Homoleptic copper(II) and copper(I) complexes of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline. Six-coordinate copper(I) in solution

Reaction of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline (L) with Cu(ClO₄)₂·6H₂O in methanol in 3:1 M ratio at room temperature yields light green [CuL₃](ClO₄)₂·H₂O (1). The X-ray crystal structure of the hemi acetonitrile solvate [CuL₃](ClO₄)₂·0.5CH₃CN has been determined which shows Jahn-Teller distortion in the CuN₆ core present in the cation [CuL₃]²⁺. Complex 1 gives an axial EPR spectrum in acetonitrile-toluene glass with g_|| = 2.262 (A_|| = 169 × 10⁻⁴ cm⁻¹) and g_⊥ = 2.069. The Cu(II/I) potential in 1 in CH₂Cl₂ at a glassy carbon electrode is 0.32 V versus NHE. This potential does not change with the addition of extra L in the medium implicating generation of a six-coordinate copper(I) species [CuL₃]⁺ in solution. B3LYP/LanL2DZ calculations show that the six Cu-N bond distances in [CuL₃]⁺ are 2.33, 2.25, 2.32, 2.25, 2.28 and 2.25 Å while the ideal Cu(I)-N bond length in a symmetric Cu(I)N₆ moiety is estimated as 2.25 Å. Reaction of L with Cu(CH₃CN)₄ClO₄ in dehydrated methanol at room temperature even in 4:1 M proportion yields [CuL₂]ClO₄ (2). Its ¹H NMR spectrum indicates that the metal in [CuL₂]⁺ is tetrahedral. The Cu(II/I) potential in 2 is found to be 0.68 V versus NHE in CH₂Cl₂ at a glassy carbon electrode. In presence of excess L, 2 yields the cyclic voltammogram of 1. From ¹H NMR titration, the free energy of binding of L to [CuL₂]⁺ to produce [CuL₃]⁺ in CD₂Cl₂ at 298 K is estimated as −11.7 (±0.2) kJ mol⁻¹.     

Silver(I)-organophosphane complexes of the dihydridobis(3-nitro-1,2,4-triazolyl)borate ligand. X-ray crystal structure of {[H2B(tz)2]Ag[P(m-tolyl)3]2} with the scorpionate ligand co-ordinated in an unidentate κ-N fashion

New silver(I) complexes have been synthesised from the reaction of AgNO₃, monodentate PR₃ (PR₃ = P(o-tolyl)₃, P(m-tolyl)₃, P(p-tolyl)₃, P(p-C₆H₄F), SeP(C₆H₅)₃) or bidentate tertiary (dppe = bis(diphenylphosphane)ethane, dppf = 1,1′-bis(diphenylphosphane)ferrocene) phosphanes and potassium dihydrobis(3-nitro-1,2,4-triazolyl)borate, K[H₂B(tz^NO2)₂]. These compounds have been characterized by elemental analyses, FT-IR, ESI-MS and multinuclear (¹H and ³¹P) NMR spectral data. The adduct {[H₂B(tz^NO2)₂]Ag[P(m-tolyl)₃]₂} has been characterized by single crystal X-ray studies. In the former, the H₂B(tz^NO2)₂ acts as a monodentate ligand utilizing the coordinating capability of only one of the additional (exo-) ring nitrogens to complete the coordination array about the silver atom.     

Silver(I) methanesulfonate complexes containing diphosphine ligands: Spectroscopic and structural characterization

1:1 and 2:1 adducts of diphosphine ligands R₂P(R′)_nPR₂ (dppm: R = Ph, R′ = CH₂, n = 1; dppe: R = Ph, R′ = CH₂, n = 2; dppp: R = Ph, R′ = CH₂, n = 3; dppb: R = Ph, R′ = CH₂, n = 4; dppf: R = Ph, R′ = ferrocenyl, n = 1) with silver(I) methanesulfonate have been synthesized and characterized both in solution (¹H, ³¹P NMR) and in the solid state (IR, single crystal X-ray structure analysis). The two different stoichiometries have been found to depend on the molar ratio of ligand to metal employed and the nature of the diphosphine ligand. In AgO₃SMe:dppp,dppb (1:1)₂, in the [Ag(P^P)₂Ag] arrays, the silver atoms are also bridged by anion oxygen atoms, in disparate fashion commensurate with the different Ag?Ag distances.     

