Ruthenium and rhodium nitrosyl complexes containing dichalcogenoimidodiphosphinate ligands

Interaction of [Ru(NO)Cl₃(PPh₃)₂] with K[N(R₂PS)₂] in refluxing N,N-dimethylformamide afforded trans-[Ru(NO)Cl{N(R₂PS)₂}₂] (R = Ph (1), Prⁱ (2)). Reaction of [Ru(NO)Cl₃(PPh₃)₂] with K[N(Ph₂PSe)₂] led to formation of a mixture of trans-[Ru(NO)Cl{N(Ph₂PSe)₂}₂] (3) and trans-[Ru(NO)Cl{N(Ph₂PSe)₂}{Ph₂P(Se)NPPh₂}] (4). Reaction of Ru(NO)Cl₃ · xH₂O with K[N(Ph₂PO)₂] afforded cis-[Ru(NO)(Cl){N(Ph₂PO)₂}₂] (5). Treatment of [Rh(NO)Cl₂(PPh₃)₂] with K[N(R₂PQ)₂] gave Rh(NO){N(R₂PQ)₂}₂] (R = Ph, Q = S (6) or Se (7); R = Prⁱ, Q = S (8) or Se (9)). Protonation of 8 with HBF₄ led to formation of trans-[Rh(NO)Cl{HN(Prⁱ₂PS)₂}₂][BF₄]₂ (10). X-ray diffraction studies revealed that the nitrosyl ligands in 2 and 4 are linear, whereas that in 9 is bent with the Rh–N–O bond angle of 125.7(3)°.     

Synthesis and structure of isopropyldimethylsilyl-substituted octamethyltitanocene

Reduction of isopropyldimethylsilyl-substituted titanocene dichloride [TiCl₂(η⁵-C₅Me₄SiMe₂Prⁱ)₂] (1) by excess magnesium in the presence of excess bis(trimethylsilyl)ethyne (btmse) in tetrahydrofuran at 60 °C yielded a mixture of products amongst them only the trinuclear Ti-Mg-Ti hydrido-bridged complex Mg[Ti(μ-H)₂(η⁵-C₅Me₄SiMe₂Prⁱ)]₂ (3) was isolated and characterized. The precursor of titanocene, [Ti(η⁵-C₅Me₄SiMe₂Prⁱ)₂(η²-btmse)] (6), was obtained from the identical system which, after initial formation of [TiCl(η⁵-C₅Me₄SiMe₂Prⁱ)₂] (2), reacted at −18 °C overnight and then the solution was rapidly separated from the remaining magnesium. Titanocene [Ti(η⁵-C₅Me₄SiMe₂Prⁱ)₂] (7) was obtained by thermolysis of 6 at 75 °C in vacuum. Crystal structures of 1, 2, 3, 6, and 7 were determined.     

Synthesis and structural studies of some titanium and zirconium complexes with chiral bis(amide), amidinate or bis(amidinate) ligands

Reaction of bis(amide) sodium Na₂[(1R,2R)-(−)-1,2-(NSiMe₃)₂-C₆H₁₀] (Na₂[L¹]) with Ti(OiPr)₂Cl₂ in different conditions gave mixed-ligand complexes [Ti(OiPr)Cl][L¹] (1) or [Ti(OiPr)₂Cl]₂[L¹] (2); 2 is a dinuclear titanium example in which Ti atoms are bridged by nitrogen and oxygen atoms simultaneously forming a distorted rhombic core. Reaction of the amine-amidinate ligand (1R,2R)-(−)-1-Li[NC(Ph)N(SiMe₃)]-2-(NHSiMe₃)-C₆H₁₀(Li[L²]) or rarely linked bis(amidinate) ligand Li₂[(1R,2R)-(−)-1,2-{NC(Ph)N(SiMe₃)}₂-C₆H₁₀](Li₂[L³]) with ZrCl₄ yielded the unbridged and bridged bis(amidinate) complexes ZrCl₂[L²]₂ (3) and [ZrCl₂(THF)][L³] (4), respectively; Moreover, the reaction of (1R,2R)-(−)-1-Li[NC(Ph)N(SiMe₃)]-2-Li(NSiMe₃)C₆H₁₀(Li₂[L²]) with Ti(OiPr)₂Cl₂ gave a new type of tridentate amido-amidinate product [Ti(OiPr)₂][L²] (6), which is a distinct model compared to [Ti(OiPr)₂Cl][L²] (5) yielded from Li[L²]. All the products have been characterized by X-ray crystallography and the structural studies are presented detailedly comparing with relevant compounds.     

