Polymeric silver(I) complexes with pyridyl dithioether ligands: experimental and theoretical investigations on the coordination properties of the ligands

The reactions of four flexible tetradentate ligands, 1,3-bis(2-pyridylthio)propane (L1), 1,4-bis(2-pyridylthio)butane (L2), 1,5-bis(2-pyridylthio)pentane (L3) and 1,6-bis(2-pyridylthio)hexane (L4) with AgX (X = BF4-, ClO4-, PF6-, or CF3SO3-) lead to the formation of seven new complexes: [AgL1(BF4)]2 (1), [[AgL2](ClO4)]infinity (2), [[AgL2(CH3CN)](PF6)]infinity (3), [[AgL3](BF4)(CHCl3)]2 (4), [[AgL3(CF3SO3)](CH3OH)(0.5)]infinity (5), [[Ag2L4(2)](BF4)2]infinity (6), and [[AgL4](PF6)]infinity (7), which have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. Single-crystal X-ray analyses show that complexes 1 and 4 possess dinuclear macrometallacyclic structures, and complexes 2, 3 and 5-7 take chain structures. In all the complexes, the nitrogen atoms of ligands preferentially coordinate to silver atoms to form normal coordination bonds, while the sulfur atoms only show weak interactions with silver atoms and the intermolecular AgS weak contacts connect the low-dimensional complexes into high-dimensional supramolecular networks. Additional weak interactions, such as pi-pi stacking, F...F weak interactions, Ag...O contacts or C-H...O hydrogen bonds, also help to stabilize the crystal structures. It was found that the parity of the -(CH2)n- spacers (n = 3-6) affect the orientation of the two terminal pyridyl rings, thereby significantly influence the framework formations of these complexes. The coordination features of ligands and their conformation changes between free and coordination states have been investigated by DFT calculations.     

Controlling the framework formation of silver(I) coordination polymers with 1,4-bis(phenylthio)butane by varying the solvents,metal-to-ligand ratio,and counteranions

The reactions of 1,4-bis(phenylthio)butane (L) with Ag(I) salts in varied conditions (varying the solvents, metal-to-ligand ratios, and counteranions) lead to the formation of four new two-dimensional (2D) coordination polymers with different network structures: [Ag(2)L(3)(ClO(4))(2)](infinity) 1, [Ag(2)L(3)(ClO(4))(2) x CH(3)OH](infinity) 2, [[AgL(2)](ClO(4))](infinity) 3, and [AgLNO(3)](infinity) 4. All the structures were established by single-crystal X-ray diffraction analysis. Crystal data for 1: triclinic, P-1, a = 11.0253(9) A, b = 11.3455(9) A, c = 11.5231(9) A, alpha = 93.931(2) degrees, beta = 92.689(2) degrees, gamma = 112.9810(10) degrees, Z = 2. 2: triclinic, P-1, a = 11.9147(13) A, b = 16.1534(17) A, c = 16.2259(17) A, alpha = 74.977(2) degrees, beta = 69.030(2) degrees, gamma = 69.986(2) degrees, Z = 2. 3: triclinic, P-1, a = 12.1617(9) A, b = 12.5054(10) A, c = 13.1547(10) A, alpha = 64.3370(10) degrees, beta =85.938 (2) degrees, gamma = 69.3010(10) degrees, Z = 2. 4: monoclinic, P2(1)/c, a = 5.4032(17) A, b = 16.974(6) A, c = 19.489(6) A, beta = 94.234(6) degrees, Z = 4. In all four complexes, each Ag(I) center has a tetracoordination geometry, and the 2D networks consist of fused large macrometallacyclic ring systems. The "hexagonal" 42-membered rings, Ag(6)L(6), observed in 1 and 2 are nearly identical, which could be considered as unique examples of self-sustaining noninterpenetrated frameworks formed with flexible ligands. The repeating rectangular 28-membered macrometallacycle, Ag(4)L(4), is the basis for the network of 3, in which the perchlorate anions occupy the voids to prevent the ring from collapsing. In 4, columns of the fused rectangular 22-membered rings, Ag(4)L(2)(NO(3))(2), are cross-linked through the L ligands to form a unique 2D network consisting of two types of 22-membered repeating units.     

Self-assemblies of new rigid angular ligands and metal centers toward the rational construction and modification of novel coordination polymer networks

Self-assemblies of rigid angular ligands with 120 degrees molecular angle and metal centers have been investigated with the aim of achieving the rational construction and modification of coordination polymer structures. The reactions of Co(NCS)(2) with 1,3-bis(trans-4-styrylpyridyl)benzene (L(1)()), 2,6-bis(trans-4-styrylpyridyl)pyridine (L(2)()), 1,3-bis(trans-4-styrylpyrimidyl)benzene (L(3)()), and 1,3-bis(trans-4-styrylquinoly)benzene (L(4)()) afford complexes [Co(L(1)())(2)(NCS)(2)]( infinity ) (1), [Co(L(2)())(2)(NCS)(2)]( infinity ) (2), Co(L(3)())(2)(NCS)(2)(CH(3)OH)(2) (3), and [Co(L(4)())(NCS)(2)]( infinity ) (4), respectively. The resulting complexes exhibit open framework, stairlike hydrogen-bonded chain and single-stranded helical coil structures, which are controlled by the variation of the geometry around the coordination site in ligands. Moreover, the coordination of L(1)() and L(2)() to Mn(hfac)(2) (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate) yields single-stranded helical coordination polymers of [Mn(L(1)())(hfac)(2)]( infinity ) (5) and [Mn(L(2)())(hfac)(2)]( infinity ) (6), respectively.     

