Structural and near-IR photophysical studies on ternary lanthanide complexes containing poly(pyrazolyl)borate and 1,3-diketonate ligands

The ligands tris[3-(2-pyridyl)pyrazol-1-yl]hydroborate (L1, potentially hexadentate) and bis[3-(2-pyridyl)pyrazol-1-yl]dihydroborate (L2, potentially tetradentate) have been used to prepare ternary lanthanide complexes in which the remaining ligands are dibenzoylmethane anions (dbm). [Eu(L1)(dbm)2] is eight-coordinate, with L1 acting only as a tetradentate chelate (with one potentially bidentate arm pendant) and two bidentate dbm ligands. [Nd(L1)(dbm)2] was also prepared but on recrystallization some of it rearranged to [Nd(L1)2][Nd(dbm)4], which contains a twelve-coordinate [Nd(L1)2]+ cation (two interleaved hexadentate podand ligands) and the eight-coordinate anion [Nd(dbm)4]- which, uniquely amongst eight-coordinate complexes having four diketonate ligands, has a square prismatic structure with near-perfect O8 cubic coordination. Formation of this sterically unfavourable geometry is assumed to arise from favourable packing with the pseudo-spherical cation. The isostructural series of complexes [Ln(L2)(dbm)2](Ln = Pr, Nd, Eu, Gd, Tb, Er, Yb) was also prepared and all members structurally characterised; again the metal ions are eight-coordinate, from one tetradentate ligand L2 and two bidentate dbm ligands. Photophysical studies on the complexes with Ln = Pr, Nd, Er, and Yb were carried out; all show the near-IR luminescence characteristic of these metal ions, with longer lifetimes in CD3OD than in CH3OH. For [Yb(L2)(dbm)2], two species with different luminescence lifetimes were observed in CH3OH solution, corresponding to species with zero or one coordinated solvent molecules, in slow exchange on the luminescence timescale. For [Nd(L2)(dbm)2] a single average solvation number of 0.7 was observed in MeOH. For [Pr(L2)(dbm)2] a range of emission lines in the visible and NIR regions was detected; time-resolved measurements show a particularly high susceptibility to quenching by solvent CH and OH oscillators.     

Cationic tris(pyrazolyl)borate bipyrimidine complexes

The cationic complexes, [Tp^RNi(bpym)]⁺ {Tp^R = tris(3,5-diphenylpyrazolyl)borate, R = Ph₂ 1; tris(3-phenyl-5-methylpyrazolyl)borate, R = Ph,Me 2} were synthesized by reacting [Tp^RNiBr] (R = Ph₂; Ph,Me) with bipyrimidine followed by subsequent addition of KPF₆ in CH₂Cl₂. The green solids have been characterized by IR, UV–Vis and ¹H NMR spectroscopy. Crystallographic studies of [Tp^Ph,MeNi(bpym)]PF₆ reveal a five-coordinate square pyramidal nickel centre with a κ³-coordinated Tp^Ph,Me ligand and a chelating bipyrimidine ligand. Cyclic voltammetric studies show irreversible reduction with the degree of reversibility dependent on the type of Tp^R ligand.     

Synthesis, structural characterization, and properties of heavier alkaline earth complexes containing bis(pyrazolyl)borate or bis(3,5-diisopropylpyrazolyl)borate ligands

Treatment of a solid mixture of KBH₄ with six equivalents of 3,5-diisopropylpyrazole (iPr₂pzH) at 180 °C afforded KTp^iPr2(iPr₂PzH)₃ in 53% yield. KBp^iPr2 was synthesized in 56% yield by treatment of a 1:2 M ratio of KBH₄ and iPr₂PzH in refluxing dimethylacetamide. Treatment of MI₂ (M = Ca, Sr, Ba) with two equivalents of KBp or KBp^iPr2 in tetrahydrofuran afforded MBp₂(THF)₂ (M = Ca, 64%, M = Sr, 81%), BaBp₂(THF)₄ (32%), and M(Bp^iPr2)₂(THF)₂ (M = Ca, 63%; M = Sr, 61%, M = Ba, 48%) as colorless crystalline solids upon workup. These complexes were characterized by spectral and analytical techniques and by X-ray crystal structure determinations of all complexes except KBp^iPr2. KTp^iPr2(iPr₂PzH)₃ contains one κ³-N,N,N-Tp^iPr2 ligand and three κ¹-iPr₂pzH ligands, with overall distorted octahedral geometry about the K ion. The iPr₂PzH nitrogen-hydrogen bonds are engaged in intramolecular hydrogen bonding to the 2-nitrogen atoms of the Tp^iPr2 ligand. The solid state structures of MBp₂(THF)₂, BaBp₂(THF)₄, and M(Bp^iPr2)₂(THF)₂ contain κ³-N,N,H Bp and Bp^iPr2 ligands, which form through metal-nitrogen bond formation to the 2-nitrogen atoms of the pyrazolyl fragments and metal-hydrogen bond formation to one boron-bound hydrogen atom per Bp ligand. SrBp₂(THF)₂has the shortest metal-hydrogen interactions among the series. A combination of preparative sublimations, solid state decomposition temperatures, and thermogravimetric analysis demonstrated that MBp₂(THF)₂, BaBp₂(THF)₄, and M(Bp^iPr2)₂(THF)₂ undergo solid state decomposition at moderate temperatures.     