Synthesis and Structural Characterization of Alkali Metal Guanidinates

Reactions of 1,3-diisopropylcarbodiimide with alkali metal amides, MN（SiMe3）2 （M=Li or Na） in hexane or THF produced the alkali metal guanidinates { （i-PrN）2C [N（SiMe3）2]Li }2 （1） and { （i-PrN）2C[N（SiMe3）2]Na（THF） } 2 （2） in nearly quantitative yields. Both complexes 1 and 2 were well characterized by elemental analysis, IR spectra, ^1H and ^13C NMR spectra, and X-ray diffraction. It was found that the guanidinates adopt different coordination modes in these complexes.     

C2-Bridged sandwich and half-sandwich entities with Ti(IV) and Cr(0) centers

The intense purple colored bi- and trimetallic complexes {Ti}(CH₂SiMe₃)[CC(η⁶-C₆H₅)Cr(CO)₃] (3) ({Ti}=(η⁵-C₅H₅)₂Ti) and [Ti][CC(η⁶-C₆H₅)Cr(CO)₃]₂ (5) {[Ti]=(η⁵-C₅H₄SiMe₃)₂Ti}, in which next to a Ti(IV) center a Cr(0) atom is present, are accessible by the reaction of Li[CC(η⁶-C₆H₅)Cr(CO)₃] (2) with {Ti}(CH₂SiMe₃)Cl (1) or [Ti]Cl₂ (4) in a 1:1 or 2:1 molar ratio. The chemical and electrochemical properties of 3, 5, {Ti}(CH₂SiMe₃)(CCFc) [Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)] and [Ti][(CC)_nMc][(CC)_mM′c] [n, m=1, 2; n=m; n≠m; Mc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄); M′c=(η⁵-C₅H₅)Ru(η⁵-C₅H₄); Mc=M′c; Mc≠M′c] will be comparatively discussed.     

General route for the synthesis of terminal phosphanylphosphido complexes of Zr(IV) and Hf(IV): Structural investigations of the first zirconium complex with a phosphanylphosphido ligand

Reactions of R₂P-P(SiMe₃)Li with [Cp₂MCl₂] (M = Zr, Hf) in hydrocarbons yield the related terminal phosphanylphosphido complexes [Cp₂M(Cl){(Me₃Si)P-PR₂-κP¹}] (R = ⁱPr and ^tBu). The solid state structures of [Cp₂M(Cl){P(SiMe₃)-PⁱPr₂-κP¹}] (M = Zr, Hf) were established by single crystal X-ray diffraction studies. The phosphido-P atoms adopt almost planar geometries and the phosphanyl P atoms adopt pyramidal geometries. The reaction of a mixture of (Me₃Si)₂PLi and Ph₂P-P(SiMe₃)Li with [CpZrCl₃] in toluene yields the dinuclear complex [Cp₂Zr₂Cl₅(Ph₂PPPSiMe₃)(Li THF DME)].     

Behavior of nitrite forms of nitrosylruthenium on extraction and back extraction of heterometalic Ru/Zn complexes with trioctylphosphine oxide

The state of ruthenium in conjugated phases upon extraction of trans-[Ru(¹⁵NO)(¹⁵NO₂)₄(OH)]^2? complex with tri-n-octylphosphine oxide (TOPO) in the presence of Zn²⁺ and subsequent back extraction with H¹⁵NO₃ and NH₃(concd.) solutions was studied by ¹⁵N NMR. Binuclear complexes [Ru(NO)(NO₂)_5?n (μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ] and [Ru(NO)(NO₂)_4?n (ONO)(μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ], where n = 2, 3, are predominant forms in extract. Kinetic restrictions for ruthenium extraction with TOPO solution in hexane and its back extraction with aqueous solutions of nitric acid and ammonia are eliminated in the absence of direct coordination of extractant to ruthenium. fac-Dinitronitrosyl forms [Ru(NO)(H₂O)₃(NO₂)₂]⁺, [Ru(NO)(H₂O)₂(NO₂)₂(NO₃)]⁰ (3 and 6 M HNO₃) and [Ru(NO)(H₂O)(NO₂)₂(NO₃)₂]^? (6 M HNO₃) prevail in nitric acid back extracts. Equilibrium constant at ambient temperature (0.05 ± 0.01) was assessed for the coordination of second nitrate ion to nitrosylruthenium dinitronitrato complex. Complex species [Ru(NO)(NO₂)₄(OH)]^2? and [Ru(NO)(NO₂)₃(ONO)(OH)]^2? prevail in ammonia back extract.     

