetry. The three independent ethynide groups exhibit different coordination modes: [mu]5-[eta]1,[eta]1,[eta]2,[eta]2,[eta]2 for C1[triple bond]C2, [mu]4-[eta]1,[eta]1,[eta]1,[eta]2 for C4[triple bond]C5 and [mu]4-[eta]1,[eta]1,[eta]2,[eta]2 for C12[triple bond]C13 (Fig. 2[link]a). Two adjacent Ag7 and Ag8 aggregates are interconnected through the linkage of three DMSO ligands (O18, O19 and O20) via the [mu]2 mode to generate a one-dimensional silver organic chain along [101] (Fig. S2a in the supporting information ). Further connection between adjacent chains through C-H...F contacts between DMSO ligands and trifluoroacetate groups (Table 2[link] and Fig. S2b in the supporting information ) generate the three-dimensional supramolecular network.

[Figure 2]
Figure 2
(a) Coordination environment of the AgI atoms and ethynide groups in (II). Symmetry codes: (A) [-x + {3\over 2}, -y + {3\over 2}, -z + 1]; (B) [-x + 1, y, -z + {1\over 2}]. The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of the supramolecular layer structure in (II), showing notable C-H...F contacts (Table 2[link]).
3.2.3. (Ag2L3)·5AgCF3CO2·5DMSO (III)

In the crystal structure of (III) the ethynide groups (C1[triple bond]C2 and C4[triple bond]C5) of ligand L3 are each encapsulated within an Ag4 basket in the [mu]4-[eta]1,[eta]1,[eta]1,[eta]2 coordination mode. The Ag...Ag distances are in the range 2.801 (2)-3.184 (2) Å (Fig. 3[link]a), which are comparable to those observed in a wide variety of AgI double and multiple salts reported by our group and attributable to argentophilic interactions (Guo et al., 1998[Guo, G.-C., Zhou, G.-D., Wang, Q.-C. & Mak, T. C. W. (1998). Angew. Chem. Int. Ed. 37, 630-632.], 1999[Guo, G.-C., Zhou, G.-D. & Mak, T. C. W. (1999). J. Am. Chem. Soc. 121, 3136-3141.]; Wang & Mak, 2001a[Wang, Q.-G. & Mak, T. C. W. (2001a). J. Am. Chem. Soc. 123, 1501-1502.],b[Wang, Q.-M. & Mak, T. C. W. (2001b). Angew. Chem. Int. Ed. 40, 1130-1133.],c[Wang, Q.-M. & Mak, T. C. W. (2001c). Chem. Commun. pp. 807-808.]). Through sharing of atom Ag3, two butterfly-shaped Ag4 segments are fused to form an Ag7 aggregate by argentophilic interaction (Fig. S3 in the supporting information ). Two adjacent Ag7 aggregates are linked by two [mu]2-coordinated DMSO ligands (O11 and O15) to generate a one-dimensional coordination chain along [101]. Neighbouring coordination chains are interconnected by weak C-H...F contacts between DMSO ligands (O13) and trifluoroacetate groups (O7/O8; Table 2[link]) to yield the three-dimensional supramolecular network (Fig. 3[link]b).

[Figure 3]
Figure 3
(a) Coordination environment of the AgI atoms and ethynide groups in (III). Symmetry code: (A) [x + {1\over 2}, -y + {1\over 2}, z + {1\over 2}]. The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of the supramolecular network structure in (III), showing notable C-H...F contacts (Table 2[link]).
3.2.4. (Ag2L4)·5AgCF3CO2·4DMSO (IV)

Complex (IV) contains two crystallographically independent L4 ligands with four ethynide groups that exhibit different coordination modes: C1[triple bond]C2, C14[triple bond]C15 and C17[triple bond]C18 adopt the [mu]4-[eta]1,[eta]1,[eta]2,[eta]2 mode and the remaining ethynide group (C4[triple bond]C5) adopts the [mu]4-[eta]1,[eta]1,[eta]1,[eta]2 mode (Fig. 4[link]a). The Ag4 ethynide aggregates come together to yield two types of Ag7 fragments: Type 1, C1[triple bond]C2 and symmetry-equivalent C17[triple bond]C18 share Ag2; Type 2, C4[triple bond]C5 and C14[triple bond]C15 share Ag7. The Type 1 Ag7 segment is associated with adjacent Type 2 Ag7 segmented through the linkage of three [mu]2-[eta]1,[eta]1 coordinated DMSO ligands (O21, O22 and O23; Fig. S4 in the supporting information ). Besides this, the Type 2 segment is linked with a symmetry-related Type 1 fragment through another four DMSO ligands (O25, O26, O27 and O28) by the same [mu]2-[eta]1,[eta]1 mode. As a result, a one-dimensional coordination chain is generated along [111]. Adjacent chains are interconnected through C-H...F contacts (Table 2[link]) between trifluoroacetate and DMSO ligands to yield the three-dimensional supramolecular network (Fig. 4[link]b).