Self-assembly, reorganization, and photophysical properties of silver(I)-Schiff-base molecular rectangle and polymeric array species

A self-assembly of AgClO(4) with a Schiff-base ligand N,N'-bis(pyridin-2-ylmethylene)benzene-1,4-diamine (1) gave a 1D zigzag polymeric array [[Ag(2)(C(18)H(14)N(4))(2)](ClO(4))(2)(CH(3)CN)](n) (3), while the self-assembly of AgClO(4) with 3,3'-dimethyl-N,N'-bis(pyridin-2-ylmethylene)biphenyl-4,4'-diamine (2) afforded the molecular rectangle [[Ag(2)(C(26)H(22)N(4))(2)](ClO(4))(2)] (4). The structures of 3 and 4 were characterized by single-crystal X-ray diffraction analysis. Structural data for 3 indicate that the Ag(I) ion is coordinated by two ligands of 1 in a distorted tetrahedral fashion thereby leading to a 1D zigzag polymeric array. The zigzag chains are interdigitated with weak pi-pi stacking interactions. The structure of 4 consists of a discrete molecular rectangle where the silver atom has a distorted square-planar coordination with the pyridyl ligands and azomethine nitrogen atoms of 2. An intramolecular pi-pi interaction between the phenyl rings of adjacent Schiff-base 2 functions to stabilize the rectangular architecture. The Ag(I)-Schiff-base coordination polymer 3 is not stable in solution. The degradation and reorganization of 3 to form a [2 x 2] grid architecture [[Ag(4)(C(26)H(22)N(4))(4)](ClO(4))(4)] (3g) was supported in a FAB-MS study. The rectangular structure of 4 remains intact in solution at ambient temperature. The complexes 3g and 4 exhibit unusual luminescence behavior in solution at room temperature with significantly red-shifted emission in the visible region.     

Novel boxlike dinuclear or chain polymeric silver(I) complexes with polypyridyl bridging ligands: syntheses, crystal structures, and spectroscopic and electrochemical properties

The syntheses, characterization, crystal structures, and photophysical and electrochemical properties of two dinuclear and two polymeric Ag(I) complexes with three polypyridyl ligands, 2,3-di-2-pyridylquinoxaline (L(1)), 2,3-di-2-pyridyl-5,8-dimethoxyquinoxaline (L(2)), and 2,3,7,8-tetrakis(2-pyridyl)pyrazino[2,3-g] quinoxaline (L(3)), are described. The structures of the two boxlike dinuclear complexes with L(1) and L(2) and two chemically the same but differently crystallized one-dimensional zigzag chain coordination polymers also consisting of boxlike dinuclear subunits have been elucidated by X-ray analysis. [AgL(1)(CH(3)CN)](2)-(BF(4))(2).2CHCl(3) (1): monoclinic, C2/c; a = 28.631(2), b = 12.2259(11), c = 14.3058(12) A; beta = 99.180(2) degrees; Z = 4. [AgL(2)(CH(3)CN)(2)](2)(ClO(4))(2) (2): triclinic, P1; a = 12.3398(2), b = 13.750(2), c = 14.326(7) A; alpha = 83.494(3), beta = 74.631(3), gamma = 76.422(3) degrees; Z = 4. [[Ag(2)L(3)(NO(3))(2)].CH(3)CN](infinity) (3a): monoclinic, P2(1)/c; a = 9.5836(8), b = 13.4691(12), c = 14.0423(12) A; beta = 107.753(2) degrees; Z = 4. [Ag(2)L(3)()(NO(3))(2)](infinity) (3b): monoclinic, P2(1)/c; a = 8.4689(6), b = 16.0447(12), c = 11.7307(8) A; beta = 102.051(1) degrees; Z = 2. The structures of the dinuclear complexes 1 and 2 are similar to each other, with the two intramolecular Ag(I) centers of each complex being spanned by two ligands thus forming a unique boxlike cyclic dimer. In 1, each Ag(I) center is four-coordinated by three nitrogen atoms of two L(1) ligands and a CH(3)CN nitrogen donor, taking a distorted tetrahedral coordination geometry. The coordination environment of Ag(I) in 2 is similar to that in 1, except the formation of an additional weak coordination bond with the oxygen atom of the methoxy group of L(2). The structures of 3a,b are very similar to each other, except for the stacking patterns in the crystal lattices, and the cyclic boxlike dinuclear unit, which is similar to the structure of 1, constitutes the fundamental building block to form the one-dimensional zigzag chain structures due to the "end-on" nature of L(3). 1-3 exhibit metal-perturbed intraligand transitions in solution in 360-390 nm regions. Cyclic voltammetric studies of these complexes show the presence of reduction peak at approximately -0.5 V vs Fc(+/0). In the solid state at 77 K, they exhibit broad emission that may be assignable to originate from the metal-perturbed intraligand transitions.     

