Polyfluorinated Tris(pyrazolyl)borates. Syntheses and Spectroscopic and Structural Characterization of Group 1 and Group 11 Metal Complexes of [HB(3,5-(CF(3))(2)Pz)(3)](-) and [HB(3-(CF(3))Pz)(3)](-)

The fluorinated tris(pyrazolyl)borate ligands [HB(3,5-(CF(3))(2)Pz)(3)](-) and [HB(3-(CF(3))Pz)(3)](-) (where Pz = pyrazolyl) have been synthesized as their sodium salts from the corresponding pyrazoles and NaBH(4) in high yield. These sodium complexes and the related [HB(3,5-(CF(3))(2)Pz)(3)]K(DMAC) were used as ligand transfer agents in the preparation of the copper and silver complexes [HB(3,5-(CF(3))(2)Pz)(3)]Cu(DMAC), [HB(3,5-(CF(3))(2)Pz)(3)]CuPPh(3), [HB(3,5-(CF(3))(2)Pz)(3)]AgPPh(3), and [HB(3-(CF(3))Pz)(3)]AgPPh(3). Metal complexes of the fluorinated [HB(3,5-(CF(3))(2)Pz)(3)](-) ligand have highly electrophilic metal sites relative to their hydrocarbon analogs. This is evident from the formation of stable adducts with neutral oxygen donors such as H(2)O, dimethylacetamide, or thf. Furthermore, the metal compounds derived from fluorinated ligands show fairly long-range coupling between fluorines of the trifluoromethyl groups and the hydrogen, silver, or phosphorus. The solid state structures show that the fluorines are in close proximity to these nuclei, thus suggesting a possible through-space coupling mechanism. Crystal structures of the sodium adducts exhibit significant metal-fluorine interactions. The treatment of [HB(3,5-(CF(3))(2)Pz)(3)]Na(H(2)O) with Et(4)NBr led to [Et(4)N][HB(3,5-(CF(3))(2)Pz)(3)], which contains a well-separated [Et(4)N](+) cation and the [HB(3,5-(CF(3))(2)Pz)(3)](-) anion in the solid state. Crystal data with Mo Kalpha (lambda = 0.710 73 ?) at 193 K: [HB(3,5-(CF(3))(2)Pz)(3)]Na(H(2)O), C(15)H(6)BF(18)N(6)NaO, a = 7.992(2) ?, b = 15.049(2) ?, c = 9.934(2) ?, beta = 101.16(2) degrees, monoclinic, P2(1)/m, Z = 2; [{HB(3-(CF(3))Pz)(3)}Na(thf)](2), C(32)H(30)B(2)F(18)N(12)Na(2)O(2), a = 9.063(3) ?, b = 10.183(2) ?, c = 12.129(2) ?, alpha = 94.61(1) degrees, beta = 101.16(2) degrees, gamma = 95.66(2) degrees, triclinic, &Pmacr;1, Z = 1; [HB(3,5-(CF(3))(2)Pz)(3)]Cu(DMAC), C(19)H(13)BCuF(18)N(7)O, a = 15.124(4) ?, b = 8.833(2) ?, c = 21.637(6) ?, beta = 105.291(14) degrees, monoclinic, P2(1)/n, Z = 4; [HB(3,5-(CF(3))(2)Pz)(3)]CuPPh(3), C(33)H(19)BCuF(18)N(6)P, a = 9.1671(8) ?, b = 14.908(2) ?, c = 26.764(3) ?, beta = 94.891(1) degrees, monoclinic, P2(1)/c, Z = 4; [HB(3,5-(CF(3))(2)Pz)(3)]AgPPh(3).0.5C(6)H(14), C(36)H(26)AgBF(18)N(6)P, a = 13.929(2) ?, b = 16.498(2) ?, c = 18.752(2) ?, beta = 111.439(6) degrees, monoclinic, P2(1)/c, Z = 4; [Et(4)N][HB(3,5-(CF(3))(2)Pz)(3)], C(23)H(24)BF(18)N(7), a = 10.155(2) ?, b = 18.580(4) ?, c = 16.875(5) ?, beta = 99.01(2) degrees, monoclinic, P2(1)/n, Z = 4.     

