A Structurally Characterized Fluoroalkyne

The facile synthesis of a stable and isolable compound with a fluoroalkynyl group, M−C≡CF, is reported. Reaction of [Ru(C≡CH)(η⁵‐C₅Me₅)(dppe)] with an electrophilic fluorinating agent (NFSI) results in the formation of the fluorovinylidene complex [Ru(=C=CHF)(η⁵‐C₅Me₅)(dppe)][N(SO₂Ph)₂]. Subsequent deprotonation with LiN(SiMe₃)₂ affords the fluoroalkynyl complex [Ru(C≡CF)(η⁵‐C₅Me₅)(dppe)]. In marked contrast to the rare and highly reactive examples of fluoroalkynes that have been reported previously, this compound can be readily isolated and structurally characterized. This has allowed the structure and bonding in the CCF motif to be explored. Further electrophilic fluorination of this species yields the difluorovinylidene complex [Ru(C=CF₂)(η⁵‐C₅Me₅)(dppe)][N(SO₂Ph)₂].     

Anion Directed Self‐Assembly of One‐Dimensional and Two‐Dimensional Coordination Polymers Containing Bridging Diphosphine Ligands

The reactions of 1,2‐bis(diphenylphosphanyl)ethane (dppe) with different silver(I) salts facilitated the formation of 1D and 2D coordination polymers, [Ag(dppe)(OAc)]_n · nH₂O ( 1 ) and [Ag₂(dppe)_1.5(NO₃)₂]_n ( 2 ), respectively. The complexes were characterized by elemental analysis, ATR‐IR spectroscopy, ¹H NMR, ¹³C NMR, and ³¹P NMR spectroscopy, and single‐crystal X‐ray diffraction. Structural analysis revealed that complex 1 exhibits a 1D infinite wavy structure, in which each silver(I) ion is bridged by dppe ligands. Structure 2 has a 2D topologically promising architecture that displays a 6.6.6 graphitic net, which corresponds to hnd topology. The nitrate ions and dppe ligands are in a μ₂ bridging mode and support the formation of this net. Moreover, significant π–π interactions between the phenyl rings in the apertures of (6,3) grid stabilized complex 2 .     

Schwefelmonoxid-komplexe: III. Ein kationischer eisen-so-komplex

The compounds [cpFe(dppe)(SO)]PF₆, the first mononuclear cationic complex of sulfur monoxide, and [cpFe(dppe)(SO₂)]PF₆ were obtained in high yield from the corresponding carbonyl [cpFe(dppe)(CO)]PF₆. From spectroscopic studies the sulfur monoxide was found to be coordinated to iron in the usual bent η¹-fashion; the sulfur dioxide complex, as expected, contains SO₂ in an η¹-planar fashion.     

Synthesis and X-ray crystal structure of trans-[MoF(CCH2 tBu)(Ph2PCH2CH2PPh2)2][BF4], a paramagnetic alkylidynefluorocomplex

Treatment of the alkynylhydridocomplex [MoH₃(CC^tBu)(dppe)₂](dppePh₂PCH₂CH₂PPh₂) with [Et₂OH][BF₄] gives trans-[MoF(CCH₂^tBu)(dppe)₂], the first example of a stable paramagnetic alkylidyne complex, the X-ray structure of which is reported.     

The preparation and crystal structure of bis(bis(diphenyl-phosphino)ethane)carbonylformylosmium(II) hexafluoroantimonatedichloromethane (1/1)

Reaction of trans[Os(CO)₂(dppe)₂]²⁺ with [KHB(OPrⁱ)₃] gives the formyl complex trans[Os(CHO)(CO)(dppe)₂][SbF₆] which is thermally very stable; the crystal structure shows it to have trans stereochemistry and a long Os-C bond.     

