Bismuth-catalyzed intermolecular hydroamination of 1,3-dienes with carbamates, sulfonamides, and carboxamides

A Bi(OTf)(3)/Cu(CH(3)CN)(4)PF(6) system efficiently promoted intermolecular 1:1 hydroamination of 1,3-dienes with various carbamates, sulfonamides, and carboxamides to afford allylic amines in good yield (up to 96%). Reaction proceeded with 0.5-10 mol % catalyst loading at 25-100 degrees C (generally at 50 degrees C) in 1,4-dioxane within 24 h. The Bi(OTf)(3)/Cu(CH(3)CN)(4)PF(6) system constitutes a new entry into series of intermolecular hydroamination catalysis. Mechanistic studies and the postulated reaction mechanism are also discussed.     

Dicopper complexes catalyzed coupling/cyclization of 2‐bromobenzoic acids with amidines leading to quinazolinones

Dicopper(I) complexes {Cu₂(bpnp)(CH₃CN)₄}(PF₆)₂] ( 2 ), [{Cu₂(bpnp)(CH₃CN)₄}(BAr₄^F)₂] ( 3 ) and [Cu₂(bpnp)Cl₂] ( 4 ) were prepared from the complexation of [Cu(CH₃CN)₄](PF₆) with 2,7‐bis(2‐pyridyl)‐1,8‐naphthyridine (bpnp) followed by anion metathesis and treatment of chloride sequentially. The X‐ray structural analysis of 4 indicates the molecule to have a twofold axis passing through the Cu₂Cl₂ core, which has the shape of a butterfly, and that the Cu atom is tetrahedrally coordinated with in a Cl₂N₂ donor set. In preliminary experiments 2 was found to be an effective catalyst in the coupling/cyclization of 2‐bromobenzoic acids with amidines, providing the corresponding quinazolinones in good yields. Copyright © 2014 John Wiley & Sons, Ltd.     

Struktur und Eigenschaften des Methylpentafluorphosphatanions, [CH3PF5]—

Structure and Properties of the Methyltetrafluorophosphate Anion, [CH₃PF₅]^— Methyltetrafluorphosphorane reacts with the fluorides NaF, KF, CsF, and (CH₃)₄NF with formation of the corresponding methylpentafluorophosphates. In case of the K and Cs salts K[CH₃PF₅] · CH₃CN and Cs[CH₃PF₅] · CH₃CN, respectively, are formed using acetonitrile as solvent. The salts are characterized by NMR, IR and Raman spectroscopy. The vibrational frequencies are compared with ab initio calculated data (RHF/6‐31+G*). The RHF/6‐31+G* calculation yields for the almost octahedral anion bond distances of d(PF_eq) = 163.7 pm, d(PF_ax) = 162.0 pm, and d(PC) = 184.8 pm.     

Preparation of Hydride‐Ethylene Complexes of Osmium

Ethylene complexes [OsH(η²‐CH₂=CH₂)L₄]Y ( 1 , 2 ) [L = PPh(OEt)₂, P(OEt)₃; Y = OTf, BPh₄] were prepared by reacting the dihydride OsH₂L₄ first with methyl triflate CH₃OTf and then with ethylene (1 atm). Alternatively, the compound [OsH(η²‐CH₂=CH₂){PPh(OEt)₂}₄]OTf was prepared by allowing the dinitrogen derivative [OsH(N₂){PPh(OEt)₂}₄]OTf to react with ethylene. Acrylonitrile CH₂=C(H)CN reacts with OsH(OTf)L₄ [L = P(OEt)₃] to give the complex [OsH{κ¹‐NCC(H)=CH₂}{P(OEt)₃}₄]BPh₄ ( 3 ). The complexes were characterized spectroscopically (IR and ¹H, ¹³C, ³¹P NMR) and by X‐ray crystal structure determination of the [OsH(η²‐CH₂=CH₂){PPh(OEt)₂}₄]BPh₄ derivative.     