Syntheses of aluminum and zinc alkyl complexes of a highly fluorinated tris(pyrazolyl)borate using [HB(3,5-(CF3)2Pz)3]Ag(THF) as the ligand transfer agent

Dimethylaluminum or ethylzinc complexes of highly fluorinated tris(pyrazolyl)borate ligand [HB(3,5-(CF(3))(2)Pz)(3)](-) can be obtained in excellent yield from the reaction between the silver adduct [HB(3,5-(CF(3))(2)Pz)(3)]Ag(THF) and the metal alkyl reagent Me(3)Al or Et(2)Zn. The X-ray crystal structure of [HB(3,5-(CF(3))(2)Pz)(3)]AlMe(2) shows that the tris(pyrazolyl)borate ligand coordinates to the aluminum center in kappa(2)-fashion. [HB(3,5-(CF(3))(2)Pz)(3)]ZnEt features the typical kappa(3)-bonded ligand.     

Adduct formation or metathesis reactions of silver complexes containing the fluorinated ligands [HB(3,5-(CF3)2Pz)3]- and [CF3SO3]-: formation of silver adducts containing unsupported silver-germanium bonds

A mixture of [HB(3,5-(CF3)2Pz)3]Ag(eta 2-toluene) and [(Me)2ATI]GeCl in CH2Cl2, rather than undergoing metathesis, formed a 1:1 adduct [HB(3,5-(CF3)2Pz)3]Ag<--GeCl[(Me)2ATI] (1, where [HB(3,5-(CF3)2Pz)3] = hydrotris(3,5-bis(trifluoromethyl)pyrazolyl)borate and [(Me)2ATI] = N-methyl-2-(methylamino)troponiminate) featuring a silver-germanium bond. Solutions of 1 (in CH2Cl2 or toluene) did not precipitate AgCl even after several days. However, it easily underwent metathesis with CF3SO3Ag, leading to the chloride-free product [HB(3,5-(CF3)2Pz)3]Ag<--Ge(OSO2CF3)[(Me)2ATI] (2). Compounds 1 and 2 were characterized by X-ray crystallography. The Ag-Ge bond distances of 1 and 2 are 2.4215(9) and 2.4116(10) A, respectively.     

Copper(I) Nitro Complex with an Anionic [HB(3,5-Me(2)Pz)(3)](-) Ligand: A Synthetic Model for the Copper Nitrite Reductase Active Site

The new copper(I) nitro complex [(Ph(3)P)(2)N][Cu(HB(3,5-Me(2)Pz)(3))(NO(2))] (2), containing the anionic hydrotris(3,5-dimethylpyrazolyl)borate ligand, was synthesized, and its structural features were probed using X-ray crystallography. Complex 2 was found to cocrystallize with a water molecule, and X-ray crystallographic analysis showed that the resulting molecule had the structure [(Ph(3)P)(2)N][Cu(HB(3,5-Me(2)Pz)(3))(NO(2))]·H(2)O (3), containing a water hydrogen bonded to an oxygen of the nitrite moiety. This complex represents the first example in the solid state of an analogue of the nitrous acid intermediate (CuNO(2)H). A comparison of the nitrite reduction reactivity of the electron-rich ligand containing the CuNO(2) complex 2 with that of the known neutral ligand containing the CuNO(2) complex [Cu(HC(3,5-Me(2)Pz)(3))(NO(2))] (1) shows that reactivity is significantly influenced by the electron density around the copper and nitrite centers. The detailed mechanisms of nitrite reduction reactions of 1 and 2 with acetic acid were explored by using density functional theory calculations. Overall, the results of this effort show that synthetic models, based on neutral HC(3,5-Me(2)Pz)(3) and anionic [HB(3,5-Me(2)Pz)(3)](-) ligands, mimic the electronic influence of (His)(3) ligands in the environment of the type II copper center of copper nitrite reductases (Cu-NIRs).     

