Search

Complex ZnLCl2·EtOH·H2O (I) where L is chiral 9,9′-bi-4,5-diazafluorenylidene containing fragments of natural monoterpenoide (–)-α-pinene is synthesized. The crystal structure of I is composed of ZnLCl2 mononuclear complex, solvate EtOH, and H2O molecules. The coordination polyhedron Cl2N2 of the Zn atom is a distorted tetrahedron. L is a bidentate cyclic ligand, involving only two N atoms in the coordination. Complex I is characterized by IR and NMR spectroscopy and its thermal properties are analyzed. In the solid phase, L exhibits photoluminescence is the visible range (λmax = 610 nm).

PdL1,2Cl2·H2O (I, II) and CuL1Cl2·H2O (III) complexes (L1 and L2 are 1-terpenyl-3-thiosemicarbazides of pinane and para-menthane series, respectively) are obtained. Single crystals of complexes I and [PdL3Cl2] (IV) (L3 is the product of hydrochlorination of ligand L2) have been grown. According to XRD data, crystal structures of I, IV consist of complex cations [PdLCl]+ and outer-sphere anions Cl−. The coordination polyhedron N2SCl is a distorted square. L1 and L3 are tridentate ligands. Free ligands L1, L2 and complexes I-III are studied using IR spectroscopy; conclusions on the structure of the Cu(II) complex are inferred from the analysis of obtained data. Cytotoxic properties of L1, complexes I and III, as well as the carboplatin pharmaceutic are studied on the Hep2 (human larynx carcinoma) cell line. Complexes I and III are shown to be moderately cytotoxic: they are twice as less toxic with respect to Hep2 cells than carboplatin that is used in the experiment as the reference complex.

Complexes [Zn(L)Cl2] (I), Cu(L)Cl2 ∙ H2O (II), Zn(L1)Cl2 ∙ 0.5H2O (III), and Cu(L1)Cl2 ∙ 0.5H2O (IV) (where L and L1 are the diaminopropylene and diaminoethylene derivatives of deoxycholic acid, respectively) are synthesized. The structure of mononuclear complex I is determined by X-ray structure analysis (CIF file CCDC no. 1875305). The coordination polyhedron of the Zn atom (Cl2N2) is a distorted tetrahedron. According to the X-ray diffraction data, the crystals of compounds III and IV are isostructural. It is shown by IR spectroscopy that the structures of complexes II–IV are similar to that of complex I. In the solid phase, compounds L and L1 possess photoluminescence in the visible spectral range (λmax = 440 and 415 nm, respectively). Complex formation with Zn2+ ions does not change the photoluminescence properties of L and L1.

Complexes [Zn(L2)2Cl2], [Pd2(L2)2Cl4], and CuL2Cl, where L2 is (−)-camphor thiosemicarbazone, were synthesized. The structures of complexes [Zn(L2)2Cl2] and [Pd2(L2)2Cl4] were determined by X-ray diffraction. The crystal structure of complex [Zn(L2)2Cl2] contains mononuclear molecules with distorted tetrahedral {ZnCl2S2} coordination units and monodentate L2 ligands. Complex [Pd2(L2)2Cl4] has binuclear structure with Pd metal centers linked by L2 ligands via μ2-S atoms. Complex CuL2Cl, according to IR and NMR spectra contains S and Cl atoms in the coordination sphere of ion Cu+. Complexes [Pd(tsc)Cl2] and Zn(tsc)2Cl2 (where tsc is thiosemicarbazide) were also obtained to determine the influence of the terpene moiety on cytotoxic properties of these compounds. Mononuclear complex [Pd(tsc)Cl2] contains an NSCl2 planar square coordination polyhedron, and tsc is a bidentate chelate ligand. The effects of tsc, L2, and the complexes with tsc and L2 on viability of the MCF-7 cell line were investigated next. The results showed that tsc and L2 are nontoxic at the tested concentrations (1–50 μM). All the complexes exerted a significant dose-dependent cytotoxic effect, whereas complex CuL2Cl was found to have the lowest half-maximal inhibitory concentration (IC50).