Synthesis and Crystal Structure of [La(phen)2(H2O)2(NO3)2]NO3 · 2(phen)(H2O) with phen = 1,10‐phenanthroline

The title compound [La(phen)₂(H₂O)₂(NO₃)₂](NO₃) · 2(phen)(H₂O) with phen = 1,10‐phenanthroline was prepared by the stoichiometric reaction of La(NO₃)₃ · 6 H₂O and 1,10‐phenanthroline monohydrate in a CH₃OH–H₂O solution. The crystal structure (triclinic, P 1 (no. 2), a = 11.052(2), b = 13.420(2), c = 16.300(2) Å, α = 78.12(1)°, β = 88.77(1)°, γ = 83.03(1)°, Z = 2, R = 0.0488, wR² = 0.1028) consists of [La(phen)₂(H₂O)₂(NO₃)₂]²⁺ complex cations, NO₃^– anions, phen and H₂O molecules. The La atom is 10‐fold coordinated by four N atoms of two bidentate chelating phen ligands and six O atoms of two H₂O molecules and two bidentate chelating NO₃^2– ligands with d(La–O) = 2.522–2.640 Å and d(La–N) = 2.689–2.738 Å. The intermolecular π‐π stacking interactions play an essential role in the formation of two different 2 D layers parallel to (001), which are formed by complex cations and uncoordinating phen molecules, respectively. The uncoordinated NO₃^– anions and H₂O molecules are sandwiched between the cationic and phen layers.     

A Molecular Barium Hydrido Complex Stabilized by a Super‐Bulky Hydrotris(pyrazolyl)borate Ligand

Hydrogenolysis of the scorpionate‐supported barium alkyl complex (Tp^Ad,iPr)Ba[CH(SiMe₃)₂](THF) (Tp^Ad,iPr=hydrotris(3‐adamantyl‐5‐isopropyl‐pyrazolyl)borate) afforded the dinuclear barium hydrido complex [(Tp^Ad,iPr)Ba(μ‐H)]₂ ( 2 ), which was characterized by NMR spectroscopy and single‐crystal X‐ray analysis. Exposure of 2 with 1 atm of CO resulted in a reductive coupling process to form the cis‐ethendiolate dianion ( 3 ). Reaction of 2 with one equivalent of PhC≡C−C≡CPh gave barium 1,4‐diphenyl‐2‐butyne‐1,4‐diyl complex {[(Tp^Ad,iPr)Ba]₂(PhCH−C≡C−CHPh) ( 4 ).     

Novel Lanthanide (III) Complexes Derived from an Imidazole–Biphenyl–Carboxylate Ligand: Synthesis,Structure and Luminescence Properties

A series of neutral mononuclear lanthanide complexes [Ln(HL)₂(NO₃)₃] (Ln = La, Ce, Nd, Eu, Gd, Dy, Ho) with rigid bidentate ligand, HL (4′-(1H-imidazol-1-yl)biphenyl-4-carboxylic acid) were synthesized under solvothermal conditions. The coordination compounds have been characterized by infrared spectroscopy, thermogravimetry, powder X-ray diffraction and elemental analysis. According to X-ray diffraction, all the complexes are a series of isostructural compounds crystallized in the P2/n monoclinic space group. Additionally, solid-state luminescence measurements of all complexes show that [Eu(HL)₂(NO₃)₃] complex displays the characteristic emission peaks of Eu(III) ion at 593, 597, 615, and 651 nm.     

