Synthesen und Schwingungsspektren der homoleptischen Acetonitrilkomplex-Kationen [Au(NCCH3)2]+, [Pd(NCCH3)4]2+, [Pt(NCCH3)4]2+ und des Adduktes CH3CN · SbF5. Kristallstrukturen der Salze [M(NCCH3)4][SbF6]2 · CH3CN,M = Pd,Pt

The Syntheses and Vibrational Spectra of the Homoleptic Metal Acetonitrile Cations [Au(NCCH₃)₂]⁺, [Pd(NCCH₃)₄]²⁺, [Pt(NCCH₃)₄]²⁺, and the Adduct CH₃CN · SbF₅. The Crystal and Molecular Structures of [M(NCCH₃)₄][SbF₆]₂ · CH₃CN, M = Pd or Pt Solvolyses of the homoleptic metal carbonyl salts [M(CO)₄][Sb₂F₁₁]₂, M = Pd or Pt, in acetonitrile leads at 50 °C both to complete ligand exchange for the cations as well as to a conversion of the di-octahedral anion [Sb₂F₁₁]^– into [SbF₆]^– and the molecular adduct CH₃CN · SbF₅ according to: [M(CO)₄][Sb₂F₁₁]₂ + 7 CH₃CN → [M(NCCH₃)₄][SbF₆]₂ · CH₃CN + 2 CH₃CN · SbF₅ + 4 CO M = Pd, Pt The monosolvated [M(NCCH₃)₄][SbF₆]₂ · CH₃CN are obtained as single crystals from solution and are structurally characterized by single crystal x-ray diffraction. Both salts are isostructural. The cations are square planar but the N–C–C-sceletial groups of the ligands depart slightly from linearity. The new acetonitrile complexes as well as [Au(NCCH₃)₂][SbF₆] and the adduct CH₃CN · SbF₅ are completely characterized by vibrational spectroscopy.     

PdII and PtII Complexes with Amphiphilic Ligands: Formation of Micelles and [5]Rotaxanes with α‐Cyclodextrin in Aqueous Solution

[3]Pseudorotaxanes [ 1 (α‐CD)₂][X] (X=Cl, NO₃), prepared from reaction of an N‐alkylbipyridinium [4,4′‐bpy‐N‐(CH₂)₁₀OC₆H₃‐3,5‐(OMe)₂][X] ([ 1 ][X]) and α‐CD, react with M(NO₃)₂(en) (M=Pd, Pt; en=1,2‐ethylenediamine) in a 2:1 molar ratio to afford [5]rotaxanes [M{(4,4′‐bpy‐N‐(CH₂)₁₀OC₆H₃‐3,5‐(OMe)₂)(α‐CD)₂}₂ (en)][NO₃]₄ ([ 2 (α‐CD)₄][NO₃]₄, M=Pd; [ 3 (α‐CD)₄][NO₃]₄, M=Pt). A similar reaction of [ 1 ][Cl] with [M(NO₃)₂(en)] (M=Pd, Pt) produces amphiphilic Pd and Pt complexes, [ 2 ][NO₃]₄ and [ 3 ][NO₃]₄. Complexes [ 2 ][NO₃]₄ and [ 3 ][NO₃]₄ form micelles in the presence of small amounts of dyes (Nile red and pyrene) in water. The critical micelle concentration (CMC) was determined by the absorption peak of the dye, which is encapsulated in the micelles in solution. Micelle formation is confirmed by dynamic light scattering measurement of the solution and TEM (transmission electron microscopy) images of the micelles deposited from the solution. Addition of α‐CD to the aqueous solution containing these amphiphilic complexes results in degradation of the micelle structure and the formation of [5]rotaxanes, [ 2 (α‐CD)₄][NO₃]₄ and [ 3 (α‐CD)₄][NO₃]₄.     