P−P Condensation and P−N/P−P Bond Metathesis: Facile Synthesis of Cationic Tri‐ and Tetraphosphanes

[L_C^RP((PhP)₂C₂H₄)][OTf] ( 4 a,b [OTf]) and [L_C^iPrP(PPh₂)₂][OTf] ( 5 b [OTf]) were prepared from the reaction of imidazoliumyl‐substituted dipyrazolylphosphane triflate salts [L_C^RP(pyr)₂][OTf] ( 3 a,b [OTf]; a : R=Me, b =iPr; L_C^R=1,3‐dialkyl‐4,5‐dimethylimidazol‐2‐yl; pyr=3,5‐dimethylpyrazol‐1‐yl) with the secondary phosphanes PhP(H)C₂H₄P(H)Ph) and Ph₂PH. A stepwise double P?N/P?P bond metathesis to catena‐tetraphosphane‐2,3‐diium triflate salt [(Ph₂P)₂(L_C^MeP)₂][OTf]₂ ( 7 a [OTf]₂) is observed when reacting 3 a [OTf] with diphosphane P₂Ph₄. The coordination ability of 5 b [OTf] was probed with selected coinage metal salts [Cu(CH₃CN)₄]OTf, AgOTf and AuCl(tht) (tht=tetrahydrothiophene). For AuCl(tht), the helical complex [{(Ph₂PPL_C^iPr)Au}₄][OTf]₄ ( 9 [OTf]₄) was unexpectedly formed as a result of a chloride‐induced P?P bond cleavage. The weakly coordinating triflate anion enables the formation of the expected copper(I) and silver(I) complexes [( 5 b )M(CH₃CN)₃][OTf]₂ (M=Cu, Ag) ( 10 [OTf]₂, 11 [OTf]₂).     

Reactivity Studies of η5‐ Indenyl and η5‐Cp* Ruthenium(II) Complexes towards some Polypyridyl Ligands

The reaction of [(η⁵‐L³)Ru(PPh₃)₂Cl], where; L³ = C₉H₇ ( 1 ), C₅Me₅ (Cp*) ( 2 ) with acetonitrile in the presence of [NH₄][PF₆] yielded cationic complexes [(η⁵‐L³)Ru(PPh₃)₂(CH₃CN)][PF₆]; L³= C₉H₇ ([3]PF₆) and L³ = C₅Me₅ ([4]PF₆), respectively. Complexes [3]PF₆ and [4]PF₆ reacts with some polypyridyl ligands viz, 2,3‐bis (α‐pyridyl) pyrazine (bpp), 2,3‐bis (α‐pyridyl) quinoxaline (bpq) yielding the complexes of the formulation [(η⁵‐L³)Ru(PPh₃)(L²)]PF₆ where; L³ = C₉H₇, L² = bpp, ([5]PF₆), L³ = C₉H₇, L² = bpq, ([6]PF₆); L³ = C₅Me₅, L² = bpp, ([7]PF₆) and bpq, ([8]PF₆), respectively. However reaction of [(η⁵‐C₉H₇)Ru(PPh₃)₂(CH₃CN)][PF₆] ([3]PF₆) with the sterically demanding polypyridyl ligands, viz. 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine (tptz) or tetra‐2‐pyridyl‐1,4‐pyrazine (tppz) leads to the formation of unexpected complexes [Ru(PPh₃)₂(L²)(CH₃CN)][PF₆]₂; L² = tppz ([9](PF₆)₂), tptz ([11](PF₆)₂) and [Ru(PPh₃)₂(L²)Cl][PF₆]; L² = tppz ([10]PF₆), tptz ([12]PF₆). The complexes were isolated as their hexafluorophosphate salts. They have been characterized on the basis of micro analytical and spectroscopic data. The crystal structures of the representative complexes were established by X‐ray crystallography.     

Synthesis and Structural Characterization of the Tetrakis(methimazolyl)borates Li[Bmt4] and [Ru(p‐cymene)(Bmt4)][PF6]

The lithium tetrakis(methimazolyl)borate, Li[Bmt₄], is accessible from the reaction of Li[BH₄] with four equivalents of methimazole. The crystal structure of Li[Bmt₄] supported by four water molecules is described. Reaction of Li[Bmt₄] with [Ru(p‐cymene)Cl₂]₂ and subsequent treatment with NH₄PF₆ in CH₃CN results in the formation of the complex [Ru(p‐cymene)(Bmt₄)][PF₆]. In addition, we report the result of the X‐ray structure analysis of the chiral Ru complex [Ru(p‐cymene)(Bmt₄)][PF₆].     