[Figure 4]
Figure 4
(a) Coordination environment of the AgI atoms and ethynide groups in (IV). Symmetry code: (A): x + 1, y + 1, z + 1. The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of the interconnection between adjacent coordination chains in (IV) showing notable C-H...O and C-H...F contacts (Table 2[link]).
3.2.5. (Ag2L5)·5AgCF3CO2·2H2O (V)

In complex (V) a crystallographic twofold axis passes through the ligand L5, with the ethynide group C1[triple bond]C2 adopting the [mu]4-[eta]1,[eta]1,[eta]1,[eta]2 coordination mode, clasped by a butterfly-shaped Ag4 basket (Fig. 5[link]a). Through vertex sharing involving Ag4, two symmetry-related Ag4 segments are fused into a larger Ag7 aggregate, with Ag...Ag distances in the range 2.7604 (9)-3.1648 (7) Å. Two adjacent Ag7 aggregates are interconnected through two pairs of symmetry-related [mu]3-[eta]1,[eta]2-coordinated trifluoroacetate groups (O3/O4 and O5/O5; Fig. S5 in the supporting information ). These Ag14 building units are linked through a pair of symmetry-related trifluoroacetate groups (O1/O2) to generate a three-dimensional silver-organic coordination network (Fig. 5[link]b), which is consolidated by O-H...O hydrogen bonds between the aqua ligands and trifluoroacetate groups (Table 2[link]).

[Figure 5]
Figure 5
(a) Coordination environment of the AgI atoms and ethynide groups in (V). Symmetry codes: (A) [-x + 1, y, -z + {3\over 2}]; (B) [-x + 1, y, -z + {1\over 2}]. The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of the coordination layer structure in (V), showing notable O-H...O hydrogen bonds and C-H...F contacts (Table 2[link]).
3.2.6. (Ag2L5)·7AgCF3CO2·(pyridine)·(CF3CO2-)2·(pyridineH+)2 (VI)

In complex (VI), the independent ethynide groups (C1[triple bond]C2 and C9[triple bond]C10) are each encapsulated within a Ag5 basket in the [mu]5-[eta]1,[eta]1,[eta]1,[eta]2,[eta]2 coordination mode with Ag...Ag distances in the range 2.8728 (11)-3.2727 (10) Å. By sharing a common vertex Ag4, two Ag5 baskets are joined to yield a Ag9 aggregate, as shown in Fig. 6[link](a). A peripheral atom Ag9 is attached to this Ag9 aggregate through an argentophilic interaction to produce a Ag10 segment. Atom Ag9 is found to exhibit positional disorder with Ag9' located at a minor site of occupancy 0.301 (11), both sites being coordinated by a pyridine ligand (Fig. 6[link]a).

[Figure 6]
Figure 6
(a) Coordination environment of the AgI atoms and ethynide groups in (VI). The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of the supramolecular network structure in (VI), showing notable hydrogen bonds and C-H...F contacts. Atoms with prime superscripts represent disordered sites of the corresponding labeled atoms.

Through argentophilic interaction between atoms Ag2, Ag3 and symmetry-related Ag7 and Ag8 (symmetry code: x - 1, y, z), two adjacent Ag9 segments come together to form a large Ag18 aggregate, which is further extended into a one-dimensional chain along the a axis (Fig. S6 in the supporting information ). Neighbouring chains are interconnected through hydrogen bonds between the uncoordinated protonated pyridine molecules and trifluoroacetate groups (Table 2[link]) to form a supramolecular layer in the ac plane. C-H...F contacts between the ligand L5 and trifluoroacetate groups yield the three-dimensional supramolecular network (Fig. 6[link]b).

