Role of inorganic and organic anions in the formation of metallosupramolecular assemblies of silver(I) coordination polymers with the twisted ligand bis(4-pyridylthio)methane (original) (raw)
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Crystal Growth & Design, 2005
A number of complexes were synthesized to rationalize the structures of Ag(I) complexes with a small flexible bidentate ligand, bis(phenylthio)methane, when the anion is varied. We compared two similar "spherical" anions, ClO 4 -(1) and BF 4 -(2), as well as two slightly "elongated" ones, CF 3 COO -(3) and CF 3 SO 3 -(4, 5). Complexes with a longer anion, CF 3 CF 2 CF 2 COO -(6), and a diacid, -OOCCF 2 CF 2 COO -(7), were also investigated. All the compounds studied form a 1D-coordination polymer. The coordination polymers of 1-4 are of the type [Ag-ligand-] ∞ and adopt two distinct conformations: gauche-trans-gauche for 1, 2, and 4, and gauche-gauche-gauche for 3. The anions in 1-4 are coordinated to the silver atoms through a single O or F atom. All these 1D-chains are associated through weak van der Waals interactions into 2D-layer structures. Solvent-induced supramolecular isomerism was observed with the CF 3 SO 3anion. With diethyl ether, the 1D-coordination polymer of 4 was observed, as indicated above, while a two-stranded chain comprising a 16-membered macrocyclic structure, Ag 4 L 1 4 , was noted when petroleum ether was used, 5. The macrocycles are connected through a small cyclic (CF 3 SO 3 ‚‚‚Ag‚‚‚) 2 dimeric unit. Another type of double-stranded ladder-like structure was noted for 6. Each of the two heptafluorobutyrate anions is coordinated through its oxygen atoms to two distinct silver atoms to form a dimeric unit. This, in turn, is connected to another unit through two Ag-S coordination bonds. The repeat unit of this coordination polymer is based on a 10-membered Ag 4 L 1 2 macrocycle. In compound 7, with the tetrafluorosuccinate anion, one observes another type of 1D-polymer best described as a [Ag 2 -tetrafluorosuccinate-] ∞ chain reinforced by Ag-ligand-Ag bonds. Most complexes containing fluorine atoms have C(H)‚‚‚F or C(H 2 )‚‚‚F short contacts (2.998-3.203 Å) that correlate with an FTIR absorption band around 521 cm -1 . Relatively short Ag‚‚‚Ag interactions are found in both 6 and 7.
Inorganic Chemistry, 2005
The synthesis and characterization of nine coordination networks based on 1,3-bis(phenylthio)propane, L 3 , and silver(I) salts of PF 6 (7−9) are reported. Only 1 and other "isostructural" complexes with weakly coordinating anions such as ClO 4and SbF 6are of the host−guest type. In all the other complexes, the anions and the acetone molecules, when present, are coordinated to the metal. Most of the complexes studied here form a 2D-coordination network. Only 4 and 5 adopt a polymer-like chain structure. The packing of the chains of 4 is pseudohexagonal compact, while that of 5 is of the centered type. In complex 1, the silver atom is tetrahedrally coordinated to the sulfur atoms of four different ligands. The PF 6anions and acetone molecules, sandwiched between silver−ligand cationic sheets, are held through van der Waals interactions. In each of the three perfluorocarboxylates (2−4), two silver atoms are joined by the anions in a diatomic bridging mode. The Ag‚‚‚Ag distances are sufficiently short to indicate weak metal‚‚‚metal interactions. The dimeric units in 2 and 3 are interconnected through the ligands, thereby generating a 2D-network of neutral sheets, while, in 4, the dimeric units are bound to four ligands and a 1D-coordination polymer is generated. In the case of the sulfonate anions (p-TsOand CF 3 SO 3 -), the crystallization solvent influences the structure adopted. Thus, in 5, 7, and 9 obtained from petroleum ether, or other nonpolar solvents, two silver atoms are bound in a double-bridge fashion, while a monobridge mode is noted for 6 and 8, both recrystallized from diethyl ether. In 8, both bridging types are observed. The thermogravimetric investigation, in the room temperature−450°C interval, of complexes 1, 3, and 7, which incorporate acetone molecules in their crystal structures, reveals a two-step weight loss for 1 (the acetone molecules are lost first followed by the ligands, leaving behind the silver salt), while complexes 3 and 7 decompose in a single step to metallic silver. Blake, A. J.; Champness, N. R.; Lemenovskii, D. A.; Majouga, A. G.; Zyk, N. V.; Schröder, M.