Titanium and zirconium complexes containing sterically hindered hydrotris(pyrazolyl)borate ligands: synthesis, structural characterization, and ethylene polymerization studies

The synthesis, characterization and ethylene polymerization behavior of a set of Tp^′MCl₃ complexes (4, M=Ti, Tp^′=HB(3-neopentyl-pyrazolyl)₃⁻(Tp^Np); 5, M=Ti, Tp^′=HB(3-tert-butyl-pyrazolyl)₃⁻(Tp^tBu); 6, M = Ti, Tp^′=HB(3-phenyl-pyrazolyl)₃⁻(Tp^Ph); 7, M=Zr, Tp^′=HB(3-phenyl-pyrazolyl)₃⁻(Tp^Ph); 8, M=Zr, Tp^′ = HB(3-tert-butyl-pyrazolyl)₃⁻(Tp^tBu)) is described. Treatment of these tris(pyrazolyl)borate Group IV compounds with methylalumoxane (MAO) generates active catalysts for ethylene polymerization. For the polymerization reactions performed in toluene at 60 °C and 3 atm of ethylene pressure, the activities varied between 1.3 and 5.1 × 10³ g of PE/mol[M] · h. The highest activity is reached using more sterically open catalyst precursor 4. The viscosity-average molecular weights () of the PE’s produced with these catalyst precursors varying from 3.57 to 20.23 × 10⁵ g mol⁻¹ with melting temperatures in the range of 127-134 °C. Further polymerization studies employing 7 varying Al/Zr molar ratio and temperature of polymerization showed that the activity as well as the polymer properties are dependent on these parameters. In that case, higher activity was attained at 60 °C. The viscosity-average molecular weights of the polyethylene’s decreases with increasing Al/Zr molar ratio.     

Cs4[La(NO3)6](NO3). HNO3: Das erste Salpetersäureaddukt eines ternären Alkali-Lanthanidnitrats

Cs₄[La(NO₃)₆](NO₃) · HNO₃: The First Nitric Acid Adduct of a Ternary Alkali Lanthanide Nitrate In the crystal structure of Cs₄[La(NO₃)₆](NO₃). HNO₃ (monoclinic, P2₁/c, Z = 2, a = 787.3(2); b = 1353.0(3); c = 1141.8(7) pm; β = 94,37(3)°) La³⁺ has a coordination number of twelve (six bidentate nitrate ligands). The structure may be viewed at as a layer structure: Layers of the composition [Cs(1)₄La₂(NO₃)₁₂]^2?, and [Cs(2)₄(NO₃)₂(HNO₃)₂]²⁺ are stacked alternatively in the [100] direction.     

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.     

Uranyl(VI) and lanthanum(III) thio-diglycolamides complexes: Synthesis and structural studies involving nitrate complexation

New tri-functional ligands of the type R₂NCOCH₂SCH₂CONR₂ (where R = iso-propyl, n-butyl or iso-butyl) were prepared and characterized. The coordination chemistry of these ligands with uranyl and lanthanum(III) nitrates was studied by using the IR, ¹HNMR and elemental analysis methods. Structures for the compounds [UO₂(NO₃)₂(ⁱPr₂NCOCH₂SCH₂CONⁱPr₂)] [UO₂(NO₃)₂(ⁱBu₂NCOCH₂SCH₂CONⁱBu₂)], [La(NO₃)₃(ⁱPr₂NCOCH₂SCH₂CONⁱPr₂)₂] and [La(NO₃)₃(ⁱBu₂NCOCH₂SCH₂CONⁱBu₂)₂] were determined by single crystal X-ray diffraction. These structures show that the ligand acts as a bidentate chelating ligand and bonds through both the carbamoyl groups to the uranyl and lanthanum(III) nitrate groups. Solvent extraction studies show that the ligand can extract the uranyl ion from the nitric acid medium but does not show any ability to extract the americium (III) ion.     

Synthesis and characterization of peroxo complexes of uranium(VI) with aroylhydrazone ligands

The uranium(VI) peroxo complexes containing aroylhydrazones ligands having composition [UO(O₂)L-L(NO₃)₂]·H₂O (where L-L = Benzoic acid[1-(Furan-2-yl)methylene] hydrazide, Benzoic acid[(thiophene-2-yl)methylene] hydrazide, Benzoic acid[1-(thiophene-2-yl)ethylidene] hydrazide, Benzoic acid(phenylmethylene) hydrazide, Benzoic acid[1-(anisol-3-yl)methylene] hydrazide and Benzoic acid[(p-chlorobenzyl)methylene] hydrazide are reported. The complexes were characterized by various physico-chemical techniques, viz. elemental analysis, molar conductivity, magnetic susceptibility measurements, infra red, electronic, mass spectral and TGA/DTA studies. These studies revealed that complexes are non-electrolytes and diamagnetic in nature. The ligands are bound to metal in a bidentate mode. Thermal analysis results provide conclusive evidence for the presence of water molecules in the complexes. Mass spectra confirm the molecular mass of the complexes. Antifungal activity of complexes revealed enhanced activity of complexes as compared to the corresponding ligands.     

