Synthesis and Crystal Structure of Mercury(II) Metal Crown Ether with N‐Heterocyclic Carbene Linkage

The mercury(II) metal crown ether ( 2a ) was obtained in high yield by reaction of the carbene precursor 1,2‐bis[N‐(1‐naphthylmethylene)imidazoliumethoxy]benzene dihexafluorophosphate ( 1 ) and Hg(OAc)₂. Addition of NaI to the acetone solution of 2a resulted in precipitation of pale yellow solid 2b . The structures of 2a and 2b were determined by single‐crystal X‐ray diffractometry. Both molecules display a helical conformation with a torsional cycle. The mercury atom in complex 2a is tricoordinated by two intramolecular carbene carbon atoms and an acetate oxygen atom. The mercury atom in complex 2b is tetracoordinated by two intramolecular carbene carbon atoms and two cis‐iodine atoms.     

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

Four Lewis‐base stabilized N‐silver(I) succinimide complexes of type [L_n·R_m·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.     

Syntheses and Structural Characterization of Four New Silver(I) Complexes with the N,N′(O)‐bidentate Bridging Ligands

Four new bridged silver(I) complexes, namely [Ag₂(μ₂‐teda)(μ₂‐fbc)₂] ( 1 ), [Ag₂(μ₂‐1,6‐dah)₂](bpdc) · 4H₂O ( 2 ), [Ag₂(μ₂‐2‐ap)(2‐ap)(bnb)] · 0.34H₂O ( 3 ), [Ag₂(μ₂‐pyc)₂(2‐apy)₂] · 0.5H₂O ( 4 ), have been synthesized and characterized by elemental analysis and crystallographic methods [fbc = 4‐fluorobenzoate, teda = triethylenediamine ( 1 ); bpdc = biphenyl‐4,4′‐dicarboxylate, 1,6‐dah = 1,6‐diaminohexane ( 2 ); bnb = 3,5‐binitrobenzoate, 2‐ap = 2‐aminopyrimidine ( 3 ); pyc = 3‐pyridinecarboxylate acid, 2‐apy = 2‐aminopyridine ( 4 )]. Complex 1 contains a 1D linear chain paralleling to the c‐axis, whereas in complex 2 silver(I) atoms were bridged by the 1,6‐dah ligand into a zigzag chain, further giving a 1D ribbon by weak Ag ··· Ag interactions. Complex 3 consists of a dinuclear silver(I) [Ag₂(μ₂‐2‐ap)(2‐ap)(bnb)] moiety and a lattice water molecule, forming a 3D network via a number of hydrogen‐bonding interactions such as N–H ··· O, N–H ··· N and C–H ··· O hydrogen bond and other weak interactions such Ag ··· Ag, Ag ··· N, N ··· O as well as O ··· O interaction. Similar to 3 , the asymmetric unit of 4 consists of one dinuclear silver(I) [Ag₂(μ₂‐pyc)₂(2‐apy)₂] moiety and half lattice water molecule, further generating a tetranuclear silver(I) {[Ag₂(μ₂‐pyc)₂(2‐apy)₂]₂ · H₂O} moiety. These moieties construct a 3D supramolecular network structure of 4 through N–H ··· O, O–H ··· O and C–H ··· O hydrogen bonds as well as other weak interactions such as Ag ··· O and N ··· O interactions.     

N‐Heterocyclic Carbene Adducts of Aluminium Triiodide

N‐Heterocyclic carbene adducts of aluminium triiodide, IMes · AlI₃ ( 1 ) and IPr · AlI₃ ( 2 ) (IMes = 1,3‐bis(2,4,6‐trimethylphenyl)imidazol‐2‐ylidene and IPr = 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) are reported. These adducts are available by the reaction of aluminium triiodide with the correspondingN‐heterocyclic carbene. Compounds 1 and 2 are soluble in hydrocarbon solvents, stable in inert atmosphere, and have been characterised by elemental analysis, NMR spectroscopy and single‐crystal X‐ray diffraction studies.     

