Synthesis, structure, and electronic study of some group VII furoyl substituted complexes

The reaction of fulvene 1 with TlOEt in THF affords [Tl{1,2-C₅H₃(COC₄H₃O)₂}] (2) in 60% yield. Treatment of 2 with [MBr(CO)₅] (M = Mn, Re) in benzene reflux gave [Mn{η⁵-1,2-C₅H₃(COC₄H₃O)₂}(CO)₃] (3A) and [Re{η⁵-1,2-C₅H₃(COC₄H₃O)₂}(CO)₃] (3B) in 61% and 66% yields, respectively. Diacyl complexes 3A and 3B were ring-closed to the pyridazine by treating with hydrazine hydrate in methanol at room temperature. Fulvene 1 and diacyl complexes 3A and 3B have been structurally characterized by X-ray crystallography. Additionally, the electronic structure of complexes 3A and 3B and their relaxed structures have been characterized with density functional calculations. Calculated vibrational frequencies are compared with the experimental characterizations.     

Evaluation of two chelators for labelling a PNA monomer with the fac-[Tc(CO)3] moiety

A PNA monomer containing thymine as nucleobase (1) was synthesized, characterized and coupled to the pyrazolyl containing ligand 3,5-Me₂pz(CH₂)₂N((CH₂)₃COOH)(CH₂)₂NHBoc (2) and to a modified cysteine S-(carboxymethyl-pentafluorphenyl)-N-[(trifluor)carbonyl]-l-cysteine methyl ester (3) yielding the bifunctional chelators 6 and 7, respectively. Reactions of 6 and 7 with the Re(I) tricarbonyl starting material [Re(CO)₃(H₂O)₃]Br afforded the complexes fac-[Re(CO)₃(κ³-6)]⁺ (8) and fac-[Re(CO)₃(κ³-7)] (9), respectively. The identity of 8 and 9 has been established based on IR spectroscopy, elemental analysis, ESI-MS spectrometry and HPLC. The multinuclear NMR spectroscopy (¹H, ¹³C, g-COSY, g-HSQC) has also been very informative in the case of complex 8, showing the presence of rotamers in solution. For 9 the NMR spectrum was too complex due to the presence of rotamers and diastereoisomers. The radioactive congeners of complexes 8 and 9, fac-[^99mTc(CO)₃(κ³-6)]⁺ (8a) and fac-[^99mTc(CO)³(κ³-7)] (9a), have been prepared by reacting the precursor fac-[^99mTc(CO)₃(H₂O)₃]⁺ with the corresponding ligands being their identity established by comparing their HPLC chromatograms with the HPLC of the rhenium surrogates.     

Reactions of rhenium and manganese carbonyl complexes with 1,8-bis(diphenylphosphino)naphthalene: Ligand chelation, C-H and C-P bond-cleavage reactions

Reaction of [Re₂(CO)₈(MeCN)₂] with 1,8-bis(diphenylphosphino)naphthalene (dppn) afforded three mono-rhenium complexes fac-[Re(CO)₃(κ¹:η¹-PPh₂C₁₀H₆)(PPh₂H)] (1), fac-[Re(CO)₃{κ¹:κ¹:η¹-(O)PPh₂C₁₀H₆(O)PPh(C₆H₄)}] (2) and fac-[ReCl(CO)₃(κ²-PPh₂C₁₀H₆PPh₂)] (3). Compounds 1-3 are formed by Re-Re bond cleavage and P-C and C-H bond activation of the dppn ligand. Each of these three complexes have three CO groups arranged in facial fashion. Compound 1 contains a chelating cyclometalated diphenylnaphthylphosphine ligand and a terminally coordinated PPh₂H ligand. Compound 2 consists of an orthometalated dppn-dioxide ligand coordinated in a κ¹:κ¹:η¹-fashion via both the oxygen atoms and ortho-carbon atom of one of the phenyl rings. Compound 3 consists of an unchanged chelating dppn ligand and a terminal Cl ligand. Treatment of [Mn₂(CO)₈(MeCN)₂] with a slight excess of dppn in refluxing toluene at 72 °C, gave the previously reported [Mn₂(CO)₈(μ-PPh₂)₂] (4), formed by cleavage of C-P bonds, and the new compound fac-[MnCl(CO)₃(κ²-PPh₂C₁₀H₆PPh₂)] (5), which has an unaltered chelating dppn and a terminal Cl ligand. In sharp contrast, reaction of [Mn₂(CO)₈(MeCN)₂] with slight excess of dppn at room temperature yielded the dimanganese [Mn₂(CO)₉{κ¹-PPh₂(C₁₀H₇)}] (6) in which the diphenylnaphthylphosphine ligand, formed by facile cleavage of one of the P-C bonds, is axially coordinated to one Mn atom. Compound 6 was also obtained from the reaction of [Mn₂(CO)₉(MeCN)] with dppn at room temperature. The XRD structures of complexes 1-3, 5, 6 are reported.     

