Novel rhodium <Emphasis Type="Italic">N</Emphasis>-heterocyclic carbene catalysed arylation of aldehydes with phenylboronic acid

Reaction of 1,3-dialkylperhydrobenzimidazolinylidene, 1,3-dialkyl-4-methylimidazolinylidene and 1,3-dialkylimidazolinylidene with [RhCl(COD)]₂ yields {1,3-dialkylperhydrobenzimidazolin-2-ylidene}-, {1,3-dialkyl-4-methylimidazolin-2-ylidene}- {1,3-dialkylimidazolin-2-ylidene}chloro(η⁴-1,5-cyclooctadiene)rhodium(I) complexes (2a–c) and (4a, b). All compounds synthesised were characterised by elemental analysis, n.m.r. spectroscopy. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of the new rhodium(I)–carbene complexes (2a–c) and (4a, b), to give the corresponding aryl secondary alcohols in good yield (73–99%).     

Zur Reaktion von Malonsäurederivaten mit Homophthalimiden Umlagerungen von Heterocyclen, 2. Mitt.

Zusammenfassung Die Homophthalimide 1 a–b reagieren mit monosubstit. Malonylchloriden in Gegenwart von N,N-Dimethylanilin zu den 4-Hydroxy-2-pyron-derivaten 4 a–d. Durch Erhitzen auf 200° werden diese Verbindungen in Dihydroxy-naphthalsäureimide (6) umgelagert. Die Aktivierungsparameter für die Reaktion 4 a6 a und 4 b6 b sind bestimmt worden. Die Verbindungen 6 a–f können auch direkt durch Umsetzung der Homophthalimide 1 a–b mit substit. Malonsäure-bis-2,4,6-trichlorphenylestern bei 240–260° gewonnen werden.

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Rearrangement reactions of heterocyclic compounds, II: The reaction of malonic acid derivatives with homophthalimides

The reaction of homophthalimides (1 a–b) and monosubstituted malonyl chlorides in the presence of N.N-dimethylaniline gives the 4-hydroxy-2-pyrone derivatives 4 a–d. These compounds are rearranged to dihydroxy-naphthalimides (6 a–d) when heated at about 200°. The kinetics of this reaction have been studied. Compounds 6 a–f are also obtained in high yield by the one step reaction between 1 a–b and 2.4.6-trichlorophenyl malonates 2 a–c at 240–260°.

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Mit 2 Abbildungen

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Herrn Prof. Dr.Erich Ziegler in Freundschaft und Verehrung zum 60. Geburtstag gewidmet.     

Square-Planar Nickel(II) O,O′-Dialkyldithiophosphato Complexes with Triphenylphosphine of the Type [NiX(S2P{OR}2)(PPh3)] (X = Cl,Br, I and NCS)

A series of new [NiX(S₂P{O-c-Hex}₂)(PPh₃)](X = Cl^–, Br^–, I^– and NCS^–)(1)–(4) and [Ni(NCS)(S₂P{OR}₂)(PPh₃)][R =n-Pr (5), i-Pr (6)] complexes has been synthesized and characterized by elemental analyses, f.i.r., i.r., u.v.–vis., ¹H-, ¹³C{¹H}- and ³¹P{¹H}-n.m.r. spectra, magnetochemical and conductivity measurements. A single crystal X-ray analysis of [Ni(NCS)(S₂P{O-n-Pr}₂)(PPh₃)](5) reveals the molecular structure of the complex and confirms a square-planar geometry around the central atom of nickel with the NCS anion coordinated via the nitrogen atom.     