Structural and spectroscopic trends in mononuclear arylchalcogenolato-palladium(II) and -platinum(II) complexes: Crystal structures of [M(TeAr)2(dppe)] {M = palladium, platinum; Ar = phenyl, 2-thienyl; dppe = 1,2-bis(diphenylphosphino)ethane}

A series of mononuclear [M(EAr)₂(dppe)] [M = Pd, Pt; E = Se, Te; Ar = phenyl, 2-thienyl; dppe = 1,2-bis(diphenylphosphino)ethane] complexes has been prepared in good yields by the reactions of [MCl₂(dppe)] and corresponding ArE⁻ with a special emphasis on the aryltellurolato palladium and -platinum complexes for which the existing structural information is virtually non-existent. The complexes have crystallized in five isomorphic groups: (1) [Pd(SePh)₂(dppe)] and [Pt(SePh)₂(dppe)], (2) [Pd(TePh)₂(dppe)] and [Pt(TePh)₂(dppe)], (3) [Pd(SeTh)₂(dppe)], (4) [Pt(SeTh)₂(dppe)] and [Pd(TeTh)₂(dppe)], and (5) [Pt(TePh)₂(dppe)]. In addition, solvated [Pd(TePh)₂(dppe)] · CH₃OH and [Pd(TeTh)₂(dppe)] · 1/2CH₂Cl₂ could be isolated and structurally characterized. The metal atom in each complex exhibits an approximate square-planar coordination. The Pd-Se, Pt-Se, Pd-Te, and Pt-Te bonds span a range of 2.4350(7)-2.4828(7) Å, 2.442(1)-2.511(1) Å, 2.5871(7)-2.6704(8) Å, and 2.6053(6)-2.6594(9) Å, respectively, and the respective Pd-P and Pt-P bond distances are 2.265(2)-2.295(2) Å and 2.247(2)-2.270(2) Å. The orientation of the arylchalcogenolato ligands with respect to the M(E₂)(P₂) plane has been found to depend on the E-M-E bond angle. The NMR spectroscopic information indicates the formation of only cis-[M(EAr)₂(dppe)] complexes in solution. The trends in the ³¹P, ⁷⁷Se, ¹²⁵Te, and ¹⁹⁵Pt chemical shifts expectedly depend on the nature of metal, chalcogen, and aryl group. Each trend can be considered independently of other factors. The ⁷⁷Se or ¹²⁵Te resonances appear as second-order multiplets in case of palladium and platinum complexes, respectively. Spectral simulation has yielded all relevant coupling constants.     

Regulation of Charge Delocalization in a Heteronuclear Fe2Ru System by a Stepwise Photochromic Process

Heteronuclear complexes FeCp₂?DTE?C?C?Ru(dppe)₂Cl ( 1 o ; dppe=1,2‐bis(diphenylphosphino)ethane, Cp=cyclopentadienyl, DTE=dithienylethene) and FeCp₂?DTE?C?C?Ru(dppe)₂?C?C?DTE?FeCp₂ ( 2 oo ), with redox‐active ferrocenyl and ruthenium centers separated by a photochromic DTE moiety, were prepared to achieve photoswitchable charge delocalization and Fe???Ru electronic communication. Upon UV‐light irradiation of 2 oo , the Fe???Ru heterometallic electronic interaction is increasingly facilitated with stepwise photocyclization, 2 oo → 2 co → 2 cc ; this is ascribed to the gradual increase in π‐conjugated systems. The near‐infrared absorptions in mixed‐valence species [ 2 oo ]⁺/[ 2 co ]⁺/[ 2 cc ]⁺ are gradually intensified following the conversion of [ 2 oo ]⁺→[ 2 co ]⁺→[ 2 cc ]⁺, which demonstrates that the extent of charge delocalization shows progressive enhancement with stepwise photocyclization. As revealed by electrochemical, spectroscopic, and theoretical studies, complex 2 exhibits nine switchable states through stepwise photochromic and reversible redox processes.     

Rearrangements in the electron-impact induced fragmentation of some β-aroyl-α-methylpropionic acids

A complex rearrangement on electron-impact for β-aroyl-α-methylpropionic acids, involving both hydrogen and hydroxy migration followed by loss of carbon monoxide and allyl radical, is described and discussed. The rearrangement process, resulting in an ion [ArCOOH₂]⁺, is favoured by electron-withdrawing substituents in the aromatic ring.     