Mononuclear zinc(ii) and cadmium(ii) complexes, ZnLCl2 (1), CdLCl2 (2), ZnL1Cl2·2H2O (3), and CdL1Cl2·2H2O (4), with chiral ligands containing a 2,2'-bipyridine moiety and natural terpene (+)-limonene (L) or (+)-3-carene (L1) moieties were synthesized. In these complexes the L and L1 ligands are shown to coordinate Zn2+ and Cd2+ ions through the 2,2'-bipyridine moiety. The acetamide group of the ligands interacts with M2+ ions by forming NM2+ and C[double bond, length as m-dash]OM2+ contacts and N-HCl hydrogen bonds with coordinated Cl- ions. In solutions the complexes have several conformers differing by the degree of the turn of the acetamide moiety relative to the ligand core and the type of its interaction with the coordination core. The ligands and complexes exhibit luminescence with the quantum yield increasing in the order: ligandcadmium(ii) complexzinc(ii) complex. The complexes 3 and 4 demostrate excitation wavelength independent single-channel fluorescence. As opposed to 3 and 4, the complexes 1 and 2 demonstrate excitation wavelength dependent emission with nanosecond and microsecond lifetimes of the excited states. According to our TD-DFT calculations, an interplay of ligand centered and halide to ligand transitions facilitates two deactivation channels in 1 and 2: S1-S0 and T1-S0.

New chiral 1,10-phenanthroline-derived ligands containing fragments of (+)-3-carene (L1) and (+)-limonene (L2) natural monoterpenoids and their complexes Zn(L1,2)Cl2·1.5H2O, Cd(L1,2)Cl2·nH2O, Zn(L1)Br2·2H2O, and Cd(L1)Br2·2H2O were synthesized. According to NMR and IR spectroscopy data, a conclusion was made about the polynuclear structure of the compounds obtained. Luminescent properties of the compounds obtained were investigated. Lifetimes of the excited states and luminescence quantum yields (φf) were determined. For free ligands, blue fluorescence was observed. In the case of Zn(II) and Cd(II) complexes, luminescence appeared in the green region of the spectrum.

The complex salt {[CuL2][Cu4I6]•MeCN}n (1) and the compound [Cu4L3I4]•3 MeCN (2) (L is a chiral ligand bearing a natural monoterpene (+)-3-carene moiety) were synthesized. The crystal structures of compounds 1 and 2 were determined by X-ray diffraction. The structure of compound 1 consists of complex cations [CuL2]2+ (N3O2 polyhedron is a trigonal bipyramid) and CuI coordination polymers (CuI4 polyhedron is a tetrahedron) as anions. The experimental magnetic moment μeff at 300 K is 1.90 μB, which is consistent with the X-ray diffraction data and the assumption that compound 1 is mixed-valence. The structure of compound 2 comprises a tetranuclear CuI complex, in which three Cu atoms are coordinated by two N atoms of the ligand L and two I atoms, and the fourth Cu atom is coordinated by four I atoms (coordination polyhedra are distorted tetrahedra). Compounds L and 2 were found to influence the viability of human laryngeal carcinoma cells (Hep2). The IC50 value for complex 2 (13.0±1.7 μM) is substantially smaller than IC50 for compound L (30.5±0.5 μM).

CuLCl, CuL1Cl, PdLCl2, and PdL1Cl2 complexes [L and L1 being (+)-camphor and (–)-carvone thiosemicarbazones, respectively] have been synthesized. The structure of binuclear [Pd2L22Cl4] complex has been determined by means of X-ray diffraction. The L2 ligand (dehydrogenated (–)-carvone thiosemicarbazone) is coordinated via the bridging S atom to two Pd atoms. The complexes of Cu(I) and Pd(II) presumably have polynuclear and binuclear structure, respectively. These facts are in good agreement with IR and NMR spectroscopy as well as mass spectrometry data which indicate the coordination of L and L1 ligands via the S atom. The influence of L1 and PdL1Cl2 on viability of the Hep2 cell line has been studied. The PdL1Cl2 complex is more cytotoxic than L1 ligand.