3.2.7. (Ag2L5)·5AgCF3CO2·(2,2'-bipyridine)2 (VII)

As shown in Fig. 7[link](a), both ethynide groups (C1[triple bond]C2 and C9[triple bond]C10) of ligand L5 are each inserted into a Ag4 basket in the [mu]4-[eta]1,[eta]1,[eta]1,[eta]2 and [mu]4-[eta]1,[eta]1,[eta]2,[eta]2 coordination modes, respectively. Through sharing atom Ag4, two Ag4 aggregates are fused to construct a Ag7 aggregate that carries two peripheral AgI atoms, each chelated by one 2,2'-bipyridine ligand (Ag3 by N1 and N2; Ag7 by N3 and N4). With an inversion centre located between symmetry-related Ag6 atoms (symmetry code: -x, -y, -z + 1; Fig. S7a in the supporting information ), two Ag7 fragments join together to yield a Ag14 aggregate through argentophilic interactions and coordination by two pairs of inversion-related trifluoroacetate groups (O7/O8 and O9/O10). As a result, a one-dimensional silver-organic chain is generated along the c axis. Adjacent chains are associated through C-H...F contacts (Table 2[link]) and C-H...O interactions between the 2,2'-bipyridine ligands and nearby trifluoroacetate groups (Table 2[link]) to form a supramolecular layer in the ac plane (Fig. S7b in the supporting information ). Further connections between adjacent layers through C-H...F and C-H...O interactions between 2,2'-bipyridine ligands and trifluoro­acetate groups (Table 2[link]) then generate the three-dimensional supramolecular network (Fig. 7[link]b).

[Figure 7]
Figure 7
(a) Coordination environment of the AgI atoms and ethynide groups in (VII). The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of the interconnection between adjacent coordination chains in (VII), showing notable C-H...O and C-H...F contacts (Table 2[link]).
3.2.8. (Ag2L6)·9AgCF3CO2·3H2O·CH3CN (VIII)

In the crystal structure of (VIII) the independent ethynide groups of L6 are each inserted into a Ag4 butterfly-shaped basket via the [mu]4-[eta]1,[eta]1,[eta]1,[eta]2 mode, and adjacent Ag4 aggregates are fused together through argentophilic interaction between atoms Ag1 and Ag8 to form a Ag8 segment (Fig. 8[link]a). Another Ag2 segment composed of Ag9 and Ag10 is linked to the Ag8 fragment through two trifluoro­acetate groups (O11/O12 and O15/O16) via [mu]3-[eta]1,[eta]2 and [mu]4-[eta]1,[eta]3 modes, respectively. The lone Ag11 atom is hitched to the Ag8 aggregate by two trifluoroacetate groups (O13/O14 and O15/O16) via [mu]3-[eta]1,[eta]2 and [mu]4-[eta]1,[eta]3 modes, respectively, and a [mu]2-coordinated aqua ligand (O2W) to produce a Ag11 coordination segment. Such Ag11 segments are interconnected through different symmetry-related pairs of trifluoroacetate groups [O1/O2 and O9/O10 via [mu]3-[eta]1,[eta]2 mode in Fig. S8(a) in the supporting information ; O5/O6 via [mu]3-[eta]1,[eta]2 mode in Fig. S8(b); O7/O8 via [mu]3-[eta]1,[eta]2 mode, O13/O14 via [mu]4-[eta]2,[eta]2 mode in Fig. S8(c); O3/O4 via [mu]4-[eta]1,[eta]3, O5/O6 via [mu]4-[eta]2,[eta]2, O17/O18 via [mu]4-[eta]1,[eta]3 in Fig. S8(d)] to generate a three-dimensional coordination network (Fig. 8[link]b), which is further consolidated by additional O-H...O hydrogen bonds involving aqua ligands and trifluoroacetate groups (Table 2[link] and Fig. S8a in the supporting information ).

[Figure 8]
Figure 8
(a) Coordination environment of the AgI atoms and ethynide groups in (VIII). The argentophilic Ag...Ag distances, shown as thick purple rods, lie in the range 2.70-3.40 Å. Ag atoms are drawn with displacement ellipsoids at 50% probability. H atoms and trifluoroacetate ligands are omitted for clarity. (b) Perspective view of a portion of the coordination layer structure in (VIII).