Synthesis,Structures, and Photophysics of Polynuclear Silver(I) Thiolate and Silver(I) Thiocarboxylate Complexes with Dppm Ligands

Trinuclear silver(I) thiolate and silver(I) thiocarboxylate complexes [Ag₃(μ‐dppm)₃(μ_n‐SR)₂](ClO₄) [n = 2, R = C₆H₄Cl‐4 ( 1 ) and C{O}Ph ( 2 ); n = 3, R = tBu ( 3 )], pentanuclear silver(I) thiolate complex [Ag₅(μ‐dppm)₄(μ₃‐SC₆H₄NO₂‐4)₄](PF₆) ( 4 ), and hexanuclear silver(I) thiolate complexes [Ag₆(μ‐dppm)₄(μ₃‐SR)₄]Y₂ [Y = ClO₄, R =C₆H₄CH₃‐4 ( 5 ) and C₁₀H₇ (2‐naphthyl) ( 7 ); Y = PF₆, R = C₆H₄OCH₃‐4( 6 )], were synthesized [dppm = bis(diphenylphosphanyl)methane] and their crystal structures as well as photophysical properties were studied. In the solid state at 77 K, trinuclear silver(I) thiolate and silver(I) thiocarboxylate complexes 1 and 2 exhibit luminescence at 470–523 nm, tentatively attributed to originate from the ³IL (intraligand) of thiolate or thiocarboxylate ligands, whereas hexanuclaer silver(I) thiolate complexes 5 and 7 produce dual emission, in which high‐energy emission is tentatively attributed to come from the ³IL of thiolate ligands and low‐energy emission is tentatively assigned to come from the admixture of metal ··· metal bond‐to‐ligand charge‐transfer (MMLCT) and metal‐centered (MC) excited states.     

Syntheses and Crystal Structures of Copper and Silver Complexes with the Ylide Ph3PCHP(O)PPh2 as Ligand

The reactivity of the hydrolysis product of hexaphenylcarbodiphosphorane, PPh₃CHP(O)Ph₂, towards different soft Lewis acids, such as CuI and Ag[BF₄] are reported. While CuI exclusively binds at the ylidic carbon atom, reaction of the silver cation in CH₂Cl₂ leads to proton abstraction from the solvent to give the cation [PPh₃CH₂P(O)Ph₂]⁺. Surprisingly, Ag⁺ replaces the methyl group of [PPh₃CHMeP(O)Ph₂]⁺ to produce a dimeric complex, in which Ag⁺ is coordinated to C and O forming an eight membered ring. The compounds were characterized by spectroscopic methods and X‐ray diffraction.     

Synthesis and Crystal Structure of Novel Coordination Polymers with Nitrilotripropionic Acid

A novel three‐dimensional (3D) lanthanide‐organic framework [Pr₃(NTP)₃(H₂O)₆] · 10H₂O ( 1 ), (H₃NTP = 3,3′,3′‐nitrilotripropionic acid) was synthesized and characterized by elemental analyses, IR spectroscopy, and X‐ray diffraction analyses. The results show that complex 1 is connected through NTP ligands to form a 3D network with microchannels. The coordination mode of the NTP ligand was found for the first time. In order to investigate the temperature effects on controlling the dimensionality of the complexes, another two complexes, namely, [Nd(NTP)(H₂O)₂] · H₂O · HBr ( 2 ) and [Pr(H₂O)][⁺NH₃(CH₂CH₂COO^–)][OOCCOO]_1.5 ( 3 ) were synthesized and characterized. Notably, in complex 3 , the NTP ligand lost its two arms because of the high temperature. Furthermore, the thermogravimetric analyses of the three complexes are discussed in detail.     

Synthesis and Characterization of N,N‐Di‐substituted Acylthiourea Copper(II) Complexes