Heterotopic silver–NHC complexes: from coordination polymers to supramolecular assemblies
Dalton Transactions, 2010
New coordination polymers based on different combinations of silver atoms and pyridyl-substituted N-heterocyclic carbene moieties are described. The addition of Zn(II) templates leads to Ag-Zn supramolecular assemblies via selective Zn ◊ ◊ ◊ N interactions; a process that can be reverted. 30 2533940; Tel: +31 30 2532538 † Electronic supplementary information (ESI) available: Characterization of compounds 2, 3, 4, 5A and 5B, GPC and UV-vis spectra of 2, and UV-vis titration experiments for assemblies 5A and 5B. CCDC reference numbers 773279-773281. For ESI and crystallographic data in CIF or other electronic format see Scheme 1 Synthesis of complexes 1-3.
Inorganic Chemistry, 2008
New coordination polymers have been obtained by the self-assembly of silver salts AgX (X ) BF 4 , PF 6 , CF 3 SO 3 ) and 2,4-diamino-6-R-1,3,5-triazines L (R ) phenyl and p-tolyl) of formulas AgLX (1-6). A complex of different stoichiometry, [Ag 3 L 2 (H 2 O)(acetone) 2 ](BF 4 ) 3 , 7 (R ) phenyl), has also been synthesized. The three-dimensional structures of five compounds have been determined by X-ray diffraction studies. For the AgLX complexes, when X ) BF 4 and R ) phenyl or p-tolyl, chiral chains with alternating Ag and L are formed. The chains are cross-linked by the counteranions in a three-dimensional fashion through hydrogen bonds and weak Ag · · · F interactions giving rise to a structure with solvent-filled channels. Different and more compact structures have been found when the counteranion is CF 3 SO 3 (OTf). When R ) phenyl, sheets are formed which consist of [Ag 2 (OTf) 2 L 2 ] units with double triflate bridges and which contain columns of π-π stacked arenes. Hydrogen bonds connect the sheets. When AgOTf is used and R is p-tolyl, a different and unusual ladderlike structure is obtained in which the rungs are double asymmetric bridges consisting of the triflate groups bonded to Ag in κ 2 O,µ 2 -O and κ 1 O,µ 2 -O fashion. The ladders are parallel to each other and are mutually linked by N-H · · · N hydrogen bonds to give a 3D architecture. A very similar ladderlike structure has been found for 7 but with a water molecule and a BF 4group acting as bridges. The role played by the hydrogen bonds in complex 6 to form the 3-D structure is played in 7 by [Ag(acetone) 2 ] fragments. The noncovalent interactions play an important role in the different solid-state 3D structures. The behavior of the new derivatives in solution has also been analyzed. A new species has been detected at low temperatures, and this exhibits restricted rotation of the phenyl ring. Moler, D. B.; Li, H.; Chen, B.; Reineke, T. M.; O'Keeffe, M.; Yagi, O. M. Acc. Chem. Res. 2001, 34, 319-330. (d) Ockwig, N. W.; Delgado-Friedrichs, O.; O'Keeffe, M.; Yagi, O. M.
Journal of Molecular Structure, 2011
Construction of AgX (X À = ClO À 4 and BF À 4 ) with highly flexible N,N,N 0 ,N 0 -tetrakis(ethylisonicotinoyl)ethylendiamine (L) has been scrutinized for the weak argentophilic, Ag anion, and AgÁsolvent interactions. All such complexes afford coordination polymers consisting of 2:1 (Ag(I):L). [Ag 2 (L)(CH 3 CN) 2 ](X) 2 (X À = ClO À 4 and BF À 4 ) and [Ag 2 (L)(H 2 O)](BF 4 ) 2 are double-stranded 1D, whereas [Ag 2 (ClO 4 ) 2 (L)(Me 2 CO) 2 ] yields a 2D network structure. The molecular construction has been affected by anions, solvents, and the crystallization method. The natures of anion-and solvent-coordination, including the argentophilic interaction play important roles in the formation of skeletal structures. For [Ag 2 (L)(CH 3 CN) 2 ](ClO 4 ) 2 , weakly coordinated solvate acetonitrile reversibly associates and dissociates in the solid state.