Bis(2,2′‐bipyridyl‐N,N′)­tris­(nitrato‐O,O′)­neodymium

The title compound, [Nd(bipy‐N,N′)₂(NO₃–O,O′)₃], is found to be isomorphous with the La and Lu analogues having three bidentate nitrate and two bipyridyl ligands giving a ten co‐ordinate environment.     

Networks based on hydrogen-bonds containing phosphorus anions and tris(3,5-dimethylpyrazolyl)borate nickel(II) moieties

Five structural kinds of nickel hydrogen-bonded networks containing hydrotris(3,5-dimethylpyrazolyl)borate ligands (Tp^∗) have been elucidated by X-ray diffraction, [Tp^∗Ni(OH₂)₃][(p-NO₂C₆H₄O)₂PO₂] (4), [Tp^∗Ni(OH₂)₃][Me₂PO₂]·Me₂P(O)OH (5), [Tp^∗Ni(OH₂)₃][(nBuO)₂PO₂]·0.5H₂O (6), [(Hpz)Tp^∗Ni(OH₂)₂][(Ph)PO₂OH] (7) and [Tp^∗Ni(OH₂)₂(Me₂PO₂)] (8). The most relevant supramolecular feature of complexes 4-8 is all of them form coordination networks based on hydrogen bonds between water molecules and phosphate, phosphonate or phosphinate anions. These hydrogen bonds are formed within the monomer units in addition to connect monomers along the chains. Their behaviors in solution were investigated by one- and two-dimensional ¹H NMR techniques.     

Synthesis and investigations of mixed-ligand lanthanide complexes with N,N′-dipyrrolidine-N′′-trichloracetylphosphortriamide,dimethyl-N-trichloracetylamidophosphate, 1,10-phenanthroline and 2,2′-bipyrimidine

Coordination compounds with general formula [Ln(L¹)₃phen], where Ln = Nd, Eu, Er, Yb, HL¹ = N,N′-dipyrrolidine-N′′-trichloracetylphosphortriamide, phen = 1,10-phenanthroline; [Ln(L¹)₃bpm], where Ln = La, Nd, Eu, Gd, Er, Y, bpm = 2,2′-bipyrimidine and [{Ln(L²)₃}₂(μ-bpm)], where Ln = La, Nd, Eu, Gd, Er, Y, HL² = dimethyl-N-trichloracetylamidophosphate have been synthesized and characterized by means of IR and UV–Vis spectroscopy. Crystal structures of [Nd(L¹)₃phen] (1), [Nd(L¹)₃bpm] (2) and [{Nd(L²)₃}₂(μ-bpm)] (3) have been determined. It was found, that in the deprotonated form the phosphoryl ligands (L¹)^? and (L²)^? are coordinated to the neodymium atoms in a bidentate manner via the oxygen atoms of the phosphoryl and the carbonyl groups with formation of six-membered metallocycles. In the case of compounds 1 and 2 the 1,10-phenanthroline (or 2,2′-bipyrimidine) molecules are coordinated to the metals in a bidentate manner via the nitrogen atoms. In contrast 2,2′-bipyrimidine acts in the bidentate-bridge mode forming binuclear complex 3. Variable-temperature magnetic susceptibility measurements of 3 and [{Gd(L²)₃}₂(μ-bpm)] (4) reveal a weak antiferromagnetic interaction between the two magnetic centres, whereas in the case of [{Eu(L²)₃}₂(μ-bpm)] (5) the presence of spin–orbit coupling leads to a deviation from the Curie and Curie–Weiss laws.     