A series of six N,N‐di‐substituted acylthiourea ArC(O)NHC(S)NRR′ ligands (denoted as HLⁿ) [Ar = 1‐Naph: NRR′ = NPh₂, HL¹ ( 1 ); N(iPr)Ph, HL² ( 2 ). Ar = Mes: NRR′ = NPh₂, HL⁴ ( 3 ); N(iPr)Ph, HL⁵ ( 4 ); NEt₂, HL⁶ ( 5 ). Ar = Ph: NRR′ = N(iPr)Ph, HL⁸ ( 6 )] were synthesized and characterized. These ligands were deprotonated to form Cu^II complexes through metathesis or combined redox reaction with copper halides. The structures of the complexes were investigated with single‐crystal X‐ray diffraction. The reaction of the 1‐naphthalene derivative HL¹ ( 1 ) with CuBr in the presence of sodium acetate produced cis‐CuL¹₂ ( 7 ), where the deprotonated ligand is bound to the Cu^II atom in a bidentate‐(O, S) coordination mode. Similarly treatment of HL² ( 2 ) with NaOAc and CuCl resulted in the formation of the cis‐arranged product [cis‐CuL²₂ ( 8 )]. The reaction of mesityl derivative HL⁴ ( 3 ) and CuBr with and without the addition of NaOAc gave the cis‐CuL⁴₂ ( 9 ) and cis‐(HL⁴)₂CuBr ( 10 ), respectively. In contrast, reaction of HL⁵ ( 4 ) and CuI in the presence of NaOAc resulted in trans‐CuL⁵₂ ( 11 ). Alternatively trans‐CuL⁶₂ ( 12 ) was obtained by the reaction of diethyl‐substituted HL⁶ ( 5 ) with CuCl₂ in the absence of a base.     

Molecular Structure and Solution Behavior of a Benzonitrile Ligated Silver(I) Complex [Ag(PhCN)2][B(C6F5)4]

The bis(benzonitrile) complex [Ag(PhCN)₂][B(C₆F₅)₄] is synthesized from its tetra(acetonitrile) ligated congener. X‐ray diffraction studies were conducted to compare the bond lengths and angles of the complex in regard with those of other nitrile ligated silver cations with weakly coordinating anions. Vibrational spectra of the solid complex and in (concentrated) benzonitrile solution reveal differences in the strength of benzonitrile‐silver ion interactions.     

Two New Silver(I) Ammine Complexes by Displacement Reaction Between [Ag(NH3)2]+ Ions and Different Pyridine‐4,5‐Imidazoledicarboxylic Acids

[Ag(NH₃)₂]⁺ ions are chosen as an initial reaction precursor because of its simple displacement reaction and intrinsic arrangement as well as specific coordination directionality. Two new silver(I) ammine complexes, Ag₂(NH₃)HL² ( 2 ) and Ag₂(NH₃)₂HL³ ( 3 ), were obtained by a simple substitution reaction between [Ag(NH₃)₂]⁺ ions and pyridine‐4,5‐imidazoledicarboxylic acid [H₃L² = 2‐(3′‐pyridyl) 4,5‐imidazoledicarboxylic acid and H₃L³ = 2‐(4′‐pyridyl) 4,5‐imidazoledicarboxylic acid]. Silver dimers are connected into a 2D layer and 1D chain in complexes 2 and 3 , respectively. In complex 2 two kinds of displacement reactions (mono‐substituting and bis‐substituting) occurred between the ammine molecules in [Ag(NH₃)₂]⁺ ions and H₃L², however, only the mono‐substituting reaction occurs in complex 3 .     

Dinuclear Macrocyclic Quinoline Bridged Mercury and Silver Bis(N‐heterocyclic Carbene) Complexes: Synthesis,Structure, and Spectroscopic Studies

Quinoline bridged imidazolium precursors 5,8‐bis(N‐R‐imidazolylidenylmethylene)quinoline PF₆^– salts [H₂L](PF₆)₂ [R = Me ( 1a ), R = naphthylmethyl ( 1b )] were prepared by quaternization of N‐methylimidazole and N‐naphthylmethylimidazole with 5,8‐bis(bromomethyl)quinoline, respectively. Reaction of the imidazolium ligands 1a and 1b with Hg(OAc)₂ and Ag₂O in acetonitrile gave the macrocyclic transition metal carbene complexes [Hg₂L₂](PF₆)₄ ( 2a and 2b ) and [Ag₂L₂](PF₆)₂ ( 3a and 3b ), respectively. All the N‐heterocyclic carbene complexes were characterized in detail by NMR, ESI‐MS, and elemental analysis. Structures of complexes 2a and 3a were determined by X‐ray diffraction studies. Structural studies revealed that the coordination arrangement of the central mercury atom in complex 2a displays a tricoordinate mode and the molecular conformation results in a“closed” form with the bridging quinoline functionality in the macrocycle, whereas the silver complex 3a does not show an coordiantion between the bridging quinoline and the Ag^I ion, which results in an “open” conformation of the macrocycle. The Hg^II and Ag^I NHC complexes showed similar UV absorption and luminescence in acetonitrile solutions.     