Silver(I) complexes in coordination supramolecular system with bulky acridine-based ligands: syntheses, crystal structures, and theoretical investigations on C-H...Ag close interaction

In our efforts to investigate the coordination architectures of transition metals and organic ligands with tailored structures, we have prepared two structurally related rigid bulky acridine-based ligands, 9-[3-(2-pyridyl)pyrazol-1-yl]- acridine (L(1)) and 9-(1-imidazolyl)acridine (L2), and synthesized and characterized four of their Ag(I) complexes, {[AgL1](ClO4)}2 (1), {[AgL1](NO3)}2 (2), [AgL2(2)](ClO4) (3), and {[(Ag3L2(3))(NO3)](NO3)2(H2O)}(infinity) (4). The single-crystal X-ray diffraction analysis shows that the structures of 1 and 2 are similar to each other, with the two intramolecular Ag(I) centers of each complex being encircled by two L1 ligands; this forms a unique boxlike cyclic dimer, which is further linked to form one-dimensional (1D) chains of 1 and a two-dimensional (2D) network of 2 by intermolecular face-to-face pi...pi stacking and/or weak C-H...O hydrogen-bonding interactions, respectively. 3 has a mononuclear structure, which is further assembled into a 2D network via intermolecular Ag...O and pi...pi stacking weak interactions. 4 possesses two different 1D motifs that are further interlinked through interlayer face-to-face pi...pi stacking and Ag...O weak interactions, resulting in a 2D network. It is worth noting that one of the interesting structural features of 1, 2, and 4 is the presence of obvious C-H...M hydrogen-bonding interactions between the Ag centers and some acridine ring H atoms identified by X-ray diffraction on the basis of the van der Waals radii. Furthermore, as a representative example, full geometry optimization on the basis of the experimental structure, the natural bond orbital (NBO), and topological analysis of 1 were carried out by DFT and AIM (Atoms in Molecules) calculations. The total C-H...Ag interaction energy in 1 is estimated to be about 14 kJ/mol. Therefore, this work offers three new rare examples (1, 2, and 4) that exhibit C-H...Ag weak interactions, in which the N donors of the acridine rings coordinate to Ag(I) ions. Also, these results strongly support the existence of C-H...Ag close interactions and allow us to have a better understanding of the nature of such interactions in the coordination supramolecular systems.     

Coordination polymers assembled from angular dipyridyl ligands and CuII, CdII, CoII salts: crystal structures and properties

Six new metal-organic coordination networks based on linking unit 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (L(1)) or 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L(3)) and inorganic Cu(II), Cd(II), and Co(II) salts have been prepared and structurally characterized by single-crystal X-ray analysis. Using L(1) to react with three different Cu(II) salts, Cu(OAc)(2).H(2)O, Cu(NO(3))(2).3H(2)O, and CuSO(4).5H(2)O, respectively, two different one-dimensional (1-D) coordination polymers, [[Cu(2)L(1)(mu-OAc)(4)](CHCl(3))(2)](n) (1) [triclinic, space group P1, a = 7.416(3) A, b = 8.207(3) A, c = 14.137(5) A, alpha = 100.333(7) degrees, beta = 105.013(6) degrees, gamma = 94.547(6) degrees, Z = 1] and [[CuL(1)(NO(3))(2)](CHCl(3))(0.5)](n) (2) [monoclinic, space group C2/c, a = 28.070(8) A, b = 9.289(3) A, c = 15.235(4) A, beta = 113.537(5) degrees, Z = 8], and a chiral 3-D open framework, [[CuL(1)(H(2)O)(SO(4))](H(2)O)(2)](n) (3) [orthorhombic, space group P2(1)2(1)2(1), a = 5.509(2) A, b = 10.545(4) A, c = 29.399(11) A, Z = 4], were obtained. Reaction of L(1) and Cd(ClO(4))(2).6H(2)O or Co(ClO(4))(2).6H(2)O, in the presence of NH(4)SCN, yielded another 3-D open framework, [[CdL(1)(NCS)(2)](CH(3)OH)(1.5)](n) (4) [monoclinic, space group C2/c, a = 28.408(10) A, b = 9.997(5) A, c = 7.358(4) A, beta = 99.013(8) degrees, Z = 4], or a 2-D network, [[Co(L(1)())(2)(NCS)(2)](H(2)O)(2.5)](n) (5) [orthorhombic, space group Pnna, a = 22.210(5) A, b = 12.899(3) A, c = 20.232(4) A, Z = 4]. When L(1) was replaced by L(3) to react with Co(ClO(4))(2).6H(2)O and NH(4)SCN, another 2-D coordination polymer, [Co(L(3))(2)(NCS)(2)](n) (6) [monoclinic, space group P2(1)/c, a = 8.120(3) A, b = 9.829(4) A, c = 17.453(6) A, beta = 103.307(6) degrees, Z = 2], was constructed. These results indicate that the nature of the ligands, metal centers, or counteranions plays the critical role in construction of these novel coordination polymers. The interesting porous natures of two 3-D open frameworks 3 and 4 were investigated by TGA and XPRD techniques, and the magnetic properties of the Cu(II) and Co(II) complexes were studied by variable-temperature magnetic susceptibility and magnetization measurements.     

