Molecular Structures Of 2a Research Articles

Synthesis of 3-substituted imidazo[1,5-a]pyridines having 1-(N-picolinamidin-2-yl) group

The 3-substituted imidazo[1,5-a]pyridine compounds having 1-(N-picolinamidin-2-yl) group (1a–h) were synthesized by heating 1 equiv of an aldehyde (eight examples), 2 equiv of 2-cyanopyridine and ammonium acetate in PEG-400. By heating 2 equiv of the aldehyde and 1 equiv of 2-cyanopyridine under the same experimental conditions, 2,4,5-trisubstituted imidazoles (2a–c) were isolated. All the reported compounds were thoroughly characterized and the molecular structures of 1a and 2b were established by single crystal X-ray diffraction studies.

Ruthenium indenylidene complexes containing dichalcogenoimidodiphosphinate ligands

Reactions of ruthenium indenylidene starting material [Ru(PPh3)2(Ind)Cl2] (Ind=3-phenylinden-1-ylidene) with potassium dichalcogenoimidodiphosphinates K[R2P(E)NP(E′)R2] afforded a series of complexes [Ru(PPh3)(Ind){кE,кE′-R2P(E)NP(E′)R2}Cl] [R=Ph, E=E′=S (1a); R=Ph, E=E′=Se (1b); R=iPr, E=E′=S (1c); R=iPr, E=E′=Se (1d); R=Ph, E=S, E′=Se (1e); R=iPr, E=S, E′=Se (1f)] which were characterized by microanalyses, IR and NMR spectroscopies. The molecular structure of 1a has been confirmed by single-crystal X-ray diffraction. The catalytic reactivity of the ruthenium indenylidene complexes in the ring closing metathesis of diethyl 1,2-diallylmalonate has also been investigated.

The preparation, spectroscopy, structure and electrochemistry of some [Co(η4-C4Ph4)(η5-C5H4C[tbnd]C–CH[dbnd]Y)], [Fe(η5-C5H5)(η5-C5H4C[tbnd]C–CH[dbnd]Y)], and related complexes