Low-valent gallium, indium, and tin compounds that contain a highly fluorinated tris(pyrazolyl)borate ligand: syntheses and characterization of

Syntheses and characterization of gallium(I), indium(I), and tin(II) complexes of the [HB(3,5-(CF3)2Pz)3]- ligand (where [HB(3,5-(CF3)2Pz)3]- = hydrotris(3,5-bis(trifluoromethyl)pyrazolyl)borate)) are reported. X-ray crystal structures of [HB(3,5-(CF3)2Pz)3]In and [HB(3,5-(CF3)2Pz)3]Sn(CF3SO3) show monomeric structures in the solid state. The In-N and Sn-N bond distances are longer than the corresponding bond distances of nonfluorinated analogues. NMR data of the gallium(I) adduct [HB(3,5-(CF3)2Pz)3]Ga are very similar to those of the indium(I) analogue suggesting similar solution structures.     

Fluorinated tris(pyrazolyl)borate ligands without the problematic hydride moiety: isolation of copper(I) ethylene and copper(I)-tin(II) complexes using [MeB(3-(CF3)Pz)3]-

The thallium derivative of a fluorinated, B-methylated, tris(pyrazolyl)borate ligand, [MeB(3-(CF3)Pz)3]-, has been synthesized via a two-step process using the corresponding pyrazole, Li[MeBH3], and thallium(I) acetate. Reaction of [MeB(3-(CF3)Pz)3]Tl with CuBr in the presence of ethylene leads to [MeB(3-(CF3)Pz)3]Cu(C2H4). It is a thermally stable solid. [MeB(3-(CF3)Pz)3]Cu(C2H4) reacts with [(Bn)2ATI]SnCl to yield [MeB(3-(CF3)Pz)3]Cu<--Sn(Cl)[(Bn)2ATI], featuring an unsupported Cu(I)-Sn(II) bond [2.4540(4) A].     

Investigation of silver salt metathesis: preparation of cationic germanium(II) and Tin(II) complexes,and silver adducts containing unsupported silver-germanium and silver-tin bonds

Syntheses of halide derivatives of germanium(II) and tin(II) aminotroponiminate (ATI) complexes and their silver salt metathesis reactions have been investigated. The treatment of GeCl(2) x (1,4-dioxane), SnCl(2), or SnI(2) with [(n-Pr)(2)ATI]Li in a 1:1 molar ratio affords the corresponding germanium(II) or tin(II) halide complex [(n-Pr)(2)ATI]MX (where [(n-Pr)(2)ATI](-) = N-(n-propyl)-2-(n-propylamino)troponiminate; M = Ge or Sn; X = Cl or I). As usually expected, [(n-Pr)(2)ATI]GeCl and [(n-Pr)(2)ATI]SnCl undergo rapid metathesis with CF(3)SO(3)Ag, leading to trifluoromethanesulfonate salts, [[(n-Pr)(2)ATI]Ge][SO(3)CF(3)] and [[(n-Pr)(2)ATI]Sn][SO(3)CF(3)], and silver chloride. However, when the silver source [HB(3,5-(CF(3))(2)Pz)(3)]Ag(eta(2)-toluene) is used, rather than undergoing metathesis, very stable 1:1 adducts [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Ge(Cl)[(n-Pr)(2)ATI] and [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Sn(Cl)[(n-Pr)(2)ATI] are formed (where [HB(3,5-(CF(3))(2)Pz)(3)](-) = hydrotris(3,5-bis(trifluoromethyl)pyrazolyl)borate). The use of the iodide derivative [(n-Pr)(2)ATI]SnI did not change the outcome either. All new compounds have been characterized by multinuclear NMR spectroscopy and X-ray crystallography. The Ag-Ge and Ag-Sn bond distances of [HB(3,5-(CF(3))(2)Pz)(3)]Ag<-- Ge(Cl)[(n-Pr)(2)ATI], [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Sn(Cl)[(n-Pr)(2)ATI], and [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Sn(I)[(n-Pr)(2)ATI] are 2.4142(6), 2.5863(6), and 2.5880(10) A, respectively. A convenient route to [(n-Pr)(2)ATI]H is also reported.     

