Über das Tetrahydrospiro [cyclohexan-1,2′(1′H)-chinazolin]-4′(3′H)-on

Zusammenfassung Das beim Erhitzen von Cyclohexanon und Harnstoff entstehende Produkt ist nicht als Cyclohexyliden-2-carbamylcyclohex-1-enylamin, sondern als 5, 6, 7, 8-Tetrahydrospiro-[cyclohexan-1,2(1H)-chinazolin]-4(3H)-on zu formulieren¹. Analog gebaute Verbindungen bilden sich aus Cyclopentanon bzw. Cycloheptanon und Harnstoff. Die genannten Kondensate sind als cyclische -Carbamylenamine aufzufassen; charakteristisch sind die Reaktivität der zur NH-Gruppe/1, in peri-Stellung befindlichen CH₂-Gruppe bzw. der Kernstelle 4a.

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-Carbamoyl enamines: 5. 6. 7. 8-Yetrahydrospiro [cyclohexane-1,2 (1H)-quinazoline]-4 (3H)-one. (Heterocycles, XXIII)

The product obtained by heating cyclohexanone with urea has been found to be 5. 6. 7. 8-tetrahydrospiro[cyclohexane-1.2(1H)-quinazoline]-4(3H)-one, not cyclohexylidene-2-carbamoylcyclohex-1-enylamine, as was previously assumed¹. Compounds with analogous structures were formed by heating cyclopentanone or cycloheptanone with urea. Characteristic features of this class of compounds, i.e. -carbamoyl enamines, are the enhanced reactivities of the nuclear 4 a-position and of the methylene group in the peri-position to NH-1.

     

Novel dioximato-bridged chromium(III)-copper(II)-chromium(III) trinuclear complexes with ferromagnetic exchange interactions

Summary Two new dioximato-bridged trinuclear Cr^II-Cu^II-Cr^III complexes, [Cr(salen)-Cu(-BD)₂-Cr(salen)] (1) and [Cr(salen)-Cu(-FD)₂-Cr(salen)]-H₂O (2), have been prepared and characterized [salen^2– = N,N-ethylene- bis (salicylideneiminate), (-BD)^2– = -benzyldioximato and (-FD)^2– = -furildioximato]. Magnetic susceptibility measurements in the 4.2–300 K range demonstrated the operation of a ferromagnetic interaction between the adjacent Cr^III and Cu^II ions through oximato bridges in both (1) and (2). Based on spin Hamiltonians =–2J(₁₂+₂₃)(S₁=S₃=3/2,S₂=1/2) the exchange integrals (J) were evaluated as 3.19 and 5.38 cm^–1 for (1) and (2), respectively.     

Thermal and some other properties of the complexes crystallizing from the system Ni(II)-en-[Ni(CN)4]2−-H2O

Seven complex compounds exhibiting the compositions Ni(en)₃Ni(CN)₄·H₂O (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄·2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2.5H₂O (VI) and-Ni(en)₂Ni(CN)₄ (VII) were prepared from the system Ni-en-[Ni(CN)₄]^2–-H₂O. These compounds were examined by the methods of infrared spectroscopy, X-ray powder diffractometry, UV-VIS reflectance spectroscopy, and also by the measurement of magnetic moments. The thermal stability, the stoichiometry of thermal decomposition and the mutual transformations were investigated with a derivatograph. The reactions proceeding according to the following schemes were observed if the system was heated to appropriate temperature: (I)(II)(III)(V)(IV) and (VI)(VII)(III)(V)(IV) Process (VII)(III) represents isomerization. The reversibility of the process (V)(IV) is due to the high hygroscopicity of the anhydrous complex. The changes in structure in the course of the individual processes are discussed.

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Zusammenfassung Aus einem System Ni-en-[Ni(CN)₄]^2–-H₂O wurden sieben Komplexe der Formeln Ni(en)₃Ni(CN)₄·H₂O (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄·2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2.5H₂O (VI) und-Ni(en)₂Ni(CN)₄ (VII) hergestellt. Diese Verbindungen wurden mittels IR-Spektroskopie, Röntgenpulverdiffraktometrie, UV-Reflexionsspektroskopie und durch Messungen des magnetischen Momentes untersucht. Die Wärmestabilität, die Stöchiometrie des thermischen Zerfalles und die gegenseitigen Umwandlungen wurden mittels eines Derivatographen untersucht. Wird das System auf geeignete Temperaturen erhitzt, kann der Reaktionsverlauf durch folgendes Schema dargestellt werden: (I)(II)(III)(V)(IV) und (VI)(VII)(III)(V)(IV).Der Prozeß (VII)(III) verkörpert eine Isomerisierung. Die Umkehrbarkeit von Prozeß (V)(IV) ist auf die ausgeprägten Hygroskopieeigenschaften des wasserfreien Komplexes zurückzuführen. Es werden die im Ablaufe der einzelnen Prozesse vorgehenden Strukturveränderungen besprochen.

