Spektroskopische Eigenschaften von Di(phthalocyaninato)metallaten(III) der Seltenen Erden Teil 1: Elektronische Absorptionsspektren und Schwingungsspektren

Spectroscopical Properties of Di(phthalocyaninato)metalates(III) of the Rare Earth Elements. Part 1: Electronic Absorption and Vibrational Spectra Di(phthalocyaninato)metalates(III) of the rare earth elements were prepared by the reaction of partially dehydrated lanthanide acetate with molten phthalodinitrile in the presence of potassium methylate and isolated as complex salts with different tetraalkylammonium cations, especially tetra(n-butyl)- and tri(n-dodecyl)n-octylammonium and di((triphenyl)phosphine)-iminium (abbrev.: (ⁿBu₄N), TDOA, PNP). Besides the typical strong π-π* transitions in the B, Q, N regions of the Pc^2? ligands low intensity bands at ca. 10, 11 and 19 kK are observed in the UV-Vis-NIR spectra and assigned to singulet–triplet transitions. In going from La to Lu the B band splits continously due to excitonic coupling extending from 0,71 (La) to 1,92 kK (Lu). The FIR-MIR and resonance Raman spectra are nearly metal independent with the exception of some hypsochromically shifted bands due to C? C and C? N stretching and deformation vibrations of the inner (CN)₈ ring. Only the FIR band at 157 cm^?1 (La) assigned to the asym. Ln? N stretching vibration is shifted to lower energy.     

A 1H, 13C, 31P and 15N NMR study of (pyrrolidine-2,2-diyl)bisphosphonic acid,tetraalkyl(pyrrolidine-2,2-diyl)bisphosphonates and acyclic tetraethyl bisphosphonates

A multinuclear magnetic resonance study (¹H, ¹³C, ³¹P, ¹⁵N) was performed on a series of new cyclic pyrrolidine bisphosphonates and acyclic bisphosphonates. Values are reported and discussed for the chemical shifts and coupling constants of the various nuclei. Copyright © 2000 John Wiley & Sons, Ltd.     

AlIII-Phthalocyanine: Darstellung,Eigenschaften und Kristallstruktur von Tetra(n-butyl)ammonium-trans-di(nitrito(O))phthalocyaninato(2−)aluminat(III)

Al^III Phthalocyanines: Synthesis, Properties, and Crystal Structure of Tetra(n-butyl)-ammonium-trans-di(nitrito(O))phthalocyaninato(2?)aluminate(III) [Al(Cl)Pc^2?] reacts with excess (ⁿBu₄N)NO₂ in dimethylformamide yielding less soluble blue tetra(n-butyl)ammonium-trans-di(nitrito(O))phthalocyaninato(2?)aluminate(III), (ⁿBu₄N)^trans[Al(ONO)₂Pc^2?], which crystallizes in the monoclinic space group C2/c (No. 15) with Z = 4. The Al atom is in the special position 4 d in the center of the Pc^2? ligand and the two nitrit ions are monodentate O-coordinated in a mutually trans arrangement to the Al atom. The Al? O and average Al? N_iso bond distances are 1.927(2) and 1.956 Å, respectively. The geometric data of the coordinated nitrite ion are: d(N? O) = 1.277(4) Å; d(N? O) = 1.221(4) Å; ?(O? N? O) = 114.3(3)°; ?(Al? O? N) = 121.3(2)°. The non-bonded O atoms are trans to the Al atom. The Pc^2? ligand is slightly ruffled. The UV-VIS-NIR spectra and the vibrational spectra are discussed.     

Synthetic,spectral, thermal and antimicrobial studies on some bis(N,N′‐dialkyldithiocarbamato) antimony(III) alkylenedithiophosphates

Bis(N, N′‐dialkyldithiocarbamato)antimony(III) alkylenedithiophosphates of the type [R₂NCS₂]₂ SbS(S)POGO [where NR₂ = N(CH₃)₂, N(C₂H₅)₂ and N(CH₂)₄; G = ? CH₂? C(C₂H₅)₂? CH₂? , ? CH₂? C(CH₃)₂? CH₂? , ? CH(CH₃)? CH(CH₃)? and ? C(CH₃)₂? C(CH₃)₂? ] were synthesized and characterized by physico‐chemical, spectral [UV, IR and NMR (¹H, ¹³C and ³¹P)] and thermal (TG, DTA and DSC) analysis. The TG decomposition analysis step of the complex indicated the formation of Sb₂S₃ as the final product. The first endothermic peak in DSC indicated the melting point of the complexes. These complexes were screened for their antimicrobial activities using the disk diffusion method. All the complexes showed good activity as antibacterial and antifungal agents on some selected bacterial and fungal strains, which increased on increasing the concentration. Chloroamphenicol and terbinafin were used as standards for comparison. Copyright © 2007 John Wiley & Sons, Ltd.     