Peculiarities of the complexation of copper and silver adducts of a 3,5-bis(trifluoromethyl)pyrazolate ligand with organoiron compounds

Interaction of the copper, {[3,5-(CF(3))(2)Pz]Cu}(3), and silver, {[3,5-(CF(3))(2)Pz]Ag}(3), macrocycles [3,5-(CF(3))(2)Pz = 3,5-bis(trifluoromethyl)pyrazolate] with cyclooctatetraeneiron tricarbonyl, (cot)Fe(CO)(3), was investigated by IR and NMR spectroscopy for the first time. The formation of 1:1 complexes was observed at low temperatures in hexane. The composition of the complexes (1:1) and their thermodynamic characteristics in hexane and dichloromethane were determined. The π-electron system of (cot)Fe(CO)(3) was proven to be the sole site of coordination in solution and in the solid state. However, according to the single-crystal X-ray data, the complex has a different (2:1) composition featuring the sandwich structure. The complexes of ferrocene with copper and silver macrocycles have a columnar structure (X-ray data).     

Trinuclear silver(I) complexes of fluorinated pyrazolates

Silver pyrazolates [[3-(CF3)Pz]Ag]3, [[3-(CF3),5-(CH3)Pz]Ag]3, [[3-(CF3),5-(Ph)Pz]Ag]3, [[3-(CF3),5-(But)Pz]Ag]3, and [[3-(C3F7),5-(But)Pz]Ag]3 have been synthesized by treatment of the corresponding pyrazole with a slight molar excess of silver(I) oxide. This economical and convenient route gives silver pyrazolates in high (>80%) yields. X-ray crystal structures of [[3-(CF3),5-(CH3)Pz]Ag]3, [[3-(CF3),5-(But)Pz]Ag]3, and [[3-(C3F7),5-(But)Pz]Ag]3 show that these molecules have trinuclear structures with essentially planar to highly distorted Ag3N6 metallacycles. [[3-(CF3),5-(CH3)Pz]Ag]3 forms extended columns via intertrimer argentophilic contacts (the closest Ag...Ag separation between the neighboring trimers are 3.355 and 3.426 A). The trinuclear [[3-(CF3),5-(But)Pz]Ag]3 units crystallize in pairs, basically forming "dimers of trimers", with the six silver atom core of the adjacent trimers adopting a chair conformation. However, in these dimers of trimers, even the shortest intertrimer Ag...Ag distance (3.480 A) is slightly longer than the van der Waals contact of silver (3.44 A). [[3-(C3F7),5-(But)Pz]Ag]3, which has two bulky groups on each pyrazolyl ring, shows no close intertrimer Ag...Ag contacts (closest intertrimer Ag...Ag distance = 5.376 A). The Ag-N bond distances and the intratrimer Ag...Ag separations of the silver pyrazolates do not show much variation. However, their N-Ag-N angles are sensitive to the nature (especially, the size) of substituents on the pyrazolyl rings. The pi-acidic [[3,5-(CF3)2Pz]Ag]3 and [[3-(C3F7),5-(But)Pz]Ag]3 form adducts with the pi-base toluene. X-ray data show that they adopt extended columnar structures of the type [[Ag3]2.[toluene]]infinity and [[Ag3]'.[toluene]]infinity ([[3,5-(CF3)2Pz]Ag]3 = [Ag3],[[3-(C3F7),5-(But)Pz]Ag]3 = [Ag3]'), in which toluene interleaves and makes face-to-face contacts with [[3-(C3F7),5-(But)Pz]Ag]3 or dimers of [[3,5-(CF3)2Pz]Ag]3.     