Photochemical reactions of Re(CO)5Br with Ph2P(CH2) n PPh2 (n = 1, dppm; 2, dppe; 3, dppp)

The new complexes fac-[Re(CO)₃Br{Ph₂P(CH₂) _n PPh₂}] (1a–3a) [(1a), n = 1; (2a), n = 2; (3a), n = 3] and [Re₂(CO)₈Br₂{-Ph₂P(CH₂) _n PPh₂}] (1b–3b) [(1b), n = 1; (2b), n = 2; (3b), n = 3] have been prepared by the photochemical reaction of Re(CO)₅Br with Ph₂P(CH₂) _n PPh₂ (n = 1, dppm; 2, dppe; 3, dppp). The complexes have been characterized by elemental analysis, mass spectroscopy, f.t.-i.r. and ³¹P-[¹H]-n.m.r. spectrometry. The spectroscopic studies suggest cis-chelate bidentate coordination of the ligand in fac-[Re(CO)₃Br{Ph₂P(CH₂) _n PPh₂}] (1a–3a) and cis-bridging bidentate coordination of the ligand between two metals in [Re₂(CO)₈Br₂{cis--Ph₂P(CH₂) _n PPh₂}] (1a–3a).     

Synthesis, spectroscopy and redox properties of mononuclear manganese(II) and manganese(IV) complexes with N-(aryl)-pyridine-2-aldimine (L) and its amide derivatives. X-ray structural characterization of [Mn(MeL)2(NCS)2] (MeL = N-(4-methylphenyl)-pyridine-2-aldimine)

A series of mononuclear Mn^II and Mn^IV complexes of general formulae [MnL₂(NCS)₂] (1a–1d) and [Mn(L)₂(NCS)₂] (2a–2c) have been prepared where L are Schiff bases obtained by the condensation of pyridine-2-aldehyde with para-alkyl-substituted aniline, and L are the corresponding amide ligands. The room temperature magnetic susceptibility data of (1a–1d) indicate that Mn^II is in a high spin state. The cyclic voltammograms of (1a–1d) exhibit a one-electron quasi-reversible Mn^IIMn^III oxidation. A linear correlation has been found when E⁰[Mn^III/Mn^II] is plotted against Hammett _p parameters. X-ray crystallographic data of (1b) shows that the central Mn^II ion adopts a distorted octahedral geometry with six different Mn–N distances. Upon oxidation of Mn^II complexes (1b–1d) by H₂O₂, the corresponding Mn^IV complexes (2a–2c) were obtained, and the Schiff base ligands were oxidized to the corresponding amides. The lowest energy LMCT bands of these Mn^IV complexes correlate linearly with Hammett _p parameters. The redox behavior of the Mn^IV complexes has been investigated by cyclic voltammetry. E.p.r. spectra of the Mn^II and Mn^IV complexes are also reported.     

New syntheses of 2,4-diaminopyrroles and aminopyrrolinones

Summary Oxazolin-2-ylidene-malononitriles3a–d, obtainable from thioketenaminals and -halogen-ketones, react with primary and secondary amines to afford 2,4-diamino-pyrroles5a–h. Mercaptobenzen as nucleophilic agent gives the 4-amino-2-phenylthio-pyrrole5j. Analogously, cyano-(3,5-diphenyl-3H-oxazol-2-ylidene)-acetic acid methyl esters were prepared as intermediates for the synthesis of 2-amino-4-oxo-pyrrolines10a–d. The isomeric 4-amino-2-oxo-pyrrolines13a–d can be obtained from 4-amino-2-methoxy-pyrroles, which serves as proof for the position of substituents. The structures were investigated by¹H and¹³C NMR spectroscopy.

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Neue Synthesen von 2,4-Diaminopyrrolen und Aminopyrrolinonen

Zusammenfassung Die Oxazolin-2-yliden-malononitrile3a–d. die aus Thioketenaminalen und -Halogenketonen erhalten wurden, reagieren mit primären und sekundären Aminen zu den 2,4-Diaminopyrrolen5a–h. Mercaptobenzol als nukleophiles Reagens liefert 4-Amino-2-phenylthiopyrrol (5j). Analog wurden Cyan-(3,5-diphenyl-3H-oxazol-2-yliden)-essigsäuremethylester als Zwischenprodukte für die Synthese der 2-Amino-4-oxo-pyrroline10a–d hergestellt. Die isomeren 4-Amino-2-oxo-pyrroline13a–d können aus den 4-Amino-2-methoxy-pyrrolen11a,b erhalten werden, was als Nachweis für die Position der Substituenten dient. Die Verbindungen wurden¹H- und¹³C NMR-spektroskopisch untersucht.