Formation of the Distinct Redox‐Interrelated Forms of Nitric Oxide from Reaction of Dinitrosyl Iron Complexes (DNICs) and Substitution Ligands

Release of the distinct NO redox‐interrelated forms (NO⁺, ^.NO, and HNO/NO^?), derived from reaction of the dinitrosyl iron complex (DNIC) [(NO)₂Fe(C₁₂H₈N)₂]^? ( 1 ) (C₁₂H₈N=carbazolate) and the substitution ligands (S₂CNMe₂)₂, [SC₆H₄‐o‐NHC(O)(C₅H₄N)]₂ ((PyPepS)₂), and P(C₆H₃‐3‐SiMe₃‐2‐SH)₃ ([P(SH)₃]), respectively, was demonstrated. In contrast to the reaction of (PyPepS)₂ and DNIC 1 in a 1:1 stoichiometry that induces the release of an NO radical and the formation of complex [PPN][Fe(PyPepS)₂] ( 4 ), the incoming substitution ligand (S₂CNMe₂)₂ triggered the transformation of DNIC 1 into complex [(NO)Fe(S₂CNMe₂)₂] ( 2 ) along with N‐nitrosocarbazole ( 3 ). The subsequent nitrosation of N‐acetylpenicillamine (NAP) by N‐nitrosocarbazole ( 3 ) to produce S‐nitroso‐N‐acetylpenicillamine (SNAP) may signify the possible formation pathway of S‐nitrosothiols from DNICs by means of transnitrosation of N‐nitrosamines. Protonation of DNIC 1 by [P(SH)₃] triggers the release of HNO and the generation of complex [PPN][Fe(NO)P(C₆H₃‐3‐SiMe₃‐2‐S)₃] ( 5 ). In a similar fashion, the nucleophilic attack of the chelating ligand P(C₆H₃‐3‐SiMe₃‐2‐SNa)₃ ([P(SNa)₃]) on DNIC 1 resulted in the direct release of [NO]^? captured by [(¹⁵NO)Fe(SPh)₃]^?, thus leading to [(¹⁵NO)(¹⁴NO)Fe(SPh)₂]^?. These results illustrate one aspect of how the incoming substitution ligands ((S₂CNMe₂)₂ vs. (PyPepS)₂ vs. [P(SH)₃]/[P(SNa)₃]) in cooperation with the carbazolate‐coordinated ligands of DNIC 1 function to control the release of NO⁺, ^.NO, or [NO]^? from DNIC 1 upon reaction of complex 1 and the substitution ligands. Also, these results signify that DNICs may act as an intermediary of NO in the redox signaling processes by providing the distinct redox‐interrelated forms of NO to interact with different NO‐responsive targets in biological systems.     

Synthesis and crystal structures of novel lithium- and palladium-1-azaallyls

Treatment of (RH₂C)₂C₅H₃N-2,6 (R=SiMe₃) with BuⁿLi followed by addition of Me₃SiCl gave the tetrasilyl pyridine derivative (R₂HC)₂C₅H₃N-2,6 1 in high yield. Further lithiation of 1 with BuⁿLi and reaction of the intermediate with PhCN led to the new lithium-1-azaallyl [Li{N(R)C(Ph)C(R)(C₅H₃N-2,6)(CHR₂)}]₂2, while metallation of the previously described di-lithium compounds [Li{N(R)C(R^′)CH}₂(C₅H₃-2,6)]Li(tmen)_n (R=SiMe₃, R^′=Bu^t, n=1 or R=SiMe₃, R^′=Ph, n=2) with PdCl₂(PhCN)₂ yielded the novel metallacycles [Pd{{N(H)(R)C(R^′)CH}{N(SiMe₂CH₂)C(R^′)CH}C₅H₃N-2,6}] 3 (R^′=Bu^t) and [Pd{{N(R)C(R^′)CH}{N(R)(H)C(R^′)CH}C₅H₃N-2,6}₂] (R^′=Ph) 4 in moderate to low yield. Compound 3 is unusual in being the first example of a crystallographically characterised PdNSiC heterocycle which is believed to be formed via an intramolecular CH-activation of a trimethylsilyl group by Pd(II). All four compounds were fully characterised by NMR-spectroscopy, microanalysis (not 4) and X-ray diffraction.     