Brightly phosphorescent trinuclear copper(I) complexes of pyrazolates: substituent effects on the supramolecular structure and photophysics

Synthetic details, solid-state structures, and photophysical properties of a group of trimeric copper(I) complexes containing pyrazolate ligands are described. The reaction of copper(I) oxide and the fluorinated pyrazoles [3-(CF(3))Pz]H, [3-(CF(3)),5-(Me)Pz]H, and [3-(CF(3)),5-(Ph)Pz]H leads to the corresponding trinuclear copper(I) pyrazolates, {[3-(CF(3))Pz]Cu}(3), {[3-(CF(3)),5-(Me)Pz]Cu}(3), and {[3-(CF(3)),5-(Ph)Pz]Cu}(3), respectively, in high yield. The {[3,5-(i-Pr)(2)Pz]Cu}(3) compound was obtained by a reaction between [Cu(CH(3)CN)(4)][BF(4)], [3,5-(i-Pr)(2)Pz]H, and NEt(3). These compounds as well as {[3,5-(Me)(2)Pz]Cu}(3) and {[3,5-(CF(3))(2)Pz]Cu}(3) adopt trimeric structures with nine-membered Cu(3)N(6) metallacycles. There are varying degrees and types of intertrimer Cu...Cu interactions. These contacts give rise to zigzag chains in the fluorinated complexes, {[3-(CF(3))Pz]Cu}(3), {[3-(CF(3)),5-(Me)Pz]Cu}(3), {[3-(CF(3)),5-(Ph)Pz]Cu}(3), and {[3,5-(CF(3))(2)Pz]Cu}(3), whereas the nonfluorinated complexes, {[3,5-(Me)(2)Pz]Cu}(3) and {[3,5-(i-Pr)(2)Pz]Cu}(3) form dimers of trimers. Out of all the compounds examined in this study, {[3-(CF(3)),5-(Ph)Pz]Cu}(3) has the longest (3.848 Angstroms) and {[3,5-(Me)(2)Pz]Cu}(3) has the shortest (2.946 Angstroms) next-neighbor intertrimer Cu...Cu distance. The Cu...Cu separations within the trimer units do not vary significantly (typically 3.20-3.26 Angstroms). All of these trinuclear copper(I) pyrazolates show bright luminescence upon exposure to UV radiation. The luminescence bands are hugely red-shifted from the corresponding lowest-energy excitations, rather broad, and unstructured even at low temperatures, suggesting metal-centered emissions owing to intertrimer Cu...Cu interactions that are strengthened in the phosphorescent state. The {[3-(CF(3)),5-(Ph)Pz]Cu}(3) compound exhibits an additional highly structured phosphorescence with a vibronic structure corresponding to the pyrazolyl (Pz) ring. The luminescence properties of solids and solutions of the trimeric compounds in this study show fascinating trends with dramatic sensitivities to temperature, solvent, concentration, and excitation wavelengths.     

Neutral Cu4N12 and Ag4N12 metallacycles with a para-cyclophane framework assembled from copper(I) and silver(I) pyrazolates and pyridazine

Trinuclear copper(I) and silver(I) pyrazolates {[3,5-(CF3)2Pz]M}3 (M = Cu and Ag) react with pyridazine to give neutral, tetranuclear metallacycles with a para-cyclophane core whereas benzo[c]cinnoline fails to break the cyclic pyrazolate trimers under similar conditions, and affords a metalla-propellane featuring both two- and three-coordinate metal sites.     

Self-assembly of a high-nuclearity chloride-centered copper(II) cluster. Structure and magnetic properties of [Au(PPh3)2][trans-Cu6(micro-OH)6[micro-(3,5-CF3)2pz]6Cl

A chloride-centered hexanuclear copper(II) pyrazolate [Au(PPh3)2][trans-Cu6(micro-OH)6[micro-(3,5-CF3)2pz]6Cl] is isolated from the reaction of the trinuclear copper(I) pyrazolate [Cu3[micro-(CF3)2pz]3] with PPh3AuCl and Ph3P in moist air. The six copper atoms are bridged by pyrazolate and hydroxyl ligands, above and below the copper plane. The chloride anion exists at the center of the planar cavity formed by the copper atoms with Cu-Cl distances of 3.02-3.13 A. The magnetic susceptibility measurements show a strong antiferromagnetic coupling between the copper centers with an estimated exchange constant of J approximately 650 cm-1.     