[Co(η4-C4Ph4)(η5-C5H4CC–CHO)], 4a, has been prepared from [Co(η4-C4Ph4)(η5-C5H4CHO)], 1a, by reactions similar to those used previously to convert [Fe(η5-C5H5)(η5-C5H4CHO)], 1b, to [Fe(η5-C5H5)(η5-C5H4CC–CHO)], 4b, i.e. via the dibromoethene [Co(η4-C4Ph4)(η5-C5H4CHCBr2)], 2a, and alkyne [Co(η4-C4Ph4)(η5-C5H4CCH)], 3a. Both 4a and 4b undergo the normal aldehyde reactions with malononitrile and 2,4-dinitrophenylhydrazines to give their respective condensation products [Co(η4-C4Ph4){η5-C5H4CC–CHC(CN)2}], 5a, and [Fe(η5-C5H5){η5-C5H4CC–CHC(CN)2}], 5b; [Co(η4-C4Ph4){η5-C5H4CC–CHN–N(H)C6H3(NO2)2-2,4}], 6a, and [Fe(η5-C5H5){η5-C5H4CC–CHN–N(H)C6H3(NO2)2-2,4}], 6b, as separable mixtures of syn- and anti-isomers; and the anti-isomers of [Co(η4-C4Ph4){η5-C5H4CC–CHN–N(Me)C6H3(NO2)2-2,4}], 7a, and [Fe(η5-C5H5){η5-C5H4CC–CHN–N(Me)C6H3(NO2)2-2,4}], 7b. With [Fe2(η-C5H5)2(CO)2(μ-CO)(μ-CMe)][BF4] 4a and 4b form blue-green [Fe2(η-C5H5)2(CO)2(μ-CO)(μ-C–CHCH-CC–C5H4-η5)Co(η4-C4Ph4)][BF4], [8a][BF4], and black [Fe2(η-C5H5)2(CO)2(μ-CO)(μ-C–CHCH–CC–C5H4-η5)Fe(η5-C5H5)][BF4], [8b][BF4] salts. 4a and 4b also react with the Wittig reagent [Fe(η5-C5H5)(η5-C5H4–CH2PPh3)][I]/nBuLi to give mixtures of Z and E-[Co(η4-C4Ph4)(η5-C5H4–CC–CHCH–C5H4-η5)Fe(η5-C5H5)], 9a, and [Fe(η5-C5H5)(η5-C5H4–CC–CHCH–C5H4-η5)Fe(η5-C5H5)], 9b, which are separable for 9b but not 9a. The Wittig reagent obtained from [Co(η4-C4Ph4)(η5-C5H4–CH2PPh3)][Cl]/nBuLi failed to react with 4a or 4b, but the reaction of 4a with [ClCH2PPh3][Cl]/tBuOK gives very low yields of one expected product, E-[Co(η4-C4Ph4)(η5-C5H4–CC–CHCH–C5H4-η5)Co(η4-C4Ph4)], E-10a, together with a number of other unidentified compounds. The IR, 1H NMR and 13C NMR, and UV/Vis spectra of 4–9 are reported, assigned and discussed. They confirm that 4–9 are Donor–π–Acceptor complexes in which Co(η4-C4Ph4)(η5-C5H4–) is a weaker donor than Fe(η5-C5H5)(η5-C5H4–), the acceptor strength increases for Acceptor CHCHFc < CHN–N(R)C6H3(NO2)2-2,4 < CHO < CHC(CN)2 < (–CHCH–Cμ+)(μ-CO)(CO)2Fe2(η5-C5H5)2, and that an ethyne linker, π = CC, is less effective than an ethene linker, π = CHCH, in promoting electronic communication between the Donor and Acceptor. The molecular structures of 2a, 3a, 4a, 4b, 5b, syn-6a, syn-6b (two crystal forms) and anti-7b have been determined by X-ray diffraction. They have normal molecular dimensions, and the C5H4–CC–CHY moiety does not deviate greatly from planarity with angles between the C5H4 and C–C(H)Y planes of 4.2–19.6°. This contrasts with the structures of Fc–CC–R (R = aryl) complexes where the C5H4 and aryl planes are orthogonal or close to it. The electrochemistry of 3a/3b, 4a/4b, 5a/5b, syn-6a/6b, anti-7a/7b, E/Z-9a, Z-9b, E-9b and [Co(η4-C4Ph4)(η5-C5H4–CC–C6H5)] has been studied. The Co(η4-C4Ph4)(η5-C5H4–) complexes undergo reversible 1e oxidations at higher E° than their Fe(η5-C5H5)(η5-C5H4–) counterparts with E° increasing as the electron-withdrawing ability of the acceptor group increases. Furthermore, like their ferrocenyl counterparts, the alkyne derivatives [Co(η4-C4Ph4)(η5-C5H4–CC–X)] are oxidised at a more positive E° than the alkene complexes [Co(η4-C4Ph4)(η5-C5H4–CHCH–X)]. The UV/Visible spectrum of the oxidized species [Co(η4-C4Ph4)(η5-C5H4–CC–C6H5)]+ shows an absorption band at 960 nm due to a C6H5 → Co(η4-C4Ph4)(η5-C5H4–) charge transfer transition; its equivalent in the spectrum of [Fe(η5-C5H5)(η5-C5H4–CC–C6H5)]+ is found at 797 nm. This implies that {Co(η4-C4Ph4)(η5-C5H4–)}+ is a stronger acceptor than {Fe(η5-C5H5)(η5-C5H4–)}+.