Synthesis and structural characterization of two new polynuclear metal thiosaccharinates: Hexakis(thiosaccharinato)hexasilver(I) and tetrakis(thiosaccharinato)tetracopper(I)

The title compounds, for short Ag₆(tsac)₆ (1) and [Cu₄(tsac)₄(MeCN)₂] · 2MeCN (2), were prepared by the reaction of thiosaccharin with Ag(I) or Cu(II) salts in different solvents. The new complexes were characterized by FT-IR, Raman, UV-Vis and NMR spectroscopy. Their crystal and molecular structures were determined by X-ray diffraction methods. The structures were solved from 1621 (1) and 7080 (2) reflections with I > 2σ(I) and refined to agreement R1-factors of 0.0261 (1) and 0.0456 (2). Ag₆(tsac)₆ molecule derives from the clustering of six Ag(tsac) moieties related to each other through the crystallographic 3-bar (S₆) symmetry operations of the space group. This results in a highly regular molecular structure where the silver atoms are at the corners of an octahedral core slightly compressed along one of its three-fold axis [inter-metallic Ag?Ag contacts of 3.1723(4) and 3.1556(4) Å]. The six thiosaccharinate ligands bridge neighboring Ag atoms along the C₃-axis through Ag-N bonds [d(Ag-N) = 2.285(2) Å] at one end and bifurcated Ag-S(thione)-Ag bonds [Ag-S distances of 2.4861(7) and 2.5014(8) Å] at the other end. In contrast, the 2 compound is arranged in the lattice as an irregular tetrameric copper complex [Cu₄(tsac)₄(MeCN)₂] where the metals show different environments. Two copper ions are four-fold coordinated to three tsac ions through the N-atom of one tsac [Cu-N distances of 2.112(3) and 2.064(3) Å] and the thione sulfur atom of the other two [Cu-S distances in the range from 2.284(1) to 2.358(1) Å] and to a MeCN solvent molecule [Cu-N distances of 1.983(4) and 2.052(3) Å]. The other two copper ions are in three-fold environment, one trans-coordinated to two tsac ions [Cu-N distances of 1.912(3) and 1.920(3) Å] and to the thione S-atom of a third ligand [d(Cu-S) = 2.531(1) Å], the other one to the thione sulfur atom of three tsac ligands [Cu-S distances in the range from 2.229(1) to 2.334(1) Å]. The clustering renders the metals to short distances from each other, the shorter Cu?Cu distance being 2.6033(7) Å, as to presume the existence of weak inter-metallic interaction within the cluster.     

One-dimensional coordination polymers made of transition metal-nitronyl nitroxide radical with dicyanoaurate(I) bridges

Three 1-D transition metal-nitronyl nitroxide radical complexes with dicyanoaurate(I) bridges, [M(NIT3py)₂][Au(CN)₂]₂ [NIT3py = 2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, M = Mn, Co, Zn (1-3)], were synthesized and structurally characterized. Three compounds are all isostructural in monoclinic, C2/c space group with Z = 4. The [Au(CN)₂]⁻ anions link [M(NIT3py)₂] units via μ₂-bridging mode, leading to a linear coordination chain. The M(II) ion adopts a distorted octahedral geometry with four N atoms from [Au(CN)₂]⁻ groups and two pyridyl-N atoms from NIT3py ligands. The magnetic behavior shows that the couplings are both weak antiferromagnetic between Mn(II) and NIT3py and between Co(II) and NIT3py.     

