Bridging Cyano Groups Research Articles

Synthesis, crystal structure and magnetic properties of a 1D mixed-metal–mixed-ligand Ni(II)/Fe(II) coordination polymer built on the nitroprusside anion

A new complex [Ni(L)Fe(CN) 5NO] · 2H 2O (L = 4,6,6-trimethyl-1,9-diamino-3,7-di-aza-nona-3-ene) has been obtained and characterized by means of X-ray crystallographic analysis and magnetochemistry. The Fe(CN) 5NO 2− anion links to the Ni(L) 2+ cation through two bridging cyanide groups in a bent fashion. The intrachain Ni⋯Ni and interchain Ni⋯Ni distances are equal to 9.81(8) and 7.75(1) Å, respectively. The magnetic behaviour of the complex indicates the zero field splitting parameter D higher than 3 cm −1 and the average exchange parameter (intra- and interchain) corresponding to direct Ni–Ni magnetic interaction in the crystal lattice equals ∼−0.2 cm −1.

Cyano-bridged bimetallic complexes based on nitroprusside [Fe(CN) 5(NO)] 2− and [Cu(TAAB-macrocycle)] 2+: Synthesis, structure and thermal stability

Two new cyano-bridged bimetallic complexes, [Cu(TAAB)Fe(CN) 5(NO)]·2H 2O ( 1) and [Mn(bpy) 2(H 2O)Fe(CN) 5(NO)]·H 2O ( 2) (where TAAB = tetrabenzo[ b, f, j, n][1,5,9,l3]tetraaza-cyclohexadecine and bpy = 2,2′-bipyridine), have been synthesized and characterized by elemental analyses, IR spectra and TG-DSC analyses. Single crystal X-ray structure analyses revealed that the complex 1 has a cyano-bridged binuclear structure in which Cu(II) center is coordinated by tetraazacyclic TAAB ligand to form an intriguing saddle-shaped structure, and Fe(II) center is in an octahedral coordination environment with nitrosyl group trans to the cyano-bridge. In complex 2, Mn(II) center is cis six-coordinated and linked to nitroprusside though a bridging cyanide group to form a binuclear structure, while the nitrosyl group is cis to the cyano-bridge. The thermal stabilities of both complexes were investigated, which shows the nitrosyl and cyanide groups of nitroprusside released by two-steps in the temperature range of 200–380 °C.

Use of multi- N-donor ligands for preparation of organic–inorganic hybrid materials: Crystal structures of ionic [M( aepn) 2][Ni(CN) 4]·H 2O and polymeric M( aepn)Ni(CN) 4 (M = Zn(II), Cd(II); aepn = N-(2-aminoethyl)-1,3-propanediamine)

From aqueous systems M- aepn-[Ni(CN) 4] 2− (M = Zn, Cd; aepn = [ N-(2-aminoethyl)-1,3-propanediamine]) using variable M: aepn molar ratios [Cd( aepn) 2] [Ni(CN) 4]·H 2O ( 1), Cd( aepn)Ni(CN) 4 ( 2), [Zn( aepn) 2][Ni(CN) 4]·H 2O ( 3) and Zn( aepn)Ni(CN) 4 ( 4) have been prepared and identified. Single crystal X-ray structure analyses have shown that the crystal structures of 1 and 3 are ionic and are built up of [Zn( aepn) 2] 2+ and [Cd( aepn) 2] 2+ cations, respectively, [Ni(CN) 4] 2− anions and water molecules of crystallisation, and 2 and 4 exhibit polymeric structures. In the three-dimensional structure of 2 two crystallographically independent tetracyanonickellate anions are placed on inversion centres and exhibit connectivities two and four, respectively, with bridging cyano groups linking cadmium and nickel atoms. Octahedrally coordinated cadmium atom exhibits connectivity three. In one-dimensional structure of 4 [Ni(CN) 4] 2− anions and [Zn( aepn)] 2+ cations are linked via bridging cyano ligands. Both building species exhibits connectivity two. One chelate bonded aepn ligand blocks three coordination sites on the penta-coordinated Zn(II) atom.

