Phenylimidorhenium(V) Complexes with 1,3‐Diethyl‐4,5‐dimethylimidazole‐2‐ ylidene Ligands

The phenylimidorhenium(V) complexes [Re(NPh)X₃(PPh₃)₂] (X = Cl, Br) react with the N‐heterocyclic carbene (NHC) 1,3‐diethyl‐4,5‐dimethylimidazole‐2‐ylidene (L^Et) under formation of the stable rhenium(V) complex cations [Re(NPh)X(L^Et)₄]²⁺ (X = Cl, Br), which can be isolated as their chloride or [PF₆]^? salts. The compounds are remarkably stable against air, moisture and ligand exchange. The hydroxo species [Re(NPh)(OH)(L^Et)₄]²⁺ is formed when moist solvents are used during the synthesis. The rhenium atoms in all three complexes are coordinated in a distorted octahedral fashion with the four NHC ligands in equatorial planes of the molecules. The Re–C(carbene) bond lengths between 2.171(8) and 2.221(3) Å indicate mainly σ‐bonding between the NHC ligand and the electron deficient d² metal atoms. Attempts to prepare analogous phenylimido complexes from [Re(NPh)Cl₃(PPh₃)₂] and 1,3‐diisopropyl‐4,5‐dimethylimidazole‐2‐ylidene (L^i?Pr) led to a cleavage of the rhenium‐nitrogen multiple bond and the formation of the dioxo complex [ReO₂(L^i?Pr)₄]⁺.     

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

[ReNCl₂(PPh₃)₂] and [ReNCl₂(PMe₂Ph)₃] react with the N‐heterocyclic carbene (NHC) 1,3,4‐triphenyl‐1,2,4‐triazol‐5‐ylidene (HL^Ph) under formation of the stable rhenium(V) nitrido complex [ReNCl(HL^Ph)(L^Ph)], which contains one of the two NHC ligands with an additional orthometallation. The rhenium atom in the product is five‐coordinate with a distorted square‐pyramidal coordination sphere. The position trans to the nitrido ligand is blocked by one phenyl ring of the monodentate HL^Ph ligand. The Re–C(carbene) bond lengths of 2.072(6) and 2.074(6) Å are comparably long and indicate mainly σ‐bonding between the NHC ligand and the electron deficient d² metal atom. The chloro ligand in [ReNCl(HL^Ph)(L^Ph)] is labile and can be replaced by ligands such as pseudohalides or monoanionic thiolates such as diphenyldithiophosphinate (Ph₂PS₂^?) or pyridine‐2‐thiolate (pyS^?). X‐ray structure analyses of [ReN(CN)(HL^Ph)(L^Ph)] and [ReN(pyS)(HL^Ph)(L^Ph)] show that the bonding situation of the NHC ligands (Re–C(carbene) distances between 2.086(3) and 2.130(3) Å) in the product is not significantly influenced by the ligand exchange. The potentially bidentate pyS^? ligand is solely coordinated via its thiolato functionality. Hydrogen atoms of each one of the phenyl rings come close to the unoccupied sixth coordination positions of the rhenium atoms in the solid state structures of all complexes. Re–H distances between 2.620 and 2.712Å do not allow to discuss bonding, but with respect to the strong trans labilising influence of “N^3?”, weak interactions are indicated.     

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.     

Syntheses and Structures of Nitridorhenium(V) and Nitridotechnetium(V) Complexes with N,N‐[(Dialkylamino)(thiocarbonyl)]‐N′‐(2‐hydroxyphenyl)benzamidines

[MNCl₂(PPh₃)₂] complexes (M = Re, Tc) react with N‐[(dialkylamino)(thiocarbonyl)]‐N′‐(2‐hydroxyphenyl)benzamidines (H₂L¹) with formation of neutral, five‐coordinate nitrido complexes of the composition [MN(L¹)(PPh₃)]. The products have distorted square‐pyramidal coordination spheres with each a tridentate, double‐deprotonated benzamidine and a PPh₃ ligand in their basal planes.     

Nitridorhenium(V) and nitridotechnetium(V) complexes with 2-(diphenylphoshinomethyl)aniline

Reactions of 2-(diphenylphosphinomethyl)aniline, H₂L¹, with [MNCl₂(PPh₃)₂] complexes (M = Re, Tc) give the bis-chelates [MNCl(H₂L¹)₂]Cl (M = Re, Tc) or the mono-chelate [ReNCl₂(PPh₃)(H₂L¹)] depending on the conditions applied. The aminophosphine reacts as a bidentate, neutral ligand in all three cases. The complexes were studied spectroscopically and by X-ray crystallography.     