2007
Three new ionic silver complexes based on the 3,5-dimethyl-4-nitropyrazole ligand ðHpz NO 2 Þ and 1:2 or 1:3 ðAg : Hpz NO 2 Þ stoichiometries, ½AgðHpz NO 2 Þ 2 ½BF 4 , ½AgðHpz NO 2 Þ 3 ½SbF 6 and ½AgðHpz NO 2 Þ 3 ½PO 2 F 2 Á Hpz NO 2 have been prepared and structurally characterised. The linear or trigonal metallic coordination environment, the NO 2 groups on the pyrazole ligand as well as the presence of counteranions of the type AX n À as BF 4 À , SbF 6 À or PF 6 À (the latter one evolving to PO 2 F 2 À) were strategically selected to produce molecular assemblies established on the basis of hydrogen-bonds (N-HÁ Á ÁX) and pÁ Á Áp or coordinative interactions involving the NO 2 group. The complex ½AgðHpz NO 2 Þ 2 ½BF 4 exhibited polymeric N-HÁ Á ÁF hydrogen-bonded chains which were assembled in a 3D network by weaker coordinative AgÁ Á ÁO(NO 2) and p(NO 2)Á Á Áp(NO 2) interactions. In the complex ½AgðHpz NO 2 Þ 3 ½SbF 6 , consistent with the three-coordinated molecular environment, the interactions were extended to give rise an open 3D cationic sub-network in which the counteranions SbF 6 À were encapsulated. By contrast, in the related complex ½AgðHpz NO 2 Þ 3 ½PO 2 F 2 Á Hpz NO 2 the presence of a fourth non-coordinated pyrazole Hpz NO 2 avoided the formation of a 3D network giving rise to a double-chained 1D structure.
Coordination polymers via self-assembly of silver(i) and cis-bis-nitrile-oxa-bowl derivatives
CrystEngComm, 2013
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. † 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 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 electronic format see CrystEngComm, 2013, 15, 9623-9633 | 9623 This journal is Scheme 1 Structure of the cis-bis-nitrile ligand L and the oxa-bowl derivatives L1-L3 (the concave faces of L1-L3 are shown). Scheme 2 Synthesis of the ligands L1-L3 (the convex faces are shown).
Influence of the counteranion on silver(I)–dithioether coordination polymers
Polyhedron, 2010
A series of coordination networks has been synthesized by the self-assembly of the small bis(methylthio)methane building block and AgX (X ) NO 3 ) in order to rationalize the effect of the size of the anions and the ligands upon the structure adopted by the supramolecular coordination network. In complexes 1-7, each silver(I) is coordinated with sulfur atoms from three different ligands. They form very similar two-dimensional solid-state organizations. The structures consist of layers, made up of Ag and bis(methylthio)methane ligands only, in which the anions complete the tetrahedral coordination of the silver atoms. Upon closer inspection, the neutral 2D networks may be sorted into two distinct classes. Group 1 incorporates the smallest anions, NO 3and ClO 4 -, whereas the more elongated anions, p-TsO -, CF 3 COO -, CF 3 CF 2 CF 2 COO -, and CF 3 SO 3 -, are found in group 2. The main difference between these groups is in the organization of the neutral layers. In group 1, the repeat unit consists of a large 14-membered metallomacrocycle, whereas in group 2, the metallomacrocycle consists of 10-membered rings. The two polymorphs of the perchlorate complexes are structurally comparable. Dimeric units are the basis for the other three complexes. In benzoate 8, the dimers are formed with two anions. They are linked by ligand molecules to form a 1D polymeric chain that adopts a distorted hexagonal packing. The silver atoms have a distorted triangular bipyramidal coordination and the Ag‚‚‚Ag distance is 2.911 Å. In complex 9, two ligands each bridge a pair of silver atoms to form a dimer (Ag‚‚‚Ag ) 3.243 Å). A neutral 1D coordination polymer is obtained when anions connect, in a dibridging mode, the silver atoms of adjacent dimers [Ag(CH 3 SCH 2 SCH 3 )] 2 . Weak hydrogen interactions between chains result in a 3D network. The silver coordination is triangular bipyramidal. Complex 10 is also a 1D coordination polymer with a centrosymmetric dimer. Two ligands and two anions are coordinated to the silver atoms. The Ag‚‚‚Ag contact is 3.067 Å. A 1D coordination polymer is obtained through H-bonding between carboxylate groups. The stoichiometries of the complexes are independent of the initial metal-to-ligand ratios and are not influenced by the solvent of recrystallization.