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Ni- -[No(N)]² -₂ Ni(en)₃Ni(CN)₄ · ₂ (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄-2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2,5H₂O (VI) -Ni(en)₂Ni(CN)₄ (VII). , , - , . , . (I)(II)(III)(V)(IV) (VI)(VII)(III)(V)(IV). (VII)(III) . (V)(IV) . .

     

On the crystal chemistry of three copper(II)-arsenates: Cu3(AsO4)2-III,Na4Cu(AsO4)2, and KCu4(AsO4)3

The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu₃(AsO₄)₂-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å^–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)^[4+1] atom in Cu₃(AsO₄)₂-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu₄(AsO₄)₃ the Cu(1)^[4]O₄ square and the As(1)O₄ tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO₄ square and the AsO₄ tetrahedron. The two Na atoms in Na₄Cu(AsO₄)₂ are [6] coordinated, the K atom in KCu₄(AsO₄)₃ is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu₃(AsO₄)₂-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å^–1.Na₄Cu(AsO₄)₂:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å^–1.KCu₄(AsO₄)₃:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å^–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)^{[4 + 1]}-Atom in Cu₃(AsO₄)₂-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu₄(AsO₄)₃ haben das Cu(1)^[4]O₄-Quadrat und das As(1)O₄-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO₄-Quadrat und AsO₄-Tetraeder bedingt. Die zwei Na-Atome in Na₄Cu(AsO₄)₃ sind durch O-Atome [6]-koordiniert, das K-Atom in KCu₄(AsO₄)₃ ist [8]-koordiniert.

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Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu₃(AsO₄)₂-III, Na₄Cu(AsO₄)₂ und KCu₄(AsO₄)₃

     

Mechanism of alkyl iodide reduction to alkanes in aqueous solutions of Na2PtCl4?NaI?HClO4

Platinum(II) catalyzes the reduction of alkyl iodides to alkanes according to a mechanism involving oxidative addition of RI to Pt(II), reduction of the product complex RPt(IV) to RPt(II) by iodide ions and protolysis of the latter particle.

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(II) , RI Pt^II, - RPt^IV RPt^II .

     

Extraction-spectrophotometric determination of iron(III) by means of quinaldic acid-N-oxide

Summary A simple and sensitive method for the determination of iron(III) is described. It is based on the extraction of the yellow-coloured complex of iron with quinaldic acid-N-oxide in chloroform. The absorption maximum is at 380 nm with molar absorptivity ₃₈₀=1.03 · 10⁴. Beer's Law is obeyed over the range 0.6–6 ppm iron with relative standard deviation of +-0.3% (Sandell sensitivity 0.005 g/ml/cm²). The absorbance of the reagent blank is however high with consequent occasional disturbances, which are avoided when measured at 395 nm; molar absorptivity ₃₉₅=7.4 · 10³; effective concentration range 3–8 ppm iron with relative standard deviation +-0.5% (Sandell sensitivity 0.008g/ml/cm²). A fairly large number of common ions do not interfere. Job's method of continuous variations and Asmus method indicate a iron-reagent ratio of 13. Heterogeneous formation constant is K _D =2 · 10⁸.

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Extraktionsphotometrische Bestimmung von Eisen(III) mit Chinaldinsäure-N-oxid

Zusammenfassung Die einfache und empfindliche Bestimmung beruht auf der Extraktion des gelben Komplexes von Eisen(III) mit Chinaldinsäure-N-oxid in Chloroform. Das Absorptionsmaximum liegt bei 380 nm mit dem molaren Extinktionskoeffizient ₃₈₀=1.03 · 10⁴. Das Beersche Gesetz gilt im Bereich 0,6–6 ppm Eisen. Die relative Standardabweichung beträgt+-0,3% (Sandell-Empfindlichkeit 0,005g/ml/cm²). Die Absorption der Blindprobe ist jedoch hoch und verursacht manchmal Störungen, die beim Messen bei 395 nm vermieden werden; molarer Extinktionskoeffizient ₃₉₅= 7,4 · 10³; im Konzentrationsbereich 3–8 ppm Eisen beträgt die relative Standardabweichung+-0,5% (Sandell-Empfindlichkeit 0,008g/ml/cm²). Eine ziemlich große Zahl von Fremdionen bewirkt keine Störung. Methoden nach Job und Asmus liefern ein Verhältnis Eisen/Reagens wie 13. Die heterogene Bildungskonstante beträgt K _D =2 · 10⁸.