Yttrium bis(alkyl) and bis(amido) complexes bearing N,O multidentate ligands. Synthesis and catalytic activity towards ring‐opening polymerization of L‐lactide

Methoxy‐modified β‐diimines HL ¹ and HL ² reacted with Y(CH₂SiMe₃)₃(THF)₂ to afford the corresponding bis(alkyl)s [L¹Y(CH₂SiMe₃)₂] ( 1 ) and [L²Y(CH₂SiMe₃)₂] ( 2 ), respectively. Amination of 1 with 2,6‐diisopropyl aniline gave the bis(amido) counterpart [L¹Y{N(H)(2,6‐iPr₂? C₆H₃)}₂] ( 3 ), selectively. Treatment of Y(CH₂SiMe₃)₃(THF)₂ with methoxy‐modified anilido imine HL ³ yielded bis(alkyl) complex [L³Y(CH₂SiMe₃)₂(THF)] ( 4 ) that sequentially reacted with 2,6‐diisopropyl aniline to give the bis(amido) analogue [L³Y{N(H)(2,6‐iPr₂? C₆H₃)}₂] ( 5 ). Complex 2 was “base‐free” monomer, in which the tetradentate β‐diiminato ligand was meridional with the two alkyl species locating above and below it, generating tetragonal bipyramidal core about the metal center. Complex 3 was asymmetric monomer containing trigonal bipyramidal core with trans‐arrangement of the amido ligands. In contrast, the two cis‐located alkyl species in complex 4 were endo and exo towards the O,N,N tridentate anilido‐imido moiety. The bis(amido) complex 5 was confirmed to be structural analogue to 4 albeit without THF coordination. All these yttrium complexes are highly active initiators for the ring‐opening polymerization of L ‐LA at room temperature. The catalytic activity of the complexes and their “single‐site” or “double‐site” behavior depend on the ligand framework and the geometry of the alkyl (amido) species in the corresponding complexes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5662–5672, 2007     

Aminostannanes and aminostannylenes containing a C,N-chelated ligand

Aminotin(II and IV) compounds {[(2,6-i-Pr-C₆H₃)(H)N]-μ-(Sn)-Cl}₂, {2-[(CH₃)₂NCH₂]C₆H₄}₂Sn[N(H)(2,6-i-Pr-C₆H₃)]₂ and {2-[(CH₃)₂NCH₂]C₆H₄}Sn[N(2,6-i-Pr-C₆H₃)(SiMe₃)] were prepared by lithium halide elimination from tin halides and corresponding lithium complexes. [(2,6-i-Pr-C₆H₃)(H)N]Li (1) reacts with one half of molar equivalent of SnCl₂ to give {[(2,6-i-Pr-C₆H₃)(H)N]-μ-(Sn)-Cl}₂. The same lithium amide (1) gave with R₃SnCl corresponding aminostannanes. Further reactions of these compounds with n-butyllithium gave the starting 1 and tetraorganostannanes. {2-[(CH₃)₂NCH₂]C₆H₄}₂SnBr₂ reacts with two equivalents of 1 to {2-[(CH₃)₂NCH₂]C₆H₄}₂Sn[N(H)(2,6-i-Pr-C₆H₃)]₂. The dimeric heteroleptic stannylene {[(2,6-i-Pr-C₆H₃)(SiMe₃)N](μ₂-Cl)Sn}₂ reacts with 2-[(CH₃)₂NCH₂]C₆H₄Li to the monomeric {2-[(CH₃)₂NCH₂]C₆H₄}Sn[N(2,6-i-Pr-C₆H₃)(SiMe₃)]. The structure in the solid state and in solution and reactivity of products is also discussed. The unique decatin cluster has been isolated by hydrolysis of {[(2,6-i-Pr-C₆H₃)(H)N]-μ-(Sn)-Cl}₂. The structure of some compounds was also evaluated by theoretical DFT methods.     