Nitridorhenium(V)‐Komplexe mit Dimercaptobernsteinsäuredimethylester. Präparation,Charakterisierung und Kristallstruktur von [Re{NC(CH3)2PPhMe2}(DMSMe2)2]

Nitridorhenium(V) Complexes with Dimercapto Succinic Acid Dimethylester. Preparation, Characterization, and Crystal Structure of [Re{NC(CH₃)₂PPhMe₂}(DMSMe₂)₂] Reaction of [ReNCl₂(Me₂PhP)₃] 1 with two equivalents of dimercaptosuccinic acid dimethylester (DMSMe₂) results in the formation of a neutral, diamagnetic rhenium(V)‐DMSMe₂ complex with a phenyldimethylphosphinoisopropyl group at the nitrido ligand as a consequence of a nucleophilic attack of the coordinated nitrido ligand on the solvent molecule. The formed complex 2 of the composition [Re{NC(CH₃)₂(Me₂PhP)}(DMSMe₂)₂] crystallizes in the triclinic space group P 1, a = 12.334(7), b = 12.412(7), c = 12.414(8) Å; α = 60.14(3)°, β = 67.98(3)°, γ = 80.63(6)°; Z = 2. Rhenium is located in a square‐pyramidal configuration of the donor atoms. The two meso‐DMSMe₂ ligands are in a syn‐endo conformation. The rhenium‐nitrogen bond (1.697(12) Å) is only slightly longer than typical Re–N bonding distances in nitrido complexes and comparable with other Re–N–C bonding distances. The addition of a solvent molecule is observed in acetone ( 2 ) as well as in methylethylketone ( 3 ). Moreover, a reaction of the nitrido group with the condensation product of ketone is found by mass spectrometry ([ReN{C(CH₃)(C₂H₅)CH₂C(O)C₂H₅(Me₂PhP)}(DMSMe₂)₂] 4 ).     

Synthesis and Reactivity of Structurally Analogous Phenylimido and Oxo Complexes of Rhenium(V) with N,N‐Dialkyl‐N′‐benzoylthioureas

[ReOCl₃(PPh₃)₂] and [Re(NPh)Br₃(PPh₃)₂] react at room temperature with equivalent amounts of N,N‐dialkyl‐N′‐benzoylthioureas (HR¹R²btu) in CH₂Cl₂ under formation of the rhenium(V) complexes [ReOCl₂(R¹R¹btu)(PPh₃)] and [Re(NPh)Br₂(R¹R²btu)(PPh₃)], respectively. The products are structurally analogous with the oxygen atoms of the benzoylthioureas binding in trans positions to the oxo or phenylimido ligands. Prolonged reaction times result in the reduction of the oxo compound by the released PPh₃ and the formation of rhenium(III) complexes of the composition [ReCl₂(PPh₃)₂(R¹R²btu)], while such a second reaction path is excluded for the phenylimido compound. Phenylimido species with more than one N,N‐dialkyl‐N′‐benzoylthioureato ligand could not be isolated, even when a large excess of HR¹R²btu was used during the reaction.     

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.     

(PPh4)2[Cl2Re(N3S2)(μ‐NSN)(μ‐N≡ReCl3)]2 – ein Rhenium(VII)‐Komplex mit einer Nitrido‐, einer Dinitridosulfato(II)‐ und einer Rhena‐3,5‐dithia‐2,4,6‐triazino‐Funktion

(PPh₄)₂[Cl₂Re(N₃S₂)(μ‐NSN)(μ‐N≡ReCl₃)]₂ – a Rhenium(VII) Complex with a Nitrido, a Dinitridosulfato(II), and a Rhena‐3,5‐dithia‐2,4,6‐triazino Function The title compound has been prepared from PPh₄[Re^VIICl₄(NSCl)₂] with N(SiMe₃)₃ in dichloromethane solution to give red‐brown single crystals, which were suitable for a crystal structure determination. As a by‐product PPh₄[ReNCl₄] is formed. (PPh₄)₂[Cl₂Re^VII(N₃S₂)(μ‐NSN)(μ‐N≡Re^VIICl₃)]₂ ( 1 ): Space group P2₁/c, Z = 2, lattice dimensions at –80 °C: a = 1280.8(2), b = 1017.5(1), c = 2467.8(3) pm, β = 95.04(1)°, R = 0.049. The complex anion of 1 consists of a planar ReN₃S₂‐heterocycle which is connected with the second rhenium atom by a μ‐nitrido bridge as well as by a μ‐dinitridosulfato(II) ligand to form a planar Re₂(N)(NSN) six‐membered heterocycle. This [Cl₂Re(N₃S₂)(μ‐NSN)(μ‐N≡ReCl₃)]^– unit dimerizes via one of the N‐atoms of the (NSN)^4– ligand to give a centrosymmetric Re₂N₂ four‐membered ring.     