Solid-state thermo- and photochromism in N,N′-bis(5-X-salicylidene)diamines (X = H, Br)

Sixteen N,N′-bis(salicylidene)diamines of common formula (o-OHC 6H 4CN-) 2Z [Z = o-C 6H 4 (1a), m-C 6H 4 (2a), p-C 6H 4 (3a), O (4a), CH 2(p-C 6H 4) 2 (5a), O(p-C 6H 4) 2 (6a), S(p-C 6H 4) 2 (7a), SO 2(p-C 6H 4) 2 (8a)] and N,N′-bis(5-bromosalicylidene)diamines of common formula (2-OH-(5-Br)C 6H 3CN-) 2Z [Z = o-C 6H 4 (1b), m-C 6H 4 (2b), p-C 6H 4 (3), O (4b), CH 2(p-C 6H 4) 2 (5b), O(p-C 6H 4) 2 (6b), S(p-C 6H 4) 2 (7b), SO 2(p-C 6H 4) 2 (8b)] have been synthesized and characterized by elemental analysis, X-ray powder diffraction, NMR, diffuse reflectance, Raman, IR and fluorescence spectroscopy. Molecular structures of 2a, 6a, 7a, 8a and 4b were elucidated by single crystal X-ray diffraction. Their structures are stabilized by two intramolecular hydrogen bonds and weak intermolecular π⋯π stacking interactions. All molecules are thermochromic, while molecules 2a and 2b exclusively display photochromism upon irradiation at 450 and 365 nm, respectively, which is reversible and exhibits relatively slow thermal relaxation. © 2012 The Royal Society of Chemistry.

Preparation of a series of Ru(ii) complexes with N-heterocyclic carbeneligands for the catalytic transfer hydrogenation of aromatic ketones

The reaction of [RuCl(2)(p-cymene](2) with Ag-N-heterocyclic carbene (NHC) complexes yields a series of [(p-cymene)Ru(NHC)] complexes (2a-f). All synthesised compounds were characterized by elemental analysis, NMR spectroscopy and the molecular structure of 2a was determined by X-ray crystallography. All complexes have been tested as catalysts for the transfer hydrogenation of aromatic ketones, showing excellent activity in this reaction.

Investigations on the Interaction of Dichloroaluminum Carboxylates with Lewis Bases and Water: an Efficient Road toward Oxo- and Hydroxoaluminum Carboxylate Complexes

A series of dichloroaluminum carboxylates [Cl(2)Al(O(2)CR)](2) (were R = Ph (1a), (t)Bu (1b), CHCH(2) (1c) and C(11)H(23) (1d)) were prepared and extended investigations on their structure and reactivity toward various Lewis bases and H(2)O performed. Compounds [Cl(2)Al(O(2)CR)](2) and their adducts with Lewis bases show a large structural variety, featuring both molecular and ionic forms with different coordination numbers of the metal center and various coordination modes of the carboxylate ligand. Upon addition of a Lewis base of moderate strength the molecular form [Cl(2)Al(O(2)CR)](2) equilibrates with new ionic forms. In the presences of 4-methylpyridine the six-coordinate Lewis acid-base adducts [Cl(2)Al(λ(2)-O(2)CR)(py-Me)(2)] [R = Ph (3a), (t)Bu (3b)] with a chelating carboxylate ligand were formed. The reactions of 1a, 1b, and 1d with 0.33 equiv of H(2)O in THF-toluene solution lead to oxo carboxylates [(Al(3)O)(O(2)CR)(6)(THF)(3)] [AlCl(4)] [where R = Ph (4a(THF)), (t)Bu (4b(THF)), and C(11)H(23) (4d(THF))] in high yield. The similar reaction of 1c in tetrahydrofuran (THF) afforded the chloro(hydroxo)aluminum acrylate [(ClAl)(2)(OH)(O(2)CC(2)H(3))(2) (THF)(4)][AlCl(4)] (5), while the hydrolysis of 1b in MeCN lead to the hydroxoaluminum carboxylate [Al(2)(OH)(O(2)C(t)Bu)(2)(MeCN)(6)][AlCl(4))(3)] (6). All compounds were characterized by elemental analysis, (1)H, (27)Al NMR, and IR spectroscopy, and the molecular structure of 1a, 3a, 3b, 4a(THF), 4b(THF), 4b(py-Me'), 5, and 6 were determined by single-crystal X-ray diffraction. The study provides a platform for testing transformations of secondary building units in Al-Metal-Organic Frameworks toward H(2)O and neutral donor ligands.

