Facile halide replacement in electron rich complexes

Reactions of MnL₅X or Mn(CO)L₄X compounds (L = several aryl isocyanides, X = halide) with AgPF₆ give [MnL₆]PF₆ or [Mn(CO)L₅]PF₆ respectively. These reactions are presumed to occur with initial halide extraction to give an intermediate solvated species [MnL₅solv]⁺ or [Mn(CO)L₄solv]⁺ which can subsequently decompose or scavenge free L from solution to give the products observed. Addition of an alternative potential ligand L′ allows preparation of mixed ligand species [MnL₅L′]PF₆ or [Mn(CO)L₄L'‵PF₆ (L = MeNC, ^tBuNC, py). Cyclic voltammetric studies on the various complexes have been carried out, and results correlated with infrared data and with theory.     

Photochemical reactions of cationic isocyanide/carbonyl complexes of iron with selected nucleophiles

Photolysis of (η⁵-C₅H₅Fe(CO)(CNMe)₂]PF₆ in the presence of excess nucleophiles resulted in efficient substitution of the carbonyl ligand, generating the new isocyanide complexes (η⁵-C₅H₅Fe(CNMe)₂)(L)]PF₆ (L = PPh₃, AsPh₃, SbPh₃, pyridine, acetonitrile, and ethylene). Similar reactions of (η⁵-C₅H₅Fe(CO)_2)(CNMe)PF₆ led to sequential replacement of both carbony groups with the exception of L  ethylene. No evidence of photochemical isocyanide substitution was found. The same carbonyl complexes failed to reach with L thermally. In the absence of light, ethylene, pyridine, and acetonitrile complexes were found to disporportionate in the manner [η⁵-C₅H₅Fe(CNMe)(L)₂]PF₆→ [η⁵C₅H₅Fe(CNMe)₂(L)]PF₆ → [η⁵-C₅H₅Fe(CNMe)₃]PF₆ with the first rearrangement occurring much faster than the second. The new isocyanide complexes are characterized by their infrared and NMR (¹H, ¹³C) spectra.     

The reactions of [Fe2(η-C5H5)2(CO)4−n(CNMe)n] (n = 0–4) complexes with halogens and mercury(II) salts

Halogens, X₂, and HgY₂ (X = Cl, Br, I; Y = X, F, NO₃, BF₄) cleave the metalmetal bonds in [Fe₂(η-C₅H₅)₂(CO)_4−n(CNMe)_n] complexes (n = 0–4). Typically, e.g., when n = 2, X₂ electrophiles give [Fe(η-C₅H₅)(CO)(CNMe)X] (a) and [Fe(η-C₅H₅)(CO)(CNMe)₂]X (b) in relative yields which depend on X, the reaction solvent and n, but HgY₂ give equimolar amounts of [Fe(η-C₅H₅)(CNMe)₂Y] (c and [Fe(η-C₅H₅)(CO)₂HgY] only. Hg(CN)₂ reacts more slowly than other HgY₂, and [Hg(PPh₃)₂I₂] does not react at all. It is suggested that the reactions which give rise to products of type (a), (b) or (c) are all two-electron oxidation which proceed by way of adducts containing μ-CA → X₂ or μ-CA → HgX₂ groups (Ca = CO or CNMe). One of these adducts has been isolated, namely [Fe₂(η-C₅H₅)₂(CNMe)₂{μ-CN(Me)HgCl₂}₂] · CHCl₃.     

Synthesis of octahedral carbonyl complexes of manganese(I) with SCN or CN ligands. Crystal structure of fac-[SCNMn(CO)3(dppm)]

The complexes fac-[XMn(CO)₃(dppm)], cis,cis-[XMn(CO)₂(dppm)(P(OPh)₃)] and trans-[XMn(CO)(dppm)₂] with X = SCN or CN have been prepared from the corresponding bromocarbonyls and the salts AgX or KX, or, in the case of the di- and mono-carbonyls, from fac-[XMn(CO)₃(dppm)] with X = SCN or CN by thermal or photochemical CO substitution by the ligands P(OPh)₃ or dppm. The structure of fac-[SCNMn(CO)₃(dppm)] has been determined by X-ray diffraction. The crystals are monoclinic, space group P2₁/n, and the structure has been refined to R = 0.058 for 4123 reflexions measured in the range 2 ⩽ θ ⩽ 30 at room temperature. The cis,cis-[NCMn(CO)₂(dppm)(P(OPh)₃)] complex can be oxidized and subsequently reduced to the isomer trans-[NCMn(CO)₂(dppm)(P(OPh)₃)]. All the neutral cyanide complexes react readily with MeI and KPF₆ to give the corresponding methylisocyanide derivatives [Mn(CO)₂(dppm)(P(OPh)₃)(CNMe)]PF₆ and [Mn(CO)(dppm)₂(CNMe)]PF₆. The stereochemistries of the compounds is discussed in relation to the ³¹P NMR spectra.     