Low-spin Manganphthalocyanine: Darstellung,Eigenschaften und elektronisches Raman-Spektrum von Di(cyano)phthalocyaninatomanganat(III) und -(II)

Low Spin Manganese Phthalocyanines: Preparation, Properties and Electronic Raman Spectrum of Di(cyano)phthalocyaninatomanganate(III) and -(II) . Iodophthalocyaninatomanganese(III) reacts with cyanide in acetone to yield di(cyano)phthalocyaninatomanganate(II), in dichloromethane, however di(cyano)phthalocyaninatomanganate(III) is formed. Both complexes are isolated as (n-Bu₄N)-salts. In the cyclovoltammogram the redox couple Mn^II/Mn^III is attributed to E_1/2 = - 0.22 V and the first ringoxidation Pc(2 -)/Pc(1 -) to E_1/2 = 0.75 V. The paramagnetic salts have magnetic moments (μ_eff = 2.11 resp. 2.95 B.M.) typical for the low spin ground state of Mn^II resp. Mn^III (S = 1/2 resp. 1). The uv-vis-nir spectra are discussed. Comparison with the dicyano-complexes of Cr^III, Fe^II/III and Co^III indicates that the multiple “extra bands” between 4 and 23 kK should be assigned to spin allowed trip-multiplets. The vibrational spectra are discussed. ν_as(Mn? C)(a_2u) is found at 350 cm^?1, ν_as(C? N)(a_2u; cyanide) at 2 092 (Mn^II) and 2 114 cm^?1 (Mn^III). The Raman spectra are dominated by resonance Raman(RR) effects. With variable-wavelength excitation polarized, depolarized and anomalously polarized vibrations assigned to phthalocyanine skeletal modes are selectively RR-enhanced for the Mn^II complex. Intensive lines between 1 650 and 3 300 cm^?1 are due to combinations and overtones of the a_2g vibrations at 1 492 and 1 602 cm^?1. In the 10 K Raman spectrum of (n-Bu₄N)[Mn(CN)₂Pc(2 -)] intraconfigurational transitions Γ₁ → Γ₄ and Γ₁ → Γ₃, Γ₅ resulting from the splitting of the ³T_1g ground state of Mn^III (O_h symmetry) by spin-orbit coupling are observed as anomalously polarized and depolarized lines at 172 and 287 cm^?1.     

Darstellung und Eigenschaften von tetragonalen α-Di(phthalocyaninato(1−))-praseodym(III)-polyhalogeniden; Kristallstruktur von α-[Pr(Pc−)2]Br1,5

Preparation and Properties of Tetragonal α-Di(phthalocyaninato(1?))praseodymium(III)-polyhalides; Crystal Structure of α-[Pr(Pc^?)₂]Br_1.5 Brown red di(phthalocyaninato(1?))-praseodym(III)-polyhalides [Pr(Pc^?)₂]X_y (X = Br, I) of variable composition (1 ≤ y ≤ 2.5) are formed by (electro)chemical oxidation of [Pr(Pc^2?)₂]^?. The thermical decomposition of these polyhalides at 250°C yields partially oxidized, green α-[PrPc^?Pc^2?]. Due to strong spin–spin coupling of the phthalocyanin-π-radicals only Pr^III contributes to the magnetic moment of ca. 3.0 B.M. for all complexes. Green metallic prisms of [Pr(Pc^?)₂]Br_1.5 crystallize in the tetragonal α-modification: space group P4/nnc with a = 19.634(5) Å, c = 6.485(2) Å; Z = 2. In the sandwich complex Pr^III is eightfold coordinated by the isoindoline N-atoms of the two staggered (41°), nearly planar Pc^?- ligands. The quasi-onedimensional character of the structure along [001] is due to the infinite columns of Pc^? ligands. The superperiod along [001] is a consequence of the distribution of the Pr atoms onto two incompletely filled crystallographic positions at a distance of c/2 and the disordered chains of the bromine atoms extending in the same direction. Powder diffractograms of Pr(Pc )₂Br2, [Pr(Pc^?)₂]I₂ und [PrPc Pc^2?] confirm the tetragonal α-modification of these complexes, too. The content of tribromide correlates with the population of the Pr(2)-site. In the UV-VIS-NTR absorption spectrum of a thin film of Pr(Pc )₂Br, the intense bands at 13.9 and 19.5 kK are assigned to the B and Q transition, respectively. The D band at 9. kK is characteristic for isolated dimeric Pc^?-π-radicals. Due to increasing electron delocalisation as a result of the growing columns the D band is shifted to lower energy appearing successively at 6.05 and 3.3 kK. The mir and resonance Raman (RR) spectra of α-[Pr(Pr^?)₂]X_y, (X = Br, I) show the well known diagnostic bands for Pc^?-π-radicals. Thc RR spectrum of the polyiodide is dominated by the overtone progression of the totally symmetric (I-I) stretching vibration of the triiodide at 108cm^?1. The FT-Raman spectra are also marked by the totally symmetric stretching vibration of the polyhalides (Br₃ : 145cm ¹; 1₃^?:105cm^?1; I₅^? 151 cm^?1).     