Charged dioxomolybdenum(VI) complexes with pyridoxal thiosemicarbazone ligands as molybdenum(V) precursors in oxygen atom transfer process and epoxidation (pre)catalysts

The reaction of [MoO2(acac)2] with hydrochloric salts of pyridoxal thiosemicarbazone ligands, H2L1–3·HCl, in dry methanol or acetonitrile resulted in the formation of the mononuclear complex [MoO2(HL1)(CH3OH)]Cl·1.5CH3OH (1a) or polynuclear complexes [{MoO2(HL1–3)}Cl]n (1–3) containing a different substituent on the nitrogen atom of the N-thioureide fragment: Ph (1 and 1a), Me (2) or H (3). New dinuclear molybdenum(V) complexes [Mo2O3(HL1–3)2]Cl2 (4–6) were obtained by oxygen atom abstraction from 1–3 with triphenylphosphine. All compounds were characterized by chemical analysis, IR spectroscopy, one- and two-dimensional NMR methods, TGA and in selected cases by DSC measurements. In addition, the crystal and molecular structure of 1a was determined by single crystal X-ray diffraction. All molybdenum(VI) species were used as (pre)catalysts for olefin epoxidation under solvent-free conditions with a 0.05% Mo loading versus olefin.

Structural Modification of Functionalized Phosphine Sulfonate-Based Palladium(II) Olefin Polymerization Catalysts

The influence of phosphine sulfonate ligands bearing a variety of functionalities on the conformation of their derived Pd(II) complexes and their catalytic behavior in olefin polymerization reactions was investigated. Analogous to the anisyl-derived 1a the methyl thioether-substituted 8 as well as methoxylated naphthalene-based compound 9 were successfully prepared. NOESY NMR spectroscopy has been applied for the interpretation of the complex configurations in solution and the correlation to the corresponding molecular structures of 1a and 9. Ethene homopolymerization reactions were used for the determination of reactivity trends and interpretation of effects originating from the altered ligand substitution. Detailed analysis of the PE microstructure shows that catalyst 9 acts as an efficient isomerization-type catalyst during the formation of low molecular weight PE. Additionally for compound 8 Pd–sulfur interactions with the introduced methyl thioether functionalities are proposed, based on NMR spectros...

Antibacterial Activities of 4‐Substituted‐2‐[(E)‐{(1S,2R)/(1R,2S)‐1‐Hydroxy‐1‐Phenylpropan‐2‐Ylimino}Methyl]Phenol

A series of norephedrine-based Schiff bases (1a-6a and 1b-6b) were synthesized by reacting substituted salicylaldehydes with d-norephedrine or l-norephedrine. The structure of these compounds was confirmed by elemental analyses and spectroscopic techniques. The molecular structures of 5a and 6a have been determined by X-ray crystallography, which revealed that the compounds are in the oxoamino form, with bent intramolecular N-H···O (N···O ≈ 2.58 Å) hydrogen bonds and that they are associated in dimers bridged by linear intermolecular O-H···O (O···O ≈ 2.69 Å) hydrogen bonds. The density functional theory calculations on 5a confirmed that the oxoamino form is more stable than the phenolimino form by 12.2 kcal/mol. All the compounds were evaluated for their antibacterial activity using resazurin dye as indicator by twofold dilution method against four bacteria namely, Bacillus subtilis (NCIM2718), Staphylococcus aureus (NCIM5021), Escherichia coli (NCIM2931), and Proteus vulgaris (NCIM2813).