Palladium‐, Platin‐ und Dieisenkomplexe mit Isocyanacetat: Ringschluß, säureinduzierte Ringöffnung,Diprotonierung

Palladium, Platinum, and Diiron Complexes with Isocyanoacetate: Ring Closure, Acid‐Induced Ring Opening, Diprotonation Substitution by isocyanoacetate (CNCH₂CO₂^?) of one chloro ligand in trans‐[MCl₂(PPh₃)₂] (M = Pd, Pt) results in the Δ²‐oxazolin‐5‐on‐2‐ato complexes 4a , b , i.e. immediate cyclization occurs in contact with these metal(II) species. In contrast, the open‐chain form of the functional isocyanide is retained in [K(18‐crown‐6][Fe₂Cp₂(CNCH₂CO₂)(CO)₃] ( 16 ) in which it occupies a terminal position. Protonation (alkylation) of the platinum complex 4b proceeds with ring cleavage and formation of isocyano acetic acid 11 (ethyl isocyanoacetate 12 ) stabilized by metal ion coordination. Protonation of 16 requires two equivalents of acid to yield the aminocarbyne‐bridged complex [{μ‐C=N(H)CH₂CO₂H}Fe₂Cp₂(CO)₃](BF₄) ( 17 ) as the only isolable product. Here isocyanoacetate displays a third kind of reactivity pattern in addition to that at Pd^II/Pt^II and that at Cr⁰/W⁰ where the primary species [M(CO)₅CNCH₂CO₂]^? and [M(CO)₅CNCH₂CO₂H] proved to be the most stable. All of the proposed structures are substantiated by analytical and the usual spectroscopic (IR, NMR{¹H, ¹³C, ³¹P}, FAB‐MS) data, that of 4b also by an X‐ray structure determination which reveals a practically perpendicular arrangement of the coordination and the ring plane, and a long C2‐O bond as the predetermined breaking point of the heterocycle.     

Über die Kristallstrukturen der Cyanokomplexe [Co(NH3)6][Fe(CN)6], [Co(NH3)6]2[Ni(CN)4]3 · 2 H2O und [Cu(en)2][Ni(CN)4]

On the Crystal Structures of the Cyano Complexes [Co(NH₃)₆][Fe(CN)₆], [Co(NH₃)₆]₂[Ni(CN)₄]₃ · 2 H₂O, and [Cu(en)₂][Ni(CN)₄] Of the three title compounds X‐ray structure determinations were performed with single crystals. [Co(NH₃)₆][Fe(CN)₆] (a = 1098.6(6), c = 1084.6(6) pm, R3, Z = 3) crystallizes with the CsCl‐like [Co(NH₃)₆][Co(CN)₆] type structure. [Co(NH₃)₆]₂[Ni(CN)₄]₃ · 2 H₂O (a = 805.7(5), b = 855.7(5), c = 1205.3(7) pm, α = 86.32(3), β = 100.13(3), γ = 90.54(3)°, P1, Z = 1) exhibits a related cation lattice, the one cavity of which is occupied by one anion and 2 H₂O, whereas the other contains two anions parallel to each other with distance Ni…Ni: 423,3 pm. For [Cu(en)₂][Ni(CN)₄] (a = 650.5(3), b = 729.0(3), c = 796.5(4) pm, α = 106.67(2), β = 91.46(3), γ = 106.96(2)°, P1, Z = 1) the results of a structure determination published earlier have been confirmed. The compound is weakly paramagnetic and obeys the Curie‐Weiss law in the range T < 100 K. The distances within the complex ions of the compounds investigated (Co–N: 195.7 and 196.4 pm, Ni–C: 186.4 and 186.9 pm, resp.) and their hydrogen bridge relations are discussed.     

Oxorhenium(V) Complexes with 1,3,4‐Triphenyl‐1,2,4‐triazol‐5‐ylidene

Reactions of the oxorhenium(V) complexes [ReOX₃(PPh₃)₂] (X = Cl, Br) with the N‐heterocyclic carbene (NHC) 1,3,4‐triphenyl‐1,2,4‐triazol‐5‐ylidene (L^Ph) under mild conditions and in the presence of MeOH or water give [ReOX₂(Y)(PPh₃)(L^Ph)] complexes (X = Cl, Br; Y = OMe, OH). Attempted reactions of the carbene precursor 5‐methoxy‐1,3,4‐triphenyl‐4,5‐dihydro‐1H‐1,2,4‐triazole ( 1 ) with [ReOCl₃(PPh₃)₂] or [NBu₄][ReOCl₄] in boiling xylene resulted in protonation of the intermediately formed carbene and decomposition products such as [HL^Ph][ReOCl₄(OPPh₃)], [HL^Ph][ReOCl₄(OH₂)] or [HL^Ph][ReO₄] were isolated. The neutral [ReOX₂(Y)(PPh₃)(HL^Ph)] complexes are purple, airstable solids. The bulky NHC ligands coordinate monodentate and in cis‐position to PPh₃. The relatively long Re–C bond lengths of approximate 2.1Å indicate metal‐carbon single bonds.     