Synthetic,spectral, thermal and antimicrobial studies of bis(N,N‐dialkyldithiocarbamato)arsenic(III) and antimony(III) complexes with diphenyldithiophos‐phate and diphenyldithiophosphinate

Bis(N,N‐dialkyldithiocarbamato)arsenic(III)/antimony(III) diphenyldithiophosphate/diphenyldi‐thiophosphinate complexes of the type [R₂NCS₂]₂MS(S)PX₂ [where M = As and Sb; NR₂ = N(CH₃)₂, N(C₂H₅)₂ and N(CH₂)₄; X = OC₆H₅ and C₆H₅] have been synthesized and characterized by physico‐chemical, spectral [UV, IR and NMR (¹H, ¹³C and ³¹P)] and thermal (TG, DTA and DSC) analysis. The TG analysis shows single‐step decomposition of the complex to Sb₂S₃. These complexes have been screened for antibacterial and antifungal activity using the disc diffusion method. All the complexes have shown good activity as antibacterial and antifungal agents, which increased on increasing the concentration. Chloroamphenicol and terbinafin were used as standards for the comparison. Copyright © 2006 John Wiley & Sons, Ltd.     

1H, 13C and 31P NMR spectral analysis of monoalkyl (α‐anilinobenzyl)phosphonates and their dipalladium(II) metallocyclic complexes

A ¹H, ¹³C and ³¹P NMR study of monoethyl (HL1) and monobutyl (HL2) esters of (α‐anilinobenzyl)phosphonic acid and their metallocyclic dipalladium complexes (Pd₂L₄,L = L1, L2) in DMSO‐d₆ was performed, based on 1D and 2D homo‐ and heteronuclear experiments including ¹H,¹³C,³¹P,APT,¹H–¹H COSY, ¹H–¹³C COSY, gs‐HMQC and gs‐HMBC NMR techniques. The results obtained are discussed with respect to those for some palladium(II) complexes reported for various anilinobenzylphosphonate derivatives. Copyright © 2002 John Wiley & Sons, Ltd.     

Darstellung,Eigenschaften und Molekülstruktur eines Titan-tris(diazadien)-Komplexes

Preparation, Properties, and Molecular Structure of a Titanium-tris(diazadiene) Complex (R = i-C₃H₇) 1 was obtained by reaction of TiCl₄ · 2 THF with Li₂(NR? CH = CH? NR) in the presence of the ligand molecules. The compound was characterized by ¹H-, ¹³C-n.m.r., and mass spectroscopy. The molecular structure was determined by X-ray diffraction. The bonding distances in the identically coordinated diazadiene ligands are similar to those of radical.     