Synthesis of trans-[Re(NO)2-(Ph2PCH2CH2PPh2)2][BF4], a formal dinitrosyl complex of rhenium(-I) and its protic denitrosylation. X-Ray structure of trans-[ReF(NO)-(Ph2PCH2CH2PPh2)2][BF4]

Treatment of a THF solution of trans-[ReCl(N₂)(dppe)₂] (dppe = Ph₂PCH₂CH₂PPh₂) with NO, in the presence of Tl[BF₄], forms trans-[Re(NO)₂(dppe)₂][BF₄], a rare formal 20-electron d⁸-rhenium nitrosyl complex which, by reaction with HX (X = BF₄, Cl or HSO₄), gives trans-[ReF(NO)(dppe)₂][BF₄] (2) (the X-ray structure of which is reported) or trans-[ReX(NO)(dppe)₂]X (3, X = Cl or HSO₄), respectively, as well as nitrous oxide.     

Pentane and tetra­hydro­furan solvates of trans‐di­chloro­bis­[1,2‐ethane­diyl­bis­(di­phenyl­phos­phine)‐P,P′]­molybdenum(II)

trans‐[MoCl₂(dppe)₂] [dppe is 1,2‐ethane­diyl­bis­(di­phenyl­phos­phine), C₂₆H₂₄P₂] was obtained as a side product from the reaction of trans‐[Mo(dppe)₂(N₂)₂] with Cp*GeCl to give the germyl­yne complex trans‐[Cl(dppe)₂Mo[triple‐bond]Ge(η¹‐Cp*)]. The crystal structures of the hemi­pentane (0.5C₅H₁₂) and di­tetra­hydro­furan (2C₄H₈O) solvates of trans‐[MoCl₂(dppe)₂], (IIIa) and (IIIb), respectively, have been determined.     

Preorganization in the Nazarov cyclization: the role of adjacent coordination sites in the highly Lewis acidic catalyst [IrMe(CO)(dppe)(DIB)](BAr4)2

The dicationic Ir(III) complex [IrMe(CO)(dppe)(DIB)](BAr₄^f)₂ where dppe=bis(diphenylphosphino)ethane and DIB=o-diiodobenzene possesses adjacent labile sites and is found to be a very active catalyst for the Nazarov cyclization. ³¹P NMR spectroscopy provides evidence for substrate-catalyst binding by chelation, and this is found to be the resting state of the system during catalysis. The efficiency of the cyclization is attributed to the electrophilicity of the Ir(III) complex and substrate activation via O,O′-chelation which employs two substrate carbonyl groups or one carbonyl and an ether function, and encourages the s-trans/s-trans conformation required for cyclization. When two point binding occurs through an oxygen atom and one of the vinyl groups, the s-trans/s-trans conformation is not achieved, and cyclization is not observed. In one case, monodentate binding of substrate occurs, and the rate of cyclization is significantly slower than when O,O′-chelation is possible. The viability of O,O′-chelation is shown by the crystal structure determination of a model substrate-catalyst complex.     

A novel series of nickel(II)-dppe-arylazoimidazole complexes. Synthesis and spectroscopic characterization

Reaction of [Ni(dppe)Cl₂/Br₂] with AgOTf in CH₂Cl₂ medium following ligand addition leads to [Ni(dppe)(OSO₂CF₃)₂] and then [Ni(dppe)(RaaiR)](OSO₂CF₃)₂ [RaaiR′ = p–R–C₆H₄–N=N–C₃H₂–NN-1–R′,(1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH₂CH₃ (2), CH₂Ph (3), OSO₂CF₃ is the triflate anion]. ³¹P{¹H}-NMR confirm that stable bis-chelated square planar Ni(II) azoimine–dppe complex formation with one sharp peaks. The ¹H NMR spectral measurements suggest azoimine link is present with lot of phenyl protons in the aromatic region. Considering all the moities there are a lot of different carbon atoms in the molecule which gives many different peaks in the ¹³C(¹H)-NMR spectrum. In the ¹H-¹H COSY spectrum in the present complexes and contour peaks in the ¹H-¹³C-HMQC spectrum in the present complexes, assign the solution structure and stereoretentive conformation in each complexes.     