1,2‐Diaza‐3,5‐diborolidine CH2BR1‐(NR2)2‐BR1: Potentielle Vorstufen zu cyclischen Diborylcarben‐Liganden

AbstractThe reaction of the aminohaloboranes (Me2N)(R)BX (1) (a: R = Ph, X = Cl; b: R = Me, X = Br; c: R = iPr, X = Cl) with the di‐Grignard reagent (BrMg)2CH2 in ethyl ether/benzene mixtures afforded the diborylmethanes [(Me2N)(R)B]2CH2 (2) (a: R = Ph; b: R = Me; c: R = iPr), which were subsequently converted into the corresponding bis(chloroboryl)methanes [(Cl)(R)B]2CH2 (3) (a: R = Ph; b: R = Me; c: R = iPr). Base‐assisted cyclocondensation of 3a–c with 1,2‐diisopropylhydrazine afforded 1,2‐diisopropyl‐1,2‐diaza‐3,5‐diorgano‐3,5‐diborolidines (4) (a: R = Ph; b: R = Me; c: R = iPr). Derivative 4a was deprotonated by potassium bis(trimethylsilyl)amide to give (1,2‐diisopropyl‐1,2‐diaza‐3,5‐diphenyl‐3,5‐diborolidinyl)potassium (5). Attempts to introduce a halogen atom to the carbon bridge between the two boron atom by treating 5 with either iodine or 1,2‐dibromoethane failed. Instead, bis(1,2‐diisopropyl‐1,2‐diaza‐3,5‐diphenyl‐3,5‐diborolidinyl) (C‐C) (6) was formed. In contrast to this, C‐silylation of the heterocycle to give 7 was effected by reaction of salt 5 with trimethylsilyl chloride. Similarly, treatment of HgCl2 with two molar equivalents of 5 gave rise to the formation of bis(1,2‐diisopropyl‐1,2‐diaza‐3,5‐diphenyl‐3,5‐diborolidinyl)mercury (8). The novel compounds were characterized by elemental analyses and various spectroscopic methods (1H‐, 11B{1H}‐, 13C{1H} NMR, MS). The molecular structures of 4a and 6–8 were elucidated by X‐ray diffraction analyses.

Synthesis and structural characterization of tridentate [C,N,S] thiosemicarbazone palladacycles. Crystal and molecular structures of [Pd{3-FC 6H 3C(Me) [dbnd]NN [dbnd]C(S)NHMe}] 4, [Pd{4-FC 6H 3C(Me) [dbnd]NN [dbnd]C(S)NHEt}] 4 and [(Pd{2-BrC 6H 3C(Me) [dbnd]NN [dbnd]C(S)NHPh}) 2(μ-Ph 2P(CH 2) 2PPh 2)

Reaction of the thiosemicarbazones 3-FC 6H 4C(Me) NN(H)C( S)NHME a, 4-FC 6H 4C(Me) NN(H)C( S)NHEt b, and 2-BrC 6H 4C(Me) NN(H)C( S)NHPh c, with potassium tetrachloropalladate(II) in ethanol, lithium tetrachloropalladate(II) in methanol or palladium(II) acetate in acetic acid gave the tetranuclear cyclometallated complexes [Pd{3-FC 6H 3C(Me) NN C(S)NHMe}] 4 1a, [Pd{4-FC 6H 3C(Me) NN C-(S)NHEt}] 4 1b, and [Pd{2-BrC 6H 3C(Me) NN C(S)NHPh}] 4 1c. Reaction of 1a– c with the diphosphines Ph 2P(CH 2) n PPh 2 dppm ( n = 1), dppe ( n = 2), dppp ( n = 3), dppb ( n = 4) or Ph 2PCH CHPPh 2 trans-dppe, in a 1:2 molar ratio gave the dinuclear phosphine-bridged complexes [(Pd{XC 6H 3C(Me) NN C(S)NHR}) 2(μ-Ph 2P(CH 2) n PPh 2)] 2a– c, 3a– c, 4a– c, 5a– c ( n = 1–4) and [(Pd{XC 6H 3C(Me) NN C(S)NHR}) 2(μ-Ph 2PCH CH-PPh 2)] 6a– c. Treatment of 1a– c with PPh 2CH 2PPh 2, dppm, in a 1:4 molar ratio gave the mononuclear cyclometallated complexes [Pd{XC 6H 3C(Me) NN C(S)NHR}-(Ph 2PCH 2PPh 2 -P)] 7a– c; however, the diphosphines with n ⩾ 2 failed to give the analogous reaction. The molecular structures of 1a, 1b and 3c have been determined by X-ray diffraction analysis and the intra- and intermolecular interactions are discussed.