Catena-Poly[[bis(2,2′-bipyridine-κ2N,N′)copper(II)]-μ-cyano-dicyanoplatinate(II)-μ-cyano

The crystal structure of the title complex, [Cu(C10H8N2)2{Pt(CN)4}]n, is built up by infinite neutral chains in which [Cu(bpy)2]2+ (bpy = 2,2′-bipyridine) complex cations are bridged by [Pt(CN)4]2− complex anions. Two bridging cyano groups of [Pt(CN)4]2− anions are in trans positions with Pt—C distances of 2.000 (9) Å. Nevertheless, the chains are not linear but zigzag, owing to the cis coordination of the cyano groups to the Cu atom [Cu—N = 2.243 (8) Å]. The remaining four coordination sites of the Cu atom are occupied by N atoms of two chelating bpy mol­ecules at distances of 2.022 (4) and 2.161 (6) Å. Cu atoms lie on twofold rotation axes and Pt atoms on inversion centres.

Dicaesium pentacyanotricuprate(I), Cs2Cu3(CN)5

Cs2Cu3(CN)5 has a layered structure consisting of [Cu3(CN)5]2− sheets stacked in an ABAB fashion along the c axis, with Cs+ cations lying between the sheets. The sheets are generated by linking –(CuCN)– chains, in which the C[triple-bond]N groups are ordered, via [Cu(CN)3]2− units. The two bridging cyanide groups of each [Cu(CN)3]2− unit show partial `head-to-tail' disorder of C and N, whilst the third C[triple-bond]N group is terminal and ordered with C bonded to Cu.

Low-dimensional Compounds Containing Cyano Groups. XIII. Structural–spectral Correlation of Copper Dicyanoargentates

The new mixed-valence mixed-metal complex Cu(py)6Cu2Ag2(CN)6 (py = pyridine) possesses a three dimensional polymeric crystal structure. The Cu(I) atom is tetrahedrally coordinated by two nitrogen atoms of pyridine molecules, by one nitrogen atom of the dicyanoargentate anion and by one carbon atom of the cyano group. Both the dicyanoargentate anion and the cyano group bridge the Cu(I) atom with neighboring Cu(II) atoms. These are hexacoordinated in the form of an elongated tetragonal bipyramid. The equatorial plane is formed by two nitrogen atoms from two pyridine molecules and two nitrogen atoms from bridging cyano groups. Axial positions are occupied by nitrogen atoms of the bridging [Ag(CN2]− anions. Correlation between structures of the title compound and seven other dicyanoargentates with their i.r. spectra has been studied. The coordination mode of [Ag(CN2]− anions in compounds Cu8-xAg x (tn)3(CN)10 x = 0.25, Cu(3-Mepy)2Ag2(CN)4, Cu(py)2Ag2(CN)4 and Cu(py)4Ag2(CN)4 (tn is 1,3-diaminopropane, 3-Mepy is 3-methylpyridine) is predicted based on this correlation.

Synthesis and Properties of a Heteronuclear Ag(I)/Ni(II) Complex

A complex, Ni(en)2Ag3 (CN)5 (en = ethylenediamine), was obtained through the reaction of [Ag (CN)2]− units with Ni II-diamine cation [Ni(en)2]2+, and the structure was determined by single crystal X-ray diffraction. It is indicated that the complex has a 3D architecture through the silver-silver interactions and the bridging cyano groups. This complex displays interesting luminescent properties caused by argentophilicity at room temperature in solid state.

Syntheses, crystal structures and magnetic properties of two cyano-bridged copper(I)–copper(II) mixed-valence complexes

Two cyano-bridged copper(II)–copper(I) mixed-valence assemblies, Cu(EAM)2[Cu(CN)2]2 1 (EAM = ethanolamine) and Cu(DETA)[Cu(CN)2]2·0.5H2O 2 (DETA = diethylenetriamine), have been prepared and structurally and magnetically characterized. IR spectra indicate the presence of bridging cyano groups in both 1 and 2, confirmed by structure analyses; Cu(I)–CN–Cu(II), Cu(I)–CN–Cu(I) and Cu(I)–Cu(I) metal bond linkages are evident. In the lattice, a 3D network is formed by two [Cu(CN)2] − units and one [Cu(EAM)2]2+unit for 1. Variable temperature magnetic susceptibilities, measured in the 5–300 K range, indicate weak antiferromagnetic exchange interactions in complex 1.