Synthesis and Crystal Structure of a One-dimensional Ladder-like Complex [Cu2(L)(dca)2]n (dca = [N(CN)2]-,L = 1,4-Bis(3-furanyl)-2,3-diaza-1,3-butadiene)

A new Cu(I)-dicyanamide with formula [Cu2(L)(dca)2]n (dca = dicyanamide anion, L = 1,4-bis(3-furanyl)-2,3-diaza-1,3-butadiene) has been synthesized and structurally characterized.The complex crystallizes in the monoclinic system, space group P21/n with a = 9.271(2), b = 7.7355(16), c = 11.967(3) -, β = 102.693(3)°, V = 837.3(3) -3, Z = 4, Mr = 223.68, Dc = 1.775 g/cm3, μ(MoKα) = 2.567 mm-1, F(000) = 444, R = 0.0782 and wR = 0.2582 for 951 observed reflections (I > 2σ(I)).Single-crystal X-ray analysis reveals that the copper atom is three-coordinated by two nitrogen atoms from two dicyanamide anions and another one from the ligand, and each copper atom is connected by two [N(CN)2]- anions to form an infinite double-stranded bridge fashion leading to 1D ladder-like motifs.     

Synthesis and Characterization of Copper(II), Zinc(II), and Potassium Complexes of a Highly Fluorinated Bis(pyrazolyl)borate Ligand

Highly fluorinated, dihydridobis(3,5-bis(trifluoromethyl)pyrazolyl)borate ligand, [H(2)B(3,5-(CF(3))(2)Pz)(2)](-) has been synthesized and characterized as its potassium salt. The copper(II) and zinc(II) complexes, [H(2)B(3,5-(CF(3))(2)Pz)(2)](2)Cu and [H(2)B(3,5-(CF(3))(2)Pz)(2)](2)Zn, have been prepared by metathesis of [H(2)B(3,5-(CF(3))(2)Pz)(2)]K with Cu(OTf)(2) and Zn(OTf)(2), respectively. All the new metal adducts have been characterized by X-ray diffraction. The potassium salt is polymeric and shows several K.F interactions. The Cu center of [H(2)B(3,5-(CF(3))(2)Pz)(2)](2)Cu adopts a square planar geometry, whereas the Zn atom in [H(2)B(3,5-(CF(3))(2)Pz)(2)](2)Zn displays a tetrahedral coordination. Bis(pyrazolyl)borate ligands in the Zn adduct show a significantly distorted boat conformation. The nature and extent of this distortion is similar to that observed for the methylated analog, [H(2)B(3,5-(CH(3))(2)Pz)(2)](2)Zn. This ligand allows a comparison of electronic effects of bis(pyrazolyl)borate ligands with similar steric properties. Crystallographic data for [H(2)B(3,5-(CF(3))(2)Pz)(2)]K: triclinic, space group P&onemacr;, with a = 8.385(1) ?, b = 10.097(2) ?, c = 10.317(1) ?, alpha = 104.193(9) degrees, beta = 104.366(6) degrees, gamma = 91.733(9) degrees, V = 816.5(3) ?(3), and Z = 2. [H(2)B(3,5-(CF(3))(2)Pz)(2)](2)Cu is monoclinic, space group C2/c with a = 25.632(3) ?, b = 9.197(1) ?, c = 17.342(2) ?, beta = 129.292(5) degrees, V = 3164.0(6) ?(3), and Z = 4. [H(2)B(3,5-(CF(3))(2)Pz)(2)](2)Zn is triclinic, space group P&onemacr;, with a = 9.104(1) ?, b = 9.278(1) ?, c = 18.700(2) ?, alpha = 83.560(6) degrees, beta = 88.200(10) degrees, gamma = 78.637(9) degrees, V = 1538.8(3) ?(3), and Z = 2. [H(2)B(3,5-(CH(3))(2)Pz)(2)](2)Zn is monoclinic, space group C2/c with a = 8.445(1) ?, b = 14.514(2) ?, c = 19.983(3) ?, beta = 90.831(8) degrees, V = 2449.1(6) ?(3), and Z = 4.     