An Unusually Delocalized Mixed‐Valence State of a Cyanidometal‐Bridged Compound Induced by Thermal Electron Transfer

The heterometallic complexes trans ‐[Cp(dppe)FeNCRu(o ‐bpy)CNFe(dppe)Cp][PF₆]_n ( 1 [PF₆]_n , n =2, 3, 4; o ‐bpy=1,2‐bis(2,2′‐bipyridyl‐6‐yl)ethane, dppe=1,2‐bis(diphenylphosphino)ethane, Cp=1,3‐cyclopentadiene) in three distinct states have been synthesized and fully characterized. 1 ³⁺[PF₆]₃ and 1 ⁴⁺[PF₆]₄ are the one‐ and two‐electron oxidation products of 1 ²⁺[PF₆]₂, respectively. The investigated results suggest that 1 [PF₆]₃ is a Class II mixed valence compound. 1 [PF₆]₄ after a thermal treatment at 400 K shows an unusually delocalized mixed valence state of [Fe^III‐NC‐Ru^III‐CN‐Fe^II], which is induced by electron transfer from the central Ru^II to the terminal Fe^III in 1 [PF₆]₄, which was confirmed by IR spectroscopy, magnetic data, and EPR and Mössbauer spectroscopy.     

Synthesis and characterizations of N,N′‐bis(diphenylphosphino)‐2‐(aminomethyl)aniline derivatives: application of a palladium(II) complex as pre‐catalyst in Heck and Suzuki cross‐coupling reactions

The reaction of 2‐(aminomethyl)aniline with 2 equivalents of PPh₂Cl in the presence of Et₃N, proceeds in CH₂Cl₂ to give N,N′‐bis(diphenylphosphino)‐2‐(aminomethyl)aniline 1 in good yield. Oxidation of 1 with aqueous H₂O₂, elemental sulfur or gray selenium gave the corresponding oxide, sulfide and selenide dichalcogenides [Ph₂P(E)NHC₆H₄CH₂NHP(E)Ph₂] (E: O, 2a; S, 2b; Se, 2c), respectively. The reaction of [Ph₂PNHC₆H₄CH₂NHPPh₂] with PdCl₂(cod), PtCl₂(cod) and [Cu(MeCN)₄]PF₆ gave the corresponding chelate complexes, PdCl₂1, PtCl₂1 and [Cu(1)₂]PF₆. The new compounds were fully characterized by NMR, IR spectroscopy and elemental analysis. The catalytic activity of the Pd(II) complex was tested in the Suzuki coupling and Heck reactions. The Pd(II) complex catalyzes the Suzuki coupling and Heck reaction, affording biphenyls and stilbenes respectively, in good yields. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of Intermolecular Interactions on Metal‐to‐Metal Charge Transfer: A Combined Experimental and Theoretical Investigation

Understanding the effects of intermolecular interactions on metal‐to‐metal charge transfer (MMCT) is crucial to develop molecular devices by grafting MMCT‐based molecular arrays. Herein, we report a series of solvent‐free {Fe₂Co₂} compounds sharing the same cationic tetranuclear {[Fe(PzTp)(CN)₃]₂[Co(dpq)₂]₂}²⁺ (PzTp^?=tetrakis(pyrazolyl)borate, dpq=dipyrido[3,2‐d:2′,3′‐f]quinoxaline) square units but having anions with different size, including BF₄^?, PF₆^?, OTf^?, and [Fe(PzTp)(CN)₃]^?. Intermolecular π???π interactions between dpq ligands, which coordinate to cobalt ions in the {[Fe(PzTp)(CN)₃]₂[Co(dpq)₂]₂}²⁺ units, can be modulated by introducing different counterions, regulating the distortion of the CoN₆ octahedron and ligand field around the cobalt ions. This change results in different MMCT behavior. Computational analyzes reveal the substantial role of the intermolecular interactions tuned by the presence of different counteranions on the MMCT behavior.     