Synthesis,Crystal Structure,and Characterization of a Novel Metallo‐Organically‐Templated Pentaborate with Mixed Ligands

A novel metallo‐organically templated pentaborate with layered framework, [Cd(TETA)(C₂H₃O₂)][B₅O₆(OH)₄] ( 1 ) (TETA = triethylenetramine), was synthesized under mild solvothermal conditions. The structure was determined by single‐crystal X‐ray diffraction and further characterized by FT‐IR spectroscopy, elemental analysis, thermogravimetric analysis, and photoluminescence spectroscopy. The structure consists of an isolated polyborate anion [B₅O₆(OH)₄]^– and the cadmium complex cation of [Cd(TETA)(C₂H₃O₂)]⁺, which contains both organic amine and organic acid ligands. The [B₅O₆(OH)₄]^– units are connected together by hydrogen bonds, and a 2D sheet‐like framework with rectangle‐like 12‐membered boron rings are formed. The [Cd(TETA)(C₂H₃O₂)]⁺ complex cations are located in the free space between the layers and connect the adjacent borate layers through hydrogen bonds to form a three‐dimensional supramolecular network. The luminescent properties of the compound were studied for the first time in the series of metallo‐organically‐templated pentaborates, and a blue luminescence occurs with an emission maximum at 468 nm upon excitation at 397 nm.     

Tricarbonylrhenium(I) Complexes with N‐Heterocyclic Thiones and Selenols

Reactions of (NEt₄)₂[Re(CO)₃Br₃] with N‐heterocyclic thiols such as 2‐mercaptobenzimidazole (H₂Sbenzim), 2‐mercaptothiazoline (HSthiaz), or 5‐mercapto‐1‐methyltetrazole (HSmetetraz) give rhenium(I) complexes of various compositions: (NEt₄)[Re(CO)₃Br₂(H₂Sbenzim)], [Re(CO)₃(HSthiaz)₃]Br, and (NEt₄)[Re₂(CO)₆(μ‐S‐Smetetraz‐κS)(μ‐N,S‐Smetetraz‐κS,N)₂]. Corresponding reactions with 2‐mercaptopyridine (HSpy) and bis(2‐pyridine)diselenide [(Sepy)₂] did not give defined products in reasonable yields, whereas [Re(CO)₅Br] reacts with HSpy and (Sepy)₂ with formation of [Re(CO)₃(HSpy)₃]Br and [Re₂(CO)₆(Sepy)₂], respectively. All reactions were performed without the addition of a supporting base and the sulfur‐containing organic ligands are coordinated in their thione forms with the exception of Smetetraz^– in its μS‐bridging coordination mode in (NEt₄)[Re₂(CO)₆(μ‐S‐Smetetraz‐κS)(μ‐N,S‐Smetetraz‐κS,N)₂], which can be regarded as thiolate. The bonding mode of the selenium containing ligands in the dimeric compound [Re₂(CO)₆(Sepy)₂] (C–Se distance: 1.93 Å) can also best be described as selenolate. The products are stable on air at an ambient temperature. They were studied spectroscopically and by X‐ray diffraction.     

Novel Benzyl‐ or 4‐Cyanobenzyl‐Substituted N‐Heterocyclic (Bromo)(carbene)silver(I) and (Carbene)(chloro)gold(I) Complexes: Synthesis and Preliminary Cytotoxicity Studies