     

Spectroscopic studies of novel porphyrin-copper(II) and zinc(II) complexes that share the pinch-porphyrin family structure of iron(III) complex models of peroxidases

Six novel pinch-porphyrin complexes [(picdien)(protoporphyrinate dimethyl ester)]copper(II) (7), [(picdien)(mesoporphyrinate dimethyl ester)]copper(II) (8) and [(picdien)(deuteroporphyrinate dimethyl ester)]copper(II) (9), [(picdien)(protoporphyrinate dimethyl ester)]zinc(II) (13), [(picdien)(mesoporphyrinate dimethyl ester)]zinc(II) (14) and [(picdien)(deuteroporphyrinate dimethyl ester)]zinc(II) (15), were prepared from the corresponding free copper(II)-porphyrins (4–6), and zinc(II)-porphyrins (10–12) and picdien (N-(3H-imidazol-4-ylmethyl)-N-{2-[(3H-imidazol-4-ylmethyl)-amino]-ethyl}-ethane-2,3-diamine). Spectroscopic studies show that complexes (7–9) and (13–15) have the pinch-porphyrin type structure previously found in iron(III) complex models of peroxidases. Complexes (7–9), were characterized by u.v.–vis., m.c.d., and e.s.r. spectroscopy. E.s.r. spectra of the copper parent compounds (4–6) at ca. 10^–2–10^–4 M concentrations were typical of copper(II)-dimers. The addition of the picdien ligand broke up the dimers as detected by e.s.r. Compounds (7–9) are predominantly monomeric at ca. 10^–3 M concentration. The presence of picdien in (7–9) distorts the porphyrin internal portion of the plane so as to make these four internal nitrogen atoms, coordinated to copper(II), e.s.r.-distinguishable. MO and ligand field theories were used to characterize and to evaluate the directional covalence parameters of compounds (7–9). A non-fully axial, out-of-the-porphyrin-plane bonding was found for (7–9), similar to the bonding of the pinch-porphyrins-iron(III). However the in-plane distortion produced by the presence of the picdien ligand on copper(II) is significantly larger than in pinch-porphyrin-iron(III). The n.m.r. data show that the porphyrin-zinc(II) is the less strained and has the weakest bonded structure. The coordination number of the pinch-porphyrin with iron(III), copper(II) and zinc(II), is in all cases six.     

Zur Kenntnis der Reaktionsfähigkeit alkylsubstituierter Thiomorpholine, 1. Mitt.

Zusammenfassung Die Darstellung einigerMannichbasen (3 a-f) bzw.Mannich-basen-hydrochloride (2 a-f) und zahlreicher s-Triazin-Derivate (4 a-d, 5 a–m, 6 a–w, 7 a–e, 8 a–d, und9 a–l) auf Basis des unsubstituierten Thiomorpholins (1 a) sowie C-mono-[2-Methylthiomorpholin (1 b) und 2-Äthylthiomorpholin (1 c)] und C-dialkylierter Thiomorpholine [2-Methyl-3-äthylthiomorpholin (1 d)] wird beschrieben.

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Concomitant action of elementary sulfur and gaseous ammonia upon ketones, LXXIX: On the reactivity of alkyl substituted thiomorpholines, I

The preparation of someMannichbases (3 a-f) andMannich base hydrochlorides (2 a-f), resp., and numerous s-triazine derivatives (4 a-d, 5 a–m, 6 a–w, 7 a–e, 8 a–d, and9 a–l) based upon unsubstituted thiomorpholine (1 a) as well as C-mono-[2-methylthiomorpholine (1 b) and 2-ethylthio-morpholine (1 c)] and C-dialkylated thiomorpholines [2-methyl-3-ethylthiomorpholine (1 d)] is described.