Coordination networks with flexible ligands based on silver(I) salts: complexes of 1,3-bis(phenylthio)propane with silver(I) salts of PF6-, CF3COO-, CF3CF2COO-, CF3CF2)CF2COO-, p-TsO-, and CF3SO3-

The synthesis and characterization of nine coordination networks based on 1,3-bis(phenylthio)propane, L(3), and silver(I) salts of PF(6)(-) (1), CF(3)COO(-) (2), CF(3)CF(2)COO(-) (3), CF(3)CF(2)CF(2)COO(-) (4), p-TsO(-) (5, 6), and CF(3)SO(3)(-) (7-9) are reported. Only 1 and other "isostructural" complexes with weakly coordinating anions such as ClO(4)(-) and SbF(6)(-) are 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(6)(-) anions 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-TsO(-) and 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 degrees 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.     

Blue phosphors of dinuclear and mononuclear copper(I) and silver(I) complexes of 3,5-bis(trifluoromethyl)pyrazolate and the related bis(pyrazolyl)borate

The synthesis, structure, and photoluminescence properties are described for the three-coordinate mononuclear and dinuclear complexes [H(2)B(3,5-(CF(3))(2)Pz)(2)]M(2,4,6-collidine), M(1)(), and [[3,5-(CF(3))(2)Pz]M(2,4,6-collidine)](2), M(2)(), respectively (M = Cu; Ag). The solids exhibit bright blue phosphorescence, at room temperature for the copper compounds and at 77 K for all compounds. Ag(1)(), Cu(1)(), and Cu(2)() exhibit blue pyrazole-based structured emissions with short phosphorescence lifetimes, 10(1)-10(2) micros, due to an internal heavy-metal effect. Meanwhile, Ag(2)() exhibits curious multiple excitation-dependent emissions.     

Silver(I) complexes of a sterically demanding fluorinated triazapentadienyl ligand [N((C3F7)C(Dipp)N)2]- (Dipp = 2,6-diisopropylphenyl)

Sterically demanding triazapentadiene [N((C3F7)C(Dipp)N)2]H affords the isolation of thermally stable, two- and three-coordinate silver complexes. The free ligand [N((C3F7)C(Dipp)N)2]H has a W-shaped ligand backbone in the solid state.[N((C3F7)C(Dipp)N)2]H reacts with silver(I) oxide in acetonitrile leading to CH(3)CNAg [N((C3F7)C(Dipp)N)2]HIt features a two-coordinate silver center and a kappa(1)-coordinated triazapentadienyl ligand. This silver acetonitrile complex serves as an excellent precursor to obtain thermally stable, silver isocyanide t-BuNCAg [N((C3F7)C(Dipp)N)2]Hand silver phosphine [[N((C3F7)C(Dipp)N)2]HAgPPh(3) adducts. IR spectroscopic data for the silver(I) isocyanide t-BuNCAg [N((C3F7)C(Dipp)N)2]Hshows nu(CN) at 2219 cm(-)(1). The silver ion coordinates to the triazapentadienyl ligand via the central nitrogen atom. The silver PPh(3) adduct,[N((C3F7)C(Dipp)N)2]HAgPPh(3), was synthesized by treating CH3CNAg [N((C3F7)C(Dipp)N)2]Hwith PPh(3). It displays relatively large Ag-P coupling in the (31)P NMR spectrum. The triazapentadienyl ligand in[N((C3F7)C(Dipp)N)2]HAgPPh(3) acts as a chelating kappa(2)-donor. The Ag-P bond is relatively short (2.3487(10) A).     

Ferromagnetic coupling between low- and high-spin iron(III) ions in the tetranuclear complex fac-[[FeIII[HB(pz)3](CN)2(mu-CN)]3FeIII(H2O)3]* 6H2O ([HB(pz)3]- = hydrotris(1-pyrazolyl)borate)