Darstellung, 11B-, 13C-, 1H-NMR- und Schwingungsspektren von Monoethoxyhydro-closo-Dodecaborat(2–) sowie Kristallstruktur von [(C5H5N)2CH2][B12H11(OC2H5)]

Preparation, ¹¹B, ¹³C, ¹H NMR and Vibrational Spectra of Monoethoxyhydro-closo-dodecaborate(2–), and the Crystal Structure of [(C₅H₅N)₂CH₂][B₁₂H₁₁(OC₂H₅)] By treatment of Na₂[B₁₂H₁₂] with dry HF in ethanol Na₂[B₁₂H₁₁(OC₂H₅)] is formed which has been separated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose from the starting compound and by-products. The X-ray structure determination of [(C₅H₅N)₂CH₂][B₁₂H₁₁(OC₂H₅)] (monoclinic, space group P2₁/m, a = 9.1906(3), b = 12.6612(8), c = 9.3640(12) Å, β = 112.947(6)°, Z = 2) reveals the complete ordering of the anion sublattice. The ¹¹B nmr spectrum exhibits the characteristic feature (1:5:5:1) of a mono substituted B₁₂ cage with a strong down-field shift of ipso-B at +6.5 ppm. In the ¹³C nmr spectrum a triplet at 67.9 ppm of the methylene group and a quartet at 19.5 ppm of the methyl group is observed. Correspondingly, the ¹H nmr spectrum shows two multiplets at 3.7 and 1.3 as expected for an ethoxy substituent, and a multiplet at 2.1 ppm due to the protons of the boron cluster. The i.r. and Raman spectra exhibit strong CH stretching vibrations between 2 963 and 2 863 cm^?1, and in the i.r. spectrum the CO and BO stretching frequencies of the B? O? C bridge are observed at 1 175 and 1 140 cm^?1.     

1H, 13C and 15N NMR spectral characterization of twenty-seven 1,2-diaryl-(4E)-arylidene-2-imidazolin-5-ones

1H, 13C and 15N NMR chemical shifts and couplings (n)J(H,C) in DMSO-d(6) at 30 degrees C have been determined for 1,2-diaryl-(4E)-arylidene-2-imidazolin-5-one derivatives 1-27. Their chemical shift assignments are based on PFG DQF 1H,1H COSY, PFG 1H,13C HMQC as well as PFG 1H,13C and 1H,15N HMBC experiments. For compounds 1-10 including aryl fluorine substituent(s) also the couplings (n)J(F,C) (n = 1 - 4) are reported.     

Direct 1H, 13C, and 15N NMR Study of Lanthanum(III), Thulium(III), and Ytterbium(III) Complex Formation with Nitrate and Isothiocyanate

An ¹H, ¹³C, and ¹⁵N NMR study has been completed for the complexes of La(III), Tm(III), and Yb(III) with nitrate and isothiocyanate in aqueous solvent mixtures. Signals for four complexes are observed for both the Tm³⁺–NO₃ ^– and Yb³⁺–NO₃ ^– solutions, with the species identified as the mono-, di-, tetra-, and either the penta - or hexanitrato. These results are consistent with those determined for the nitrate complexes of the Ce(III)–Eu(III) metal ions. The chemical shifts for the Tm(III) and Yb(III) nitrate complexes indicate a pseudocontact binding mechanism prevails. The complexes of diamagnetic La(III) with NO₃ ^– produce three signals in the ¹⁵NO₃ ^– spectra, with assignments paralleling those observed with the paramagnetic lanthanides. Three complexes are formed in the La³⁺–NCS^– solutions, with signals assigned to the mono-, di-, and triisothiocyanato species.     

A direct hydrogen-1, carbon-13, and nitrogen-15 NMR study of lutetium(III)-isothiocyanate complexation in aqueous solvent mixtures

A direct, low-temperature hydrogen-1, carbon-13, and nitrogen-15 nuclear magnetic resonance study of lutetium(III)-isothiocyanate complex formation in aqueous solvent mixtures has been completed. At –100°C to –120°C in water-acetone-Freon mixtures, ligand exchange is slowed sufficiently to permit the observation of separate¹H,¹³C, and¹⁵N NMR signals for coordinated and free water and isothiocyanate ions. In the¹³C and¹⁵N spectra of NCS^–, resonance signals for five complexes are observed over the range of concentrations studied. The¹³C chemical shifts of complexed NCS^– varied from –0.5 ppm to –3 ppm from that of free anion. For the same complexes, the¹⁵N chemical shifts from free anion were about –11 ppm to –15 ppm. The magnitude and sign of the¹⁵N chemical shifts identified the nitrogen atom as the binding site in NCS^–. The concentration dependence of the¹³C and¹⁵N signal areas, and estimates of the fraction of anion bound at each NCS^–:Lu³⁺ mole ratio, were consistent with the formation of [(H₂O)₅Lu(NCS)]²⁺ through [(H₂O)Lu(NCS)₅]^2–. Although proton and/or ligand exchange and the resulting bulk-coordinated signal overlap prevented accurate hydration number measurements, a good qualitative correlation of the water¹H NMR spectral results with those of¹³C and¹⁵N was possible.     