3.3. Discussion

3.3.1. Influence of ring size of alicycles and ancillary ligands

Systematic investigation of the present series of silver complexes (I)-(VIII) demonstrates the general utility of the silver ethynide supramolecular synthon R-C[triple bond]C[\supset]Agn (n = 4, 5) in coordination network assembly. Among the eight complexes reported, silver-olefin binding is not observed as silver-ethynide bonding takes precedence, and the ethenyl group in L1-L6 is far from the AgI aggregates around the two conjugated ethynide groups. Isomorphous complexes (I) and (II) exhibit a one-dimensional silver organic chain with the L1 and L2 ligands, respectively, alternately positioned in a zigzag manner. On the other hand, in complexes (III) and (IV) the L3 and L4 ligands direct arrangement of the larger alicyclic rings on the same side of their respective one-dimensional silver organic coordination chains. Notably, each alicyclic ring system in L1-L4 retains its most stable conformation (`envelope' for L1, `chair' for L2 and L3, and `twisted tub' for L4), which is not influenced by the steric congestion of the multinuclear AgI aggregates nearby. In complex (VIII) replacing the ring system by two bromo-substituents (in L6) favours the generation of a more densely packed three-dimensional coordination network.

In ligand L5 the ethenyl group of the cyclohexene ring and the pair of ethynide groups constitute a [pi]-conjugated system, but the possible silver-olefin interaction in complex (V) is hampered by coordination of the trifluoroacetate groups to the AgI baskets on the opposite side. With relatively less steric hindrance from the twisted conformation of the more rigid cyclohexene ring, a more closely packed three-dimensional coordination network is obtained in complex (V). Incorporation of ancillary N-donor ligands in complexes (VI) and (VII) breaks up the coordination network of (V). Consequently, a one-dimensional silver organic chain composed of higher nuclearity Ag9 silver aggregates is generated in (VI) via pyridine coordination (Ag9-N1). As expected, the ancillary 2,2'-bipyridyl ligands in (VII) function in the chelating mode to stabilize two peripheral AgI atoms (Ag3 and Ag7) of the Ag7 segment that embraces the ethynide groups of L5, such that their hydrophobic ring skeletons are positioned in a zigzag manner along the silver-organic chain. In both (VI) and (VII), the N-donor ligands, which are either co-crystallized in the crystalline lattice or coordinated to the silver aggregates, serve as bridges to interconnect adjacent silver-organic chains, yielding a higher-dimensional supramolecular network structure through C-H...O and C-H...F hydrogen bonding with trifluoroacetate groups.

3.3.2. Role of weak intermolecular interactions

With the exception of (VI) and (VII), all complexes incorporate either solvated DMSO or water molecules in their crystalline lattices. In those complexes that contain co-crystallized solvent molecules, hydrogen bonds (C-H...F or C-H...O) between solvent molecules and trifluoroacetate groups confer extra stability to the coordination network [(V) and (VIII)] or connect the metal-organic coordination chains into a three-dimensional supramolecular network [(I)-(IV)]. Lacking co-crystallized solvent molecules in (VI) and (VII), weak C-H...F and C-H...O interactions between N-donor ancillary ligands and trifluoroacetate groups come into play, thereby contributing to the linkage of adjacent silver chains to generate a three-dimensional supramolecular network.

4. Conclusion

In summary, this paper reports the synthesis and structural characterization of a series of eight silver(I) trifluoroacetate complexes containing designed alicyclic ligands each bearing an enediyne substituent, from which each ethynide group of the ligands is invariably inserted into a Agn (n = 4-5) basket, leading to the generation of coordination chain or network structures, but the well shielded ethenyl group does not take part in silver-olefin binding. Variation of alicyclic ring size is shown to influence the construction of the organosilver(I) networks, which are consolidated by weak intermolecular interactions in the crystal structures. The presence of ancillary N-donor ligands tends to convert a one-dimensional coordination silver-organic chain to a higher-dimensional supramolecular network consolidated by weak C-H...F and C-H...O interactions.

Acknowledgements

We gratefully acknowledge financial support by the Hong Kong Research Grants Council (GRF CUHK 402710) and the Wei Lun Foundation, and the award of a Postdoctoral Research Fellowship to S. C. K. Hau and a Postgraduate Studentship to D. Y. S. Tam by The Chinese University of Hong Kong.

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Acta Cryst (2014). B70, 37-46   [ doi:10.1107/S2052520614000171 ]