Dinuclear Dysprosium and Ytterbium Complexes Incorporating N,N‐Bis(pyrrolyl‐α‐methyl)‐N‐methylamine Ligand: Syntheses and Structures

Reaction of DyCl₃ with two equivalents of NaN(SiMe₃)₂ in THF yielded {Dy(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ ( 1 ). X‐ray crystal structure analysis revealed that 1 is a centrosymmetric dimer with asymmetrically bridging chloride ligands. The metal coordination arrangement can be best described as distorted trigonal bipyramid. The bond lengths of Ln–Cl and Ln–N showed a decreasing trend with the contraction of the size of Ln³⁺. Treatment of N,N‐bis(pyrrolyl‐α‐methyl)‐N‐methylamine (H₂dpma) with 1 and known compound {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂, respectively, led to the formations of [Dy(μ‐Cl)(dpma)(THF)₂]₂ ( 2 ) and {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ ( 3 ). Compounds 2 and 3 were fully characterized by single‐crystal X‐ray crystallography, elemental analysis, and ¹H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving LnCl₃ (Ln = Dy and Yb), LiN(SiMe₃)₂, and H₂dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma^2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma^2– ligand.     

Barium-Catalysed Dehydrocoupling of Hydrosilanes and Borinic Acids: A Mechanistic Insight

Two very rare cases of barium boryloxides, the homoleptic [Ba(OB{CH(SiMe₃)₂}₂)₂⋅C₇H₈] and the heteroleptic [{LO^NO4}BaOB{CH(SiMe₃)₂}₂] stabilised by the multidentate aminoetherphenolate {LO^NO4}⁻, are presented, and their structural properties are discussed. The electron-deficient [Ba(OB{CH(SiMe₃)₂}₂)₂⋅C₇H₈] shows, in particular, resilient η⁶-coordination of the toluene molecule. Together with its amido parents [Ba{N(SiMe₃)₂}₂⋅thf₂] and [Ba{N(SiMe₃)₂}₂]₂, this complex catalyses the fast and chemoselective dehydrocoupling of borinic acids R₂BOH and hydrosilanes HSiR′₃, yielding borasiloxanes R₂BOSiR′₃ in a controlled fashion. The assessment of substrate scope indicates that, for now, the reaction is limited to bulky borinic acids. Kinetic analysis shows that the rate-limiting step of the catalytic manifold traverses a dinuclear transition state. A detailed mechanistic scenario is proposed on the basis of DFT computations, the results of which are fully consistent with experimental data. It consists of a stepwise process with rate-determining nucleophilic attack of a metal-bound O-atom onto the incoming hydrosilane, involving throughout dinuclear catalytically active species.     

Synthesis and structure of metalloid aluminum clusters—intermediates on the way to the elements

Metastable Aluminum(I) halide solutions proved to have a high potential for the synthesis of novel subvalent Al compounds, such as Al_nX_m species (X=Cl, Br, I; n<m, average oxidation state of Al below +3 or n>m, average oxidation state of Al below +1) or Al_nR_m species (R=bulky ligand; n>m). There are two principal reaction types, which are essential for the formation of the compounds discussed herein. The disproportionation, which finally results in Al(III) halides and Al metal and the metathesis which leads to a substitution of X atoms against R groups. By this way the metalloid cluster compounds [Al₇{N(SiMe₃)₂}₆]⁻, [Al₁₂{N(SiMe₃)₂}₈]⁻, [Al₁₄I₆{N(SiMe₃)₂}₆]²⁻, [Al₆₉{N(SiMe₃)₂}₁₈]³⁻, and [Al₇₇{N(SiMe₃)₂}₂₀]²⁻ could be isolated. The characteristic feature of these metalloid Al clusters is the number of AlAl contacts being larger than the number of Alligand bonds, i.e. there are more ‘naked’ than ligand-bonded Al atoms. Furthermore, the topology of the closest packing in Al metal is already pre-formed in these compounds.     

Bis(arylimido) Molybdenum(VI) Amidinate and Guanidinate Complexes; Molecular Structures of [(ArN)2MoMe{N(Cy)C[N(i‐Pr)2]N(Cy)}] (Ar = 2,6‐i‐Pr2C6H3; Cy = Cyclohexyl) and [(2,6‐i‐Pr2C6H3N)2MoCl2] · [NH=C(C6H5)CH(SiMe3)2]