Ligand-directed molecular architectures: self-assembly of two-dimensional rectangular metallacycles and three-dimensional trigonal or tetragonal prisms

Three angular ditopic ligands (1,3-bis(benzimidazol-1-ylmethyl)-4,6-dimethylbenzene L(1), 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L(2), and 1,4-bis(benzimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene L(3)) and one tripodal ligand 1,3,5-tris(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L(4) have been prepared. Reaction of these shape-specific designed ligands with different metal salts affords a series of discrete molecular architectures: [Ag(2)L(1)(2)](BF(4))(2) 1, [Ag(2)L(2)(2)](CF(3)SO(3))(2) 2, [CF(3)SO(3)(-) subset Ag(2)L(3)(2)]CF(3)SO(3) 3, [CF(3)SO(3)(-) subset Ag(2)L(3)(3)]CF(3)SO(3) 4, [ClO(4)(-) subset Cu(2)L(2)(4)](ClO(4))(3) 5, [4H(2)O subset Ni(2)L(2)(4)Cl(4)].6H(2)O 6, [BF(4)(-) subset Ag(3)L(4)(2)](BF(4))(2) 7, [ClO(4)(-) subset Ag(3)L(4)(2)](ClO(4))(2) 8, and [CuI(3)(2-) subset Cu(3)L(4)(2)](2)[Cu(2)I(4)] 9. The compounds were characterized by elemental analysis, ESI-MS, IR, and NMR spectroscopy, and X-ray crystallography. 1 is a dinuclear metallacycle with 2-fold rotational symmetry in which two syn-conformational L(1) ligands are connected by two linearly coordinated Ag(+) ions. 2 and 3 are structurally related, consisting of rectangular structures assembled from two linearly coordinated Ag(+) ions and two L(2) or L(3) ligands. The structure of 4 is a trigonal prismatic box consisting of two Ag(+) ions in trigonal planar coordination linked by three L(3) ligands, while the structures of 5 and 6 are tetragonal prismatic cages constructed by two square planar Cu(2+) or Ni(2+) ions linked by four L(2) ligands. The topologies of 7-9 are similar to that of 4; however, these three structures are assembled from three linearly coordinated Ag(+) or Cu(+) ions and two tripodal ligands, representing an alternative strategy to assembling a trigonal prism. (1)H NMR and ESI-MS were utilized to elucidate the solution structures of these macrocycles.     

Novel lanthanide coordination polymers with a flexible disulfoxide ligand, 1,2-bis(ethylsulfinyl)ethane: structures, stereochemistry, and the influences of counteranions on the framework formations

The reactions of meso-1,2-bis(ethylsulfinyl)ethane (meso-L) with Ln(ClO(4))(3) [Ln(NO(3))(3) or Ln(NCS)(3)] in MeOH and CHCl(3) gave a series of new lanthanide coordination polymers, [[Ln(micro-meso-L)(rac-L)(2)(CH(3)OH)(2)](ClO(4))(3)](n) [Ln: La (1), Nd (2), Eu (3), Gd (4), Tb (5), Dy (6), and Yb (7)], [Yb(micro-meso-L)(1.5)(NO(3))(3)](n) (8), and [La(micro-meso-L)(2.5)(NCS)(3)](n) (9). All the structures were established by single-crystal X-ray diffraction. Complexes 1-7 are isostructural with infinite single micro-chain structure, in which the L ligands take two kinds of coordination modes: bidentate chelating and bis-monodentate bridging. Six sulfur atoms of the sulfoxide groups around each Ln(III) center adopt alternatively the same R or S configuration in the chain. In addition, the configuration change of partial ligands occurred from the meso to the rac form when reacting with Ln(ClO(4))(3). To our knowledge, this is the first example of disulfoxide complexes with two kinds of coordination modes and three kinds of configurations (R,R, S,S, and R,S) occurring simultaneously in the same complex. 8 exhibits single-double bridging chain structure, in which dinuclear macrometallacycles formed through bridging two Yb(III) by two meso-L ligands are further linked by another meso-L ligand. In 9 each La(III) ion is linked to five other La(III) ions by five meso-L ligands to form a 5-connected 2-D (3/4,5) network containing two types of macrometallacyclic arrays: quadrilateral and triangle grids. The structural differences among 1-7, 8, and 9 show that counteranions play important roles in the framework formation of such coordination polymers. In addition, the luminescent properties of 3 and 5 were also investigated.     

Novel eclipsed 2D cadmium(II) coordination polymers with open-channel structure constructed from terephthalate and 3-(2-pyridyl)pyrazole: crystal structures, emission properties, and inclusion of guest molecules

Five new eclipsed two-dimensional (2D) coordination polymers, [[Cd(2)(TPT)(2)L(2)](GM(1))(3/2)(H(2)O)](infinity) (1) (TPT = terephthalate, L = 3-(2-pyridyl)pyrazole, GM(1) = terephthalic acid), [[Cd(TPT)L](GM(2))(H(2)O)(2)]( infinity) (2) (GM(2) = L = 3-(2-pyridyl)pyrazole), [[Cd(TPT)L](GM(3))(1/2)(H(2)O)](infinity) (3) (GM(3) = mesitylene), [[Cd(4)(TPT)(4)L(4)](GM(4))(7/2)](infinity) (4) (GM(4) = tetramethylbenzene), and [[Cd(TPT)L](GM(5))(1/2)](infinity) (5) (GM(5) = naphthalene), have been synthesized and characterized by X-ray diffraction. All the five complexes take the similar eclipsed 2D open-channel framework with different guest molecules included in the cavities of their channels. TGA analysis indicates that the eclipsed open-channel frameworks are thermally stable up to 300 degrees C. The porous property of the 2D framework of 5 was also investigated by the XRPD technique, which indicated that the guest molecules included in the open-channel frameworks are removable and the framework is maintained after the removal of the guest molecules. Moreover, complexes 1-5 also display strong blue emission in the solid state.     