     

Cobalt(II) and nickel(II) chloride complexes with some 2-(4′-Methyl-2′-pyridyl and 2′- or 8′-quinolyl)benz-X-azoles

Summary Complexes of general formula ML_mCl₂ · nH₂O, where M=cobalt(II) or nickel(II); L=2-(4-methyl, 2-pyridyl)-benzimidazole (mpbi), 2-(4-methyl, 2-pyridyl)benzothiazole (mpbt), 2-(4-methyl, 2-pyridyl)benzoxazole (mpbo), 2-(4-methyl, 2-quinolyl)benzoxazole (mqbo), or 2-(4-methyl, 8-quinolyl)benzoxazole (mqbo); m=1,2; n=0–3, were prepared and characterized by t.g.a., conductance and magnetic measurements, i.r. and diffuse-reflectance electronic spectra.All the ligands behave as bidentate and coordinate through the pyridine- and isoxazole-nitrogen atoms.The nickel complexes have distorted octahedral or fivecoordinate structures. The cobalt complexes arepseudo-tet- rahedral except Co(mpbo)₂Cl₂·2H₂O where the metal is six-coordinate.     

Thermal analysis of the interaction of phosphorite with condensed phosphates of calcium

The thermal reactions between Maardu (Estonia) phosphorite and acidic phosphates were investigated. TG, DTG and DTA of mixtures with H₃PO₄, Ca(H₂PO₄)₂ · H₂O, Ca₂P₂O₇ and [Ca(PO₃)₂]_n in different molar ratios showed a maximum mass loss when the CaO P₂O₅ value was 2. The main temperature ranges of the mass losses were determined. The probable reactions relating to the mass losses are given on the basis of the thermal curves and IR spectra.

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Zusammenfassung Die thermische Reaktion zwischen Phosphorit aus Maardu (Estnien) und sauren Phosphaten wurde untersucht. TG, DTG und DTA von Gemischen mit H₃PO₄, Ca(H₂PO₄)₂ · H₂O, Ca₂P₂O₇ und [Ca(PO₃)₂]_n in verschiedenen molaren VerhÄltnissen zeigten den grö\ten Massenverlust bei dem VerhÄltnis von CaO P₂O₅=2. Die wichtigsten Temperaturbereiche der Massenverluste wurden bestimmt. Die den Massenverlusten zugeordneten wahrscheinlichen Reaktionen werden aus den erhaltenen thermischen Kurven und IR Spektren ermittelt.

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Résumé Etude de l'effet thermique lié à la réaction entre la phosphorite de Maardu (Estonie) et les hydrogénophosphates. Etude par TG, TGD et ATD de mélanges de H₃PO₄ avec Ca(H₂PO₄)₂ · 2 H₂O, Ca₂P₂O₇ et [Ca(PO₃)₂]_n réalisés avec différents rapports molaires; mise en évidence d'une perte de masse maximale pour le rapport CaO P₂O₅ égal à deux. Détermination des principaux domaines de température où s'effectuent les pertes de masse. On donne les réactions probables correspondant aux pertes de masse en s'appuyant sur les courbes d'analyse thermique et spectres infrarouges.

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() . TG, DTG DTA H₃PO₄, Cc(H₂PO₄)₂. H₂O, Ca₂P₂O₇ [Ca(PO₃)₂] _n , CaOP₂O₅ 2. . , .

     

Crystal and Molecular Structure of 1-( p -Tolyl)-4-[4-(N-naphthalimido)butyl]piperazine

An X-ray structure analysis of 1-(p-tolyl)-4-[4-(N-naphthalimido)butyl]piperazine (I) was carried out: a=9.551(3), b=13.775(3), á=8.917(4) , =103.96(3), =101.47(4), =92.60(3)°, V=1110.4(7) ³, Z=2,_calc=1.279 g/cm³, =0.644 mm, space group P 1, 4239 nonzero reflections, R=0.056. The molecule is linear elongated. The p-tolyl and naphthalimide fragments are almost planar, while the piperazine cycle has a chair conformation. The long well-packed molecules form parallel and antiparallel chains with van der Waals interactions between them.     