New RuII(arene) Complexes with Halogen‐Substituted Bis‐ and Tris(pyrazol‐1‐yl)borate Ligands

[RuCl(arene)(μ‐Cl)]₂ dimers were treated in a 1:2 molar ratio with sodium or thallium salts of bis‐ and tris(pyrazolyl)borate ligands [Na(Bp)], [Tl(Tp)], and [Tl(Tp^{iPr, 4Br})]. Mononuclear neutral complexes [RuCl(arene)(κ²‐Bp)] ( 1 : arene=p‐cymene (cym); 2 : arene=hexamethylbenzene (hmb); 3 : arene=benzene (bz)), [RuCl(arene)(κ²‐Tp)] ( 4 : arene=cym; 6 : arene=bz), and [RuCl(arene)(κ²‐Tp^{iPr, 4Br})] ( 7 : arene=cym, 8 : arene=hmb, 9 : arene=bz) have been always obtained with the exception of the ionic [Ru₂(hmb)₂(μ‐Cl)₃][Tp] ( 5′ ), which formed independently of the ratio of reactants and reaction conditions employed. The ionic [Ru(CH₃OH)(cym)(κ²‐Bp)][X] ( 10 : X=PF₆, 12 : X=O₃SCF₃) and the neutral [Ru(O₂CCF₃)(cym)(κ²‐Bp)] ( 11 ) have been obtained by a metathesis reaction with corresponding silver salts. All complexes 1 – 12 have been characterized by analytical and spectroscopic data (IR, ESI‐MS, ¹H and ¹³C NMR spectroscopy). The structures of the thallium and calcium derivatives of ligand Tp, [Tl(Tp)] and [Ca(dmso)₆][Tp]₂ ? 2 DMSO, of the complexes 1 , 4 , 5′ , 6 , 11 , and of the decomposition product [RuCl(cym)(Hpz^{iPr, 4Br})₂][Cl] ( 7′ ) have been confirmed by using single‐crystal X‐ray diffraction. Electrochemical studies showed that 1 – 9 and 11 undergo a single‐electron Ru^II→Ru^III oxidation at a potential, measured by cyclic voltammetry, which allows comparison of the electron‐donor characters of the bis‐ and tris(pyrazol‐1‐yl)borate and arene ligands, and to estimate, for the first time, the values of the Lever E_L ligand parameter for Bp, Tp, and Tp^{iPr, 4Br}. Theoretical calculations at the DFT level indicated that both oxidation and reduction of the Ru complexes under study are mostly metal‐centered with some involvement of the chloride ligand in the former case, and also demonstrated that the experimental isolation of the μ³‐binuclear complex 5′ (instead of the mononuclear 5 ) is accounted for by the low thermodynamic stability of the latter species due to steric reasons.     

Lanthanide nitrate complexes of diphenylmethylphosphine oxide: synthesis and spectroscopic studies. Crystal structures of [La(Ph2MePO)3(NO3)3], [La(Ph2MePO)4(NO3)3]·xMe2CO and [Yb(Ph2MePO)4(NO3)2]PF6

The reaction of Ln(NO₃)₃·6H₂O (Ln=lanthanide except Pm) with Ph₂MePO in a 1:3 or 1:4 ratio in acetone or ethanol produces [Ln(Ph₂MePO)₃(NO₃)₃] which have been characterised by analysis, IR, ¹H and ³¹P{¹H} NMR spectroscopy and conductance measurements. The [Ln′(Ph₂MePO)₃(NO₃)₃] (Ln′=Pr–Tb) exist only as tris complexes in solution and are unaffected by the presence of excess Ph₂MePO. In contrast the [Ln″(Ph₂MePO)₃(NO₃)₃] (Ln″=Ho–Lu) partially decompose in CH₂Cl₂ solution into [Ln″(Ph₂MePO)₄(NO₃)₂]⁺, and [Ln″(Ph₂MePO)₄(NO₃)₂]PF₆ are readily isolated from Ln″(NO₃)₃, Ph₂MePO and NH₄PF₆ in acetone. For lanthanum only, a neutral 1:4 complex [La(Ph₂MePO)₄(NO₃)₃] was isolated. X-ray crystal structures show that [La(Ph₂MePO)₃(NO₃)₃] contains nine-coordinate La, whilst [La(Ph₂MePO)₄(NO₃)₃]·xMe₂CO contains a ten-coordinate metal centre. The structure of [Yb(Ph₂MePO)₄(NO₃)₂]PF₆ reveals an eight-coordinate cation and all complexes contain bidentate nitrato-groups.     