Polymeric [{Cd(en)}3{Fe(CN)6}2]·4H2O: Preparation, Crystal Structure and Characterization (en = 1,2–diaminoethane)

AbstractA new polymeric coordination compound [{Cd(en)}3{Fe(CN)6}2]·4H2O (1; en = 1,2–diaminoethane) was isolated from a reaction mixture containing CdCl2·2.5H2O, en, K3[Fe(CN)6] and [R4N]+ (R = propyl (Pr), butyl (Bu)) and was characterized by chemical analysis, X‐ray diffraction, IR and Mössbauer spectroscopy, and magnetic studies. Its crystal structure is 3D, where the cyanometallate framework is electrically neutral and four water molecules per formula unit are placed in the octahedral cavities of the formed structure. The framework is built up of hexacyanoferrate(3‐) anions exhibiting connectivity 6 and two crystallographically independent [Cd(en)]2+ cations with connectivities 4. Both CdII atoms are hexacoordinated by six nitrogen atoms from one chelate bound en molecule and four bridging cyano groups. The water molecules are connected by hydrogen bonds to form a four‐membered ring. The Mössbauer spectra confirm FeIII to be in the low spin state (S = 1/2). The magnetic properties are well described by the Curie law down to 5 K.

Syntheses, Structures, and Magnetic Properties of Cyano-Bridged Heterobimetallic Complexes Based on [Fe(bpca)(CN)3]-

Two new cyano-bridged one-dimensional heterobimetallic coordination polymers, [(bpca)(2)Fe(III)(2)(CN)(6)Cu(H(2)O)(2).1.5H(2)O](n)() (2) and [(bpca)Fe(III)(CN)(3)Cu(bpca)(H(2)O).H(2)O](n)() (3), and a trinuclear complex, [(bpca)(2)Fe(III)(2)(CN)(6)Mn(CH(3)OH)(2)(H(2)O)(2)].2H(2)O (4), have been synthesized using the tailored tricyanometalate precursor (Bu(4)N)[Fe(bpca)(CN)(3)].H(2)O (1) (Bu(4)N(+) = tetrabutylammonium cation; bpca = bis(2-pyridylcarbonyl)amidate anion) as a building block and structurally characterized. In complex 2, the Cu(II) ions are six-coordinated in an elongated distorted octahedral environment, and they are linked by distorted octahedrons of [Fe(bpca)(CN)(3)](-) to form 1D chain of squares. Complex 3 is an unexpected chiral heterobimetallic helical chain complex, in which the helical chain consists of the asymmetric unit of [(bpca)Fe(CN)(3)Cu(bpca)(H(2)O)]. In complex 4, there are two independent trinuclear clusters in one asymmetric unit, and the coordination modes of the two methanol and two water molecules coordinating to the central Mn(II) ion are different (cis and trans). Complex 2 shows metamagnetic behavior with a Neel temperature of T(N) = 2.2 K and a critical field of 250 Oe at 1.8 K, where the cyanides mediate the intrachain ferromagnetic coupling between the Cu(II) and Fe(III) ions. Complex 3 shows ferromagnetic coupling between Cu(II) and Fe(III) ions, the best-fit for chi(M)T versus T using a 1D alternating chain model leads to the parameters J(1) = 7.9(3) cm(-)(1), J(2) = 1.03(2) cm(-)(1), and g = 2.196(3). Complex 4 exhibits ferrimagnetic behavior caused by the noncompensation of the local interacting spins (S(Mn) = 5/2 and S(Fe) = 1/2) which interact antiferromagnetically through bridging cyano groups.