Interaction of gold(I) with thiosulfate-sulfite mixed ligand systems

The system was studied at 25 °C and at I = 0.1 M NaClO₄ using hydrodynamic voltammetry, gold potentiometry, UV-Vis spectrophotometry and Raman spectroscopy. The presence of two mixed-ligand species, Au(S₂O₃)(SO₃)³⁻ and , was detected from the Raman experiments and supported by the gold potentiometric experiments. The stepwise formation constant, log K_11r, for the reaction was found to be 1.1 (r = 1) and 4.8 (r = 2) from the hydrodynamic voltammetric experiments.     

Structure and luminescence of copper(I) cyanide-amine and -sulfide networks

Copper(I) cyanide reacts with various liquid amines and sulfides (L) under solvent-less conditions to form (CuCN)L_n, n = 0.5, 0.57, 0.75, 0.8, 1, 1.25, 1.5, 2. New X-ray structures are reported for L = Py (Py = pyridine, n = 0.57), 2-MePy (n = 1), 3-EtPy (n = 1.5), 2-ClPy (n = 1), 3-ClPy (n = 2), 3-MeOPy (n = 2), 4-^tBuPy (n = 1.5), piperidine (n = 1.25), N-methylmorpholine (n = 1), N,N-dimethylcyclohexylamine (n = 1), 1-methylimidazole (n = 3), Me₂S (n = 1), and tetrahydrothiophene (n = 1). The amine structures (except for the monomeric 1-methylimidazole complex) reveal 1D CuCN chains decorated with 0-2 L per metal atom. Chain structures observed include zigzag, helical and figure-8 helical. The CuCN-sulfide structures show sulfur-bridging of CuCN chains. In some cases (CuCN)L_?1.5 species are transformed to (CuCN)L under vacuum. Thermal analysis shows facile release of ligand, yielding CuCN. Most of the (CuCN)L_n products are photoluminescent, emitting in the visible region. In some cases, coordination of very similar amines results in remarkably different emission spectra.     

The synthesis of triethylphosphine gold(I) 4-nitrobenzenethiolate and solvent dependent visible absorption spectra of 4-nitrobenzenethiolate

The synthesis of triethylphosphine gold(I) 4-nitrobenzenethiolate, Et₃PAu(SC₆H₄NO₂-4), is reported. Et₃PAu(SC₆H₄NO₂-4) displays a low energy visible electronic absorption band which is solvent dependent: EtOH (λ_max = 385 nm), acetonitrile (λ_max = 391 nm), THF (λ_max = 395 nm), and DMSO (λ_max = 402 nm). The corresponding low energy visible electronic absorption band of 4-nitrobenzenethiolate, 4-NO₂C₆H₄S⁻ also shows solvent dependency: acetonitrile, (λ_max = 484 nm), DMSO (λ_max = 502 nm), dimethylformamide (λ_max = 505 nm). The positive solvatochromic shifts for Et₃PAu(SC₆H₄NO₂-4) and 4-NO₂C₆H₄S⁻ are consistent with an intraligand (IL) charge transfer transition, i.e. π(S) → ∗π (C₆H₄NO₂-4) or n(S) → ∗π (C₆H₄NO₂-4). Assignment of 4-NO₂C₆H₄S⁻ was aided by a DFT calculation.     

Synthesis, structure and cytotoxicity studies of diisopropylammonium and triethylammonium salts of triphenylphosphinegold(I) sulfanylcarboxylates

Compounds of the type [HQ][Au(PPh₃)(xspa)] and [HP][Au(PPh₃)(xspa)] {HQ = diisopropylammonium; HP = triethylammonium; H₂xspa = 3-aryl-2-sulfanylpropenoic acids [x: p = 3-phenyl-, f = 3-(2-furyl)-, t = 3-(2-thienyl)-, -o-py = 3-(2-pyridyl)-, Clp = 3-(2-chlorophenyl)-, -o-mp = 3-(2-methoxyphenyl)-, -p-mp = 3-(4-methoxyphenyl)-, -o-hp = 3-(2-hydroxyphenyl)-, -p-hp = 3-(4-hydroxyphenyl)-, diBr-o-hp = 3-(3,5-dibromo-2-hydroxyphenyl]} were synthesized and characterized by IR and NMR (¹H, ¹³C and ³¹P) spectroscopy and by FAB mass spectrometry. The structures of [HQ][Au(PPh₃)(Clpspa)] and [HQ][Au(PPh₃)(-o-mpspa)] show that the crystal contains hydrogen-bonded diisopropylammonium cations and [Au(PPh₃)(xspa)]⁻ anions. The anions in the two compounds have different structures, with the carboxylate group either coordinated or not coordinated to the gold atom, respectively. The in vitro antitumour activities against the HeLa-229, A2780 and A2780cis cell lines were determined for all complexes. The diisopropylammonium derivatives were generally found to be more active, in particular against the A2780cis cell line, and showed a high ability to circumvent the cellular resistance to cisplatin.     