Synthesis, crystal structures and DFT studies of 1-[2-(5-methyl-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole and 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole

The title compounds, 1-[2-(5-methyl-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazole (5a) and 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazole (5b), were synthesized. The crystal and molecular structures of 5a and 5b have been determined by elemental analyses, IR, 1H NMR, ESI-MS and single-crystal X-ray diffraction. Molecular geometries of 5a and 5b in the ground state have been calculated using the density functional method (DFT) with B3LYP/6-31G(d,p) basis set and compared with the experimental data. In addition, the molecular electrostatic potential maps and frontier molecular orbitals of 5a and 5b were performed.

A Rigid Angular Bidentate Ligand for the Design of a New Class of Coordination Polymers Based on Silver(I) Salts – Influence of the Anion on Coordination Assemblies

AbstractThe synthesis of a new family of coordination polymers [AgL2X]n (1a, X = CF3SO3; 1b, X = BF4; 1c, X = NO3; 1d, X = PF6) using 5‐methoxy‐1,3‐bis(pyridin‐3‐ylethynyl)benzene (L2) as the self‐assembling ligand is described. All compounds have been fully characterized by spectroscopic techniques and elemental analysis. In particular the X‐ray molecular structures of 1a and 1b are reported and confirm the formation of 1D silver(I) chains. Their arrangements are described as a function and the nature of the anion. The supramolecular product 1a exhibits argentophilic Ag···Ag interactions to afford infinite double chains. Additionally, η1–AgI–π interactions lead to the formation of a network of stacked layers of double chains. In contrast, 1b lacks metal–counterion bonding and is constituted of infinite coordination polymers, which are held together by π–π interactions. The pivotal role of the counteranions on the overall packing arrangement of the polymers is presented and discussed.

Syntheses and reactivities of azido coordinated CpCo(dithiolene) complexes

Azido coordinated dithiolene complexes [CpCo(N 3){S 2C 2(CO 2Me) 2}( S-CHR 1R 2)], where R 1, R 2 = H ( 4a); R 1 = H, R 2 = SiMe 3 ( 4b); R 1 = H, R 2 = CO 2Et ( 4c), were synthesized by the reactions of the corresponding Cl − coordinated precursors [CpCo(Cl){S 2C 2(CO 2Me) 2}( S-CHR 1R 2)] ( 3a– 3c) with sodium azide. The Cl − coordinated complex 3d (R 1, R 2 = CO 2Me) did not produce any N 3 − coordinated complexes but formed the CR 1R 2-bridged alkylidene adduct [CpCo{S 2C 2(CO 2Me) 2}(CR 1R 2)] ( 2d; R 1, R 2 = CO 2Me). The structure of 4a was determined by X-ray diffraction study. In the molecular structure of 4a, the coordinated N 3 − ligand and CHR 1R 2 group were located at the same side with respect to the dithiolene ring ( syn form), although the corresponding Cl − precursor ( 3a; R 1, R 2 = H) was anti form. A structural conversion of syn/ anti was conceivable during the Cl −/N 3 − ligand exchange. Thermal (80 °C) and photochemical reactions (Hg lamp) of 4a– 4c were performed. Among them, 4c was relatively well reacted compared with the others to form the CR 1R 2-bridged alkylidene adduct ( 2c; R 1 = H, R 2 = CO 2Et), followed by a formal HN 3 elimination, and the reaction also produced non-adduct of the cobalt dithiolene complex [CpCo{S 2C 2(CO 2Me) 2}] ( 1). The electrochemical 1e − reduction of 4c underwent a formal N 3 − ligand elimination, and successive second reduction caused the CHR 1R 2 group elimination or reformed the CR 1R 2-bridged alkylidene adduct 2c.