On the Reaction of [(CO)3Fe(μ‐Me2NCO)2Fe(CO)2(NHMe2)] with Chelating Ligands — X‐Ray Structures of New Binuclear μ‐Carbamoyl Complexes

Reaction of the binuclear μ‐carbamoyl complex [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂(HNMe₂)] ( 1 ) in toluene with the chelating ligands Ph₂PCH₂PPh₂ (dppm) and Ph₂PCH₂CH₂PPh₂ (dppe) gives different results. With dppm only the complex [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂(dppm)] ( 3 ) with a dangling ligand is obtained under replacement of amine, whereas with dppe depending on the reaction conditions up to three compounds are found. A 1 : 1 mixture of the educts generates the related complex [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂(dppe)] ( 4 ) together with the tetranuclear complex [{(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)₂}₂(dppe)] (5 ). 4 slowly converts into [(CO)₃Fe(μ‐Me₂NCO)₂Fe(CO)(dppe)] ( 6 ) with dppe acting as a chelating ligand. 6 is the first compound in this series in which one of the five CO groups is replaced by another donor. A 2 : 1 molar ratio of 1 and dppe quantitatively produces 5 . Addition of CO to a solution of 6 proceeds under slow reversible conversion of the complex into 4 . The compounds were characterized by the usual spectroscopic methods; 3 , 5 and 6 were also studied by X‐ray diffraction analyses.     

A study of the protonation and alkylation oft-butyl isocyanide intrans-[M(CNBu-t 2(Ph2PCH2CH2PPh2)2] (M = Mo or W): Formation of carbyne-type complexes and theirtrans- tocis-isomerization

Summary Treatment of complexestrans-[M(CNBu-t)₂(dppe)₂][(1) M = Mo or W, dppe = Ph₂PCH₂CH₂PPh₂] with protic acid gives a mixture of the aminocarbyne complexestrans- pluscis-[M(CNHBu-t)(CNBu-t)(dppe)₂]⁺ (2) and the hydridocompounds [MH(CNBu-t)₂(dppe)₂]⁺ (3), whereas reaction with an alkylating agent (R⁺) appears to give the dialkylaminocarbyne compounds [M(CNRBu-t)(CNBu-t)(dppe)₂]⁺ (4) also as a mixture of thetrans andcis isomers.     

Ring‐to‐Cage Structural Conversion via Template Effect in a Gold(I) Metallosupramolecular System

A unique example of a ring‐to‐cage structural conversion in a multinuclear gold(I) coordination system with d ‐penicillamine (d ‐H₂pen) is reported. The reaction of [Au₂Cl₂(dppe)] (dppe=1,2‐bis(diphenylphosphino)ethane) with d ‐H₂pen in a 1:1 ratio gave [Au₄(dppe)₂(d ‐pen)₂] ([ 1 ]), in which two [Au₂(dppe)]²⁺ units are linked by two d ‐pen S atoms in a cyclic form so as to have two bidentate‐N,O coordination arms. The subsequent reaction of [ 1 ] with Cu(OTf)₂ afforded [Au₄Cu(dppe)₂(d ‐pen)₂]²⁺ ([ 2 ]²⁺), in which a Cu^II ion is chelated by the two coordination arms in [ 1 ] to form an Au^I₄Cu^II bicyclic metallocage. A similar reaction using Cu(NO₃)₂ was accompanied by the ring expansion of [ 1 ] to [Au₈(dppe)₄(d ‐pen)₄], leading to the production of [Au₈Cu₂(dppe)₄(d ‐pen)₄]⁴⁺ ([ 3 ]⁴⁺). In [ 3 ]⁴⁺, two Cu^II ions are each chelated by the two coordination arms to form an Au^I₈Cu^II₂ tricyclic metallocage, accommodating a nitrate ion. The use of Ni(NO₃)₂ or Ni(OAc)₂ instead of Cu(NO₃)₂ commonly gave a tricyclic metallocage of [Au₈Ni₂(dppe)₄(d ‐pen)₄]⁴⁺ ([ 4 ]⁴⁺), but a water molecule was accommodated inside the Au^I₈Ni^II₂ metallocage.     

A ruthenium(II) complex with the propionate ion: Synthesis,characterization and cytotoxic activity

The complex [Ru(η²-O₂CCH₂CH₃)(dppe)₂]PF₆ (dppe = 1,2-bis(diphenylphosphino)ethane) was prepared and characterized by elemental analysis, spectroscopic techniques, X-ray crystallography, HRESIMS and HRESIMS/MS. The characterization data are consistent with a cis arrangement for the dppe ligands and a bidentate coordination of the propionate ligand through carboxylate oxygens. Cytotoxicity assays were carried out on human and murine cancer and normal cell lines. In general, the [Ru(η²-O₂CCH₂CH₃)(dppe)₂]PF₆ complex was more cytotoxic than both its precursor cis–[RuCl₂(dppe)₂] and the reference metallodrug cisplatin. The best results against the HepG2 human tumour cell line and S180 murine tumour cell line were found with IC₅₀ values of 6.5 ± 0.2 and 0.18 ± 0.03 μM, respectively.     