The Challenge of Deciphering Linkage Isomers in Mixtures of Oligomeric Complexes Derived from 9‐Methyladenine and trans‐(NH3)2PtII Units

Metal coordination to N9‐substituted adenines, such as the model nucleobase 9‐methyladenine (9MeA), under neutral or weakly acidic pH conditions in water preferably occurs at N1 and/or N7. This leads, not only to mononuclear linkage isomers with N1 or N7 binding, but also to species that involve both N1 and N7 metal binding in the form of dinuclear or oligomeric species. Application of a trans‐(NH₃)₂Pt^II unit and restriction of metal coordination to the N1 and N7 sites and the size of the oligomer to four metal entities generates over 50 possible isomers, which display different feasible connectivities. Slowly interconverting rotamers are not included in this number. Based on ¹H NMR spectroscopic analysis, a qualitative assessment of the spectroscopic features of N1,N7‐bridged species was attempted. By studying the solution behavior of selected isolated and structurally characterized compounds, such as trans‐[PtCl(9MeA‐N7)(NH₃)₂]ClO₄ ? 2H₂O or trans,trans‐[{PtCl(NH₃)₂}₂(9MeA‐N1,N7)][ClO₄]₂ ? H₂O, and also by application of a 9MeA complex with an (NH₃)₃Pt^II entity at N7, [Pt(9MeA‐N7)(NH₃)₃][NO₃]₂, which blocks further cross‐link formation at the N7 site, basic NMR spectroscopic signatures of N1,N7‐bridged Pt^II complexes were identified. Among others, the trinuclear complex trans‐[Pt(NH₃)₂{μ‐(N1‐9MeA‐N7)Pt(NH₃)₃}₂][ClO₄]₆ ? 2H₂O was crystallized and its rotational isomerism in aqueous solution was studied by NMR spectroscopy and DFT calculations. Interestingly, simultaneous Pt^II coordination to N1 and N7 acidifies the exocyclic amino group of the two 9MeA ligands sufficiently to permit replacement of one proton each by a bridging heterometal ion, Hg^II or Cu^II, under mild conditions in water.     

Dinuclear complexes with a μ-cyano ligand. Part XI(1). Synthesis and characterization of several derivatives ofcis-[Co(NH3)(en)2(H2O)]3+

Summary The new complex double saltscw-[Co(NH₃)(en)₂(H₂O)]₂ [M(CN)₄]₃ (en = ethylenediamine; M = Ni, Pd or Pt),cis-[Co(NH₃(en)₂(H₂O)]₂[FeNO(CN)₅]₃ andcis-[Co(NH₃)(en)₂(H₂O)][Co(CN)₆] have been synthesized and by anation in the solid state the corresponding new dinuclear complexes with a cyano bridgecis- ortrans-[(NH₃)(en)₂Co-NC-M(CN)₃]₂ [M(CN)₄] (M = Ni, Pd or Pt);cis-, trans-[(NH₃)(en)₂Co-NC-FeNO(CN)₄]₂[FeNO(CN)₅] andcis-[(NH₃)(en)₂Co-NC-Co(CN)₅ have been prepared. The complexes have been characterized by chemical analysis, t.g. measurements, and by i.r. and electronic spectroscopy. With [Ni(CN)₄][^2– and [Co(CN)in]₆ ^3– only thecis-isomer is produced; with [Pd(CN)₄]^2–, [Pt(CN)₄]^2– and [FeNO(CN)₅]^2– thetrans- isomer is the dominant species. The dinuclear complex derived from [Pt(CN)₄]^2– shows strong Pt-Pt interactions both in the solid state and in solution.     

Syntheses and Structures of New Rare‐Earth Metal Tetracyanidoborates

Six new rare‐earth metal tetracyanidoborates were prepared and characterized by single‐crystal X‐ray diffraction. Crystals of these salts contain co‐crystallized solvent molecules, such as water, acetone, ethanol, or diethyl ether. In [La(EtOH)₃(H₂O)₂{B(CN)₄}₃] ( 1 ), [La(EtOH)(H₂O)₄{B(CN)₄}₃] · Et₂O ( 2 ), and [Y(EtOH)(H₂O)₄{B(CN)₄}₃] · EtOH ( 6 ) the tetracyanidoborate anions are all or in part bonded to the RE³⁺ ions, whereas in [Pr(H₂O)₉][B(CN)₄]₃ · (CH₃)₂CO ( 3 ), [Er(H₂O)₈][B(CN)₄]₃ · (CH₃)₂CO ( 4 ), and [Lu(EtOH)(H₂O)₇][B(CN)₄]₃ · EtOH · 0.5H₂O ( 5 ) the [B(CN)₄]^– anions are not coordinated to the central metal atoms. Only in 1 , one of the three crystallographically independent [B(CN)₄]^– anions acts as a bridging ligand.     