Hydrothermal synthesis and structure of a Cu(I) bromide coordination polymer, [(tpyprz)3Cu10Br10] (tpyprz = tetra-2-pyridylpyrazine)

The hydrothermal reaction of CuBr₂ and tpyprz in the presence of NH₄VO₃ and HF for 72 h at 170 °C provided [(tpyprz)₃Cu₁₀Br₁₀] (1) in 20% yield. The two-dimensional structure of 1 may be described as Cu(I)-tpyprz chains, linked through {Cu₄Br₅}⁻ clusters in the ac-plane and decorated with {Cu₃Br₅}²⁻ clusters projecting from one face of the layer in the b-direction. The Cu(I) sites exhibit distorted trigonal coordination {CuBr₃} and distorted tetrahedral geometries, {CuBr₂N₂} and {CuN₄}. Crystal data for 1: monoclinic space group C2, a = 12.7561(8) Å, b = 19.359(1) Å, c = 15.860(1) Å, β = 97.178(1)°, V = 3885.8(4) Å³, Z = 2, D_calc = 2.222 g cm⁻³, μ(Mo Kα) = 78.75 cm⁻¹.     

Assembly of two low-dimensional coordination polymers from Ag(I) and Cd(II) and 2,3-bis(2-pyridyl)pyrazine

Polydentate nitrogen heterocycle ligand 2,3-bis(2-pyridyl)pyrazine (2,3-dpp) reacted with M(NO₃)_x (M = Ag, x = 1; M = Cd, x = 2) to give two new complexes [Ag(2,3-dpp)(NO₃)]₂ (1) and [Cd(2,3-dpp)(NO₃)₂]_n (2). Both complexes have been characterized by single-crystal X-ray diffraction, elemental analyses, IR and ¹H NMR spectroscopy. Single-crystal X-ray analyses showed that complex 1 crystallized in monoclinic, space group P2₁/n is a dimmer containing penta-coordinated Ag⁺ ion. While compound 2 has 1D chain-like structure with repeat unit Cd(2,3-dpp)(NO₃)₂, in which the Cd(II) presents octa-coordinated N4O4 donor set with two four-membered chelating rings and two five-membered chelating rings around Cd(II) ion. Meanwhile, every neutral chain [Cd(2,3-dpp)(NO₃)₂]_n is mutually connected by face-to-face π?π packing interactions to form a two dimensional layer. Furthermore, antibacterial activities of compound 1 and luminescent property of the compound 2 are also investigated.     

Synthesis and structural characterization of the adducts of silver(I) perchlorate and nitrate with triphenylphosphine and bis(pyrazolyl)methane ligands of 1:1:1 stoichiometry

Six new adducts of the form AgX:PPh₃:H₂C(pz^x)₂ (1:1:1) (H₂C(pz^x)₂ = H₂C(pz)₂ = bis(pyrazolyl)methane or H₂C(pz^Me2)₂ = bis(3,5-dimethylpyrazolyl)methane; X = ClO₄, NO₃, SO₃CF₃) have been synthesized and characterized by analytical, spectroscopic (IR, far-IR, ¹H and ³¹P NMR) and two of them also by single crystal X-ray diffraction studies for comparison with counterpart adducts with 2,2′-bipyridyl (‘bpy’) derivatives reported in a previous paper, the bpy-derived ligands forming five-membered chelate rings, while the present H₂C(pz^x)₂ should, potentially, form six-membered rings. Such is the case, the two adducts exhibiting quasi-planar N₂AgP coordination environments, perturbed by the approach of the oxyanion, unidentate in the case of the perchlorate but, in the case of the nitrate, an interesting disordered aggregate of differing unidentate modes.     