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HerrE. Wilms dankt der Deutschen Texaco AG. für die Gewährung eines Stipendiums herzlichst.     

Catalytic studies of 2-benzthiazolethiol (BzTa)-linked manganese(III) and cobalt(II) porphyrin complexes

Four 2-benzthiazolethiol (BzTa)-linked porphyrins (1)–(4), and their complexes with Co^II and Mn^III, (5)–(12), were prepared and characterized by elemental analysis, ¹H-n.m.r., i.r., u.v.–vis. and mass spectra. The hydroxylation of cyclohexane in the presence of these complexes and PhIO under mild conditions was investigated. The catalytic activities of these complexes were higher than that of corresponding TPPMn^IIICl and TPPCo^II species respectively, which indicated that the terminal group, BzTa, played an important role in the catalysis. A possible mechanism is proposed.     

Synthesis,Spectral and Electrochemical Studies of Mixed-Ligand Oxovanadium(IV) and Oxovanadium(V) Complexes Incorporating the Tridentate ONO Donor Schiff Base Derived from Acetylacetone and Benzoylhydrazine

Mixed-ligand oxovanadium(IV) and oxovanadium(V) complexes with a tridentate dinegative ONO donor Schiff base ligand [viz., 4-(1-hydroxybenzylidenehydrazono)-2-penten-2-ol (H₂L)] and bidentate NN [viz., 2,2-bipyridine (bipy) and 1,10-phenanthroline (phen): complexes (1) and (2), respectively] or OO^–[viz., ethylene glycol (H₂gol), salicylaldehyde (Hsal) and vanillin (Hvan): complexes (3)–(5), respectively] donor ligands have been prepared and characterized by elemental analyses and by i.r., e.p.r., n.m.r., and u.v.–vis. spectroscopies. The complexes with NN donor ligands are one electron paramagnetic, displaying axial e.p.r. spectra and exhibiting two ligand-field transitions in the visible region, whereas the complexes with OO^– donor ligands are diamagnetic and display only LMCT bands. ¹H n.m.r. spectral data indicate that the pentavalent complexes (4) and (5) exist in two isomeric forms [(4A), (4B) and (5A), (5B) in 1:1 and 4:1 ratios, respectively]. The vanadyl(IV) complexes display an irreversible oxidation peak near +0.67 V while among the vanadyl(V) complexes, (3), displays an irreversible reduction peak near –0.20 V and (4) and (5) display a quasi-reversible one electron reduction peak near +0.25 V versus s.c.e. The trend in redox potential values and the selective stabilization of VO²⁺ and VO³⁺ motifs have been explained on the basis of the basicity of the bidentate auxiliary ligands.     

A novel fluorescein-porphyrinatozinc(II) hybrid: synthesis and its supramolecular self-assembly with imidazolyl-linked porphyrinatomanganese(III) by coordinative bonding

A novel fluorescein–porphyrinatozinc(II) hybrid, Zn(Fl–PPTPP), was synthesized and characterized by u.v.–vis., i.r., ¹H-n.m.r, ESMS and elemental analyses. The supramolecular self-assembly of Zn(Fl–PPTPP) with an imidazolyl-linked porphyrinatomanganese(III), Mn^(III)(p-ImBPTPP)Cl, complex has been studied by fluorescence spectroscopic titration, VPO measurements and ESMS, which indicates that the formation of the Zn(Fl–PPTPP)–Mn^(III)(p-ImBPTPP)Cl. supramolecular complex is driven by coordinative bonding formed by the coordination of imidazolyl group in Mn^(III)(p-ImBPTPP)Cl to Zn(II) in Zn(Fl–PPTPP). The association constant of the supramolecular complex was calculated from the fluorescence spectroscopic titration data. It was found that the conformation of the Zn(Fl–PPTPP)–Mn^(III)(p-ImBPTPP)Cl supramolecular complex, the steric hindrance and the electronic effect of the fluorescein group linked to porphyrin through a flexible long alkoxy chain are all acting on the association constant of the Zn(Fl–PPTPP)–Mn^(III)(p-ImBPTPP)Cl supramolecular complex. It seems that the steric hindrance and the electronic effect of the fluorescein group are the primary factors effecting the association constant of Zn(Fl–PPTPP)–Mn^(III)(p-ImBPTPP)Cl supramolecular complex, especially the electronic effect of the fluorescein group, which is the reason for the association constant of Zn(Fl–PPTPP)–Mn^(III)(p-ImBPTPP)Cl being smaller than that of ZnTPP–Mn^(III)(p-ImBPTPP)Cl.     