Poly[dipyridinecopper(II)-μ-cyano-copper(II)-tri-μ-cyano

The crystal structure of the title compound, [Cu(C5H5N)2{Cu(CN)4}]n, comprises [Cu(py)2]2+ (py is pyridine) and [Cu(CN)4]2− subunits which are connected through bridging cyano groups to form a three-dimensional network, with Cu atoms located on sites of symmetry 2/m and 222 for the cation and anion, respectively.

Syntheses, Structures and Vibrational Spectroscopy of Some Adducts of Copper(I) Cyanide with Unidentate Organic Nitriles

Abstract A number of adducts of copper(I) cyanide, CuCN, have been synthesized by crystallization from its solutions in various unidentate organic nitriles, RCN. Low temperature single crystal X-ray structure determinations are recorded for a number of these, of the form CuCN : RCN (m : n) for R = Me, Et (m : n = 1 : 1), and Ph, o-tolyl (3:2). The 1 : 1 adduct with acetonitrile is a two-dimensional polymeric web, (CN)Cu(μ-CN)2Cu(NC) units being linked by the peripheral nitrogen and carbon atoms, with a fourth coordination site about each copper having MeCN pendant. The other three adducts are onedimensional polymers, the propionitrile adduct being of the form . . .Cu(NCEt)CNCu(NCEt)CN. . . with trigonal planar copper, the bridging cyanide groups being replaced in the benzo- and o-toluo nitrile adducts by linear Cu(CN)−2 moieties. The vibrational spectra of bulk samples are largely consistent with the single crystal structural results, but reveal the possible existence of adducts of higher CuCN content in the case of the CuCN/benzonitrile system.

Syntheses, Structures and Vibrational Spectroscopy of Some Adducts of Silver(I) Cyanide with (Oligo-)Pyridine Bases

Abstract Crystalline materials obtained by the crystallization of silver(I) cyanide from/with a variety of (oligo-)pyridine bases, L, of various bulk, have been characterized by room temperature single crystal X-ray structure determination. From L = quinoline (= ’quin’), AgCN : quin (1:2), is obtained, the structure being a single-stranded polymer, the successive silver atoms located on two-fold axes linked by linearly bridging cyanide groups and four-coordinate, the other two coordination sites being occupied by symmetry related quinoline nitrogen atoms. From L = 2,4,6-trimethylpyridine (‘collidine’ ≡ ‘coll’) AgCN : coll (1:1) is obtained; it is similarly a one-dimensional polymer with bridging cyanide linkages, but now with three-coordinate silver(I), the one ligand nitrogen being coordinated. The adduct for L = pyridine (= ‘py’), is of novel AgCN : py (10:9) stoichiometry; it also is a onedimensional polymer, with three-coordinate silver(I) atoms also coordinated by pyridine nitrogen, but with periodic ‘errors’ in a wave-like array (similar to that recently reported for ‘LT-CuCN’), here associated with the incorporation of occasional two-coordinate silver(I) lacking the pyridine - an unusual coordination complex example of a ’modulated’ structure? 1:1 adducts are obtained with L = 2,2’-bipyridine, ‘bpy’, 1,10-phenanthroline, ’phen’, and 2,9- dimethylphenanthroline, ‘dmp’, the latter two adducts being ’solvated’ with additional moles of phen and pyridine respectively. AgCN : bpy (1:1) is a single-stranded polymer with four-coordinate silver atoms linearly bridged by cyanides. The complex components of AgCN : phen (1:2) (≡ AgCN : phen (1:1). phen) and AgCN : dmp (: py) (1:1(:1)) are both mononuclear 1:1 species, [LAgCN], with threecoordinate metal atoms. With 2,2’:6’,2”-terpyridyl, ‘tpy’, a pyridine solvated adduct of AgCN : tpy : py (8:2:1) stoichiometry is found, the pyridine being incorporated in the one-dimensional polymer which comprises an . . .Ag’(NCAgCN)Ag’(NCAgCN)Ag’. . . spine, with (tpy)Ag(NCAgCN)Ag’ and Ag’(NCAg(py)CN)(tpy) units pendant to either side at alternate three-coordinate Ag’. In all of the oligodentate ligand complexes, the molecular packing is of interest, being dominated by the usual interleaving and perpendicular aromatic planar moieties. The IR spectra of the one-dimensional polymers show bands that are assigned to vibrations of the extended AgCN chains in these complexes: ν(CN), ν(AgC/N) (the AgC/AgN stretching mode, involving vibration of the CN group between its two neighbouring Ag atoms), δ (AgCN) (the restricted rotation of the CN group), and δ (NAgC) (the counter-vibration of the Ag substructure against the CN substructure). The ν(CN) and ν(AgC/N) bands in AgCN : py (10:9) occur in the ranges 2096 - 2154 and 360 - 460 cm−1 respectively, and show splittings that can be attributed to the unusual structure of this complex in the solid state. The Raman spectra of the py complex in the solid state and in solution are also discussed. In the other two unidentate ligand complexes, single bands are observed for the ν(CN) and ν(AgC/N) modes at 2140, 392 (AgCN : coll (1:1)) and 2140, 422 cm−1 (AgCN : quin (1:2)) respectively. The monomeric AgCN : bidentate ligand complexes AgCN : phen (1:1) and AgCN : dmp (1:1) show lower ν(CN) and ν(AgC/N) frequencies than the polymeric AgCN : bpy (1:1), despite the fact that the Ag-C/N distances in the former are shorter than that in the latter, in agreement with previously observed trends in AgCN/ER3 compounds.