Convenient Access to α‐Fluorinated Alkylammonium Salts

A series of novel α‐fluoroalkyl ammonium salts was obtained from the corresponding cyano compounds or nitriles by reaction with anhydrous HF. Room‐temperature stable trifluoromethyl ammonium salts were obtained in quantitative yield in a one‐step reaction at ambient temperature from the commercially available starting materials BrCN or ClCN. The novel cations [CF₃CF₂NH₃]⁺, [HCF₂CF₂NH₃]⁺, and [(NH₃CF₂)₂]²⁺ were obtained from CF₃CN, HCF₂CN, and (CN)₂, respectively, and anhydrous HF. The aforementioned fluorinated ammonium cations were isolated as room temperature stable [AsF₆]^? and/or [SbF₆]^? salts, and characterized by multi‐nuclear NMR and vibrational spectroscopy. The salts [HCF₂NH₃][AsF₆] and [CF₃NH₃][Sb₂F₁₁] were characterized by their X‐ray crystal structure.     

阴离子导向组装：两个具有不同阳离子的多维Ag(I)配合物的晶体结构

Assembly of [Ag（CN）2]^- units with M（Ⅱ）-diamine complex cations [Cu（LN-N）2]^2＋, where LN-N represents L2-diaminopropane （pn） and ethylenediamine （en）, afforded two complexes, [Cu（pn）2][Ag2（CN）4] （1） and [Cu（en）2][Ag3（CN）5] （2）, which were characterized by elemental analysis, IR, UV-Vis and ESR spectra. Single crystal X-ray analyses show that these complexes have 2D and 3D architectures through silver-silver interactions and other weak interactions. The luminescence behaviors of the two complexes were also studied by means of emission spectra.     

PtII Coordination to N1 of 9‐Methylguanine: Why it Facilitates Binding of Additional Metal Ions to the Purine Ring

The preparation and X‐ray crystal structure analysis of {trans‐[Pt(MeNH₂)₂(9‐MeG‐N1)₂]} ? {3 K₂[Pt(CN)₄]} ? 6 H₂O ( 3 a ) (with 9‐MeG being the anion of 9‐methylguanine, 9‐MeGH) are reported. The title compound was obtained by treating [Pt(dien)(9‐MeGH‐N7)]²⁺ ( 1 ; dien=diethylenetriamine) with trans‐[Pt(MeNH₂)₂(H₂O)₂]²⁺ at pH 9.6, 60 °C, and subsequent removal of the [(dien)Pt^II] entities by treatment with an excess amount of KCN, which converts the latter to [Pt(CN)₄]^2?. Cocrystallization of K₂[Pt(CN)₄] with trans‐[Pt(MeNH₂)₂(9‐MeG‐N1)₂] is a consequence of the increase in basicity of the guanine ligand following its deprotonation and Pt coordination at N1. This increase in basicity is reflected in the pK_a values of trans‐[Pt(MeNH₂)₂(9‐MeGH‐N1)₂]²⁺ (4.4±0.1 and 3.3±0.4). The crystal structure of 3 a reveals rare (N7,O6 chelate) and unconventional (N2,C2,N3) binding patterns of K⁺ to the guaninato ligands. DFT calculations confirm that K⁺ binding to the sugar edge of guanine for a N1‐platinated guanine anion is a realistic option, thus ruling against a simple packing effect in the solid‐state structure of 3 a . The linkage isomer of 3 a , trans‐[Pt(MeNH₂)₂(9‐MeG‐N7)₂] ( 6 a ) has likewise been isolated, and its acid–base properties determined. Compound 6 a is more basic than 3 a by more than 4 log units. Binding of metal entities to the N7 positions of 9‐MeG in 3 a has been studied in detail for [(NH₃)₃Pt^II], trans‐[(NH₃)₂Pt^II], and [(en)Pd^II] (en=ethylenediamine) by using ¹H NMR spectroscopy. Without exception, binding of the second metal takes place at N7, but formation of a molecular guanine square with trans‐[(Me₂NH₂)Pt^II] cross‐linking N1 positions and trans‐[(NH₃)₂Pt^II] cross‐linking N7 positions could not be confirmed unambiguously, despite the fact that calculations are fully consistent with its existence.     