A new synthesis for 1,2,4-triazolo[1,5-a]-pyridines and 1,2,4-triazolo[1,5-a]isoquinolines

Summary Condensation of cyano acid hydrazide1 with cyclopentanone in refluxing ethanolic piperidine yields hydrazone2. With mixtures of aliphatic aldehydes and different active methylene reagents,2 reacts to 1,2,4-triazolo[1,5-a]pyridines (8a–f). Compound2 also reacts with arylidenes9a–g to give triazolopyridines10a–g. Reaction of2 with aromatic aldehydes affords compounds13a–c. Diazotation of2 with aryldiazonium chloride in ethanol at 0 °C leads to the azo adducts15a–d. The thieno-1,2,4-triazolopyridine16 is obtained by reaction of8a with elementary sulfur.16 undergoes cycloaddition with -nitrostyrene, maleic anhydride, N-arylmalemide, and acrylonitrile yielding the isoquinolines21–24. All new compounds have been characterized by their IR,¹H NMR, and mass spectra.

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Ein neuer Syntheseweg für 1,2,4-Triazolo[1,5-a]pyridine und 1,2,4-Triazolo[1,5-a]isochinoline

Zusammenfassung Kondensation des Cyanohydrazids1 mit Cyclopentanon in ethanolischem Piperidin bei Rückflußtemperatur ergibt das Hydrazon2. Mit Gemischen aus aliphatischen Aldehyden und verschiedenen Verbindungen mit aktiven Methylengruppen reagiert2 zu 1,2,4-Triazolo[1,5-a]pyridinen (8a–f). Verbindung2 reagiert außerdem mit den Arylidenen9a–g zu den Triazolopyridinen10a–g. Umsetzung von2 mit aromatischen Aldehyden führt zu den Verbindungen13a–c. Diazotierung von2 mit Aryldiazoniumchloriden in Ethanol bei 0°C ergibt die Azoaddukte15a–d. Das Thieno-1,2,4-triazolylpyridin16 erhält man durch Reaktion von8a mit elementarem Schwefel.16 geht it -Nitrostyrol, Maleinsäureanhydrid, N-Arylmaleimid und Acrylnitril eine Cycloaddition zu den Isochinolinen21–24 ein. Alle neuen Verbindungen wurden durch ihre IR-,¹H-NMR- und Massenspektren charakterisiert.

     

Synthesis,characterization and charge-transfer photochemistry of trans-aquo azido-N,N′-trimethylenebis(naphthylideneiminato)chromium(III)

A new Cr^III complex, viz. trans-[Cr(naphprn)(H₂O)₂]ClO₄·2H₂O, (1) {naphprn=N,N-trimethylenebis(naphthylideneimine)} has been synthesized and characterized. Aquo ligand substitution of ( 1 ) by the azide ligand gave rise to trans-[Cr(naphprn)(N₃)(H₂O)], ( 2 ). Irradiation of ( 2) in DMF gave nitrido(naphprn)chromium(V) ( 3 ). Solutions of ( 3 ) showed e.p.r. spectra at room temperature (g _iso=1.9865). The i.r. spectra showed disappearance of a band at 2067cm^–1 showing the breakdown of NN and appearance of a new band at 1074cm^–1which is assigned to the Cr¹⁴N, stretching frequency indicating the formation of a nitrido chromium(V) complex, ( 3). The u.v.–vis. spectrum of complex ( 3 ) exhibited a d–d band maximum at 553nm (=120M^–1cm^–1). The rate of formation of ( 2 ) was found to be 5.0×10^–3M^–1s^–1 in an aqueous acidic medium at [Cr^III]=0.5×10^–3M; [N₃ ^–]=0.01–0.15M; [H⁺]=0.001M and I=0.2M (LiClO₄). The rate of photo-decomposition of ( 2 ) to give rise to ( 3 ) was found to be 0.15×10^–3s^–1 in DMF.     