The reaction of [(ArN)₂MoCl₂] · DME (Ar = 2,6‐i‐Pr₂C₆H₃) ( 1 ) with lithium amidinates or guanidinates resulted in molybdenum(VI) complexes [(ArN)₂MoCl{N(R¹)C(R²)N(R¹)}] (R¹ = Cy (cyclohexyl), R² = Me ( 2 ); R¹ = Cy, R² = N(i‐Pr)₂ ( 3 ); R¹ = Cy, R² = N(SiMe₃)₂ ( 4 ); R¹ = SiMe₃, R² = C₆H₅ ( 5 )) with five coordinated molybdenum atoms. Methylation of these compounds was exemplified by the reactions of 2 and 3 with MeLi affording the corresponding methylates [(ArN)₂MoMe{N(R¹)C(R²)N(R¹)}] (R¹ = Cy, R² = Me ( 6 ); R¹ = Cy, R² = N(i‐Pr)₂ ( 7 )). The analogous reaction of 1 with bulky [N(SiMe₃)C(C₆H₅)C(SiMe₃)₂]Li · THF did not give the corresponding metathesis product, but a Schiff base adduct [(ArN)₂MoCl₂] · [NH=C(C₆H₅)CH(SiMe₃)₂] ( 8 ) in low yield. The molecular structures of 7 and 8 are established by the X‐ray single crystal structural analysis.     

Formation of paramagnetic mononuclear iron nitrosyl complexes from diamagnetic di- and tetranuclear iron-sulphur nitrosyls: characterisation by EPR spectroscopy and study of thiolate and nitrosyl ligand exchange reactions

The diamagnetic Roussin esters Fe₂(SR)₂(NO)₄ readily underwent exchange with thiols R′SH to yield Fe₂(SR′)₂(NO)₄: the exchange was faster in polar, coordinating solvents where paramagnetic, mononuclear complexes of types [Fe(NO)₂(solvent)₂]⁺ and Fe(NO) ₂(SR)(solvent) were formed. With the corresponding thiolate anions RS^-, the esters Fe₂(SR)₂(NO)₄ formed the mononuclear complexes [Fe(SR)₂(NO)₂]^-, which were fully characterised by EPR spectroscopy for R = H, Me, Et, i-Pr, t-Bu and PhCH₂: assignments of hyperfine couplings were confirmed by use of ¹⁵N. With Fe₂(SR)₂(NO)₄ and a different set of thiolate anion, R′S ^-, in excess, thiol exchange occurred to give [Fe(SR′)₂(NO)₂]^-. A mechanism for formation of Fe₂(SR′)₂(NO)₄ from Fe₂(SR)₂(NO)₄ has been proposed. The paramagnetic mononuclear complexes [Fe(SR)₂(NO)₂] were also readily formed from the diamagnetic clusters [Fe₄S₃(NO)₇]^- and Fe₄S₄(NO)₄, together with [Fe(SR)₃(NO)]^-, and additionally from [Fe(CO)₃NO]^-. [Fe(SMe)₂(NO)₂]^-. was found to be a precursor of isolable Fe₂(SMe)₂(NO)₄, and [Fe(SH)₂ (NO)₂]^- to be the common precursor of both Roussin′s red anion [Fe₂S₂(NO)₄]^- and Roussin's black anion [Fe₄S₃ (NO)₇]^- interconvertible by appropriate adjustment of pH. The nitrosyl groups in these complexes were freely labile, and mononitrosyliron and dinitrosyliron fragments were readily interconvertible: FE(NO) fragments were favoured by the dimethyldithiocarbamate ligand (Me₂NCS ₂) and Fe(NO)₂ fragments by thiolate ligands, RS^-, regardless of the origin of the Fe(NO)_x(x = 1,2) fragment: both mono- and dinitrosyliron complexes persisted with [(i-PrO)₂S₂]^- as ligand. Isotopic labelling showed the occurrence of rapid exchange of nitrogen between nitrosyl ligands and added nitrite in Fe(NO)(S₂CNMe₂)₂ and [Fe(SR)₂(NO)₂]^-     