Template synthesis of a macrocycle with a mixed NHC/phosphine donor set

Reaction of cis-[ReCl(NHC)(CO)₄] cis-[1] (NHC = NH,NH-substituted saturated cyclic diaminocarbene) with diphosphine (2-F-C₆H₄)₂P-CH₂CH₂-P(C₆H₄-2-F)₂2 yields complex fac-[Re(NHC)(2)(CO)₃]Cl fac-[3]Cl. Deprotonation of the NH,NH-NHC ligand in fac-[3]Cl with KOtBu leads to an intramolecular nucleophilic aromatic substitution of one fluorine atom from each -P(C₆H₄-2-F) group by the NHC ring nitrogen atoms with formation of complex fac-[4]Cl bearing a facially coordinated [11]ane-P₂C^NHC ligand. Reaction of cis-[MnBr(NHC)(CO)₄] cis-[5] (NHC = NH,NH-substituted saturated cyclic diaminocarbene) with diphosphine 2 yields complex [MnBr(NHC)(2)(CO)₂] [6] without substitution of the bromo ligand and with the phosphine donors from the bidentate diphosphine occupying one cis and one trans position to the NHC donor.     

New complexes of the fac-{(CO)3Re} fragment bearing a diaminediphosphine ligand

The mono- and binuclear hydride compounds fac-[ReH(CO)₃L] (1a) and [{ReH(CO)₄}₂(μ-L)] (1b) have been prepared by reaction of [ReH(CO)₅] with Ph₂PN(CH₃)(CH₂)₂N(CH₃)PPh₂ (L) under UV light. Protonation reactions of the hydride compound 1a with equimolar amounts of HSO₃CF₃ or HCl yielded the triflato or the chlorido compounds fac-[Re(OSO₂CF₃)(CO)₃L] (2) and fac-[ReCl(CO)₃L] (3), respectively. The compounds have been characterised by elemental analysis, IR and NMR spectroscopic data, and mass spectrometry. Their structures have been confirmed by X-ray crystallography.     

Tricarbonylrhenium(I) and manganese(I) complexes of 2-(pyrazolyl)-4-toluidine

A series of tricarbonyl rhenium(I) and manganese(I) complexes of the electroactive 2-(pyrazolyl)-4-toluidine ligand, H(pzAn^Me), has been prepared and characterized including by single crystal X-ray diffraction studies. The reactions between H(pzAn^Me) and M(CO)₅Br afford fac-MBr(CO)₃[H(pzAn^Me)] (M = Mn, 1a; Re, 1b) complexes. The ionic species {fac-M(CH₃CN)(CO)₃[H(pzAn^Me)]}(PF₆) (M = Mn, 2a; Re, 2b) were prepared by metathesis of 1a or 1b with TlPF₆ in acetonitrile. Complexes 1a and 1b partly ionize to {M(CH₃CN)(CO)₃[H(pzAn^Me)]⁺}(Br⁻) in CH₃CN but retain their integrity in less donating solvents such as acetone or CH₂Cl₂. Each of the four metal complexes reacts with (NEt₄)(OH) in CH₃CN to give poorly-soluble crystalline [fac-M(CO)₃(μ-pzAn^Me)]₂ (M = Mn, 3a; Re, 3b). The solid state structures of 3a and 3b are of centrosymmetric dimeric species with bridging amido nitrogens and with pyrazolyls disposed trans- to the central planar M₂N₂ metallacycle. In stark contrast to the diphenylboryl derivatives, Ph₂B(pzAn^Me), none of the tricarbonyl group 7 metal complexes are luminescent.     