Ruthenium(II) <Emphasis Type="Italic">N</Emphasis>-heterocyclic Carbene Complexes in the Transfer Hydrogenation of Ketones

Six ruthenium-N-heterocyclic carbene complexes (2–7) have been prepared and the new compounds characterized by C, H, N analyses, ¹H-n.m.r. and ¹³C-n.m.r. The reduction of ketones to alcohols via transfer hydrogenation was achieved with catalytic amounts of complexes (2–7) in the presence of t-BuOK.     

Synthesis of 2H-pyrano[2,3-d]pyrimidine derivatives

Two series of 2H-pyrano[2,3-d]pyrimidine-2,5(6H)-dione derivatives have been prepared. Thus, the reaction of 6-hydroxy-pyrimidin-4(3H)-ones (1 a–c) with bis-2,4,6-trichlorphenyl malonates (2 a–d) or diethyl malonates (3 a–d) afforded good yields of 4-hydroxy-2H-pyrano[2,3-d]pyrimidine-2,5(6H)-diones (4 a-l). Application of our modifiedPechmann reaction^9–11 using -aminocrotonate (5) or -keto esters (6, 7) in the presence of ammonium acetate yielded the 2H-pyrano[2,3-d]pyrimidinediones8 a–h.Dedicated to Prof. Dr.Karl Schlögl, University of Vienna, on the occasion of his 60th birthday.     

Reaction of Ru(PPh3)3Cl2 with arylazoimidazoles: spectral characterisation and redox studies of [bis-{N(1)-alkyl-2-(arylazo)imidazole}-bis-(triphenylphosphine)]-ruthenium(II) perchlorate

Ru(PPh₃)₃Cl₂ reacts with N(1)-alkyl-2-(arylazo)imidazoles, p-RC₆H₄N=NC₃H₂N₂X, [RaaiX, R = H(a), Me(b), Cl(c); X = Me(1), Et(2), Bz(3)] under refluxing conditions in EtOH to give [Ru(RaaiX)₂(PPh₃)₂](ClO₄)₂ · H₂O complexes (4–6). RaaiX is a bidentate chelator (N, N) with N(imidazole), N and N(azo), N donor centres. Three isomers are present in the mixture in which the pairs of PPh₃, N and N occupy cis–cis–trans, cis–trans–cis and cis–cis–cis, positions respectively. The isomers were identified by ¹H-n.m.r. spectra. Four signals are observed in the aliphatic zone for N(1)-X; two are of equal intensity at higher and the other two signals at lower in the ratio 1:0.3:0.2 suggesting the presence of cis–cis–cis, cis–trans–cis and cis–cis–trans-geometry. The complexes display the allowed t ₂(Ru) ^*(RaaiX) transition. Cyclic voltammetry indicates two consecutive Ru^III/II couples along with azo reductions.     

Crystal structure of [Cu4(pytp)2(SO4)2(H2O)10](SO4)2 · 4H2O. A tetranuclear copper(II) complex with a new asymmetric ligand,pytp*, as a bridge

A new asymmetric bridge ligand, pytp, was prepared and characterized systematically by f.t.i.r., u.v.–vis., ¹H-n.m.r. and by FAB-MS spectroscopy. A tetranuclear Cu^II complex [Cu₄(pytp)₂(SO₄)₂(H₂O)₁₀](SO₄)₂·4H₂O (1) was prepared and characterized by elemental analysis and u.v.–vis. spectroscopy. A crystal structure analysis indicates that there are two different coordination spheres in (1) and that two of the copper centers are bridged by two ₂-SO₄ entities, creating a most unusual sulphate bridge.     