The one-dimensional structure of Cu(dmen)2Pd(CN)4 (dmen is N,N-dimethylethylenediamine).

The title compound, catena-poly[[μ-cyano-1:2κ 2 C:N-dicyano-1κ 2 C-bis(N,N-dimethylethylenediamine-2κ 2 N,N')-palladium(II)copper(II)]-μ-cyano-1:2'κ 2 C:N], [CuPd(CN) 4 -(C 4 H 12 N 2 ) 2 ] n , consists of infinite quasi-linear chains with all metal positions on centers of symmetry. The paramagnetic [Cu(dmen) 2 ] 2+ cations are linked by diamagnetic [Pd(CN) 4 ] 2- anions via bridging cyano groups, which occupy trans positions in both cation and anion, giving rise to 2,2-TT-type chains. The coordination polyhedron of the paramagnetic Cu atom is an octahedron exhibiting typical elongation due to the Jahn-Teller effect, with two longer Cu-N(≡C) bonds in the axial positions [2.5528 (13) A] and four shorter Cu-N dmen bonds (dmen is N,N-dimethylethylenediamine) in the equatorial plane [1.9926 (11) and 2.1149 (12) A]. The Cu-N≡C angle is 138.03(12)°. Neighboring chains form weak N-H...NC hydrogen bonds.

Synthesis, crystal structure, EPR and magnetic properties of a cyano-bridged Cuii–Niiiheterobimetallic complex: an unusual structure with long-range ferromagnetic exchange through hydrogen bonding

A cyano-bridged CuII–NiII dimeric complex [Cu(Me6Cy)][Ni(CN)4] has been synthesized and characterized by its single crystal X-ray structure determination. The square planar [Cu(Me6Cy)]2+ cation is converted to a distorted trigonal bipyramidal (TBP) geometry through ligation to one of the cyano groups of [Ni(CN)4]2− in the equatorial plane, keeping the other three as terminal. Inspection of the X-ray data reveals that the Cu–N(6)–C(6) angle of the bridging cyano group is perfectly linear (180°). The room temperature (RT) EPR spectrum of polycrystalline [Cu(Me6Cy)][Ni(CN)4] is typical for mononuclear copper(II) complexes of axial symmetry, where the flattened out symmetry axis is characterized by g⊥ = 2.143 ± 0.005 and g‖ = 2.002 ± 0.005. No half field (ΔM = 2) signals were observed. RT EPR spectrum of polycrystalline [CuII(Me6Cy)](ClO4)2 yields an EPR signal with g‖ = 2.394 ± 0.005 and g⊥ = 2.045 ± 0.005, indicating that this parent compound has a different geometry than [Cu(Me6Cy)][Ni(CN)4]. Variable temperature magnetic moment studies on [Cu(Me6Cy)][Ni(CN)4] indicate a very weak long-range ferromagnetic exchange through hydrogen bonding between copper(II) ions (S = ½). The present investigation provides a unique example where the original square planar [Cu(Me6Cy)]2+ moiety rearranges itself to a trigonal bipyramidal geometry under the influence of [Ni(CN)4]2−. This is probably only the second, rare example, and perhaps the first, for a macrocyclic precursor using only one cyano group of [Ni(CN)4]2− for bridging, leading to a discrete dinuclear complex.