Effects of cis/trans-Configuration and Ligand Substitution of the Cyanidometal Bridge on Metal to Metal Charge Transfer Properties in Mixed Valence Complexes

To investigate the effects of cis/trans-configuration of the cyanidometal bridge and the electron donating ability of the auxiliary ligand on the cyanidometal bridge on metal to metal charge transfer (MMCT) in cyanidometal-bridged mixed valence compounds, two groups of trinuclear cyanidometal-bridged compounds cis/trans-[Cp(dppe)Fe(μ-NC)Ru(4,4’-dmbpy)₂(μ-CN)Fe(dppe)Cp][PF₆]_n (n=2 ( cis/trans - 1[PF₆]₂ ), 3 ( cis/trans - 1[PF₆]₃ ), 4 ( cis/trans - 1[PF₆]₄ )) and cis/trans-[Cp(dppe)Fe(μ-NC)Ru(bpy)₂(μ-CN)Fe(dppe)Cp][PF₆]₃ ( cis/trans - 2[PF₆]₃ ) were synthesized and fully characterized. The experimental results indicate that for these one- and two-electron oxidation mixed valence compounds, the trans-configuration compounds are more beneficial for MMCT than the cis-configuration compounds, and increasing the electron donating ability of the auxiliary ligand on the cyanidometal bridge is also conductive to MMCT. Moreover, compounds cis/trans - 1[PF₆]_n (n=3, 4) and cis/trans - 2[PF₆]₃ belong to localized compounds by analyzing the experimental characterization results, supported by the TDDFT calculations.     

Disproportionation reactions of the acetonitrile derivatives of group VI hexacarbonyls

The disproportionation reactions of [M(CO)₆-n_-n(CH₃CN)n_n] (M = Cr,Mo, W; n = 1—3) proceed in solution according to the sequence M(CO)₃(CH₃CN)₃ → M(CO)₄(CH₃CN)₂ → M(CO)₅(CH₃CN) → M(CO)₆.Rapid changes are observed in Nujol and acetone at ambient temperature, but in acetonitrile comparable changes require higher temperatures. Additional carbon monoxide groups are provided by the complete decomposition of part of the sample of the complex but free carbon monoxide is not detected in solution. The observed disproportionation reaction enabble the use of M(CO)₃(CH₃CN)₃ complexes for the synthesis of M(CO)₄ derivatives to be rationalised. The nature of an intermediate absorbing at 1996 cm^-1 in the IR spectrum is discussed.     

Reactions of isonitriles with [Fe3(CO)12] and [Ru3(CO)12] monitored by electrospray mass spectrometry: structural characterisation of [Fe3(CO)10(CNPh)2] and [Ru4(CO)11(μ3-η-CNPh)2(CNPh)]

The reactions of [Fe₃(CO)₁₂] or [Ru₃(CO)₁₂] with RNC (R=Ph, C₆H₄OMe-p or CH₂SO₂C₆H₄Me-p) have been investigated using electrospray mass spectrometry. Species arising from substitution of up to six ligands were detected for [Fe₃(CO)₁₂], but the higher-substituted compounds were too unstable to be isolated. The crystal structure of [Fe₃(CO)₁₀(CNPh)₂] was determined at 150 and 298 K to show that both isonitrile ligands were trans to each other on the same Fe atom. For [Ru₃(CO)₁₂] substitution of up to three COs was found, together with the formation of higher-nuclearity clusters. [Ru₄(CO)₁₁(CNPh)₃] was structurally characterised and has a spiked-triangular Ru₄ core with two of the CNPh ligands coordinated in an unusual μ₃-η² mode.     