Tricarbonylmanganese(I) derivatives of [Di(pyrazolyl)(2-pyridyl)methyl]aryl scorpionates

The cobalt(II) chloride catalyzed Peterson rearrangement reactions between sulfinyldi-(pyrazolyl) and aryl(pyridyl)methanone derivatives yield di(pyrazolyl)(pyridyl)hetero-scorpionate ligands. Reaction of these ligands with Mn(CO)₅Br in the presence of a silver salt produces the monometallic complexes {[κ³-PhC(pz)₂(2-py)]Mn(CO)₃}(O₃SCF₃) (1a), {[κ³-PhC(pz)₂(2-py)]Mn(CO)₃}(PF₆) (1b), {[κ³-PhC(^4-Mepz)₂(2-py)]Mn(CO)₃}(PF₆) (2), {[κ³-p-BrC₆H₄C(pz)₂(2-py)]Mn(CO)₃}(PF₆) (3), and the bimetallic complexes [(CO)₃Mn{m-C₆H₄[C(pz)₂(2-py)]₂}Mn(CO)₃](BF₄)₂ (5a) and {m-C₆H₄[C(pz)₂(2-py)Mn(CO)₃]₂}(PF₆)₂ (5b) (pz = pyrazolyl ring, py = pyridyl ring). These octahedral manganese complexes show interesting structural diversity, with the complexes being organized in the solid state into complex supramolecular structures by an array of non-covalent forces.     

Synthesis and structural characterization of sterically crowded hydridotris(pyrazolyl)borato complexes: Unusual double 1,2-borotropic shift at a titanium centre

The potassium and thallium(I) derivatives of the hydrido-tris(3-Me₂Bz,5-Me-pyrazol-1-yl)borato ligand, K[Tp^Me2^Bz,Me] (1) and Tl[Tp^Me2^Bz,Me] (2), are reported. Their reactions with TiCl₄ under mild conditions afforded, after rearrangement of the ligand, recognized as a double 1,2-borotropic shift, the related Ti(IV) complex {hydrido-[bis(3-Me,5-Me₂Bz)(3-Me₂Bz,5-Me)-pyrazol-1-yl]borato}trichlorotitanium(IV), [Tp^Me2^Bz,Me∗∗] TiCl₃ (3). The ¹H- and ¹³C NMR spectra of the new compounds are discussed, the molecular structure of 3 has been determined by X-ray diffraction methods, the titanium centre has a pseudo-octahedral coordination, with the nitrogen and chloride ligands in a fac geometry. A possible mechanism of formation of 3 is proposed.     

Rhenium(I)- and technetium(I) tricarbonyl complexes anchored by bifunctional pyrazole-diamine and pyrazole-dithioether chelators