(PPh4)2[(SN)ReCl3(μ‐N)(μ‐NSN)ReCl3(THF)] – ein Nitrido‐Thionitrosyl‐Dinitridosulfato‐Komplex des Rheniums

(PPh₄)₂[(SN)ReCl₃(μ‐N)(μ‐NSN)ReCl₃(THF)] – a Nitrido‐Thionitrosyl‐Dinitridosulfato‐Complex of Rhenium The title compound has been prepared from PPh₄[Re^VIICl₄(NSCl)₂] with excess N(SiMe₃)₃ in dichloromethane solution to give red‐brown single crystals after recrystallisation from acetonitrile/THF solutions. As a by‐product PPh₄[ReNCl₄] is formed. (PPh₄)₂[(SN)ReCl₃(μ‐N)(μ‐NSN)ReCl₃(THF)] ( 1 ): Space group P2₁/n, Z = 4, lattice dimensions at –80 °C: a = 1024.1(1), b = 2350.2(1), c = 2315.4(2) pm, β = 94.09(1)°, R₁ = 0.0403. In the complex anion of 1 the rhenium atoms are connected by an asymmetric Re≡N–Re bridge as well as by a (NSN)^4–‐bridge to form a planar Re₂N(NSN) six‐membered heterocycle. Both rhenium atoms are coordinated by three chlorine atoms, one of them by a thionitrosyl ligand, the other one by the oxygen atom of a thf molecule.     

Synthese und Struktur der Nitrido‐Komplexe [(n‐Bu)4N]2[{(L)Cl4Re≡N}2PtCl2] (L = THF und H2O) und [(n‐Bu)4N]2[(H2O)Cl4Re≡N‐PtCl(μ‐Cl)]2

Synthesis and Crystal Structure of the Nitrido Complexes [(n‐Bu)₄N]₂[{(L)Cl₄Re≡N}₂PtCl₂] (L = THF und H₂O) and [(n‐Bu)₄N]₂[(H₂O)Cl₄Re≡N‐PtCl(μ‐Cl)]₂ The threenuclear complex [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}_2—PtCl₂] ( 1a ) is obtained by the reaction of [(n‐Bu)₄N][ReNCl₄] with [PtCl₂(C₆H₅CN)₂] in THF/CH₂Cl₂. It forms red crystals with the composition 1a · 2 CH₂Cl₂ crystallizing in the tetragonal space group I4₁/a with a = 3186.7(2); c = 1311.2(1) pm and Z = 8. If the reaction of the educts is carried out without THF, however under exposure to air the compound [(n‐Bu)₄N]₂[{(H₂O)Cl₄Re≡N}₂PtCl₂] ( 1b ) is obtained as red trigonal crystals with the space group R3 and a = 3628.3(3), c = 1231.4(1) pm and Z = 9. In the centrosymmetric complex anions [{(L)Cl₄Re≡N}₂PtCl₂]^2— a linear PtCl₂moiety is connected in a trans arrangement with two complex fragments [(L)Cl₄Re≡N]^— via asymmetric nitrido bridges Re≡dqN‐Pt. For Pt^II such results a square‐planar coordination PtCl₂N₂. The linear nitrido bridges are characterized by distances Re‐N = 169.5 pm and Pt‐N = 188.8 pm ( 1a ), respectively, Re‐N = 165.6 pm and Pt‐N = 194.1 pm ( 1b ). By the reaction of [(n‐Bu)₄N][ReNCl₄] with PtCl₄ in CH₂Cl₂ platinum is reduced forming the heterometallic Re^VI/Pt^II complex, [(n‐Bu)₄N]₂[(H₂O)Cl₄Re≡N‐PtCl(μ‐Cl)]₂ ( 2 ). It crystallizes in the monoclinic space group C2/c with a = 2012.9(1); b = 1109.0(2); c = 2687.4(4) pm; β = 111.65(1)° and Z = 4. In the central unit ClPt(μ‐Cl)₂PtCl of the anionic complex [(H₂O)Cl₄Re≡N‐PtCl(μ‐Cl)]₂^2— with the symmetry C₂ the coordination of the Pt atoms is completed by two nitrido bridges Re≡N‐Pt to nitrido complex fragments [(H₂O)Cl₄Re≡N] ^— forming a square‐planar arrangement for the Pt atoms. The distances in the linear nitrido bridges are Re‐N = 165.9 pm and Pt‐N = 190.1 pm.     