The reactions of AgY salts with [Fe2(η-C5H5)2(CO)4-n(CNMe)n] complexes (Y−  NO3−, BF4− or PF6−; n  0, 1 or 2). The crystal structure of [Fe(η-C5H5)2(CNMe)]BF4

The oxidative cleavage of [Fe₂(η-C₅H₅)₂(CO)_4-n(CNMe)_n] (n=0−2) by 2AgX gives mononuclear products. It is shown to be a two-electron process in most solvents but a one-electron process in acetonitrile. The two-electron oxidations proceed by way of adducts such as [Fe₂(η-C₅H₅)₂(CO)(CNMe)(μ-CO){;μ-CN(Me)AgPPh₃};]BF₄ which are isolable when n = 2, detectable when n = 1 and postulatetd when n = 0. The one-electron process gives no adducts, and 1AgX cleaves all of the substrate to [Fe(η-C₅H₅)(CO)(L)(NCMe)]⁺ and [Fe(η-C₅H₅)(CO)(L)]^. (L  CO or CNME). The latter may combine or react with added CHBr₃ to give [Fe(η-C₅H₅)(CO)(L)Br]. The structure of [Fe(η-C₅H₅)(CO)₂-(CNMe)]BF₄ has been determined by X-ray diffraction.     

Oxidative Addition vs. Ligand-Exchange: Fe(II)-Mixed-Phenylchalcogenolate Complexes fac-[PPN][Fe(CO)3(TePh)n(SePh)3-N] (n = 1, 2)

Diphenyldichalcogenides (PhE)₂ (E = Te, Se) react with Fe(0)-phenylchalcogenolate [PPN] [PhEFe(CO)₄] to yield the products of oxidative addition, Fe(II)-mixed-phenylchalcogenolate fac- [PPN][Fe(CO)₃(TePh)_n(ScPh)_3-n] (n = 1, 2). Reactions of [PPN][REFe(CO)₄] (E=Se, R=Me; E=S, R=Et) and diphenyldichalcogenides yielded ligand-exchange products [PPN][PhEFe(CO)₄] (E=Te, Se, S). The compounds [Fe(CO)₃(TePh)(ScPh)₂]^? (l) and [Fe(CO)₃(TePh)₂ (2) crystallize in the isomorphous monoclinic space group C_2/e, with a = 32.035(8), b = 11.708(6), c = 28.909(6) Å, Z = 8, R = 0.048, and R_w = 0.044 (1); with a = 32.089(5), b= 11.745(2), c = 28.990(8) Å, Z = 8, R = 0.048, and R_w = 0.048 (2). The complexes 1 and 2 crystallize as discrete cations of PPN⁺ and anions of [Fe(CO)₃(TcPh)_u(ScPh)_3-n] (n=1, 2), and one half solvent molecule THF. The geometry around Fe(II) is a distorted octahedron with three carbonyl groups and three phenylchalcogenolate ligands occupying facial positions.     

Darstellung und Schwingungsspektren von Chloro-Bromo-Dirhodaten(III), [Rh2ClnBr9−n]3−, n = 0–9

Preparation and Vibrational Spectra of Nonahalogenodirhodates(III), [Rh₂Cl_nBr_9-n]^3?, n = 0–9 The pure nonahalogenodirhodates(III), A₃[Rh₂Cl_nBr_9-n], A = K, Cs, (TBA); n = 0–4, 9, have been prepared. They are formed from the monomer chlorobromorhodates(III), [RhCl_nBr_6-n]^3?, n = 0–6, which are bridged to confacial bioctahedral complexes by ligand abstraction in less polar organic solvents. From the mixtures the complexions are separated by ion exchange chromatography on DEAE-cellulose. The solid, air-stable, air-stable, K-, Cs- and (TBA)-salts of [Rh₂Cl_nBr_9-n]^3?, n = 0–4, are green, of [Rh₂Cl₉]^3? are brown. The IR and Raman spectra of [Rh₂Br₉]^3? and [Rh₂Cl₉]^3? are assigned according to the point group D_3h. The chlorobromodirhodates exist as mixtures of geometrical and structural isomers, which belong to different point groups. The vibrational spectra exhibit bands in characteristic regions; at high wavenumbers stretching vibrations with terminal ligands v(Rh—Cl_t): 360–320, v(Rh—Br_t): 280–250; in a middle region with bridging ligands v(Rh—Cl_b): 300–270, v(Rh—Br_b): 210–170 cm^?1; the deformation bands are observed at distinct lower frequencies. The terminal ligands are fixed very strong, and the distance between v(Rh—X_t) and v(Rh—X_b) increases with decreasing size of the cations.     