Monitoring and Understanding the Paraelectric–Ferroelectric Phase Transition in the Metal–Organic Framework [NH4][M(HCOO)3] by Solid‐State NMR Spectroscopy

The paraelectric–ferroelectric phase transition in two isostructural metal–organic frameworks (MOFs) [NH₄][M(HCOO)₃] (M=Mg, Zn) was investigated by in situ variable‐temperature ²⁵Mg, ⁶⁷Zn, ¹⁴N, and ¹³C solid‐state NMR (SSNMR) spectroscopy. With decreasing temperature, a disorder–order transition of NH₄⁺ cations causes a change in dielectric properties. It is thought that [NH₄][Mg(HCOO)₃] exhibits a higher transition temperature than [NH₄][Zn(HCOO)₃] due to stronger hydrogen‐bonding interactions between NH₄⁺ ions and framework oxygen atoms. ²⁵Mg and ⁶⁷Zn NMR parameters are very sensitive to temperature‐induced changes in structure, dynamics, and dielectric behavior; stark spectral differences across the paraelectric–ferroelectric phase transition are intimately related to subtle changes in the local environment of the metal center. Although ²⁵Mg and ⁶⁷Zn are challenging nuclei for SSNMR experiments, the highly spherically symmetric metal‐atom environments in [NH₄][M(HCOO)₃] give rise to relatively narrow spectra that can be acquired in 30–60 min at a low magnetic field of 9.4 T. Complementary ¹⁴N and ¹³C SSNMR experiments were performed to probe the role of NH₄⁺–framework hydrogen bonding in the paraelectric–ferroelectric phase transition. This multinuclear SSNMR approach yields new physical insights into the [NH₄][M(HCOO)₃] system and shows great potential for molecular‐level studies on electric phenomena in a wide variety of MOFs.     

Desymmetrization of an Octahedral Coordination Complex Inside a Self‐Assembled Exoskeleton

The synthesis of a centrally functionalized, ribbon‐shaped [6]polynorbornane ligand L that self‐assembles with Pd^II cations into a {Pd₂ L ₄} coordination cage is reported. The shape‐persistent {Pd₂ L ₄} cage contains two axial cationic centers and an array of four equatorial H‐bond donors pointing directly towards the center of the cavity. This precisely defined supramolecular environment is complementary to the geometry of classic octahedral complexes [M(XY)₆] with six diatomic ligands. Very strong binding of [Pt(CN)₆]^2? to the cage was observed, with the structure of the host–guest complex {[Pt(CN)₆]@Pd₂L₄} supported by NMR spectroscopy, MS, and X‐ray data. The self‐assembled shell imprints its geometry on the encapsulated guest, and desymmetrization of the octahedral platinum species by the influence of the D_4h‐symmetric second coordination sphere was evidenced by IR spectroscopy. [Fe(CN)₆]^3? and square‐planar [Pt(CN)₄]^2? were strongly bound. Smaller octahedral anions such as [SiF₆]^2?, neutral carbonyl complexes ([M(CO)₆]; M=Cr, Mo, W) and the linear [Ag(CN)₂]^? anion were only weakly bound, showing that both size and charge match are key factors for high‐affinity binding.     

IV Dodekaedrische [Mo(CN)8]‐Koordination in den cyanoverbrückten Cobalt‐ und Nickel‐Amminkomplexen MII2(NH3)8[Mo(CN)8] · 1,5 H2O (MII = Co,Ni) und Ni2(NH3)9[Mo(CN)8] · 2 H2O