New Rhenium(V) Nitrofuryl Semicarbazone Complexes.Crystal Structure of [ReOCl2(PPh3)(3‐(5‐Nitrofuryl)acroleine semicarbazone)]

The synthesis and characterization of the first two Re complexes with semicarbazone ligands is presented. Selected ligands are 5‐Nitro‐2‐furaldehyde semicarbazone (Nitrofurazone) ( L1 ) and its derivative 3‐(5‐Nitrofuryl)acroleine semicarbazone ( L2 ). Complexes of general formula [Re^VOCl₂(PPh₃) L ], where L = L1 and L2 , were prepared in good yields and high purity by reaction of [Re^VOCl₃(PPh₃)₂] with L in ethanol or methanol solutions. The complexes formula and molecular structures were supported by elemental analyses and electronic, FTIR, ¹H, ¹³C and ³¹P NMR spectroscopies. In addition, the crystal and molecular structure of [Re^VOCl₂(PPh₃) L2 ] was determined by X‐ray diffraction methods. [ReOCl₂(PPh₃)(3‐(5‐Nitrofuryl)acroleine semicarbazone)] crystallizes in the space group P‐1 with a = 11.2334(2), b = 11.3040(2), c = 12.5040(2) Å, α = 81.861(1), β = 63.555(1), γ = 83.626(1)°, and Z = 2. The Re(V) ion is in a distorted octahedral environment, equatorially coordinated to a deprotonated semicarbazone molecule acting as a bidentate ligand through its carbonylic oxygen and azomethynic nitrogen atoms, to an oxo ligand and a chlorine atom. The six‐fold coordination is completed by another chlorine atom and a triphenylphosphine ligand at the axial positions.     

Synthese und Strukturen von [ReNBr2(Me2PhP)3] und (Me2PhPH)[fac‐Re(NBBr3)Br3(Me2PhP)2]

Syntheses and Structures of [ReNBr₂(Me₂PhP)₃] and (Me₂PhPH)[ fac ‐Re(NBBr₃)Br₃(Me₂PhP)₂] [ReNBr₂(Me₂PhP)₃] ( 1 ) has been prepared by the reaction of [ReNCl₂(Me₂PhP)₃] with Me₃SiBr in dichloromethane. The bromo complex reacts with BBr₃ under formation of [Re(NBBr₃)Br₂(Me₂PhP)₃] ( 2 ) or (Me₂PhPH)[fac‐Re(NBBr₃)Br₃(Me₂PhP)₂] ( 3 ) depending on the experimental conditions. The formation of the nitrido bridge leads to a significant decrease of the structural trans influence of the nitrido ligand which is evident by the shortening of the Re‐(trans)Br bond from 2.795(1) Å in [ReNBr₂(Me₂PhP)₃] to 2.620(1) Å in [fac‐Re(NBBr₃)Br₃(Me₂PhP)₂]^– and 2.598(1) Å in [Re(NBBr₃)Br₂(Me₂PhP)₃], respectively.     

trans‐[Re(NH3)I2(Me2PhP)3]I3 – Bildung eines Amminaus einem Nitridoliganden

trans ‐[Re(NH₃)I₂(Me₂PhP)₃]I₃ – Formation of an Ammine Ligand from a Nitrido Ligand The reaction of [ReNCl₂(Me₂PhP)₃] (Me₂PhP = dimethylphenylphosphine) with Me₃SiI in dichloromethane results in the formation of trans‐[Re(NH₃)I₂(Me₂PhP)₃]I₃. The unusual protonation of a nitrido ligand is due to the partial decomposition of the solvent.     