The three-dimensional coordination polymer tetraethylammonium (ethylenediamine)cadmium(II) hexacyanoferrate(III), (Et(4)N)[[Cd(en)](4)[Fe(CN)(6)](3)

The title compound, tetraethylammonium dodeca-mu-cyano-hexacyanotetrakis(ethylenediamine)tetracadmium(II)triferrate(III), (C(8)H(20)N)[Cd(4)Fe(3)(CN)(18)(C(2)H(8)N(2))(4)], was prepared from a reaction mixture containing CdCl(2), K(3)[Fe(CN)(6)], ethylenediamine (en) and [Et(4)N]Br in a 1:1:3:1 molar ratio. The crystal structure consists of a negatively charged three-dimensional framework of [[Cd(en)](4)[Fe(CN)(6)](3]n)(n-) anions, with [Et(4)N](+) cations located in the cavities of the framework. The Cd atom is octahedrally coordinated by one disordered chelating en molecule [mean Cd-N = 2.35 (3) A] and four N-bonded bridging cyano groups [Cd-N distances are in the range 2.283 (2)-2.441 (2) A]. There are two crystallographically independent [Fe(CN)(6)](3-) anions in the structure and in each the Fe atom lies on a twofold axis. In the first [mean Fe-C = 1.941 (5) A], all the cyano groups are bridging ligands, while in the second [mean Fe-C = 1.945 (2) A], there are two terminal cyano ligands in trans positions. The Cd-N-C angles range from 128.6 (2) to 172.8 (2) degrees.

Magneto-structural correlations in one-dimensional Ni( en) 2Pd(CN) 4: magnetic properties and redetermination of the crystal structure at two temperatures

The magneto-structural correlations in Ni( en) 2Pd(CN) 4 (NEPC) have been studied. The crystal structure is formed by infinite electroneutral 2,2-TT type chains [Ni( en) 2NCPd(CN) 2CN] ( en=1,2-diaminoethane) in which the paramagnetic nickel atoms are bridged by diamagnetic tetracyanopalladate anions. Contrary to the previous room temperature X-ray analysis of NEPC, the results of the current structure determinations at both 293 and 150 K showed the nickel atom to be coordinated in the form of slightly elongated octahedron with two chelate bonded and disordered en molecules in the equatorial plane (mean NiN distance of 2.096 Å at both temperatures) and N-bonded bridging cyano groups in the axial positions (NiN distances of 2.117 and 2.108 Å at 293 and 150 K, respectively). Consequently, the zero field splitting parameter D is finite and positive. The chains are held together by weak hydrogen bonds of the NH⋯N(C) type. Magnetisation, susceptibility and specific heat measurements indicate that NEPC represents an S=1 Heisenberg magnetic chain characterised by strong planar anisotropy, D/ k B≈5 K, weak in-plane anisotropy, E/ D=0.1, and by a small exchange coupling constant, J/ k B≈0.25 K. These properties are similar to those exhibited by an analogous compound Ni( en) 2Ni(CN) 4.