Lewis-base copper(I) formates: Synthesis, reaction chemistry, structural characterization and their use as spin-coating precursors for copper deposition

Consecutive synthesis methodologies for the preparation of a series of copper(I) formates [L_mCuO₂CH] (L = ⁿBu₃P: 4a, m = 1; 4b, m = 2; 5, L = [Ti](CCSiMe₃)₂, m = 1, [Ti] = (η⁵-C₅H₄SiMe₃)₂Ti) and [L_mCuO₂CH·HO₂CR] (L = ⁿBu₃P: 7a, m = 1, R = H; 7b, m = 2, R = H; 7c, m = 2, R = Me; 7d, m = 2, R = CF₃; 7e, m = 2, R = Ph. L = (^cC₆H₁₁)₃P, R = H: 8a, m = 2; 8b, m = 3. L = (CF₃CH₂O)₃P, R = H: 9a, m = 2; 9b, m = 3. L = (CH₃CH₂O)₃P, R = H: 10a, m = 2; 10b, m = 3. L = [Ti](CCSiMe₃)₂; m = 1: 11a, R = H; 11b, R = Ph) is reported using [CuO₂CH] (1) and L (2a, L = ⁿBu₃P; 2b, L (^cC₆H₁₁)₃P; 2c, L = (CF₃CH₂O)₃P; 2d, L = (CH₃CH₂O)₃P; 3, L = [Ti](CCSiMe₃)₂) as key starting materials. Addition of formic acid (6a) or carboxylic acid HO₂CR (6b, R = Me; 6c, R = CF₃; 6d, R = Ph) to the afore itemized copper(I) formates 4 and 5 gave metal-organic or organometallic 7-11. The molecular structures of 8a and 11a in the solid state are reported showing a threefold coordinated copper(I) ion, setup by either two coordinatively-bonded phosphorus atoms and one formate oxygen atom (8a) or two π-bonded alkyne ligands and one oxygen atom (11a). A formic acid molecule is additionally hydrogen-bonded to the CuO₂CH moiety. The use of 7b as suitable precursor for the deposition of copper onto TiN-coated oxidized silicon wafers by the spin-coating process below 300 °C is described. Complex 7b offers an appropriate transformation behavior into metal phase by an elimination-decarboxylation mechanism. The morphology of the copper films strongly depends on the annealing conditions. A closed grain network densified by a post-treatment is obtained (8 °C min⁻¹, N₂/H₂ carrier gas). Hydrogen post-anneal to 420 °C after film deposition gave a copper film showing resistivities from 2.5 to 3.7 μΩ cm. This precursor was also used for gap-filling processes.     

The synthesis, structure, and characterization of three novel 1D nitrogen-heterocyclic copper(I)-diphosphine polymers

At ambient temperature, three 1D nitrogen-heterocyclic Cu(I)-diphosphine polymers, {[Cu₂(dppm)₂(BF₄)₂(pyz)](CH₂Cl₂)₂}_n (1), {[Cu₂(dppm)₂(4,4′-bpy)(CF₃SO₃)](CF₃SO₃)(CH₃OH)}_n (2), {[Cu₂(dppe)₂ (phen)₂](ClO₄)₂(CH₂Cl₂)}_n (3) (dppm = bis(diphenylphosphino)methane, dppe = bis(diphenylphosphino)ethane, pyz = pyrazine, 4,4′-bpy = 4,4′-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by X-ray crystallography, luminescence, IR, ¹H, and ³¹P NMR. Structure analysis shows that 1 is a 1D linear polymer, 2 is a 1D stair-shaped polymer, and 3 is a 1D W-shaped polymer. A photoluminescent study of them shows that they exhibit fluorescent emission bands at ca. 555 nm, 535 nm and 557 nm, respectively.     