Organochromium(II) and Organonitridochromium(V) N‐Heterocyclic Carbene Complexes: Synthesis and Structural Characterization

The N‐heterocyclic carbene‐stabilized chromium(II) alkyl, aryl, and alkynyl complexes (IPM)₂CrR₂ [R = Me ( 2 ), Ph ( 3 ), C≡CPh ( 3 ); IPM = 1,3‐diisopropyl‐4,5‐dimethylimidazole‐2‐ylidene] were prepared by metathesis reactions of (IPM)₂CrCl₂ ( 1 ) with the corresponding organolithium reagents. Further reaction of 3 with an organic azide, 1‐azidoadamantane, yielded an organonitridochromium(V) compound (IPM)₂Ph₂Cr≡N ( 5 ). Compounds 2 – 5 are fully characterized by ¹H NMR and IR spectroscopy, X‐ray crystallography as well as by elemental analysis. The structural analysis shows that the metal atom adopts a nearly square‐planar arrangement in the respective 2 , 3 , and 4 and a square‐pyramidal one in 5 . The reaction of 3 with the organic azide to 5 appears a novel way to the organonitridochromium compound.     

Reactions of Nitridotechnetium(V) Complexes with Boranes

Nitrido bridges between technetium and boron were formed during reactions of [TcN(PMe₂Ph)(Et₂dtc)₂] (Et₂dtc^? = diethyldithiocarbamate) and BH₃ or BPhCl₂ at low temperatures. X‐Ray structure determinations show that the products contain almost linear Tc–N–B bonds with Tc–N distances which are only slightly lengthened with respect to the triple bonds in the precursor molecule. However, a significant lengthening of the Tc–S bond trans to the nitrido ligand is detected by the decrease of the structural trans influence of “N^3?”N. The compounds are instable and decompose at room temperature under cleavage of the N–B bonds. A reaction between [TcNCl₂(PPh₃)₂] and BCl₃ does not yield a product with a nitrido bridge. Prolonged heating in dichloromethane results in decomposition of the technetium complex and the formation of (HPPh₃)₂[TcCl₆]. Hydrogen bonds are established between the complex anion and each two counter ions.     

Oxidative Addition of 2‐Halogenoazoles—Direct Synthesis of Palladium(II) Complexes Bearing Protic NH,NH‐Functionalized NHC Ligands

The chemistry of N‐heterocyclic carbenes (NHCs) is dominated by N,N′‐dialkylated or ‐diarylated derivatives. Such NHC ligands are normally obtained by C2‐deprotonation of azolium cations or by reductive elimination from azol‐2‐thiones. A simple one‐step procedure is described that leads to complexes with NH,NH‐functionalized NHC ligands by the oxidative addition of 2‐halogenoazoles to complexes of zero‐valent transition metals.     

[{ReN(Me2PhP)(Et2dtc)Cl}2{ReN(Et22tc)2}2{SbCl3}2] — ein neuer vierkerniger Rheniumkomplex mit asymmetrischen Nitridobrücken

[{ReN(Me₂PhP)(Et₂dtc)Cl}₂{ReN(Et₂dtc)₂}₂{SbCl₃}₂] — a Novel Tetranuclear Rhenium Complex with Asymmetric Nitrido Bridges The reaction of [ReN(Et₂dtc)₂(Me2₂hP)] (Me₂PhP = dimethylphenylphosphine, Et₂dtc^‐ = diethyldithiocarbamate) with SbCl₃ in dichloromethane results in the formation of [{ReN(Me₂PhP)(Et2₂tc)Cl}₂{ReN(Et₂dtc)₂}₂{SbCl₃}₂]. A {Re≡N‐}₄ ring with asymmetric nitrido bridges is stabilised by the co‐ordination of SbCl₃ onto the chloro ligands and sulphur atoms of the dithiocarbamates. The compound decomposes upon heating in acetonitrile and the fragments of the tetrameric complex re‐arrange to form [ReN‐(Me₂PhP)(Et₂dtc)Cl]₄ and [ReN(Et₂dtc)₂]. The multinuclear rhenium compounds have been studied by X‐ray crystallography. The 8‐membered {Re≡N‐}₄ ring system in [{ReN(Me₂PhP)(Et₂dtc)Cl}2₂ReN(Et₂dtc)₂}₂{SbCl₃}₂] is almost planar, while that of [ReN(Me₂PhP)(Et₂dtc)Cl]₄ is clearly V‐shaped when viewed down either diagonal Re…Re axis. A dihedral angle of 47.88(2)° has been found between the contributing planes.     