Crystal Structures of Octacyanomolybdates(IV). IV Dodecahedral [Mo(CN)₈] Coordination of the Cyano‐Bridged Cobalt and Nickel Ammin Complexes M^II₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (M^II = Co, Ni) and Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O At single crystals of the hydrated cyano complexes Co₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 910.0(4), b = 1671(2), c = 1501(1) pm, β = 93.76(6)°) and Ni₂(NH₃)₈[Mo(CN)₈] · 1.5 H₂O (a = 899.9(9), b = 1654.7(4), c = 1488(1) pm, β = 94.01°), isostructurally crystallizing in space group P2₁/c, Z = 4, and of trigonal Ni₂(NH₃)₉[Mo(CN)₈] · 2 H₂O (a = 955.1(1), c = 2326.7(7) pm, P3₁, Z = 3), X‐ray structure determinations were performed at 168 resp. 153 K. The [Mo(CN)₈]^4– groups of the three compounds, prepared at about 275 K and easily decomposing, show but slightly distorted dodecahedral coordination (mean distances Mo–C: 216.3, 215.4 and 216.1 pm). Within the monoclinic complexes the anions twodimensionally form cyano bridges to the ammin cations [M(NH₃)₄]²⁺ and are connected with the resulting [MN₆] octahedra (Co–N: 215.1 pm, Ni–N: 209.8 pm) into strongly puckered layers. The trigonal complex exhibits a chain structure, as one [Ni(NH₃)₅]²⁺ cation is only bound as terminal octahedron (Ni–N: 212.0 pm). Details and the influence of hydrogen bridges are discussed.     

Neon‐Bearing Ammonium Metal Formates: Formation and Behaviour under Pressure

The incorporation of noble gas atoms, in particular neon, into the pores of network structures is very challenging due to the weak interactions they experience with the network solid. Using high‐pressure single‐crystal X‐ray diffraction, we demonstrate that neon atoms enter into the extended network of ammonium metal formates, thus forming compounds Ne_x[NH₄][M(HCOO)₃]. This phenomenon modifies the compressional and structural behaviours of the ammonium metal formates under pressure. The neon atoms can be clearly localised within the centre of [M(HCOO)₃]₅ cages and the total saturation of this site is achieved after ～1.5 GPa. We find that by using argon as the pressure‐transmitting medium, the inclusion inside [NH₄][M(HCOO)₃] is inhibited due to the larger size of the argon. This study illustrates the size selectivity of [NH₄][M(HCOO)₃] compounds between neon and argon insertion under pressure, and the effect of inclusion on the high‐pressure behaviour of neon‐bearing ammonium metal formates.     

Tellurium‐Halogen Secondary Bonding in the Crystal Structures of [Q]+[PhTeCl4]— (Q = C5NH6, 2‐Br‐C5NH5, {2‐Br‐C5NH5}{Co(NH3)4Cl2})

The reaction of diphenylditelluride with pyridine, 2‐bromopyridine or 2‐bromopyridine/tetraamminedichlorocobalt(III) chloride in 12 M hydrochloric acid afforded the tetrachlorophenyltellurate(IV) compounds [C₅NH₆][PhTeCl₄] ( 1 ), [2‐Br‐C₅NH₅] [PhTeCl₄] ( 2 ), and [{2‐Br‐C₅NH₅}{Co(NH₃)₄Cl₂}] [PhTeCl₄]₂ ( 3 ). They were all characterized structurally by single crystal X‐ray diffraction. In all structures, the arrangement about the tellurium atoms is square pyramidal. The [PhTeCl₄]^— anions in 1 and 2 form trimeric and dimeric units, respectively, through Te···Cl secondary bonding. Compound 3 shows an unusual face‐to‐face packing of the [PhTeCl₄]^—anions with hydrogen bonding to the bromopyridium cation.     

Zweikernige Palladium(II)‐, Platin(II)‐ und Iridium(III)‐Komplexe von Bis[imidazol‐4‐yl]alkanen

Dinuclear Palladium(II), Platinum(II), and Iridium(III) Complexes of Bis[imidazol‐4‐yl]alkanes The reaction of bis(1,1′‐triphenylmethyl‐imidazol‐4‐yl) alkanes ((CH₂)_n bridged imidazoles L(CH₂)_nL, n = 3–6) with chloro bridged complexes [R₃P(Cl)M(μ‐Cl)M(Cl)PR₃] (M = Pd, Pt; R = Et, Pr, Bu) affords the dinuclear compounds [Cl₂(R₃P)M–L(CH₂)_nL–M(PR₃)Cl₂] 1 – 17 . The structures of [Cl₂(Et₃P)Pd–L(CH₂)₃L–Pd(PEt₃)Cl₂] ( 1 ), [Cl₂(Bu₃P)Pd–L(CH₂)₄L–Pd(PBu₃)Cl₂] ( 10 ), [Cl₂(Et₃P)Pd–L(CH₂)₅L–Pd(PEt₃)Cl₂] ( 3 ), [Cl₂(Et₃P)Pt–L(CH₂)₃L–Pt(PEt₃)Cl₂] ( 13 ) with trans Cl–M–Cl groups were determined by X‐ray diffraction. Similarly the complexes [Cl₂(Cp*)Ir–L(CH₂)_nL–Ir(Cp*)Cl₂] (n = 4–6) are obtained from [Cp*(Cl)Ir(μ‐Cl)₂Ir(Cl)Cp*] and the methylene bridged bis(imidazoles).     