Structure and solution behaviour of cyclooctadiene complexes of platinum(II)

The substitution behaviour of [PtCl(R)(COD)] (R⁻ = Me and Fc) complexes, by the stepwise addition of phosphine ligands, L (L = PPh₃, PEt₃ and P(NMe₂)₃), were investigated in situ by ¹H and ³¹P NMR spectroscopy. Addition of less than two equivalents of the phosphine ligand results in the formation of dimeric molecules with the general formula trans-[Pt(R)(μ-Cl)(L)]₂ for the sterically demanding systems where R⁻ = Me/L = P(NMe₂)₃ and R⁻ = Fc/L = PEt₃, PPh₃ and P(NMe₂)₃ while larger quantities resulted in cis- and trans mixtures of mononuclear complexes being formed. In the case of the relatively small steric demanding, strongly coordinating, PEt₃ ligand the trans-[PtCl(R)(PEt₃)₂] mononuclear complexes were exclusively observed in both cases. The crystal structures of the two substrates, [PtCl(R)(COD)] (R⁻ = Me or Fc), as well as the cis-[PtCl(Fc)(PPh₃)₂] substitution product are reported.     

Dinuclear triphenylphosphinegold(I) sulfanylcarboxylates: Synthesis, structure and cytotoxic activity against cancer cell lines

Compounds of the type [(AuPPh₃)₂(xspa)]; H₂xspa [x:p = 3-phenyl-, f = 3-(2-furyl)-, t = 3-(2-thienyl)-, -o-py = 3-(2-pyridyl)-, Clp = 3-(2-chlorophenyl)-, -o-mp = 3-(2-methoxyphenyl)-, -p-mp = 3-(4-methoxyphenyl)-, -o-hp = 3-(2-hydroxyphenyl)-, -p-hp = 3-(4-hydroxyphenyl)-, -diBr-o-hp = 3-(3,5-dibromo-2-hydroxyphenyl)-; spa = 2-sulfanyl propenoato] were synthesized and characterized by IR and NMR (¹H, ¹³C and ³¹P) spectroscopy and by FAB mass spectrometry. The structures of [(AuPPh₃)₂(Clpspa)], [(AuPPh₃)₂(o-hpspa)], [(AuPPh₃)₂(p-hpspa)]·MeOH and [(AuPPh₃)₂(diBr-o-hpspa)]·2Me₂CO show the dinuclear nature of the complexes with the two gold atoms, one of which is also O-bonded to an O atom of the carboxylate group, bonded to the S atom. The in vitro antitumor activities against the HeLa-229, A2780 and A2780cis cell lines were determined and the compounds were found to be highly effective, in particular against the A2780cis cell line, with eight of the nine compounds having IC₅₀ values better than that of cisplatin. This behavior is indicative of a high ability to circumvent the cellular resistance to this drug.     

Copper(I)-organophosphine complexes of bis(3,5-dimethylpyrazol-1-yl)dithioacetate ligand

Copper(I) complexes have been synthesized from the reaction of CuCl, monodentate tertiary phosphines PR₃ (PR₃ = P(C₆H₅)₃; P(C₆H₅)₂(4-C₆H₄COOH); P(C₆H₅)₂(2-C₆H₄COOH); PTA, 1,3,5-triaza-7-phosphaadamantane; P(CH₂OH)₃, tris(hydroxymethyl)phosphine) and lithium bis(3,5-dimethylpyrazolyl)dithioacetate, Li[LCS₂]. Mono-nuclear complexes of the type [LCS₂]Cu[PR₃] have been obtained and characterized by elemental analyses, FT-IR, ESI-MS and multinuclear (¹H, ¹³C and ³¹P) NMR spectral data; in these complexes the ligand behaves as a κ³-N,N,S scorpionate system. One exception to this stoichiometry was observed in the complex [LCS₂]Cu[P(CH₂OH)₃]₂, where two phosphine co-ligands are coordinated to the copper(I) centre. The solid-state X-ray crystal structure of [LCS₂]Cu[P(C₆H₅)₃] has been determined. The [LCS₂]Cu[P(C₆H₅)₃] complex has a pseudo tetrahedral copper site where the bis(3,5-dimethylpyrazolyl)dithioacetate ligand acts as a κ³-N,N,S donor.     