Trimethylphosphite stabilized disilver(I) methanedisulfonates as MOCVD precursors

New disilver(I) methanedisulfonates complexes {CH 2(SO 3) 2Ag 2·[P(OMe) 3] n } ( n = 2, 2a; n = 4, 2b; n = 6, 2c) were prepared by reacting [CH 2(SO 3) 2Ag 2], which could be synthesized from methanedisulfonic acid and Ag 2CO 3 in water, with trimethylphosphite in dichloromethane. The molecular structure of 2a was determined using X-ray single crystal analysis. Complex 2a exhibits an infinite chain structure with eight-membered rings (AgOSOAgOSO) fully interconnected by the third sulfonic O atoms. Complex 2b was used to deposit silver films by metal organic chemical vapor deposition (MOCVD) for the first time. The silver film obtained was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersion X-ray analysis (EDX).

Synthesis, structure and theoretical studies of Hg(II)–NH carbene complex of annulated ligand pyridinyl[1,2-a]{2-pyridylimidazol}-3-ylidene hexaflurophosphate

Experimental and theoretical studies of a new class of novel annulated imidazolium scffords 2a, 2b, 2c and their Hg(II)–NHC complexes 3a, 3b and 3c have been synthesized and characterized by different spectroscopic techniques. Molecular structures of 3a and 3b have been determined by single crystal X-ray diffraction studies. Virtual linear geometry [Ccarbene–Hg–Ccarbene 176.56(17)°] around Hg of the complex 3b is observed where as in 3a and 3c its deviate a more. DFT calculations provide geometrical parameters in conformity with the experimental values in case of 3a. The molecules prefer syn configuration over the anti due to lower energy supported by theoretical studies. Attention has given paid for theoretical calculations and comparison of 3a and 3c to observe the steric effect of –CH3 group in the scaffords where as in case of 3b the –CH3 group remain innocent.

Lewis‐Base Stabilized N‐Silver(I) Succinimide Complexes: Synthesis, Crystal Structures and Their Use as CVD‐Precursors

AbstractFour Lewis‐base stabilized N‐silver(I) succinimide complexes of type [Ln·Rm·AgNC4H4O2] (L = N,N,N′,N′‐tetramethylethylenediamine (TMEDA), n = 1, m = 0, 2a; L = P(OEt)3, n = 2, m = 0, 2b; L = PPh3, m = 0, n = 2, 2c; L = P(OMe)3, R = TMEDA, n = 1, m = 1, 2d) were prepared by a “one‐pot” synthesis methodology and characterized. The molecular structures of 2a and 2c have been determined by using X‐ray single crystal analysis. Complex 2a exists as ion pair {[Ag(TMEDA)2]+[Ag(NC4H4O2)2]–} in the solid state and complex 2c is a monomer with the three‐coordinate silver atom. Complex 2b was used as precursor in the deposition of silver for the first time by using MOCVD technique. The silver films obtained were characterized using scanning electron microscopy (SEM) and energy‐dispersion X‐ray analysis (EDX). SEM and EDX studies show that the dense and homogeneous silver films could be obtained.

Control of On–Off or Off–On Fluorescent and Optical [Cu2+] and [Hg2+] Responses via Formal Me/H Substitution in Fully Characterized Thienyl “Scorpionate”-like BODIPY Systems