The synthesis and crystal structure of a cubane-like tungsten copper sulphur cluster, [W4CuS4 2P(OEt)2 3(I)(μ2-PhCO2)(MeCN)]

Summary The title compound [W₃C₃S₄{S₂P(OEt)₂}₃(I)(₂ ^–PhCO₂)(MeCN)] crystallized in triclinic system with space group P1 and cell dimensiona=11.645(6),b=18.565(2),c=11.292(7)Å, =96.15(3)°, =113.65(3)°, =93.77(3)°, V=2207.6ų, Z=2, Mr=1588.09, D_c=2.39 g cm^–3. MoK radiation, =0.71073 Å, =97.3 cm^–1, F(000)=1488, R=0.042 for 5588 observed unique reflections I3(I). There are some distortions in the cubane-like W₃CuS₄ core, with three W-W bonds and three weak W-Cu bonds. Two W atoms are coordinated by PhCO₂ bridge ligand, the other W atom is coordinated to the N atom of MeCN.     

Synthesis and structure of [(OC)4Os(PbMe2)]2 and some derivatives of the type Os2(CO)7(SnMe2)2(L)

The complexes [(OC)₄Os(PbMe₂)]₂ (3) and [(OC)₄OsSnBu ₂ ]₂ (4) have been prepared from be reaction of Na₂[Os(CO)₄] with Me₂PbCl₂ and Bu ₂ SnCl₂, respectively, in THF and their X-ray crystal structures determined. The red derivative,3, was light-sensitive in solution. The reactions or [(OC)₄ Os(SnMe₂)]₂ (2), or its decarbonylated derivative [Os₃(CO)₇(SnMe₂)₂]₂ (7), with olefins or phosphorus donor ligands have also been investigated, and the structures of two derivatives, viz. [Os₂(CO)₇(SnMe₂)₂(C₂H₄)] (5a) and [Os₂(CO)₇(SnMe₂)₂(PMe₃)] (6a), have been determined; the noncarbonyl ligand occupies an equatorial site in each case. The X-ray crystal structures of all these compounds, like those of [(OC)₄Os(EMe₂)]₂ (E=Ge (1), Sn (2)) which have been reported previously, show leaning of the axial carbonyl ligands toward the metal tetracycle, i.e., an umbrella effect. Crystallographic data for compound3: space group, P2₁/a;a=13.4404(13) Å,b=10.7494(14) A,c=148967(18) A,=98.204(9)°,R=0.035, 1983 observed reflections. For compound4: space group,P1;a=9.016(1) Å,b=9.370(1),c=11.334(1) A, =103.67(1)°,=100.30(1)°, =115.03(1)°, R=0.046, 2026 observed reflections. For compound5a: space group,P1;a=9.2933(11)Å,b=9.7181(3),c=12.2508(15) A, =89.21(1)°,=87.61(1)°, =86.13(1)°,R=0.038, 2770 observed reflections. For compound6a space groupP1:a=8.7244(9)Å,b=10.9318(6),c=13.2560(13) A, =87.815(6)°,=83.655(8)°, =82.343(6)°, R=0.030, 3497 observed reflections.     

Synthesis and X-Ray Crystal Structure Study of ]2-Methyl-4-(2-methylbenzoyl)-phenoxy] Acetic Acid Hydrazide

Benzophenone analog 3 has been synthesized and characterized by the X-ray diffraction (XRD) method. The compound crystallizes in a monoclinic space group P2₁/c with cell parameters a = 7.701(8) Å, b = 7.151(5) Å, c= 28.323(3) Å, = 104.639(4)°, Z = 4. The structure exhibits intra- and intermolecular hydrogen bonding of the type N–HO, C–HO, and N–HN. The molecules are interlinked through hydrogen bonds forming an infinite chain. This polymeric-like structure may play an important role in biological activity.     

Evaluation of Incomplete Gamma Functions Using Downward Recursion and Analytical Relations

New downward recursion and analytical approaches are presented for the calculation of incomplete gamma functions (,x) and (,x). The efficiency of calculation with an adequate interval of these expressions is compared with those of other methods and great numerical stability and good rate of convergence is obtained for wide range of integral parameters. It is shown that the downward recursive relations are stable for all values of and x of (,x).     

Photoinduced Acylotropic Rearrangement of Crown-Containing 2-[N-Acetyl-N-(4-aminobenzo-15-crown-5)methylene]-2,3-dihydrobenzo[b]thiophen-3-one

2-N-(4-Aminobenzo-15-crown-5)methylene-2,3-dihydrobenzo[b]thiophen-3-one and its acetyl derivative were synthesized. Their treatment with lithium, sodium, or potassium iodide in acetonitrile solution leads to formation of the corresponding crown-metal complexes. Irradiation of the acylated compounds at 436 nm induces NO migration of the acetyl group to give O-acyl isomer which is characterized by a considerable blue shift of the long-wave absorption band ( = 70 nm). The quantum yields of the photo- induced acylotropic reaction for the free ligand and its complexes with alkali metal cations change in the series: _L > K⁺ > Na⁺ > Li⁺.     