Reactions of dichlorobis(ditertiaryphosphine)-ruthenium(II) with carbon monoxide: Preparation of dicarbonylbis(ditertiaryphosphine) ruthenium(II) cations

Reactions of RuCl₂(L-L)₂ (L-L = dppm or dppe) with CO and silver salts of non coordinating anions produce [Ru(CO)₂(L-L)₂]X₂ which, once formed, are stable to CO loss. However, the fluxional five coordinate intermediates [Ru(Cl) (L-L)₂]X, which in some cases may contain ion pairs, are sufficiently electrophilic to abstract fluoride ion from [BF₄]^? or to coordinate other ions in solution such as [O₂PF₂]^? formed by hydrolysis of [PF₆]^?. A series of complexes of general formula [Ru(CO)₂ (dppm)₂AgY]X₂ may also be isolated and are shown to contain a dppm ligand bridging ruthenium and silver, the bond between which is reversibly cleaved by nitromethane on the nmr timescale.     

Rhodium- and iridium-manganese carbonyl complexes containing bridging Ph2PCH2PPh2 ligands

Treatment of mer,cis-[MnCl(CO)₂(dppm-PP′)(dppm-P)] with [Rh₂Cl₂(CO)₄] in the presence of CO and PF₆⁻ gives [Cl(OC)₂Mn(μ-dppm)₂Rh(CO)₂]PF₆ which might have a bridging chloride ligand. Similar treatment of mer,cis-[MnBr(CO)₂(dppm-PP')(dppm-P)] gave [Br(OC)₂Mn(μ-dppm)₂Rh(CO)₂]PF₆ which ³¹P-{¹H} NMR spectroscopy showed to be a mixture of two closely related species. Treatment of mer,cis-[MnCl(CO)₂(dppm-PP') (dppm-P)] with [Rh₂Cl₂(CO)₄] at −30°C probably gave [Cl(OC)₂Mn(μ-dppm)₂ Rh(CO)₂]Cl but this decomposes above 0°C: the corresponding dibromide was made similarly and is somewhat more stable than the dichloride. Treatment of mer,cis-[MnX(CO)₂(dppm-PP')(dppm-P)] (X = Cl or Br) with [IrCl(CO)₂(p-toluidine)] and CO-PF₆⁻ gave [X(OC)₂Mn(μ-dppm)₂Ir(CO)₂]PF₆. Neutral complexes of type [X(OC)₂Mn (μ-dppm)₂Ir(CO)X'] (X and X' = Cl or Br) are very labile and rapidly decompose to give [Ir(CO)(dppm-PP')₂]⁺ and other (unidentified) products. Treatment of mer,cis-[MnX-(CO)₂(dppm-PP')(dppm-P)] with [RhH(CO)(PPh₃)₃] gave [X(OC)Mn(μ-dppm)₂(μ-H)(μ-CO)Rh(CO)] (X = Cl or Br). These heterobimetallic compounds generally showed broad ¹³P-{¹H} resonances for the P nuclei bonded to Mn at ca 20°C due to some coupling with the ⁵⁵Mn nucleus (I = 100% abundant), but at −30°C these resonances sharpened up due to more rapid quadrupolar relaxation at the lower temperature. NMR and IR data are given.     

Darstellung von Tetracarbonyl-triphenylphosphinmanganorganoplumbanen R4−nPb[Mn(CO)4P(C6H5)3]n (RCH3, C6H5; n = 1,2)

Preparation of R_4?nPb[Mn(CO)₄P(C₆H₅)₃]_n Compounds (R?CH₃, C₆H₅; n = 1, 2) As the first examples of organolead manganese carbonyls substituted in the manganese carbonyl ligand compounds of the type R_4?nPb[Mn(CO)₄P(C₆H₅)₃]_n (R?CH₃, C₆H₅; n = 1, 2) have been prepared by the alkali salt method from R_4?nPbCl_n and NaMn(CO)₄P(C₆H₅)₃. (C₆H₅)₂Sn[Mn(CO)₄P(C₆H₅)₃]₂ has been gained by the same method and also by thermal ligand exchange. According the IR data the ligand P(C₆H₅)₃ is trans to the tetrahedrally surrounded lead. In solution to compounds are monomeric.     