The novel pyrazolyl containing ligands 4-(HOOC)pz(CH₂)₂NH(CH₂)₂NH₂ (L¹) and 4-(HOOCCH₂)-3,5-Me₂pz(CH₂)₂NH(CH₂)₂NH₂ (L²), and 3,5-Me₂pz(CH₂)₂S(CH₂)₂SCH₂CH₃ (L³), 3,5-Me₂pz(CH₂)₂S(CH₂)₂SCH₂COOEt (L⁴) and 3,5-Me₂pz(CH₂)₂S(CH₂)₂SCH₂COOH (L⁵) were synthesized, and their ability to stabilise complexes with the fac-[M(CO)₃]⁺ (M = Re,^99mTc) moiety was evaluated. Reactions of L¹-L⁵ with the Re(I) tricarbonyl starting materials (NEt₄)₂[Re(CO)₃Br₃] and/or [Re(CO)₅Br] afforded complexes fac-[Re(CO)₃(κ³-L)] (L = L¹-L⁵ (1-5)), which contain the pyrazolyl ancillary ligands coordinated in a tridentate fashion. Complexes 1-5 were characterized by the common analytical techniques, which included single crystal X-ray diffraction analysis in the case of 4. The structural analysis of 4 confirmed the tridentate coordination mode of the pyrazole-dithioether ligand, which is facially coordinated to the Re(I) centre through the nitrogen from the pyrazole ring and the two thioether sulphur atoms, without involvement of the terminal ester functional group. The distorted octahedral coordination environment around the metal is completed by the three facial carbonyl ligands. The radioactive congeners of complexes 1, 3 and 4, fac-[^99mTc(CO)₃(κ³-L)]⁺ (L = L¹ (1a), L³ (3a), L⁴ (4a)), have been prepared by reacting the precursor fac-[^99mTc(CO)₃(H₂O)₃]⁺ with the corresponding ligands, and their identity confirmed by HPLC comparison with the rhenium surrogates. Complexes 1a and 3a have been challenged in the presence of a large excess of histidine or cysteine, in order to evaluate their in vitro stability. Only a negligible displacement was observed, indicating that pyrazole-diamine and pyrazole-dithioether chelators provide a high kinetic inertness and/or stability to organometallic complexes with the fac-[^99mTc(CO)₃]⁺ moiety.     

Novel tricarbonyl rhenium complexes of 5,8-quinolinedione derivatives - Synthesis, spectroscopic characterisation, X-ray structure and DFT calculations

The molecular structure of 7-acetamido-2-methyl-quinoline-5,8-dione has been determined and the reactivity of 7-acetamido-2-methyl-quinoline-5,8-dione (1) and 6-acetamido-2-methyl-quinoline-5,8-dione (2) towards Re(CO)₅Cl has been examined. Two novel tricarbonyl rhenium complexes, fac-[Re(CO)₃(7-acetamido-2-methyl-quinoline-5,8-dione)Cl]·CHCl₃ (3·CHCl₃) and fac-[Re(CO)₃(6-acetamido-2-methyl-quinoline-5,8-dione)Cl]₂·CHCl₃ (4·CHCl₃), have been synthesized and characterized spectroscopically and structurally. The electronic spectrum of 3 was investigated at the TDDFT level employing B3LYP functional in combination with LANL2DZ.     

Preparation and reactivity of the heterobimetallic ReIr face-shared bioctahedral compounds Cp*Ir(μ-Cl)3Re(CO)3 and Cp*Ir(μ-SC6H4Me-4)3Re(CO)3: X-ray diffraction structures and redox behavior

Thermolysis of the dinuclear compound [Cp*IrCl₂]₂ (1) with ClRe(CO)₅ (2) leads to the formation of the confacial bioctahedral compound Cp*Ir(μ-Cl)₃Re(CO)₃ (3) in high yield. Whereas the substitution of the chloride ligands in 3 is observed on treatment with excess p-methylbenzenethiol to furnish the sulfido-bridged compound Cp*Ir(μ-SC₆H₄Me-4)₃Re(CO)₃ (4), 3 undergoes fragmentation upon reaction with tertiary phosphines [PPh₃ and P(OMe)₃] to furnish the mononuclear compounds Cp*IrCl₂P and fac-ClRe(CO)₃P₂. Both 3 and 4 have been isolated and fully characterized in solution by IR and ¹H NMR spectroscopies, and their solid-state structures have been established by X-ray crystallography. The redox properties of 3 and 4 have been explored by cyclic voltammetry, and the results are discussed relative to extended Hückel MO calculations.     