N‐Heterocyclic carbene (NHC) complexes bromo(1,3‐dibenzyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene)silver(I) ( 2a ), bromo[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene]silver(I) ( 2b ), and bromo[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐benzimidazol‐2‐ylidene]silver(I) ( 2c ) were prepared by the reaction of 1,3‐dibenzyl‐1H‐imidazol‐3‐ium bromide ( 1a ), 3‐(4‐cyanobenzyl)‐1‐methyl‐1H‐imidazol‐3‐ium bromide ( 1b ), and 3‐(4‐cyanobenzyl)‐1‐methyl‐1H‐benzimidazol‐3‐ium bromide ( 1c ), respectively, with silver(I) oxide. NHC Complexes chloro(1,3‐dibenzyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene)gold(I) ( 3a ), chloro[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐imidazol‐2‐ylidene]gold(I) ( 3b ), and chloro[1‐(4‐cyanobenzyl)‐3‐methyl‐1,3‐dihydro‐2H‐benzimidazol‐2‐ylidene]gold(I) ( 3c ) were prepared via transmetallation of corresponding (bromo)(NHC)silver(I) complexes with chloro(dimethylsulfido)gold(I). The complex 3a was characterized in two polymorphic forms by single‐crystal X‐ray diffraction showing two rotamers in the solid state. The cytotoxicities of all three bromo(NHC)silver(I) complexes and three (chloro)(NHC)gold(I) complexes were investigated through 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bormide (MTT)‐based preliminary in vitro testing on the Caki‐1 cell line in order to determine their IC₅₀ values. (Bromo)(NHC)silver(I) complexes 2a – 2c and (chloro)(NHC)gold(I) complexes 3a – 3c were found to have IC₅₀ values of 27±2, 28±2, 34±6, 10±1, 12±5, and 12±3 μM , respectively, on the Caki‐1 cell line.     

Dinuclear Gold(I) Complexes Bearing N,N′‐Allyl‐Bridged Bisimidazolylidene Ligands

A novel N,N’‐allyl‐bridged bisimidazolium salt and a novel dinuclear Ag(I) and a Au(I) NHC complex are reported. Both metallacyclic complexes have a twisted structural shape due to the rigid allylic system and form two different isomers relating to the position of the double bonds. The allyl‐group shows photoisomerisation, but no reactivity towards bases for the additional coordination of Pd(II).     

Structure and Reactivity of a Unique Y‐Shaped Tricoordinate Bis(silyl)platinum(II)–NHC Complex

Y not? A unique, three‐coordinate Y‐shaped bis(silyl)platinum(II) complex was isolated and characterized (see structure; C light gray, N blue, Si pink, Pt dark gray). DFT studies on a model system shed light on the nature of this unusual coordination mode for platinum(II).

     

Single‐Crystal‐to‐Single‐Crystal Transformation and Solvochromic Luminescence of a Dinuclear Gold(I)–(Aza‐[18]crown‐6)dithiocarbamate Compound

The treatment of [AuCl(SMe₂)] with an equimolar amount of NaO₅NCS₂ (O₅NCS₂=(aza‐[18]crown‐6)dithiocarbamate) in CH₃CN gave [Au₂(O₅NCS₂)₂] ? 2 CH₃CN ( 2? 2 CH₃CN), and its crystal structure displays a dinuclear gold(I)‐azacrown ether ring and an intermolecular gold(I) ??? gold(I) contact of 2.8355(3) Å in crystal lattices. It is noted that two other single crystals of 2 ?tert‐butylbenzene?H₂O and 2? 0.5 m‐xylene can be successfully obtained from a single‐crystal‐to‐single‐crystal (SCSC) transformation process by immersing single crystals of 2? 2 CH₃CN in the respective solvents, and both also show intermolecular gold(I) ??? gold(I) contacts of 2.9420(5) and 2.890(2)–2.902(2) Å, respectively. Significantly, the emissions of all three 2 ?solvates are well correlated with their respective intermolecular gold(I) ??? gold(I) contacts, where such contacts increase with 2? 2 CH₃CN (2.8355(3) Å)< 2? 0.5 m‐xylene (2.890(2)–2.902(2) Å)< 2? tert‐butylbenzene?H₂O (2.9420(5) Å), and their emission energies increase with 2? 2 CH₃CN (602 nm)< 2? 0.5 m‐xylene (583 nm)< 2? tert‐butylbenzene?H₂O (546 nm) as well. In this regard, we further examine the solvochromic luminescence for some other aromatics, and finally their emissions are within 546–602 nm. Obviously, the above results are mostly ascribed to the occurrence of intermolecular gold(I) ??? gold(I) contacts in 2 ?solvates, which are induced by the presence of various solvates in the solid state, as a key role to be responsible for their solvochromic luminescence.