Quantitative phase analysis from permeability versus temperature curves

The expressions for quantitative phase analysis from permeability versus temperature curves are discussed, and the results are illustrated by the determination of magnetic Co₂ Y remnants (2CoO·2BaO·6Fe₂O₃) in Co₂Z (2CoO·3BaO·12Fe₂O₃) samples. The method is well suited for the determination of small inclusions of a magnetic phase in a given magnetic material, in a range where X-ray methods become useless as a rule.

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Zusammenfassung Zwecks quantitativer Phasenuntersuchungen wird die Auswertung von Permeabilitäts-Temperatur Diagrammen näher beschrieben und die Ergebnisse mit der Bestimmung von magnetischen Co₂Y Resten (2CoO · 2BaO · 6Fe₂O₃) in Co₂Z (2CoO·3BaO·12Fe₂O₃) Proben illustriert. Diese Methode ist zur Bestimmung von geringen, mittels röntgenographischen Verfahren nicht feststellbaren magnetischen Phaseneinschlüssen in einem bestimmten magnetischen Material sehr geeignet.

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, Co₂Y (2CoO·2BaO·6Fe₂O₃) Co₂Z (2CoO·3BaO·12Fe₂O₃). , , , .

     

Kinetics of autoxidation of potassium O-butyl dithiocarbonate catalyzed by cobalt(II) tetrasulfophthalocyanine

Autoxidation kinetics of potassium O-butyl dithio-carbonate catalyzed by cobalt(II) tetrasulfophthalocyanine has been studied polarographically. The reaction follows two parallel pathways of zero and first order with respect to dioxygen, each being a Michaelis function of the substrate concentration. On the basic of data obtained and those reported previously for cysteine autoxidation, a general reaction mechanism is suggested.

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O- , - (II). , , . , , .

     

Paramagnetic products of [Ni (C4H6)2]n interaction with diethylaluminium chloride

ESR method has been used to identify metastable Ni⁺ complexes in toluene solution formed by the interaction of [Ni(C₄H₆)₂] with Et₂AlCl. Reversible changes in the ground state of Ni⁺ ions after the introduction of supplementary neutral ligands (PPh₃, C₂H₄) into the system have been established.

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Ni⁺ , [Ni (C₄H₆)₂]_n c Et₂AlCl. Ni⁺ (PPh₃, C₂H₄) .

     

Studies of the reactions of Br(2P3/2) and Br(2P1/2) with SiH4

Photobromination of SiH₄ under uv-irradiation at various wavelengths has been studied. Rate constants for the elementary reactions Br(²P_3/2)+SiH₄HBr+SiH₃ (k=3.2×10^–11 exp(–21.8±2.5)/RT, cm³/s) and Br^* (²P_1/2)+SiH₄HBr+SiH₃ (k^*=(3±1)×10^–13 cm³/s) have been determined in the temperature range from 300 to 415 K.

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- . Br(²P_3/2)+SiH₄HBr+SiH₃, k=3,2×10^–11 exp (–21,8±2,5)/RT ³/ Br^*(²P_1/2)+SiH₄HBr+SiH₃, k^*=(3±1)×10^{–13 3}/ 300–415 K.

     

Cobalt(II) and nickel(II) chloride and bromide complexes of 2-(2′-methyl-8′-quinolyl)benzoxazole and 2-(2′ or 4′-methyl 8′-quinolyl)benzimidazole

Summary Cobalt(II) and nickel(II) halide complexes of the ligands 2-(2-methyl-8-quinolyl)benzoxazole (mqbo), 2-(2-methyl8quinolyl)benzimidazole (mqbi) and 2-(4-methyl-8-quinolyl)benzimidazole (mqbi) were synthesized and characterized by analytical, thermogravimetric, conductivity and magnetic data, and i.r. and electronic spectra.The ligands are bidentate N-donors yielding complexes where the coordination geometry depends on the metal ion and steric hindrance. All the cobalt complexes have formula [CoL₂X₂] and distorted tetrahedral geometry. Different types of nickel compounds were obtained: i) complexes of formula NiLX₂ · n H₂O (or EtOH) (L = mqbo or mqbi; n=0–1.5) which arepseudo-tetrahedral or five-coordinate and ii) complexes NiL₂X₂ · n H₂O (L = mqbi, n=3 or 4) where the metal is bound to four nitrogen atoms and the overall coordination geometry is tetragonal. The structural changes occurring after removal of water or alcohol from the complexes are also reported.