Influence of the ligand donor atoms on the in vitro stability of rhenium(I) and technetium (I)-99m complexes with pyrazole-containing chelators: Experimental and DFT studies

The new pyrazole-containing ligand 3,5-Me₂pz(CH₂)₂S(CH₂)₂COOH (L¹H) was synthesized and used to prepare the complexes fac-[M(κ³-L¹)(CO)₃] (M = Re (1), ^99mTc(1a)), which were obtained in high yield albeit with a low specific activity in the case of ^99mTc. The X-ray diffraction analysis of 1 confirmed that L¹ coordinates to the metal as monoanionic and through a (N,S,O) donor atom set. Challenge experiments of 1a against cysteine and histidine showed that this complex suffers considerable transchelation in vitro. This contrasts with the behavior exhibited by the related complex fac-[^99mTc(κ³-L²)(CO)₃] (2a) (L² = 3,5-Me₂pz-(CH₂)₂NH-CH₂-COO), anchored by a (N₂O)-tridentate ligand. Biodistribution studies of 1a and 2a in mice indicated that both compounds have a relatively similar biological profile. Nevertheless, the fastest blood clearance and minor hepatic retention found for 2a has shown that this complex is more adequate to be further explored in radiopharmaceutical sciences. DFT calculations (ADF program) were performed for these neutral complexes and related cationic M(I) (M = Re, Tc) tricarbonyl complexes anchored by pyrazole-containing ligands, in order to have a better understanding of the influence of the donor atom set (N,N,O vs. N,O,S; N,N,N vs. N,N,S vs. N,S,S) on their in vitro stability. The differences of the calculated binding energies are not significant, suggesting that the in vitro behavior of these Re(I)/Tc(I) tricarbonyl complexes is not determined by thermodynamic factors.     

Synthesis and characterisation of new pyrazole-phosphinite ligands and their ruthenium(II) arene complexes

The new potentially bidentate pyrazole-phosphinite ligands [(3,5-dimethyl-1H-pyrazol-1-yl)methyl diphenylphosphinite] (L¹) and [2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl diphenylphosphinite] (L²) were synthesised and characterised. The reaction of L¹ and L² with the dimeric complexes [Ru(η⁶-arene)Cl₂]₂ (arene = p-cymene, benzene) led to the formation of neutral complexes [Ru(η⁶-arene)Cl₂(L)] (L = L¹, L²) where the pyrazole-phosphinite ligand is κ¹-P coordinated to the metal. The subsequent reaction of these complexes with NaBPh₄ or NaBF₄ produced the [Ru(η⁶-p-cymene)Cl(L²)][BPh₄] and [Ru(η⁶-benzene)Cl(L²)][BF₄] compounds which contain the pyrazole-phosphinite ligand κ²-P,N bonded to ruthenium. All the complexes were fully characterised by analytical and spectroscopic methods. The structure of the complex [Ru(η⁶-p-cymene)Cl(L²)][BPh₄] was also determined by a X-ray single crystal diffraction study.     

Reactions of P4S10 and pyPS2Cl with N,N′-diphenylurea and N,N′-diphenylthiourea

The reaction of P₄S₁₀ (1) with N,N′-diphenylurea (PhNH)₂CO (2) results in new heterocyclic compounds: the pyridinium salt of 1,3-diphenyl-2-sulfido-2-thioxo-1,3-diaza-2λ⁵-phosphetidine (3) (with a P–N–C–N cycle) and the pyridinium salt of 1,4-diphenyl-2,5-disulfido-2,5-dithioxo-1,4-dithiadiaza-2λ⁵,5λ⁵-diphosphinane (4), containing the (P–S–N)₂ cycle and the cyclic thiophosphates [pyH]₂[P₂S₈] (5), [pyH]₂[P₂S₇] (6) and [pyH]₃[P₃S₉] (7). A similar reaction, but carried out with N,N′-diphenylthiourea (PhNH)₂CS (8), leads to the formation of 4 and 6. pyPS₂Cl (9), used as an alternative starting material, also yields compounds 3, 4, 5, and further [pyH][PS₂Cl₂] (10) and S₈ after reaction with 2. Compound 3 reacts with Pd(CH₃COO)₂, with the formation of the complex [Pd(Ph₂N₂COPS₂)₂] (11). The crystal structures of 3 and 7 were determined by single-crystal X-ray diffraction.     