Synthesis,Characterization and Assessment of the Antioxidant Activity of Cu(II), Zn(II) and Cd(II) Complexes Derived from Scorpionate Ligands

Seeking to enrich the yet less explored field of scorpionate complexes bearing antioxidant properties, we, here, report on the synthesis, characterization and assessment of the antioxidant activity of new complexes derived from three scorpionate ligands. The interaction between the scorpionate ligands thallium(I) hydrotris(5-methyl-indazolyl)borate (TlTp^4Bo,5Me), thallium(I) hydrotris(4,5-dihydro-2H-benzo[g]indazolyl)borate (TlTp^a) and potassium hydrotris(3-tert-butyl- pyrazolyl)borate (KTp^tBu), and metal(II) chlorides, in dichloromethane at room temperature, produced a new family of complexes having the stoichiometric formula [M(Tp^4Bo,5Me)₂] (M = Cu, 1; Zn, 4; Cd, 7), [M(Tp^a)₂] (M = Cu, 2; Zn, 5; Cd, 8), [Cu(Hpz^tBu)₃Cl₂] (3), [Zn(Tp^tBu)Cl] (6) and [Cd(Bp^tBu)(Hpz^tBu)Cl] (9). The obtained metal complexes were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and elemental analysis, highlighting the total and partial hydrolysis of the scorpionate ligand Tp^tBu during the synthesis of the Cu(II) complex 3 and the Cd(II) complex 9, respectively. An assessment of the antioxidant activity of the obtained metal complexes was performed through both enzymatic and non-enzymatic assays against 1,1-diphenyl-2-picryl- hydrazyl (DPPH^·), 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^+·), hydroxyl (HO^·), nitric oxide (NO^·), superoxide (O₂⁻) and peroxide (OOH^·) radicals. In particular, the complex [Cu(Tp^a)₂]⋅0.5H₂O (2) exhibited significant antioxidant activity, as good and specific activity against superoxide (O₂^−·), (IC50 values equal to 5.6 ± 0.2 μM) and might be identified as auspicious SOD-mimics (SOD = superoxide dismutase).     

Synthesis and lanthanide coordination chemistry of 2-[(phosphinoyl)methyl]-4,5-dihydrooxazole and 2-[(phosphinoyl)methyl]benzoxazole ligands

Syntheses for [(diphenylphosphinoyl)methyl]-4,5-dihydrooxazole (2) and [(diarylphosphinoyl)methyl]benzoxazoles [aryl = phenyl (3), tolyl (4), 2-trifluoromethylphenyl (5) and 3,5-bis(trifluoromethyl)phenyl (6)] have been developed. Each ligand has been characterized by spectroscopic methods and single crystal X-ray diffraction analyses have been completed for 2, 3, 4 and 5. The coordination chemistry of the ligands with Nd(NO₃)₃ and Yb(NO₃)₃ has been examined and structure determinations for [Nd(2)₂(NO₃)₃(CH₃OH)], [Nd(2)₂(NO₃)₃], [Yb(3)₂(NO₃)₃(H₂O)]·0.5(CH₃OH), [Nd(3)₂(NO₃)₃]·3(CHCl₃), [Nd(4)₂(NO₃)₃(H₂O)], [Yb(4)₂(NO₃)₃(H₂O)] and [Yb(5)₂(NO₃)₃(H₂O)]·0.5(CH₃CN) are reported. Depending upon conditions, the ligands act as monodentate PO or bidentate, chelating PO,N donors.     

Synthesis,structure and magnetic properties of a Pr(III) complex with chelating nitronyl nitroxide radicals

The synthesis and structure of Pr(III) complex with chelating nitronyl nitroxide radicals of formula [Pr(III)(NIT2Py)₂(NO₃)₃] (NIT2Py?=?2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) is reported. Pr(III) is ten-coordinate with three bidentate nitrate anions and two radicals. The radical behaves as a bidentate chelating ligand through one oxygen atom of the nitronyl nitroxide group and one nitrogen atom of a pyridine ring. The electronic spectrum for the complex in THF and magnetic susceptibilities from 77–300?K are reported.     

Coordination of Bimuth(III) to Cucurbit[8]uril. Preparation and X‐ray Structure of [{Bi(NO3)(H2O)5}2(Q8)][Bi(NO3)3(H2O)4]2[Bi(NO3)5]2·Q8·19H2O

Bi(NO₃)₃ reacts with cucurbit[8]uril, (Q8), in 3M HNO₃ to give the title complex whose structure includes three discrete Bi complexes: [{Bi(NO₃)(H₂O)₅}₂(Q8)]⁴⁺ (CN of Bi = 9, both NO₃^— and cucurbit[8]uril are bidentate), [Bi(NO₃)₅]^2— (CN of Bi = 10, all NO₃^— are bidentate), and [Bi(NO₃)₃(H₂O)₄] (CN of Bi = 10, all NO₃^— are bidentate).