Organometallic gold(I)–nickel(II)–aryldiethynyl (–C≡C(Ar)C≡C–) phosphine complexes: synthesis and multinuclear n.m.r. study

Silver triflate [AgOTf] assisted de-bromination gives [Ni(dppm/dppe/(PPh₃)₂)(OTf)₂], which on reaction with aryldiethynyls and gold(I) phosphines in CH₂Cl₂ medium, by the self assembly technique, leads to [{Ni(dppm/dppe/(PPh₃)₂}{(1,4-AB)Au(PPh₃)}₂] [{Ni₄(dppm/dppe/(PPh₃)₂)₄(1,4AB)₄}] [dppm/dppe = diphenyl phosphino-methane (1), -ethane (2), where OSO₂CF₃ is the triflate anion]. The maximum molecular peak of the corresponding molecule is observed in the ESI mass spectrum. I.r. spectra of the complexes show –C=C– and –C=N–, as well as phosphine stretching. The ¹H-n.m.r. spectra as well as ³¹P(¹H)-n.m.r. suggest solution stereochemistry, proton movement, phosphorus proton interaction. Considering all the moities there are a lot of carbon atoms in the molecule reflected by the ¹³C-n.m.r. spectrum. In the ¹H–¹H-COSY spectrum of the present complexes and contour peaks in the ¹H–¹³C-HMQC spectrum, assign the solution structure and stereo-retentive transformation in each step.     

Reactivity of carbyne and carbene complexes of molybdenum and tungsten

Summary The interconversion of carbyne, carbyne and hydride complexes derived from protonations oftrans-[M(CNMe)₂(dppe)₂](M = Mo or W) has been studied. The initial site of protonation is shown to be the isonitrile nitrogen and all protonations proceed through the common carbyne intermediatetrans-[M(CNHMe)(CNMe)(dppe)2]⁺. The CNHMe group in traps-[M(CNHMe)₂(dppe)₂]²⁺ is shown to be susceptible to electrophilic attack at N and nucleophilic attack at ligating C, the new complexestrans-[W(CNH2Me)(CNHMe)(dppe)₂](BF₄)₃ andtrans-[Mo(CHNHMe)(CNHMe)(dppe)2]BF4 being formed, respectively.     

The chemical oxidation and electronic spectra of the complexes trans-[M(CNR)2(Ph2PCH2CH2PPh2)2] (M = Mo or W)

Oxidation of the complexes $\text{trans}$-[M(CNR)₂(dppe)₂] (A) (M = Mo or W; R = Me, Bu^t or CH₃C₆H₄-$\text{4}$; dppe = Ph₂PCH₂CH₂PPh₂) with diiodine or silver (I) salts gives the paramagnetic cations $\text{trans}$-[M(CNR)₂(dppe)₂]⁺, (M = Mo, R = CH₃C₆H₄-$\text{4}$; M = W, R = Bu^t) and $\text{trans}$-[M(CNR)₂(dppe)₂]²⁺ (M = Mo, R = Me or CH₃C₆H₄-$\text{4}$; M = W, R = Me or Bu^t). Mixtures of products are generally produced when dichlorine or dibromine are the oxidising agents, however pure salts, the seven-coordinate complex cations [MX(CNC₆H₄CH₃-$\text{4}$)₂(dppe)₂]⁺ (B, X = Cl or Br) have been isolated. A simple molecular orbital scheme is proposed for complexes (A) and used to discuss their electronic spectra and their oxidation.     

Synthesis and crystal structure of [MoH3(CCBut)(Ph2PCH2CH2PPh2)2], a trihydrido-alkynyl complex

Reaction of Bu^tCCH with trans-[Mo(N₂)₂(dppe)₂] (dppe = Ph₂PCH₂CH₂PPh₂) gives [MoH₃(CCBu^t)(dppe)₂], whose X-ray structure is reported.