Synthetic,spectral as well as in vitro antimicrobial studies on some bismuth(III) bis(N,N‐dialkyldithiocarbamato) alkylenedithiophosphates

Mixed sulfur donor ligand complexes of the type bismuth(III) bis(N,N‐dialkyldithiocarbamato) alkylenedithiophosphate, [R₂NCS₂]₂BiS₂POGO [where R = CH₃ and C₂H₅; G = ‐CH₂‐C(C₂H₅)₂‐CH₂‐, ‐CH₂‐C(CH₃)₂‐CH₂‐, ‐CH(CH₃)‐CH(CH₃)‐ and ‐C(CH₃)₂‐C(CH₃)₂‐] were synthesized in 1:1 molar ratio of bismuth(III) bis(N,N‐dialkyldithiocarbamate) chloride and ammonium alkylenedithiophosphate in refluxing benzene and characterized by melting point, molecular weight determinations, elemental analysis (C, H, N, Bi and S) and spectral [UV, IR,NMR (¹H,¹³C and ³¹P) and powder X ray diffraction] studies; all these studies were in good agreement with the synthesized complexes. These newly synthesized derivatives are yellow and brown colored solids and are soluble in common organic solvents like benzene, chloroform, dichloromethane and DMF. Based on the physicochemical and spectral studies, a tentative structure of these newly synthesized complexes was assigned and the average particle size of the synthesized complexes determined by powder XRD, showing that nano range polycrystalline particles were formed with a monoclinic crystal system. These complexes were also screened for their antimicrobial activities using the well diffusion method. The free ligands as well as their mixed metal complexes were tested in vitro against four bacterial strains: two Gram‐positive, Staphylococcus aureus (ATCC 9144) (G⁺) and Bacillus subtilis (ATCC 6051), (G⁺) and two Gram‐negative, Escherichia coli (ATCC 9637) (G^?) and Pseudomonas aeruginosa (ATCC 25619) (G^?) to assess their antimicrobial properties. The results were indeed positive and exhibited good antibacterial effects. Chloroamphenicol used as a standard for comparison and synthesized complexes showed good antibacterial effects over chloroamphenicol. On the basis of these studies, the synthesized complexes help to understand the different structural and biological properties of main group elements with sulfur donor ligands. Copyright © 2010 John Wiley & Sons, Ltd.     

Komplexchemie P‐reicher Phosphane und Silylphosphane. XXII. Die Bildung von [η2‐{tBu–P=P–SiMe3}Pt(PR3)2]aus (Me3Si)tBuP–P=P(Me)tBu2 und [η2‐{C2H4}Pt(PR3)2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXII. The Formation of [η²‐{^tBu–P=P–SiMe₃}Pt(PR₃)₂] from (Me₃Si)^tBuP–P=P(Me)^tBu₂ and [η²‐{C₂H₄}Pt(PR₃)₂] (Me₃Si)^tBuP–P = P(Me)^tBu₂ reacts with [η²‐{C₂H₄}Pt(PR₃)₂] yielding [η²‐{^tBu–P=P–SiMe₃}Pt(PR₃)₂]. However, there is no indication for an isomer which would be the analogue to the well known [η²‐{^tBu₂P–P}Pt(PPh₃)₂]. The syntheses and NMR data of [η²‐{^tBu–P=P–SiMe₃}Pt(PPh₃)₂] and [η²‐{^tBu–P=P–SiMe₃}Pt(PMe₃)₂] as well as the results of the single crystal structure determination of [η²‐{^tBu–P=P–SiMe₃}Pt(PPh₃)₂] are reported.     