1‐Silacyclopent‐2‐enes and 1‐silacyclohex‐2‐enes bearing functionally substituted silyl groups in 2‐positions. Novel electron‐deficient Si?H?B bridges

The reactions of alkyn‐1‐yl(vinyl)silanes R₂Si[C?C‐Si(H)Me₂]CH?CH₂ [R = Me (1a), Ph (1b)], Me₂Si[C?C‐Si(Br)Me₂]CH?CH₂ (2a), and of alkyn‐1‐yl(allyl)silanes R₂Si[C?C‐Si(H)Me₂]CH₂CH?CH₂ (R = Me (3a), R = Ph (3b)] with 9‐borabicyclo[3.3.1]nonane in a 1:1 ratio afford in high yield the 1‐silacyclopent‐2‐ene derivatives 4a, b and 5a, and the 1‐silacyclohex‐2‐ene derivatives 6a, b, respectively, all of which bear a functionally substituted silyl group in 2‐position and the boryl group in 3‐position. This is the result of selective intermolecular 1,2‐hydroboration of the vinyl or allyl group, followed by intramolecular 1,1‐organoboration of the alkynyl group. In the cases of 4a, b, potential electron‐deficient Si? H? B bridges are absent or extremely weak, whereas in 6a,b the existence of Si? H? B bridges is evident from the NMR spectroscopic data (¹H, ¹¹B, ¹³C and ²⁹Si NMR). The molecular structure of 4b was determined by X‐ray analysis. Copyright © 2005 John Wiley & Sons, Ltd.     

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.     

Mono‐ and Perfluoroaryliodine(III) Cyano Compounds – Synthesis,Reactivity, and Structure

C₆F₅I(CN)₂ and x‐FC₆H₄I(CN)₂ (x = 2, 3, 4) were isolated from reactions of the corresponding aryliodine difluorides ArIF₂ and a stoichiometric excess of Me₃SiCN in CCl₃F (0 °C) or CH₂Cl₂ (20 °C), respectively. In addition, x‐FC₆H₄I(CN)₂ compounds were synthesized in good yields on alternative routes, namely from 3‐ or 4‐FC₆H₄I(OC(O)CH₃)₂ or 4‐FC₆H₄I(OC(O)CF₃)₂ or from 4‐FC₆H₄IO and Me₃SiCN in CH₂Cl₂ at 20 °C. In the 1 : 1 reaction of C₆F₅IF₂ and Me₃SiCN a lower temperature was necessary to suppress partial disubstitution and to obtain the first example of a new type of aryliodine(III) cyanide compounds, C₆F₅I(CN)F. 4‐FC₆H₄I(CN)F could be isolated from the equimolar reaction of 4‐FC₆H₄IF₂ and Me₃SiCN in CH₂Cl₂ even at 20 °C. The new products were characterized by multi‐NMR and Raman spectroscopy. The molecular structures of C₆F₅I(CN)₂, 3‐ and 4‐FC₆H₄I(CN)₂, C₆F₅I(CN)F, and 4‐FC₆H₄I(CN)F are discussed and compared with that of C₆F₅IF₂. The reactivity of C₆F₅I(CN)F towards fluoride acceptors EF_n (BF₃, AsF₅) and R_xEX_?x (C₆F₅SiF₃, C₆H₅SiF₃, C₆H₅PF₄, Me₃SiCl, Me₃SiC₆F₅) were investigated and showed differing reaction patterns (fluoride abstraction, aryl transfer, chloride transfer). Besides the molecular entities C₆F₅I(CN)F and C₆F₅I(CN)Cl, the corresponding iodonium salts [C₆F₅(CN)I][BF₄] and [C₆F₅(CN)I][AsF₆] were isolated. The thermal stability of ArI(CN)₂ and ArI(CN)F, neat and in solution, as well as the reactivity of 4‐FC₆H₄I(CN)₂ towards the Lewis acid BF₃ are reported.     

Synthesis and characterization of transition metal complexes of thiophene‐2‐methylamine: X‐ray crystal structure of palladium (II) and platinum (II) complexes and use of palladium(II) complexes as pre‐catalyst in Heck and Suzuki cross‐coupling reactions