Bimolecular substitution and oxidation reactions of 17-electron pentacoordinate metal carbonyl radicals

Summary Quantitative and semiquantitative data for reactions of M₂(CO)_10-2nL_2n (M=Mn or Re; L=P-donor ligand; n=0, 1) are analyzed to provide information regarding the mechanisms and relative rates of substitution and oxidation reactions of the [M(CO)_5-nL_n] radicals. Both associative and dissociative paths for substitution can be inferred, but the dissociative paths are generally much slower and occur only at high temperatures and/or when associative substitution is sterically disfavoured. Quantitative comparison of the reactivities of various radicals is made.     

Homoleptic phenyl isocyanide complexes of molybdenum and tungsten: zerovalent six-coordinate versus divalent seven-coordinate

Electrochemical and chemical oxidations of Mo(CNPh)₆ and W(CNPh)₆ have been shown to yield seven-coordinate [M(CNPh)₇]²⁺. These catons, stabilized as their PF₆^? salts, can be obtained in yields of 80%. The redox and substitution chemistry of these new complexes have been explored. A convenient synthesis of W(CNPh)₆ has been devised starting from W₂(dmhp)₄ (dmhp is the anion of 2,4-dimethyl-6-hydroxypyrimidine).     

A Comparative Study of (Poly)ether Adducts of Alkaline Earth Iodides – An Overview Including New Compounds

New homoligand and mixed‐ligand adducts of the heavier alkaline earth metal (Ca, Sr, Ba) halides with oxygen‐donor polyether ligands have been isolated and characterized and are compared with previously obtained compounds of the same class in order to give an overview on structures and properties. Homoligand halide adducts, discussed herein, are [CaI(DME)₃]I ( 1 ), trans‐[SrI₂(DME)₃] ( 2 ), trans‐[BaI₂(DME)₃] ( 3 ), (DME = ethylene glycol dimethyl ether), [CaI(diglyme)₂]I ( 4 ), cis‐[SrI₂(diglyme)₂] ( 5 ), trans‐[BaI₂(diglyme)₂] ( 6 ),(diglyme = diethylene glycol dimethyl ether, [SrI(triglyme)₂]I ( 7 ), and [BaI(triglyme)₂]I ( 8 ), (triglyme = triethylene glycol dimethyl ether). Introduction of the mono‐coordinating THF ligand (THF = tetrahydrofuran) in the coordination sphere of 1 , 2 , 3 , 4 allows the formation of the new mixed‐ligand compounds trans‐[CaI₂(DME)₂(THF)] ( 9 ), trans‐[SrI₂(DME)₂(THF)] ( 10 ), trans‐[BaI₂(DME)₂(THF)₂] ( 11 ), and trans‐[CaI₂(diglyme)₂(THF)₂] ( 12 ). These compounds were obtained from the metal halide salts in solution with pure or mixtures of ether solvents. While compounds 1 – 8 appear to be very stable and non‐reactive, adducts 9 – 12 present a comparable reactivity to the well known THF adducts [MI₂(thf)_n] (M = Ca, n = 4; Sr, Ba, n = 5).     

Field desorption mass spectra of [M(CO)3(η-arene)]X (MMn,Re; XBF4, PF6) salts

Field desorption mass spectra are reported for a range of [M(CO)₃(η-arene)]X (MMn or Re, XBF₄ or PF₆) salts. In most cases the spectra are simple, being dominated by molecular, [M]^+·, [M + 1]⁺, and [MCO]⁺ ions for the cationic part of their structure. However, with the π-chloroarene complexes [Mn(CO)₃(η-ClC₆H₅)]PF₆ and [Mn(CO)₃(η-1-Cl, 4-MeC₆H₄)]PF₆, facile loss of the chloro substituent and further fragmentation leads to unusually complex spectra, which include strong peaks arising from recombination of fragment species. Cluster ions are also noted in several cases, allowing identification of the anion.     