One 8-phenyl and two 8-mesityl-substituted "scorpionate"-like BODIPY-type species of the formula [3,4,4-tris(5-R-(2-thienyl))-8-(2,4,6-R'-phenyl)-4-bora-3a,4a-diaza-s-indacene (R = H, R' = H, 3a; R, = H, R' = Me, 2a; R, = Me, R' = Me, 2b)] have been synthesized and fully characterized. Importantly, differences in their solution (MeCN) optical Cu(2+) and Hg(2+) probing capacity via SSS-chelation were investigated. Compounds 2a-3a were prepared from the requisite 8-substituted BODIPY complexes. They were characterized first by complete (1)H, (11)B and (13)C NMR spectroscopic assignments (CD(3)Cl or CD(3)C(O)CD(3)); the molecular structures of 2a and 3a were determined by X-ray crystallography. Compounds 2a-3a were studied by UV-vis and fluorescence spectroscopy [Φ(F) = 0.27 ± 0.013 (2a); 0.024 ± 0.0016 (2b); 0.0034 ± 0.00047 (3a)]. Importantly, low [Cu(2+)] with 3a (<3.0 × 10(-5) M) gave rise to an increase of fluorescence intensity (off-on; 6.3-fold), whereas with 2a it decreased (on-off). When [Hg(2+)] (<3.0 × 10(-5) M) was added to 2b, the λ(em,max) value increased (off-on; 3.2-fold), and for 2a, it decreased (on-off). The association constant (K(a)) for Hg(2+)·2a was determined to be 3120 ± 307 M(-1). An approximate stoichiometric 1:1 binding determined by Job plot analysis is in line with successful DFT modeling of SSS-Cu(2+) binding for this system type. (1)H NMR spectroscopy also revealed tentative sets of product complex peaks. These simple differences caused by formal ligand Me-group incorporation are the first for any related fluorophores, to the best of our knowledge.

Synthesis of fluorinated geminal diisocyanides stabilized on a transition metal

Chromium complexes of the geminal diisocyanides bis(pentacarbonyl)-μ-2,2-diisocyano-1,1,1,3,3,3-hexafluoropropane)dichromium 1a and bis(pentacarbonyl)-μ-2,2-diisocyano-1,1,1,3,3-pentafluorobutane)dichromium 1b were obtained by radical alkylation of pentacarbonylcyanochromate besides pentacarbonyl(2-isocyano-1,1,1,3,3,3-hexafluoropropane)chromium 2a and pentacarbonyl(2-isocyano-1,1,1,3,3-pentafluorobutane)chromium 2b, respectively. Pentacarbonyl(2-isocyano-1,1,1,2,3,3,3-heptafluoropropane)chromium 2c was prepared analogously. The crystal and molecular structures of 1a and b were determined by X-ray diffraction.

Photocleavage of Coordinated NO under Visible Light from Two Different Classes of Organometallic Ruthenium Nitrosyl Complexes: Reversible Binding of Phenolato Function

The structurally similar Ru(III) complexes [Ru(LSB1)(PPh3)2Cl] (1), where LSB1H2 = 2-(4-chlorobenzylidineamino)phenol and H = dissociable protons, and [Ru(LAZ1)(PPh3)2Cl] (2), where LAZ1H2 = 4-methyl-2-(p-tolyldiazenyl)phenol and H = dissociable protons, were reacted with in situ generated NO derived from acidified nitrite solution. These reactivity studies on 1 and 2 afforded the complexes [Ru(LSB2H)(PPh3)2(NO)Cl](ClO4) (1a) and [Ru(LAZ2H)(PPh3)2(NO)Cl](ClO4) (2a), respectively, where LSB2H = 2-(4-chlorobenzylidineamino)-4-nitrophenol, LAZ2H = 4-methyl-2-nitro-6-(p-tolyldiazenyl)phenol, and H = dissociable proton. Complexes 1a and 2a were found to be diamagnetic and were characterized by 1H and 31P NMR spectral studies. Both 1a and 2a exhibited νNO bands near 1800 cm−1 in their IR spectra. The molecular structures of 1a·CH2Cl2·3H2O and 2a·2H2O were determined by X-ray crystallography, and NO coordination as well as ligand nitration were authenticated from the crystal structure. In both of the nitrosyl complexes coordinated NO was found to be photolabile under visible light and photocleaved NO was transferred to reduced myoglobin. The photolability of NO in 1a and 2a afforded the complexes [Ru(LSB2)(PPh3)2Cl] (1b) and [Ru(LAZ2)(PPh3)2Cl] (2b), respectively, and the molecular structure of 1b·2CH2Cl2 was confirmed by an X-ray crystal structure solution. A novel type of reversible binding of the phenolato function to the metal center was revealed during NO coordination and photocleavage.