The novel mononuclear PPh4-fac-[FeIII[HB(pz)3](CN)3]*H2O (1) [PPh4+= tetraphenylphosphonium cation; (HB(pz)3)- = hydrotris(1-pyrazolyl)borate] and tetranuclear fac-[[FeIII[HB(pz)3](CN)2(mu-CN)]3FeIII(H2O)3]*6H2O (2) have been prepared and characterized by X-ray diffraction analysis. Crystal data for compound 1: monoclinic, space group P21/c, a = 9.575(3) A, b = 21.984(4) A, c = 16.863(3) A, beta = 100.34(2) degrees, U = 3486(1) A3, Z = 4. Crystal data for compound 2: orthorhombic, space group Pnam, a = 14.084(3) A, b = 14.799(4) A, c = 25.725(5) A, U = 5362(2) A3, Z = 4. Compound 1 is a low-spin iron(III) compound with three cyanide ligands in fac arrangement and a tridentate pyrazolylborate ligand building a distorted octahedral environment around the iron atom. Compound 2 is the first example of a molecular species containing three peripheral low-spin iron(III) ions linked to a central high-spin iron(III) cation by single cyanide bridges, the anion of 1 acting as a monodentate ligand in 2. Variable-temperature magnetic susceptibility measurements of 2 reveal the occurrence of a significant ferromagnetic coupling between the three peripheral low-spin iron(III) centers and the central high-spin iron(III) ion cations leading to a low-lying nonet spin state.     

Coinage metal complexes of tris(pyrazolyl)methanide [C(3,5-Me2pz)3]-: kappa3-coordination vs. backbone functionalisation

Tris(pyrazolyl)methanides, [C(3,5-R2pz)3]-, contain an unassociated tetrahedral carbanionic centre in the bridgehead position. In addition to nitrogen donor centres for transition metal coordination, an accessible reactive site for further manipulations is available in the backbone of the ligand. The coordination variability of the ambidental C-/N ligand [C(3,5-Me2pz)3]- was elucidated by investigating its coinage metal complexes. Two principle coordination modes were found for complexes of general formula [LMPR3] (with M = Cu(I), Ag(I), Au(I); L =[C(3,5-Me2pz)3]-; R = Ph, OMe). While for Cu(I) (2,3) and Ag(I) (4) complexes the anionic ligand acts as a face-capping, six electron N3-donor, gold(I) (5) is coordinated by the bridging carbanion yielding a two coordinate Au(I) complex comprising a covalent Au-C bond. The complexes featuring the kappa3-coordinated N3-donor ligand were investigated by 31P CP (MAS) NMR in the solid state.     

Synthesis, structural characterization and the first electroluminescent properties of tris- and bis-cycloiridiated complexes of sterically hindered electron-poor 2-(3,5-bis(trifluoromethyl)phenyl)-4-trifluoromethylpyridine

An application of the new sterically hindered electron-poor 2-(3,5-bis(trifluoromethyl)phenyl)-4-trifluoromethylpyridine [HC--N] (1) in the one-step high temperature cyclometalation by Ir(III)Cl3 in the presence of Ag(I)OC(O)CF3 resulted in the synthesis of tris-cyclometalated complexes [C--N]2Ir[C--C] (3) and [C--N]3Ir (5). A neutral silver cluster with a repeating unit of hexa-silver groups in an infinite chain of (2) was isolated from the above reaction as well. When this cyclometalation was carried out in trimethylphosphate at lower temperature, bis-cyclometalated derivatives [C--N]2Ir(mu-Cl)2Ir[CN]2 (6), [C--N]2Ir[eta2-(O(C((t)Bu))2CH] (7), and [C--N]2Ir(mu-O-P(OMe)2-O)2Ir[C--N]2 (8) were synthesized. According to X-ray analyses complex (3), while trivalent, contains four cyclometalated single Ir-C bonds. One of the Ir-C bonds, next to the nitrogen atom of the CC pyridinium ligand, was found to be the shortest to date (1.977(4) angstroms) for a single bond between iridium and carbon atoms. The coordination of the C--C ligand in (3) to iridium has a decidedly interesting bonding pattern and can be explained by various formulations. The first one is considering this ligand as a monoanionic chelating ligand, in which the second coordination site arises from a carbene or azomethine ylide. Overall the best single picture may be a dianionic ligand making two normal Ir-C bonds, in which the ligand just happens to contain a pyridinium function that compensates for one negative charge on the iridium. LEDs constructed with compounds (7) and (8) give blue-green emission with peak electroluminescent efficiency of 15 and 2 cd A(-1), respectively. An LED constructed with compound (5) gives a yellowish emission with peak electroluminescent efficiency of 5.5 cd A(-1).