Synthese und Kristallstrukturen der heteronuklearen Nitrido‐Komplexe [(Me2PhP)3(MeCN)ClRe≡N–MCl5] mit M = Sn und Zr

Synthesis and Structures of the Dinuclear Nitrido Complexes [(Me₂PhP)₃(MeCN)ClRe≡N–MCl₅] with M = Sn and Zr The water sensitive complexes [(Me₂PhP)₃(MeCN)ClRe≡N–MCl₅] (M = Sn ( 1 ) und Zr ( 2 )) are obtained in dichloromethane from [ReNCl₂(PMe₂Ph)₃] and the acetonitrile adducts of SnCl₄ or ZrCl₄. The compounds crystallize as dichloromethane solvate isotypically with [(Me₂PhP)₃(MeCN)ClRe≡N–TiCl₅] · CH₂Cl₂ in the space group P2₁/n. From toluene crystallize monoclinic crystals of 1 · MeCN · C₇H₈. In the diamagnetic complexes 1 and 2 an anion [MCl₅]^– coordinates to the nitrido ligand of the cationic complex [ReNCl(MeCN)(PMe₂Ph)₃]⁺. The resulting nitrido bridges Re≡N–M are almost linear and asymmetric with Re–N = 169.5 pm, Sn–N = 230.1 pm and Re–N–Sn = 164.5° for 1 and Re–N = 168.4 pm, Zr–N = 237.2 pm and Re–N–Zr = 165.6° for 2 . The phosphine ligands at the Re atom are in a meridional arrangement.     

Synthese und Struktur der Komplexe [(n‐Bu)4N]2[{(THF)Cl4Re≡N}2PdCl2], [Ph4P]2[(THF)Cl4Re≡N‐PdCl(μ‐Cl)]2 und [(n‐Bu)4N]2[Pd3Cl8]

Synthesis and Crystal Structure of the Complexes [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂PdCl₂], [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ and [(n‐Bu)₄N]₂[Pd₃Cl₈] The threenuclear complex [(n‐Bu)₄N]₂[{(THF)Cl₄Re≡N}₂ PdCl₂] ( 1 ) is obtained in THF by the reaction of PdCl₂(NCC₆H₅)₂ with [(n‐Bu)₄N][ReNCl₄] in the molar ration 1:2. It forms orange crystals with the composition 1· THF crystallizing in the monoclinic space group C2/c with a = 2973.3(2); b = 1486.63(7); c = 1662.67(8)pm; β = 120.036(5)° and Z = 4. If the reaction is carried out with PdCl₂ instead of PdCl₂(NCC₆H₅)₂, orange crystals of hitherto unknown [(n‐Bu)₄N]₂[Pd₃Cl₈] ( 3 ) are obtained besides some crystals of 1· THF. 3 crystallizes with the space group P1¯ and a = 1141.50(8), b = 1401.2(1), c = 1665.9(1)pm, α = 67.529(8)°, β = 81.960(9)°, γ = 66.813(8)° and Z = 2. In the centrosymmetric complex anion [{(THF)Cl₄Re≡N}₂PdCl₂]^2— a linear PdCl₂ moiety is connected in trans arrangement with two complex fragments [(THF)Cl₄Re≡N]^— via asymmetric nitrido bridges Re≡N‐Pd. For Pd(II) thereby results a square‐planar coordination PdCl₂N₂. The linear nitrido bridges are characterized by distances Re‐N = 163.8(7)pm and Pd‐N = 194.1(7)pm. The crystal structure of 3 contains two symmetry independent, planar complexes [Pd₃Cl₈]^2— with the symmetry 1¯, in which the Pd atoms are connected by slightly asymmetric chloro bridges. By the reaction of equimolar amounts of [Ph₄P][ReNCl₄] and PdCl₂(NCC₆H₅)₂ in THF brown crystals of the heterometallic complex, [Ph₄P]₂[(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂ ( 2 ) result. 2 crystallizes in the monoclinic space group P2₁/n with a = 979.55(9); b = 2221.5(1); c = 1523.1(2)pm; β = 100.33(1)° and Z = 2. In the central unit ClPd(μ‐Cl)₂PdCl of the centrosymmetric anionic complex [(THF)Cl₄Re≡N‐PdCl(μ‐Cl)]₂^2— the coordination of the Pd atoms is completed by two nitrido bridges Re≡N‐Pd to nitrido complex fragments [(THF)Cl₄Re≡N]^— forming a square‐planar arrangement for Pd(II). The distances in the linear nitrido bridges are Re‐N = 163.8(9)pm and Pd‐N = 191.5(9)pm.