Preparation, structure and magnetic properties of two tetracyanonickellates: one-dimensional Ni(dien)(mea)Ni(CN) 4 and ionic [Ni(aepn) 2][Ni(CN) 4]·H 2O

Two new homobimetallic compounds Ni(dien)(mea)Ni(CN) 4 (NDMC) and [Ni(aepn) 2][Ni(CN) 4]·H 2O (NANCH) were prepared and characterised for the first time (dien=diethylenetriamine, mea=2-aminoethanole, aepn=N-(2-aminoethyl)-1,3-propanediamine). NDMC exhibits a novel type of one-dimensional structure which is formed of [Ni(dien)(mea)] 2+ cations (C) and planar [Ni(CN) 4] 2− anions (A) linked by bridging cyano groups. The anion utilises cis-positioned cyano groups for bridging to two different cations and these complete a distorted square bipyramid of the cation. The crystal structure consists of 1D chains {⋯– 3C 6– 1A 4– 3C 6– 1A 4–⋯} ∞ where the spin multiplicity is marked as a superscript and the coordination number as a subscript. A considerable local magnetic anisotropy was found ( D/ hc=−7.0 cm −1) owing to the synergy effect of the ligand sphere asymmetry around the cation. NANCH is formed of isolated [Ni(aepn) 2] 2+ cations ( 3C 6), which are hexacoordinate ( S=1), and planar diamagnetic [Ni(CN) 4] 2− anions ( 1A 4) which are linked by water molecules via hydrogen bonds forming chain of the type {⋯ 1A 4⋯HOH⋯} ∞. The magnetic anisotropy dropped significantly owing to a nearly octahedral {NiN 6} chromophore.

Low-dimensional compounds containing cyano groups. III: a structural, spectral and thermal study of dicyanoargentates containing 4-methylpyridine

The complexes CuII(4-Mepy)2Ag2(CN)4(1) and CuII(4-Mepy)3Ag2−xCuIx(CN)4(2) (4-Mepy = 4-methylpyridine, x = 0.07) were isolated from a reaction mixture containing 4-Mepy, K[Ag(CN)2] and CuSO4. I.r. spectra indicated the presence of both monodentate and bridging cyano groups in (1) and (2), confirmed by their known structures, both consisting of neutral zigzag chains. Two neighbouring chains in (2) are linked by argentophilic interactions between Ag atoms of bridging dicyanoargentate anions, whose positions are partly occupied by CuI ions to the extent of 7 at.%, with an unusually short Ag...Ag distance of 2.9264(5) A, to form a ladder. Individual ladders are tied together as sheets by weaker argentophilic interactions between silver atoms of interdigitated monodentate dicyanoargentate anions of two different ladders. Thermal decomposition of (2) occurs in two separated stages. In the first stage, three 4-Mepy molecules are liberated from the formula unit and, in the second stage, redox decomposition of the cyano groups occurs. The thermal decomposition of (1) is more complicated as the release of two 4-Mepy molecules is overlapped by decomposition of one cyano group followed by further redox decomposition of the remaining cyano groups.

Cu2(dien)2Ag5(CN)9 containing the one-dimensional polymeric cation [Cu(dien)Ag(CN)2](n+)(n) and the unusual [Ag2(CN)3]- anion (dien is diethylenetriamine).

From the 1:1 system of [Cu(dien)(2)](NO(3))(2) and K[Ag(CN)(2)] in water (dien is diethylenetriamine, C(4)H(13)N(3)), the novel compound catena-poly[bis[[mu-cyano-1:2kappa(2)C:N-diethylenetriamine-2kappa(3)N-copper(II)silver(I)]-mu-cyano-1:2'kappa(2)C:N] dicyanosilver(I) tricyanodisilver(I)], [CuAg(CN)(2)(dien)](2)[Ag(CN)(2)][Ag(2)(CN)(3)], has been isolated. The structure is formed from positively charged [-Cu(dien)-NC-Ag-CN-](n+)(n) chains and two isolated centrosymmetric [Ag(CN)(2)](-) and [Ag(2)(CN)(3)](-) anions. In the cationic chains, the Cu atoms are linked by bridging dicyanoargentate groups, and the deformed square-pyramidal coordination polyhedron of the Cu(II) cation is formed from a tridentate chelate-like bonded dien ligand and two N-bonded bridging cyano groups. One of the bridging cyano groups occupies the apical (ap) position [mean Cu-N(eq) = 2.02 (2) A, and Cu-N(ap) = 2.170 (3) A; eq is equatorial]. Short argentophilic interactions in the range 3.16-3.30 A are present in the crystal structure.