The reactions of thiophene‐2‐(N‐diphenylphosphino)methylamine, Ph₂PNHCH₂‐C₄H₃S, 1 and thiophene‐2‐[N,N‐bis(diphenylphosphino)methylamine], (Ph₂P)₂NCH₂‐C₄H₃S, 2, with MCl₂(cod) (M = Pd, Pt; cod = 1,5‐cyclooctadiene) or [Cu(CH₃CN)₄]PF₆ yields the new complexes [M(Ph₂PNHCH₂‐C₄H₃S)₂Cl₂], M = Pd 1a, Pt 1b, [Cu(Ph₂PNHCH₂‐C₄H₃S)₄]PF₆, 1c, and [M(Ph₂P)₂NCH₂‐C₄H₃S)Cl₂], M = Pd 2a, Pt 2b, {Cu[(Ph₂P)₂NCH₂‐C₄H₃S]₂}PF₆, 2c, respectively. The new compounds were isolated as analytically pure crystalline solids and characterized by ³¹P‐, ¹³C‐, ¹H‐NMR and IR spectroscopy and elemental analysis. Furthermore, the solid‐state molecular structures of representative palladium and platinum complexes of bis(phosphine)amine, 2a and 2b, respectively, were determined using single crystal X‐ray diffraction analysis. The palladium complexes were tested as potential catalysts in the Heck and Suzuki cross‐coupling reactions. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and Characterization of β‐Diketiminate Aluminum Compounds and Their Use in the Ring‐Opening Polymerization of ε‐Caprolactone

Four aluminum alkyl compounds, [CH{(CH₃)CN‐2,4,6‐MeC₆H₂}₂AlMe₂] ( 1 ), [CH{(CH₃)CN‐2,4,6‐MeC₆H₂}₂AlEt₂] ( 2 ), [CH{(CH₃)CN‐2‐iPrC₆H₄}₂AlMe₂] ( 3 ), and [CH{(CH₃)CN‐2‐iPrC₆H₄}₂AlEt₂] ( 4 ), bearing β‐diketiminate ligands [CH{(Me)CN‐2,4,6‐MeC₆H₂}]₂ (L¹H) and [CH{(Me)CN‐2‐ⁱPrC₆H₄}]₂ (L²H) were obtained from the reactions of trimethylaluminum, triethylaluminum with the corresponding β‐diketiminate, respectively. All compounds were characterized by ¹H NMR and ¹³C NMR spectroscopy, single‐crystal X‐ray structural analysis, and elemental analysis. Compounds 1 – 4 were found to catalyze the ring‐opening polymerization (ROP) of ε‐caprolactone (ε‐CL) with good activity.     

Solid-phase based synthesis of biologically promising triazolyl aminoacyl (peptidyl) penicillins

An efficient and versatile methodology for the preparation of valuable triazolyl aminoacyl (peptidyl) penicillins is described. Solid-phase Cu(I)-catalyzed Hüisgen 1,3-dipolar cycloaddition was used as the key step showing general applicability and excellent regioselectivity either with CuI or [Cu(CH₃CN)₄]PF₆ as Cu(I) source.     

Anion-templated assembly of half-sandwich rhodium-based multinuclear metallamacrocycles

A series of half‐sandwich rhodium‐based metallamacrocycles with tetra‐ and hexanuclearities have been synthesized. They are assembled by linking the deprotonated 2,4‐diacetyl‐5‐hydroxy‐5‐methyl‐3‐(3‐pyridinyl)cyclohexanone (HL) ligand in the presence of counteranions. When the counteranion was the tetrahedral BF₄^? ion, tetranuclear metallamacrocycle [(Cp*RhL)₄][BF₄]₄ ( 1 d ) was formed. However, the larger OTf^?, PF₆^?, and SbF₆^? counterions favored the formation of hexanuclear metallamacrocycles [(Cp*RhL)₆?2OTf][OTf]₄ ( 1 a ), [(Cp*RhL)₆?2PF₆][PF₆]₄ ( 1 b ), and [(Cp*RhL)₆?2SbF₆][SbF₆]₄ ? 6CH₃CN ( 1 c ) when the reactions were performed under the same conditions. Single‐crystal X‐ray analysis indicated that, in the solid state, two counteranions were encapsulated in each belt‐like host molecule of hexanuclear metallamacrocycles 1 a , b , and c . Based on the results of ¹H NMR analysis in methanol, the nuclearities of 1 a – c and the two encapsulated anions in each molecular cavity were maintained in solution. In addition, tetranuclear metallamacrocycle 1 d was converted into the hexanuclear metallamacrocycles 1 a′ , b , and c after addition of the appropriate anion as its [NBu₄]⁺ salt. The compound 1 a′ was characterized by single‐crystal X‐ray diffraction to have the formula [(Cp*RhL)₆?2OTf][BF₄]₄ ? 2M eOH ? 2H₂O. From the interconversion of the hexanuclear metallamacrocycles, we have concluded that the hexanuclear belt‐like host in 1 a – c has an clear selectivity for larger anions, in the sequence SbF₆^?≈PF₆^?>OTf^?>BF₄^?>Cl^?.     