Syntheses, crystal structures, and magneto-structural correlations of novel Cu(II) complexes containing a planar [Cu(mu-L1)]2 (HL1 = 3-(2-pyridyl)pyrazole) unit: from dinuclear to tetranuclear and then to one-dimensional compounds

Seven new Cu(II) complexes based on a binuclear planar unit [Cu(mu-L(1))](2), [[Cu(mu-L(1))(NO(3))(H(2)O)](2) (1), [Cu(mu-L(1))(HL(1))(ClO(4))](2) (2), [Cu(4)(mu-L(1))(6)(NO(3))(2)] (3), [Cu(4)(mu-L(1))(6)(L(1))(2)] (4), [Cu(4)(mu-L(1))(6)(mu-L(2))](n) (5), [Cu(4)(mu-L(1))(6)(mu-L(3))](n) (6), [[Cu(4)(mu-L(1))(4)(mu-L(4))(2)](H(2)O)(3)](n) (7) (HL(1) = 3-(2-pyridyl)pyrazole, L(2) = 1,8-naphthalenedicarboxylate, L(3) = terephthalate, L(4) = 2,6-pyridinedicarboxylate)}, have been synthesized and characterized by elemental analysis, IR, and X-ray diffraction. In 1 and 2, the Cu(II) centers are linked by deprotonated pyrazolyl groups to form dinuclear structures. 3 and 4 have similar gridlike tetranuclear structures in which two additional deprotonated L(1) ligands bridge two [Cu(mu-L(1))](2) units perpendicularly. 5 and 6 consist of similar one-dimensional (1-D) chains in which gridlike tetranuclear copper(II) units similar to that of 3 are further linked by L(2) or L(3) ligands, respectively. And, in 7, L(4) ligands link [Cu(mu-L(1))](2) binuclear units to form a tetranuclear gridlike structure in chelating/bridging mode and simultaneously bridge the tetranuclear units to form a 1-D chain. The magnetic properties of all complexes were studied by variable-temperature magnetic susceptibility and magnetization measurements. The obtained parameters of J range from -33.1 to -211 cm(-1), indicating very strong antiferromagnetic coupling between Cu(II) ions. The main factor that affects the |J| parameter is the geometry of the Cu(N(2))(2)Cu entity. From the magnetic point of view, 1 and 2 feature "pure" dinuclear, 3 and 5 tetranuclear, and 4, 6, and 7 pseudodinuclear moieties.     

Dinuclear silver(I) complexes for the design of metal-ligand networks based on triazolopyrimidines

Silver(I) coordination complexes with the versatile and biomimetic ligands 1,2,4-triazolo[1,5-a]pyrimidine (tp), 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) and 7-amine-1,2,4-triazolo[1,5-a]pyrimidine (7atp) all feature dinuclear [Ag(2)(μ-tp)(2)](2+) building units (where tp is a triazolopyrimidine derivative), which are the preferred motif, independently of the counter-anion used. According to AIM (atoms in molecules) and ELF (electron localization function) analyses, this fact is due to the great stability of these dinuclear species. The complexes structures range from the dinuclear entities [Ag(2)(μ-tp)(2)(CH(3)CN)(4)](BF(4))(2) (1), [Ag(2)(μ-tp)(2)(CH(3)CN)(4)](ClO(4))(2) (2), [Ag(2)(μ-7atp)(2)](ClO(4))(2) (3) and [Ag(2)(μ-dmtp)(2)(CH(3)CN)](PF(6))(ClO(4)) (4) over the 1D polymer chain [Ag(2)(μ-CF(3)SO(3))(2)(μ-dmtp)(2)](n) (5) to the 3D net {[Ag(2)(μ(3)-tp)(2)](PF(6))(2)·～6H(2)O}(n) (6) with NbO topology.     

Preparation and solid-state characterization of mixed-ligand coordination/organometallic oligomers and polymers of copper(I) and silver(I) using diphosphine and mono- and diisocyanide ligands

The dimers [Cu(2)(dppm)(2)(CN-t-Bu)(3)](BF(4))(2) and [Ag(2)(dppm)(2)(CN-t-Bu)(2)](X)(2) (X(-) = BF(4)(-), ClO(4)(-)) and the coordination polymers [[M(diphos)(CN-t-Bu)(2)]BF(4)](n) (M = Cu, Ag; diphos = bis(diphenylphosphino)butane (dppb), bis(diphenylphosphino)pentane (dpppen), bis(diphenylphosphino)hexane (dpph)), [[Ag(2)(dppb)(3)(CN-t-Bu)(2)](BF(4))(2)](n), and [[Ag(dpppen)(CN-t-Bu)]BF(4)](n) have been synthesized and fully characterized as model materials for the mixed bridging ligand polymers which exhibit the general formula [[M(diphos)(dmb)]BF(4)](n) (M = Cu, Ag; dmb = 1,8-diisocyano-p-menthane) and [[Ag(dppm)(dmb)]ClO(4)](n). The identity of four polymers ([[Ag(dppb)(CN-t-Bu)(x)]BF(4)](n) (x = 1, 2), [[Ag(2)(dppb)(3)(CN-t-Bu)(2)](BF(4))(2)](n), [[Ag(dppm)(dmb)]ClO(4)](n)) and the two dimers has been confirmed by X-ray crystallography. The structure of [[Ag(dppm)(dmb)]ClO(4)](n) exhibits an unprecedented 1-D chain of the type "[Ag(dmb)(2)Ag(dppm)(2)(2+)](n)", where d(Ag(.)Ag) values between tetrahedral Ag atoms are 4.028(1) and 9.609(1) A for the dppm and dmb bridged units, respectively. The [[Ag(dppb)(CN-t-Bu)(x)]BF(4)](n) polymers (x = 1, 2) form zigzag chains in which the Ag atoms are tri- and tetracoordinated, respectively. The [[Ag(2)(dppb)(3)(CN-t-Bu)(2)](BF(4))(2)](n) polymer, which is produced from the rearrangement of [[Ag(dppb)(CN-t-Bu)(2)]BF(4)](n), forms a 2-D structure described as a "honeycomb" pattern, where large [Ag(dppb)(+)](6) macrocycles each hosting two counterions and two acetonitrile guest molecules are observed. Properties such as glass transition temperature, morphology, thermal decomposition, and luminescence in the solid state at 293 K are reported. The luminescence bands exhibit maxima between 475 and 500 nm with emission lifetimes ranging between 6 and 55 micros. These emissions are assigned to a metal-to-ligand charge transfer (MLCT) of the type M(I) --> pi(NC)/pi(PPh(2)).     