Structural studies of phosphor-1,1-diselenoato Mn(I) and Re(I) complexes

Mononuclear complexes of the type, M(CO)₄[Se₂P(OR)₂] (M = Mn, R = ⁱPr, 1a; Et, 1b; M = Re, R = ⁱPr, 3a; Et, 3b) can be prepared from either [-Se(Se)P(OⁱPr)₂]₂ (A) or [Se{-Se(Se)P(OEt)₂}₂] (B) with M(CO)₅Br. O,O′-dialkyl diselenophosphate ([(RO)₂PSe₂]^-, abbreviated as dsep) ligands generated from A and B act as a chelating ligand in these complexes. Upon refluxing in acetonitrile, these mononuclear complexes yield dinuclear complexes with a general formula of [M₂(CO)₆{Se₂P(OR)₂}₂] (M = Mn, R = ⁱPr, 2a; Et, 2b; M = Re, R = ⁱPr, 4a; Et, 4b). Dsep ligands display a triconnective, bimetallic bonding mode in the dinuclear compounds and this kind of connective pattern has never been identified in any phosphor-1,1-diselenoato metal complexes. Compounds 2b, 3b, and 4 are structurally characterized. Compounds 2b and 3b display weak, secondary Se?Se interactions in their lattices.     

Tin(IV) complexes obtained by reacting 2-benzoylpyridine-derived thiosemicarbazones with SnCl4 and Ph2SnCl2

Reaction of 2-benzoylpyridine thiosemicarbazone (H2Bz4DH, HL1) and its N(4)-methyl (H2Bz4Me, HL2) and N(4)-phenyl (H2Bz4Ph, HL3) derivatives with SnCl₄ and diphenyltin dichloride (Ph₂SnCl₂) gave [Sn(L1)Cl₃] (1), [Sn(L1)PhCl₂] (2), [Sn(L2)Cl₃] (3), (4) [Sn(L3)PhCl₂] (5) and [Sn(L3)Ph₂Cl] (6). Infrared and ¹H, ¹³C and ¹¹⁹Sn NMR spectra of 1-3, 5 and 6 are compatible with the presence of an anionic ligand attached to the metal through the N_py-N-S chelating system and formation of hexacoordinated tin complexes. The crystal structures of 1-3, 5 and 6 show that the geometry around the metal is a distorted octahedron formed by the thiosemicarbazone and either chlorides or chlorides and phenyl groups. The crystal structure of 4 reveals the presence of and trans [Ph₂SnCl₄]²⁻.     

Bis(silylaminodiarylphosphoranylsilylmethyl-C,N)-tin(II) and -lead(II) complexes and their precursors; structures of H(LL′), H(LL″), Sn(LL″)2 and Pb(LL″)2; [LL′] = [CH(SiMe3)P(Ph)2NSiMe3],

We report a series (a)-(d) of tandem reactions involving the conversion of: (a) 2CH₂(SiMe₃)P(Ph)₂NSiMe₃ [2H(LL′)] (III) into successively [Li(LL′)]₂ (1a) and [Pb(LL′)₂] (3a); (b) 1a in turn into {[Li(LL″)]₂} (2) and [Pb(LL″)₂] (4); (c) 1a successively into Sn(LL′)Cl (5) and [Sn(LL″)₂] (6); (d) (1b) into (3b). Experimental details for the preparation and characterisation (including elemental analysis and multinuclear NMR spectra in C₆D₆ and EI mass spectra) of 1a, 2, 3a, 3b, 4, 6, III (a new synthesis) and IV are provided. The X-ray structures of crystalline 4, 6, III and IV are presented; those of 1a, 2 and 3a were previously published.     