Reaktionen von Cyclostibanen (RSb)n [R = (Me3Si)2CH,n = 3; Me3CCH2, n = 4, 5] mit den Übergangsmetallcarbonyl‐Komplexen [W(CO)5(thf)], [CpxMn(CO)2(thf)], [CpxCr(CO)3]2 und [Co2(CO)8]; Cpx = MeC5H4

Reactions of Cyclostibanes, (RSb)_n [R = (Me₃Si)₂CH, n = 3; Me₃CCH₂, n = 4, 5] with the Transition Metal Carbonyl Complexes [W(CO)₅(thf)], [Cp^xMn(CO)₂(thf)], [Cp^xCr(CO)₃]₂, and [Co₂(CO)₈]; Cp^x = MeC₅H₄ (RSb)₃ [R = (Me₃Si)₂CH] reacts with [W(CO)₅(thf)], [Cp^xMn(CO)₂(thf)], or [Co₂(CO)₈] to give [(RSb)₃W(CO)₅] ( 1 ), [RSb{Mn(CO)₂Cp^x}₂] ( 2 ) or [RSbCo(CO)₃]₂ ( 3 ). The reaction of (R′Sb)_n (n = 4, 5; R′ = Me₃CCH₂) with [Cp^xCr(CO)₃]₂ leads to [(R′Sb)₄{Cr(CO)₂Cp^x}₂] ( 4 ); Cp^x = MeC₅H₄, thf = Tetrahydrofuran.     

Zur kenntnis der chemie der metallcarbonyle und der cyanokomplexe in flüssigem ammoniak : XXXIII. Über die darstellung neuer carbamoylcarbonyl-komplexe aus bekannten und neuen kationischen carbonylverbindungen des mangans und rheniums

The covalent carbamoyl carbonyl compounds Re(CO)₅COHN₂, cis-M(CO)₄(L)CONH₂, M(CO)₃(L)₂CONH₂ and M(CO)₃(D)CONH₂ (M = Mn, Re; L = PPh₃, PEt₃; D = bipy, phen) are formed by reactions of the cationic complexes [Re(CO)₆]⁺, [M(CO)₅L]⁺, [M(CO)₄L₂]⁺ and [M(CO)₄D]⁺ (M = Mn, Re; L = PPh₃, PEt₃; D = bipy, phen) with liquid NH₃ with concomitant deprotonation: [M(CO)_6?nL_n]⁺ + 2 NH₃ → M(CO)_5?nL_nCONH₂ + NH₄⁺ (n = 0, 1, 2) and [M(CO)₄D]⁺ + 2 NH₃ → M(CO)₃(D)CONH₂ + NH₄⁺ The stability of the above-mentioned carbamoyl carbonyl complexes increases from the penta- to the tetra- to the tri-carbonyl derivatives. In all cases the rhenium compounds are much more stable than the corresponding manganese complexes. Whereas the carbamoyl compound Re(CO)₄(PEt₃)CONH₂ can be isolated by reaction of [Re(CO)₅PEt₃]⁺ with NH₃, the corresponding manganese complex undergoes Hofmann degradation of amides even at ?70°C to form HMn(CO)₄PEt₃ and NH₄NCO. The IR and some mass and ¹H NMR spectra of the new hexacoordinated carbamoyl carbonyl complexes are discussed and the reactions of these compounds with liquid NH₃, HCl and CH₃OH are described.     

Thermodynamics of complexation of zinc(II) with chloride,bromide and iodide ions in hexamethylphosphoric triamide

The complexation of zinc(II) with chloride, bromide and iodide ions has been studied by calorimetry in hexamethylphosphoric triamide (HMPA) containing 0.1 mol-dm^–3 (n-C₄H₉)₄NClO₄ as a constant ionic medium at 25°C. The formation of [ZnX_n]^(2–n)+ (n=1,2,3,4 for X=Cl; n=1,2 for X=Br, I) is revealed, and their formation constants, enthalpies and entropies were determined. It is proposed that the zinc(II) ion is fourcoordinated in HMPA and the coordinating HMPA molecules are stepwise replaced with halide ions to form [ZnX_n(hmpa)_4–n]^(2–n)+ (n=1–4), as is the case for the cobalt(II) ion. Furthermore, the formation of [ZnClI], [ZnBrI], [ZnBrCl] and [ZnBrCl₂]^– is revealed in the relevant ternary systems. It is found that the affinity of a given halide ion X^– to [ZnCl]⁺, [ZnBr]⁺ and [Znl]⁺ is practically the same.