Single-strand helical complexes constructed from 2-pyridinyl-3-pyridinylmethanone: tuning the helical pitch length by variation of metal cation and/or counter anion

The new ligand 2-pyridinyl-3-pyridinylmethanone (L) proves to be an excellent building block for the construction of single-strand helical architectures. A series of helical complexes have been synthesized by the reaction of L with various metal salts, in which L exhibits three kinds of coordination modes involving two kinds of bridging conformations, resulting in four types of single-strand helical chains. The counter anions in the series of 2(1) helical silver(I) complexes {[Ag(L)]X}(infinity)(X = NO(3), 1; PF(6), 2; BF(4), 3; ClO(4), 4; CF(3)CO(2), 5; CF(3)SO(3), 6) are fully or partially embedded inside the cylindrical helix, and the pitch length corresponds not only to the size of the anion but also to its manner of docking into the groove of the helix. Formation of the helical structure in {[Cu(L)(CH(3)CN)(H(2)O)(ClO(4))]ClO(4)}(infinity)(7) is driven by Ow-H...O (perchlorate) hydrogen bonding that leads to a stable triangular motif which rigidly fixes the configuration of the helix. In {[Co(L)(H(2)O)(3)](ClO(4))(2).2H(2)O}(infinity)(8) and {[Zn(L)(H(2)O)(3)](CF(3)SO(3))(2).H(2)O}(infinity)(9), similar helical chains without anion embedment suggest that the pitch length can be tuned by the size of metal cations. Notably, complex {[Ag(L)]CF(3)SO(3)}(infinity)(10), a conformational polymorph of , has a 4(1) helix induced by argentophilic interaction.     

Formation of N-heterocyclic diphosphine ligands from Ag(I)-assisted condensation reactions between bdppeda and formaldehyde and their binuclear silver(I) complexes

The reaction of [Ag(MeCN)(4)]ClO(4) with N,N,N',N'-tetra(diphenylphosphanylmethyl)ethylenediamine (dppeda) in CH(2)Cl(2)/MeOH afforded an unexpected cationic binuclear complex [Ag(2)(L(1))(2)(η,η-μ-ClO(4))(2)](ClO(4))(2) (L(1) = N,N'-bis(diphenylphosphanylmethyl)-3H-4,5-dihydroimidazole-1-ium) (1). Compound 1 was also prepared in high yield from reactions of [Ag(MeCN)(4)]ClO(4) with N,N'-bis(diphenylphosphanylmethyl)ethylenediamine (bdppeda) in the presence of formaldehyde (HCHO) or formic acid (HCOOH). Analogous reactions of AgCl with bdppeda and HCHO resulted in the formation a neutral binuclear complex [Ag(2)(L(2))(2)(μ-Cl)(2)] (L(2) = N,N-bis(diphenylphosphanylmethyl)-tetrahydroimidazole) (2). Treatment of 1 with concentrated HCl gave rise to a partially anion-exchanged product [Ag(2)(L(1))(2)(μ-Cl)(2)](ClO(4))(2) (3). Compounds 1 and 3 have a similar cationic binuclear structure, in which a [Ag(2)(η,η-μ-ClO(4))(2)] or [Ag(2)(μ-Cl)(2)] ring is sandwiched by two in situ-formed cationic L(1) ligands. The L(1) ligand may be generated by the Ag(I)-assisted condensation reaction between bdppeda and HCHO or HCOOH. Compound 2 holds a neutral binuclear structure, in which a [Ag(2)(μ-Cl)(2)] ring is connected by two in situ-formed L(2) ligands from its top and bottom sites. The neutral ligand L(2) may be produced from another Ag(I)-assisted condensation reaction between bdppeda and HCHO. The in situ formation of the L(1) and L(2) ligands provides a new route to the N-heterocyclic diphosphine ligands, and an interesting insight into the coordination chemistry of their metal complexes.     