Synthese,Struktur und Reaktivität von Bis(dialkylamino)diphosphanen

Synthesis, Structure, and Reactivity of Bis(dialkylamino)diphosphines Starting with the aminochlorophosphines ⁱPr₂N? PCl₂ 1 and (ⁱPr₂N)₂P? Cl 2 , the synthesis of some new functionalized aminophosphines (ⁱPr₂N)₂P? SiMe₃ 3a , (ⁱPr₂N)₂P? SnMe₃ 3b , (ⁱPr₂N)(DMP)P? Cl 4 , ⁱPr₂N? P(SiMe₃)₂ 5 and ⁱPr₂N? P(SiMe₃)Cl 6 is reported. Reactions of 2 with different phosphides yield the aminodiphosphines (ⁱPr₂N)₂P? P(SiMe₃)₂ 7a , (ⁱPr₂N)₂P? P(SiMe₂^tBu)₂ 7b , (ⁱPr₂N)₂P? PPh₂ 8 and (ⁱPr₂N)₂P? PH₂ 9 . The phosphines 3a/b react with halogenophosphines to the aminohalogenodiphosphines (ⁱPr₂N)₂P? PCl₂ 10 , (ⁱPr₂N)₂P? P^tBuCl 11 and (ⁱPr₂N)₂P? P(NⁱPr₂)Cl 12 . The ambivalente aminophosphine 6 gives the aminotrichlorodiphosphine Cl(ⁱPr₂N)P? PCl₂ 13 after condensation with PCl₃, while the reactions with the corresponding lithiumphosphides yield the aminosilyldiphosphines (ⁱPr₂N)(SiMe₃)P? P(SiMe₃)₂ 14a and (ⁱPr₂N)(SiMe₃)P? P(SiMe₂^tBu)₂ 14b . The aminochlorophosphines 2/4 are reductively coupled with magnesium leading to the symmetrically substituted tetraaminodiphosphines (ⁱPr₂N)₂P? P(ⁱPr₂N)₂ 15a and DMP(ⁱPr₂N)P? P(ⁱPr₂N)DMP 15b . The functionalized aminosilyldiphosphine 7a is treated with methanol to yield the diphosphine (ⁱPr₂N)₂P? PH(SiMe₃) 16 and gives the lithium phosphinophosphide (ⁱPr₂N)₂P? PLi(SiMe₃) 17 after metallation with n-BuLi. The compounds are characterized by their NMR and mass spectra and the ³¹P-NMR values of the diphosphines are discussed according to their substituents. The crystal structures of 7b, 8 and 15b showing significantly differing conformations are presented.     

Electronic structures of tetragonal nitrido and nitrosyl metal complexes

The standard oxidation states of central metal atoms in C _4v nitrido ([M(N)(L)₅] ^z ) complexes are four units higher than those in corresponding nitrosyls ([M(NO)(L)₅] ^z ) (L=CN: z = 3−, M = Mn, Tc, Re; z = 2−, M = Fe, Ru, Os; L = NH₃: z = 2+, M = Mn, Tc, Re; z = 3+, M = Fe, Ru, Os). Recent work has suggested that [Mn(NO)(CN)₅]³⁻ behaves electronically much closer to Mn(V)[b ₂(xy)]², the ground state of [Mn(N)(CN)₅]³⁻, than to Mn(I)[b ₂(xy)]²[e(xz,yz)]⁴. We have employed density functional theory and time-dependent density functional theory to calculate the properties of the ground states and lowest-lying excitations of [M(N)(L)₅] ^z and [M(NO)(L)₅] ^z . Our results show that [M(N)(L)₅] ^z and [M(NO)(L)₅] ^z complexes with the same z value have strikingly similar electronic structures.     

First Copper(I) and Silver(I) Complexes Containing Phosphanylphosphido Ligands

Three new complexes with phosphanylphosphido ligands, [Cu₄{μ₂‐P(SiMe₃)‐PtBu}₄] ( 1 ), [Ag₄{μ₂‐P(SiMe₃)‐PtBu₂}₄] ( 2 ) and [Cu{η¹‐P(SiMe₃)‐PiPr₂}₂]^–[Li(Diglyme)₂]⁺ ( 3 ) were synthesized and structurally characterized by X‐ray diffraction, NMR spectroscopy, and elemental analysis. Complexes 1 and 2 were obtained in the reactions of lithium derivative of diphosphane tBu₂P‐P(SiMe₃)Li · 2.7THF with CuCl and [iBu₃PAgCl]₄, respectively. The X‐ray diffraction analysis revealed that the complexes 1 and 2 present macrocyclic, tetrameric form with Cu₄P₄ and Ag₄P₄ core. Complex 3 was prepared in the reaction of CuCl with a different derivative of lithiated diphosphane iPr₂P‐P(SiMe₃)Li · 2(Diglyme). Surprisingly, the X‐ray analysis of 3 revealed that in this reaction instead of the tetramer the monomeric form, ionic complex [Cu{η¹‐P(SiMe₃)‐PiPr₂}₂]^–[Li(Diglyme)₂]⁺ was formed.