Syntheses, crystal structures and properties of Co(II) complexes with N,N′-bis(3-pyridylmethyl)-1,4-benzenedimethyleneimine (bpb), and Cd(II), Hg(II) complexes with reduced bpb

Five novel coordination polymers, [Co(bpb)₂Cl₂] (1), [Co(bpb)₂(SCN)₂] (2), [Cd(H₄bpb)_0.5(dmf)(NO₃)₂] (3), [Cd₂(H₄bpb)Br₄] (4), and [Hg₂(H₄bpb)I₄] (5) [bpb=N,N′-bis(3-pyridylmethyl)-1,4-benzenedimethyleneimine, H₄bpb=N,N′-bis(3-pyridylmethyl)-1,4-benzenedimethylamine], were synthesized and their structures were determined by X-ray crystallography. In the solid state, complex 1 is a 1D hinged chain, while 2 has 2D network structure with the ligand bpb serving as a bridging ligand using its two pyridyl N atoms. The imine N atoms keep free of coordination and bpb acts as a bidentate ligand in both 1 and 2. Complexes 3, 4, and 5 with reduced bpb ligand, i.e. H₄bpb, show similar 2D network structure, in which ligand H₄bpb serves as a tetradentate ligand. Thermogravimetric analyses for complexes 1-5 were carried out and found that they have high thermal stability. The magnetic susceptibilities of compounds 1, 2 were measured over a temperature range of 75-300 K.     

Synthesis and characterization of new oxazoline-based palladacycles with bridging or terminal imidate ligands. Crystal structures of [{Pd(μ-dibromomaleimidate)(Phox)}2], [Pd(dibromomaleimidate)(Phox)(PPh3)] and [Pd(glutarimidate)(Phox)(PPh3)] (Phox = 2-(2-oxazolinyl)phenyl))

The dinuclear hydroxo complex [{Pd(μ-OH)(Phox)}₂] (I) (Phox = 2-(2-oxazolinyl)phenyl) reacts in a 1:2 molar ratio with several imidate ligands to yield new cyclometallated palladium complexes [{Pd(μ-NCO)(Phox)}₂] containing asymmetric imidate –NCO– bridging units. [–NCO– = succinimidate (succ) (1), phtalimidate (phtal) (2), maleimidate (mal) (3), 2,3-dibromomaleimidate (2,3-diBrmal) (4) and glutarimidate (glut) (5)]. The reaction of these complexes with tertiary phosphines provides novel mononuclear N-bonded imidate derivatives of the general formula [Pd(imidate)(Phox)(PR₃)] [R = Ph (a), 4-F–C₆H₄ (b) or CH₂CH₂CN (c)]. The new complexes were characterized by partial elemental analyses and spectroscopic methods (IR, FAB, ¹H, ¹³C and ³¹P). The single-crystal structures of compounds 4, 4a and 5a have been established.     

Synthesis of tridentate 2,6-bis(imino)pyridyl aminechlorohydro ruthenium(II) complexes: The convenient use of amine hydrochlorides to generate metal-hydride

The reaction of low-valent ruthenium complexes with 2,6-bis(imino)pyridine ligand, [η²-N₃]Ru(η⁶-Ar) (1) or {[N₃]Ru}₂(μ-N₂) (2) with amine hydrochlorides generates six-coordinate chlorohydro ruthenium (II) complexes with amine ligands, [N₃]Ru(H)(Cl)(amine) (4). Either complex 1 or 2 activates amine hydrochlorides 3, and the amines coordinate to the ruthenium center to give complex 4. This is a convenient and useful synthetic approach to form ruthenium complexes with amine and hydride ligands using amine hydrochloride.