Spiral, herringbone, and triple-decker silver(I) complexes of benzopyrene derivatives assembled through eta(2)-coordination

Three novel silver(I) complexes with benzopyrene derivatives were synthesized and characterized in this paper. Treatment of AgClO(4)*H(2)O with 7-methylbenzo[a]pyrene (L(1)) afforded [Ag(2)(L(1))(toluene)(0.5)(ClO(4))(2)](n)() (1) which exhibits a 2-D sheet structure with double-stranded helical motifs. Reaction of AgCF(3)SO(3) with dibenzo[b,def ]chrysene (L(2)) gave rise to an unprecedented cocrystallization structure, ([Ag(2)(L(2))(CF(3)SO(3))(2)][Ag(2)(toluene)(2)(CF(3)SO(3))(2)])(n)() (2), formed by a 2-D neutral lamellar polymer and a 1-D neutral rodlike one. The ligand benzo[e]pyrene (L(3)) coordinated to silver(I) ions generating a closed triple-decker tetranuclear complex [Ag(4)(L(3))(4)(p-xylene)(ClO(4))(4)] (3) which can be regarded as a stacking polymer owing to existing intermolecular pi-pi stack interactions. The structural diversity of the silver(I) coordination polymers with polycyclic aromatic hydrocarbons is not only related to the stacking patterns of free polycyclic aromatic hydrocarbons in the crystalline state, but also the geometric shapes of the molecules for these free ligands. In addition, the coordination of solvents to metal ions plays a crucial role in the formation of the unprecedented coordination polymeric architectures. The ESR spectroscopic results, conductivity, and synthesis properties are also discussed.     

Coordination-position isomeric M(II)Cu(II) and Cu(II)M(II) (M = Co, Ni, Zn) complexes derived from macrocyclic compartmental ligands

The dinucleating macrocyclic ligands (L(2;2))(2-) and (L(2;3))(2-), comprised of two 2-[(N-methylamino)methyl]-6-(iminomethyl)-4-bromophenolate entities combined by the -(CH(2))(2)- chain between the two aminic nitrogen atoms and by the -(CH(2))(2)- or -(CH(2))(3)- chain between the two iminic nitrogen atoms, have afforded the following M(II)Cu(II) complexes: [CoCu(L(2;2))](ClO(4))(2).MeCN (1A), [NiCu(L(2;2))](ClO(4))(2) (2A), [ZnCu(L(2;2))](ClO(4))(2).0.5MeCN.EtOH (3A), [CoCu(L(2;3))(MeCN)(2-PrOH)](ClO(4))(2) (4A), [NiCu(L(2;3))](ClO(4))(2) (5A), and [ZnCu(L(2;3))](ClO(4))(2).1.5DMF (6A). [CoCu(L(2;2))(MeCN)(3)](ClO(4))(2) (1A') crystallizes in the monoclinic space group P2(1)/n, a = 11.691(2) A, b = 18.572(3) A, c = 17.058(3) A, beta= 91.18(2) degrees, V = 3703(1) A(3), and Z = 4. [NiCu(L(2;2))(DMF)(2)](ClO(4))(2) (2A') crystallizes in the triclinic space group P(-)1, a = 11.260(2) A, b = 16.359(6) A, c = 10.853(4) A, alpha= 96.98(3) degrees, beta= 91.18(2) degrees, gamma= 75.20(2) degrees, V = 1917(1) A(3), and Z = 2. 4A crystallizes in the monoclinic space group P2(1)/c, a = 15.064(8) A, b = 11.434(5) A, c = 21.352(5) A, beta= 95.83(2)degrees, V = 3659(2) A(3), and Z = 4. The X-ray crystallographic results demonstrate the M(II) to reside in the N(amine)(2)O(2) site and the Cu(II) in the N(imine)(2)O(2) site. The complexes 1-6 are regarded to be isomeric with [CuCo(L(2;2)))](ClO(4))(2).DMF (1B), [CuNi(L(2;2)))](ClO(4))(2).DMF.MeOH (2B), [CuZn(L(2;2)))](ClO(4))(2).H(2)O (3B)), [CuCo(L(2;3)))](ClO(4))(2).2H(2)O (4B), [CuNi(L(2;3)))](ClO(4))(2) (5B), and [CuZn(L(2;3)))](ClO(4))(2).H(2)O (6B) reported previously, when we ignore exogenous donating and solvating molecules. The isomeric M(II)Cu(II) and Cu(II)M(II) complexes are differentiated by X-ray structural, magnetic, visible spectroscopic, and electrochemical studies. The two isomeric forms are significantly stabilized by the "macrocyclic effect" of the ligands, but 1A is converted into 1B on an electrode, and 2A is converted into 2B at elevated temperature.     

Molecular squares, cubes and chains from self-assembly of bis-bidentate bridging ligands with transition metal dications

The two new ligands L(fur) and L(th) consist of two chelating pyrazolyl-pyridine termini connected to furan-2,5-diyl or thiophene-2,5-diyl spacers via methylene groups. Reaction of these with a range of transition metal dications that prefer octahedral coordination affords a series of unusual structures which are all based on a 2M : 3L ratio. [M(8)(L(fur))(12)]X(16) (M = Co, Cu, X = BF(4); and M = Zn, X = ClO(4)) are octanuclear cubes with approximate D(4) symmetry in which two cyclic tetranuclear helicate M(4)L(4) units are connected by four additional 'pillar' ligands. In contrast [Ni(4)(L(fur))(6)](BF(4))(8) is a centrosymmetric molecular square consisting of two dinuclear Ni(2)L(2) units of opposite chirality that are connected by a pair of additional L(fur) ligands such that the four edges of the Ni(4) square are spanned by alternately two and one bridging ligands. [M(4)(L(th))(6)](BF(4))(8) (M = Co, Ni, Cu) are likewise molecular squares with similar structures to [Ni(4)(L(fur))(6)](BF(4))(8) with the significant difference that the two crosslinked double helicate M(2)L(2) units are now homochiral. The Cd(II) complexes both behave quite differently to the first-row metal complexes, with [Cd(L(fur))(BF(4))](BF(4)) being a simple mononuclear complex with a single ligand in which the furan oxygen atom is weakly interacting with the Cd(II) centre. In contrast, in {[Cd(2)(L(th))(3)](BF(4))(4)}(∞), where this quasi-pentadentate coordination mode of the ligand is not possible because thiophene is too poor an electron donor, the ligand reverts to bis-bidentate bridging coordination to afford a one-dimensional chain consisting of an infinite sequence of crosslinked, homochiral, Cd(2)(L(th))(2) double helicate units.     