Synthesen und NMR‐Untersuchungen von Salzen mit den neuen Anionen [PtXn(CF3)6‐n]2— (n = 0 ‐ 5, X = F,OH, Cl,CN) und die Kristallstrukturanalyse von K2[(CF3)2F2Pt(μ‐OH)2PtF2(CF3)2]·2H2O

Syntheses and NMR Spectroscopic Ivestigations of Salts containing the Novel Anions [PtX_n(CF₃)_6‐n]^2— (n = 0 ‐ 5, X = F, OH, Cl, CN) and Crystal Structure of K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O The first syntheses of trifluoromethyl‐complexes of platinum through fluorination of cyanoplatinates are reported. The fluorination of tetracyanoplatinates(II), K₂[Pt(CN)₄], and hexacyanoplatinates(IV), K₂[Pt(CN)₆], with ClF in anhydrous HF leads after working up of the products to K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O. The structure of the salt is determined by a X‐ray structure analysis, P2₁/c (Nr. 14), a = 11.391(2), b = 11.565(2), c = 13.391(3)Å, β = 90.32(3)°, Z = 4, R₁ = 0.0326 (I > 2σ(I)). The reaction of [Bu₄N]₂[Pt(CN)₄] with ClF in CH₂Cl₂ generates mainly cis‐[Bu₄N]₂[PtCl₂(CF₃)₄] and fac‐[Bu₄N]₂[PtCl₃(CF₃)₃], but in contrast that of [Bu₄N]₂[Pt(CN)₆] with ClF in CH₂Cl₂ results cis‐[Bu₄N]₂[PtX₂(CF₃)₄], [Bu₄N]₂[PtX(CF₃)₅] (X = F, Cl) and [Bu₄N]₂[Pt(CF₃)₆]. In the products [Bu₄N]₂[PtX_n(CF₃)_6‐n] (X = F, Cl, n = 0—3) it is possibel to exchange the fluoro‐ligands into chloro‐ and cyano‐ligands by treatment with (CH₃)₃SiCl und (CH₃)₃SiCN at 50 °C. With continuing warming the trifluoromethyl‐ligands are exchanged by chloro‐ and cyano‐ligands, while as intermediates CF₂Cl and CF₂CN ligands are formed. The identity of the new trifluoromethyl‐platinates is proved by ¹⁹⁵Pt‐ and ¹⁹F‐NMR‐spectroscopy.     

Metallkomplexe mit biologisch wichtigen Liganden. CLVII [1] Halbsandwich‐Komplexe mit Isocyanoacetylaminosäureestern und Isocyanoacetyldi‐ und tripeptidestern („Isocyano‐Peptide”︁)

Metal Complexes of Biologically Important Ligands, CLVII [1] Halfsandwich Complexes of Isocyanoacetylamino acid esters and of Isocyanoacetyldi‐ and tripeptide esters (?Isocyanopeptides”?) N‐Isocyanoacetyl‐amino acid esters CNCH₂C(O) NHCH(R)CO₂CH₃ (R = CH₃, CH(CH₃)₂, CH₂CH(CH₃)₂, CH₂C₆H₅) and N‐isocyanoacetyl‐di‐ and tripeptide esters CNCH₂C(O)NHCH(R¹)C(O)NHCH(R²)CO₂C₂H₅ and CNCH₂C(O)NHCH(R¹)C(O)NHCH (R²)C(O)NHCH(R³)CO₂CH₃ (R¹ = R² = R³ = CH₂C₆H₅, R² = H, CH₂C₆H₅) are available by condensation of potassium isocyanoacetate with amino acid esters or peptide esters. These isocyanides form with chloro‐bridged complexes [(arene)M(Cl)(μ‐Cl)]₂ (arene = Cp*, p‐cymene, M = Ir, Rh, Ru) in the presence of Ag[BF₄] or Ag[CF₃SO₃] the cationic halfsandwich complexes [(arene)M(isocyanide)₃]⁺X^? (X = BF₄, CF₃SO₃).     

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).