Nuclease activity of mixed ligand complexes of copper(II) with heteroaromatic derivatives and picoline

New picoline adducts with carbamic acid [(furan-2-yl)methylene]hydrazide–Cu^II (CFMH) (1); thiocarbamic acid [(furan-2-yl)methylene]hydrazide–Cu^II (TFMH) (2); carbamic acid [(furan-2-yl)ethylidene]hydrazide–Cu^II (CFEH) (3), thiocarbamic acid [(furan-2-yl)ethylidene]hydrazide–Cu^II (TFEH) (4); carbamic acid [(thiophene-2-yl) methylene]hydrazide–Cu^II (CTMH) (5), thiocarbamic acid [(thiophene-2-yl)methylene]hydrazide–Cu^II (TTMH) (6), carbamic acid [(thiophene-2-yl)ethylidene]hydrazide–Cu^II (CTEH) (7), thiocarbamic acid [(thiophene-2-yl)ethylidene]hydrazide–Cu^II (TTEH) (8) have been prepared and characterized by analytical, i.r., electronic, e.s.r. and c.v. spectral data. The electronic spectra suggest distorted octahedral geometry for all the picoline adducts. E.s.r. g values lie between 2.251–2.286 at l.n.t. All the adducts undergo a quasi-reversible one-electron reduction in the range +0.47 to +0.51 V versus s.c.e., attributable to the Cu^III/Cu^II redox couple. The electron transfer is much faster in the semicarbazone complexes than in the thiosemicarbazone complexes. All adducts showed increased nuclease activity in the presence of oxidant; the nuclease activity is compared with that of the parent copper(II) complexes.     

The Reaction of Alkenes with Triangulo-Clusters [Pt3(μ-CO)3(PR3)3]

The reactions of the cluster complexes [Pt₃(-CO)₃L₃], where L=PPh₃ 1a, PPh₂Bz 1b and PCy₃ 1c, with activated mono-olefins have been studied under preparative and equilibrium conditions. At low temperature the olefins react quantitatively giving the adducts [Pt₃(-CO)₃L₃(olefin)] (olefin=trans-dicyanoethene, DCE 2a–2c, maleic anhydride, MA 3a–3c). The stereo-chemistry of these unstable clusters has been deduced from low temperature ³¹P, ¹³C, ¹⁹⁵Pt-NMR and I.R. spectra. At higher temperature these adducts in presence of excess of olefin convert quantitatively to stable mononuclear Pt(0) complexes [Pt(CO)L(olefin)] (olefin=DCE 4a–4c, MA 5a–5c, maleimide, MI 6a–6c and 1–4-naphthoquinone, NQ 7a, 7c).     

Novel complexes of 5-(4-carboxyl)phenylene-methanaminophenyl-10,15,20-tri-phenylporphyrin with zinc(II), iron(III), manganese(III) and zinc(II)–iron(III), zinc(II)–manganese(III) supramolecular self-assembly by hydrogen bonding

5-(p-Carboxyl)phenylene-methanaminophenyl-10,15,20-triphenylporphyrin (p-CPTPP) and its Zn^II[Zn(p-CPTPP)], Fe^III[Fe^III(p-CPTPP)Cl], Mn^III[Mn^III(p-CPTPP)Cl] complexes were prepared and characterized by elemental analysis, ¹H-n.m.r., i.r. and u.v.–vis. spectroscopy. The behaviour of the supramolecular self-assemblies, Zn(p-CPTPP)–Fe^III(p-CPTPP)Cl and Zn(p-CPTPP)–Mn^III(p-CPTPP)Cl, were studied by steady-state fluorescence spectroscopic titration and u.v.–vis. spectra. The formation constants were determined from the data of fluorescence spectroscopic titration. The fact that the Zn(p-CPTPP)–Mn^III(p-CPTPP)Cl system has a higher formation constant than the Zn(p-CPTPP)–Fe^III(p-CPTPP)Cl system is discussed.