Variations of structures and gas sorption properties of three coordination polymers induced by fluorine atom positions in azamacrocyclic ligands

Three coordination polymers of [(NiL(1))(3)(TCBA)(2)] (1), [(NiL(2))(3)(TCBA)(2)] (2), and [(NiL(3))(3)(TCBA)(2)] (3) have been constructed using azamacrocyclic Ni(II) complexes [NiL(1)](ClO(4))(2)/[NiL(2)](ClO(4))(2)/[NiL(3)](ClO(4))(2) and TCBA(3-) as building blocks (L(1) = 3,10-bis(2-fluorobenzyl)-1,3,5,8,10,12-hexaazacyclotetradecane; L(2) = 3,10-bis(3-fluorobenzyl)-1,3,5,8,10,12-hexaazacyclotetradecane; L(3) = 3,10-bis(4-fluorobenzyl)-1,3,5,8,10,12- hexaazacyclotetradecane; TCBA(3-) = tri(4-carboxy-benzyl)amine). The results of X-ray diffraction analyses reveal that 1 shows a 2D Borromean structure, while 2 and 3 form 2D layer structures, and the 2D layers are further connected by the interlayer F···F interactions in 2 and C-H···F interactions in 3 to generate two 3D porous structures with 1D fluorine atoms interspersed channels. Gas sorption measurements illustrate that the desolvated 2 and 3can adsorb N(2), H(2), and CO(2) molecules. The different structures and gas sorption properties of 1 and 2/3 are mainly induced by the different positions of F atoms in azamacrocycle ligands.     

Luminescent Ag i-Cu i heterometallic hexa-, octa-, and hexadecanuclear alkynyl complexes

A series of Ag(I)-Cu(I) heteronuclear alkynyl complexes were prepared by reaction of polymeric (MCCC(6)H(4)R-4)(n)() (M = Cu(I) or Ag(I); R = H, CH(3), OCH(3), NO(2), COCH(3)) with [M'(2)(mu-Ph(2)PXPPh(2))(2)(MeCN)(2)](ClO(4))(2) (M' = Ag(I) or Cu(I); X = NH or CH(2)). Heterohexanuclear complexes [Ag(4)Cu(2)(mu-Ph(2)PNHPPh(2))(4)(CCC(6)H(4)R-4)(4)](ClO(4))(2) (R = H, 1; CH(3), 2) were afforded when X = NH, and heterooctanuclear complexes [Ag(6)Cu(2)(micro-Ph(2)PCH(2)PPh(2))(3)(CCC(6)H(4)R-4)(6)(MeCN)](ClO(4))(2) (R = H, 3; CH(3), 4; OCH(3), 5; NO(2), 6) were isolated when X = CH(2). Self-assembly reaction between (MCCC(6)H(4)COCH(3)-4)(n) and [M'(2)(mu-Ph(2)PCH(2)PPh(2))(2)(MeCN)(2)](ClO(4))(2), however, gave heterohexadecanuclear complex [Ag(6)Cu(2)(micro-Ph(2)PCH(2)PPh(2))(3)(CCC(6)H(4)COCH(3)-4)(6)](2)(ClO(4))(4) (7). The heterohexanuclear complexes 1 and 2 show a bicapped cubic skeleton (Ag(4)Cu(2)C(4)) consisting of four Ag(I) and two Cu(I) atoms and four acetylide C donors. The heterooctanuclear complexes 3-6 exhibit a waterwheel-like structure that can be regarded as two Ag(3)Cu(CCC(6)H(5))(3) components put together by three bridging Ph(2)PCH(2)PPh(2) ligands. The heterohexadecanuclear complex 7 can be viewed as a dimer of heterooctanuclear complex [Ag(6)Cu(2)(micro-Ph(2)PCH(2)PPh(2))(3)(CCC(6)H(4)COCH(3)-4)(6)](ClO(4))(2) through the silver and acetyl oxygen (Ag-O = 2.534 (4) A) linkage between two waterwheel-like Ag(6)Cu(2) units. All of the complexes show intense luminescence in the solid states and in fluid solutions. The microsecond scale of lifetimes in the solid state at 298 K reveals that the emission is phosphorescent in nature. The emissive state in compounds 1-5 is likely derived from a (3)LMCT (CCC(6)H(4)R-4 --> Ag(4)Cu(2) or Ag(6)Cu(2)) transition, mixed with a metal cluster-centered (d --> s) excited state. The lowest lying excited state in compounds 6 and 7 containing electron-deficient 4-nitrophenylacetylide and 4-acetylphenylacetylide, respectively, however, is likely dominated by an intraligand (3)[pi --> pi] character.