Experimental and quantum‐chemical studies of 1H, 13C and 15N NMR coordination shifts in Au(III), Pd(II) and Pt(II) chloride complexes with picolines

¹H, ¹³C and ¹⁵N NMR studies of gold(III), palladium(II) and platinum(II) chloride complexes with picolines, [Au(PIC)Cl₃], trans‐[Pd(PIC)₂Cl₂], trans/cis‐[Pt(PIC)₂Cl₂] and [Pt(PIC)₄]Cl₂, were performed. After complexation, the ¹H and ¹³C signals were shifted to higher frequency, whereas the ¹⁵N ones to lower (by ca 80–110 ppm), with respect to the free ligands. The ¹⁵N shielding phenomenon was enhanced in the series [Au(PIC)Cl₃] < trans‐[Pd(PIC)₂Cl₂] < cis‐[Pt(PIC)₂Cl₂] < trans‐[Pt(PIC)₂Cl₂]; it increased following the Pd(II) → Pt(II) replacement, but decreased upon the trans → cis‐transition. Experimental ¹H, ¹³C and ¹⁵N NMR chemical shifts were compared to those quantum‐chemically calculated by B3LYP/LanL2DZ + 6‐31G**//B3LYP/LanL2DZ + 6‐31G*. Copyright © 2008 John Wiley & Sons, Ltd.     

Multinuclear magnetic resonance analysis of 2-(trifluoromethyl)-2-oxazoline

(1)H, (19)F, (13)C, (15)N, and (17)O NMR chemical shifts and (1)H-(1)H, (1)H-(19)F, (1)H-(13)C, (19)F-(13)C, and (19)F-(15)N coupling constants are reported for 2-(trifluoromethyl)-2-oxazoline.     

1H, 13C, 15N and 195Pt NMR studies of Au(III) and Pt(II) chloride organometallics with 2‐phenylpyridine

¹H, ¹³C, ¹⁵N and ¹⁹⁵Pt NMR studies of gold(III) and platinum(II) chloride organometallics with N(1),C(2′)‐chelated, deprotonated 2‐phenylpyridine (2ppy*) of the formulae [Au(2ppy*)Cl₂], trans(N,N)‐[Pt(2ppy*)(2ppy)Cl] and trans(S,N)‐[Pt(2ppy*)(DMSO‐d₆)Cl] (formed in situ upon dissolving [Pt(2ppy*)(µ‐Cl)]₂ in DMSO‐d₆) were performed. All signals were unambiguously assigned by HMBC/HSQC methods and the respective ¹H, ¹³C and ¹⁵N coordination shifts (i.e. differences between chemical shifts of the same atom in the complex and ligand molecules: Δ^1H_coord = δ^1H_complex ? δ^1H_ligand, Δ^13C_coord = δ^13C_complex ? δ^13C_ligand, Δ^15N_coord = δ^15N_complex ? δ^15N_ligand), as well as ¹⁹⁵Pt chemical shifts and ¹H‐¹⁹⁵Pt coupling constants discussed in relation to the known molecular structures. Characteristic deshielding of nitrogen‐adjacent H(6) protons and metallated C(2′) atoms as well as significant shielding of coordinated N(1) nitrogens is discussed in respect to a large set of literature NMR data available for related cyclometallated compounds. Copyright © 2009 John Wiley & Sons, Ltd.     

1H{15N} GHMQC study of 5,7‐diphenyl‐1,2,4‐triazolo[1,5‐a]pyrimidine and 1H, 13C and 15N NMR coordination shifts in Au(III) chloride complexes of 1,2,4‐triazolo[1,5‐a]pyrimidines

The ¹H{¹⁵N} NMR spectrum of 5,7‐diphenyl‐1,2,4‐triazolo[1,5‐a]‐pyrimidine ( 3 ) was measured by GHMQC, unambiguously assigned and compared with the spectra of 1,2,4‐triazolo[1,5‐a]pyrimidine ( 1 ) and 5,7‐dimethyl‐1,2,4‐triazolo[1,5‐a]pyrimidine ( 2 ). A series of Au(III) chloride complexes of general formula AuLCl₃, where L = 1 , 2 , 3 , was synthesized and studied by ¹HH{¹⁵N} GHMQC and ¹H{¹³C} GHMBC. Low‐frequency shifts of 72–74 ppm (¹⁵N) and 5–6 ppm (¹³C) were observed upon complexation by Au(III) ions for the coordination site N‐3 and adjacent C‐2, C‐3a atoms, respectively. The ¹³C signals of C‐5, C‐6, C‐7 and the ¹H resonances of H‐2, H‐6 were shifted to higher frequency. Comparison with analogous Pd(II), Pt(II) and Pt(IV) complexes revealed that in the case of Au(III) coordination the ¹⁵N shifts were relatively smaller, whereas those for ¹³C and ¹H were larger. Copyright © 2002 John Wiley & Sons, Ltd.