Regioselective Synthesis and Characterization of Multinuclear Convex‐Bound Ruthenium‐[n]Cycloparaphenylene (n=5 and 6) Complexes

Mono‐ and multinuclear complexes of ruthenium and [n]cycloparaphenylene (CPP, n=5 and 6) were synthesized in excellent yields through ligand exchange of the cationic complex [(Cp)Ru(CH₃CN)₃](PF₆) with CPP. In the multinuclear complexes, ruthenium selectively coordinated to alternate paraphenylene units to give bis‐ and tris‐coordinated Ru complexes for [5] and [6]CPPs, respectively. Single‐crystal X‐ray analysis revealed the Ru was coordinated with η⁶‐hapticity on the convex surface of CPP.     

Influence of Central Metalloligand Geometry on Electronic Communication between Metals: Syntheses,Crystal Structures,MMCT Properties of Isomeric Cyanido‐Bridged Fe2Ru Complexes,and TDDFT Calculations

To investigate how the central metalloligand geometry influences distant or vicinal metal‐to‐metal charge‐transfer (MMCT) properties of polynuclear complexes, cis‐ and trans‐isomeric heterotrimetallic complexes, and their one‐ and two‐electron oxidation products, cis/trans‐ [Cp(dppe)Fe^IINCRu^II(phen)₂CN‐Fe^II(dppe)Cp][PF₆]₂ (cis/trans‐ 1 [PF₆]₂), cis/trans‐[Cp(dppe)Fe^IINCRu^II(phen)₂CNFe^III‐(dppe)Cp][PF₆]₃ (cis/trans‐ 1 [PF₆]₃) and cis/trans‐[Cp(dppe)Fe^IIINCRu^II(phen)₂CN‐Fe^III(dppe)Cp][PF₆]₄ (cis/trans‐ 1 [PF₆]₄) have been synthesized and characterized. Electrochemical measurements show the presence of electronic interactions between the two external Fe^II atoms of the cis‐ and trans‐isomeric complexes cis/trans‐ 1 [PF₆]₂. The electronic properties of all these complexes were studied and compared by spectroscopic techniques and TDDFT//DFT calculations. As expected, both mixed valence complexes cis/trans‐ 1 [PF₆]₃ exhibited different strong absorption signals in the NIR region, which should mainly be attributed to a transition from an MO that is delocalized over the Ru^II‐CN‐Fe^II subunit to a Fe^III d orbital with some contributions from the co‐ligands. Moreover, the NIR transition energy in trans‐ 1 [PF₆]₃ is lower than that in cis‐ 1 [PF₆]₃, which is related to the symmetry of their molecular orbitals on the basis of the molecular orbital analysis. Also, the electronic spectra of the two‐electron oxidized complexes show that trans‐ 1 [PF₆]₄ possesses lower vicinal Ru^II→Fe^III MMCT transition energy than cis‐ 1 [PF₆]₄. Moreover, the assignment of MMCT transition of the oxidized products and the differences of the electronic properties between the cis and trans complexes can be well rationalized using TDDFT//DFT calculations.     

Ethyl‐Zinc(II)‐Cation Equivalents: Synthesis and Hydroamination Catalysis

Ion‐like ethylzinc(II) compounds with weakly coordinating aluminates [Al(OR^F)₄]^? and [(R^FO)₃Al‐F‐Al(OR^F)₃]^? (R^F=C(CF₃)₃) were synthesized in a one‐pot reaction and fully characterized by single‐crystal X‐ray diffraction, NMR and vibrational spectroscopy, and by quantum chemical calculations. The catalytic activity of ion‐like Et‐Zn[Al(OR^F)₄] in intermolecular hydroamination and in the unusual double hydroamination of anilines and alkynes was investigated. Favorable performance was also found in comparison to the Et₂Zn/ [PhNMe₂H]⁺[B(C₆F₅)₄]^? system generated in situ at lower catalyst loadings of 2.5 mol %.