Assembly of 1D, 2D and 3D silver(I) coordination polymers with nitrilotriacetate and 2-aminopyrimidyl mixed ligands

Three mixed ligands coordination polymers (CPs) [Ag_1.5(apym)(nta)_0.5]_n (1), [(NH₄)Ag₂(mapym)(nta)·(H₂O)₃]_n (2), [Ag₂(dmapym)₃(Hnta)]_n (3) (apym = 2-aminopyrimidine, mapym = 4-methyl-2-aminopyrimidine, dmapym = 4, 6-dimethyl-2-aminopyrimidine, H₃nta = nitrilotriacetate) were synthesized and characterized. For 1-3, as the substituents change from H to one methyl and two methyl groups, the dimensionalities of 1-3 decrease from three-dimension (3D) to one-dimension (1D) due to the steric effect of methyl groups. For 1, the μ₂-apym ligands link the Ag(I) ions to form a 1D double-chain incorporating ligand unsupported Ag···Ag interaction. The nta³⁻ ligands extend the 1D double-chain into a 3D framework. In 2, one heptadentate nta³⁻ ligand binds four Ag(I) ions and incorporates μ₂-mapym ligand to link metal centers to form a 2D sheet which can be simplified to be a 10³ net. Complex 3 features a 1D chain structure incorporating Hnta²⁻ and monodentate dmapym ligands. The substituents on the pyrimidyl ring intensively influence the coordination environments of metal ion and the coordination modes of the carboxyl group, and thus determine the structures of the CPs. The photoluminescent properties of 1-3 were also investigated.     

Tris(pyrazol-1-yl)borate and tris(pyrazol-1-yl)methane: A DFT study of their different binding capability toward Ag(I) and Cu(I) cations

Density functional theory has been used to study the electronic structure of [M(tp)] and [M(tpm)]⁺ conformers (M = Cu, Ag; tp = tris(pyrazol-1-yl)borate anion, tpm = tris(pyrazol-1-yl)methane) and the energetics of their interconversions. Results for the free tp ligand are similar to those of tpm [M. Casarin, D. Forrer, F. Garau, L. Pandolfo, C. Pettinari, A. Vittadini, J. Phys. Chem. A 112 (2008) 6723], indicating an intrinsic instability of the tripodal conformation (κ³-like). This points out that, though frequently observed, the κ³-coordinative mode is unlikely to be directly achieved through the interaction of M(I) with the κ³-like tp/tpm conformer. Analogously to the [M(tpm)]⁺ molecular ions, the energy barrier for the κ²-[M(tp)] → κ³-[M(tp)] conversion is computed to be negligible. Though κⁿ-[M(tp)] and κⁿ-[M(tpm)]⁺ (n = 1, 2, 3) have similar metal-ligand covalent interactions, the negative charge associated to the tp ligand makes the M-tp bonding stronger.     

The synthesis, structure and luminescence of two 1D pyrazine-connected Cu(I)-dppm polymers

Two pyrazine-connected 1D copper(I) dppm polymers, {[Cu₃(dppm)₃Br₂][Cu₂(dppm)(pyz)Br₂] Br · (CH₃OH)₂}_n (1) and {[Cu₂(dppm)₂(NO₃)₂(pyz)](pyz)}_n (2) (dppm = bis(diphenylphosphino)methane, pyz = pyrazine) have been synthesized and characterized by X-ray crystallography, luminescence, IR, ¹H, and ³¹P NMR. Structure analysis shows that complex 1 is a neutral 1D polymer in sine-curve-like form, while complex 2 is in linear form. And photoluminescent study of them shows that they exhibit fluorescent emission bands at ca. 434 nm and 431 nm, respectively.