Complexes ZnLCl2 (I) and [CdLCl2] n (IV), where L is chiral bis-pyridine containing fragments of natural monoterpenoide (–)-α-pinene are synthesized. Single crystals of [ZnLCl2]·CH2Cl2 (II), [ZnLCl2]·i-PrOH (III), and IV compounds are grown. The crystal structures of II and III are composed of mononuclear ZnLCl2 complex molecules and solvate CH2Cl2 and i-PrOH molecules; the coordination polyhedron of the zinc atom Cl2N2 is a distorted tetrahedron. According to the single crystal XRD data, complex IV is a 1D coordination polymer; the coordination core CdN2Cl4 is a distorted octahedron and Cl atoms are bridging ligands. In the structures of II, III, and IV the L molecule functions as a bidentate chelate ligand. In the solid phase, complexes I and IV exhibit photoluminescence in the visible range (λmax 505 nm and 460 nm respectively). The band intensity in the photoluminescence spectra of I and IV complexes considerably exceeds the band intensity in the spectrum of free L.

Complexes Pd(LH)Cl2 (LH is the N-derivative of β-alanine based on (–)-α-pinene) and PdLEtCl2 (LEt is ethyl ester of LH) are synthesized. The X-ray diffraction analysis (СIF file ССDC no. 1471432) shows that the single crystals of the [PdLEtCl2] complex belong to the racemate. The crystal structure contains (+)- and (–)-enantiomeric molecules of the mononuclear complex. Ligand LEt is bidentate chelating. The coordination PdCl2N2 core is a distorted square. The contacts Pd…Cl and hydrogen bonds N–H…Cl between molecules of the (+)- and (–)-enantiomers result in the formation of dimeric ensembles, which are joined into chains due to the C–H…Cl hydrogen bonds. According to the X-ray powder diffraction data, the products of the synthesis of complex [PdLEtCl2] contain both the racemate and (+)-enantiomer. The (+)-enantiomer is isolated by the recrystallization of the synthesis product. Complex Pd(LH)Cl2 is an optically active right-handed compound. According to the NMR data, complex PdLEtCl2 does not dissociate in a CDCl3 solution. The results of IR and NMR spectroscopy indicate that the molecular structure of complex Pd(LH)Cl2 is similar to that of [PdLEtCl2].

Mononuclear and dinuclear zinc(II) and cadmium(II) complexes, [ZnLCl2] (1) and [Cd2L2Cl4] (2), with a chiral pentacyclic dihydrophenanthroline ligand L bearing a natural monoterpene (–)-α-pinene fragment were synthesized. DFT calculations of the specific rotation [α] and an NMR study show that the molecules of ligand L, complex 1 and the monomeric form of complex 2 exist in CDCl3 solutions with the P-helix conformation for the dihydrophenanthroline moiety. The dihydrophenanthroline fragments of L and mononuclear complex 1 also exists as a P-helix in the solid state, whereas the crystalline dinuclear complex 2 exists as an asymmetric dimer, [Cd2Cl4LPLM], where LP and LM are the ligand with P-helix and M-helix conformations of the dihydrophenanthroline fragment respectively. Full sets of photophysical parameters for L and complexes 1 and 2 have been determined. Compounds L, 1 and 2 display blue luminescence (λmax = 427, 405 and 415 nm in the solid state, respectively). The ligand L and complex 2 show moderate-to high quantum yields of 44% and 24%, respectively. The quantum yield for complex 1 is 6%. The emission lifetimes increase on going along the spectrum of luminescence, and in the deep red region, a rise of luminescence with times of 200–500 ps is observed. These processes can be explained by the migration of excitons and the capture of excitation by “defective” centers.

The complexes [Cu(HL)Cl] · 0.25H2O (I), [Cu(HL1)Cl] · 0.5H2O (II), [Ag(HL)] · 0.5H2O (III) were obtained; HL– and (HL1)– are the anions of the chiral N-substituted aminoacetic acid derivatives containing the natural monoterpenes (+)-3-carene and (–)-α-pinene, respectively. The µeff values for paramagnetic complexes I and II are 1.92 and 1.81 µB, respectively. Single crystals of the coordination 1D polymer [Cu(HL)Cl · 2H2O]n (IV) were grown. According to the X-ray diffraction data (CIF file CCDC No. 1035219), the crystal structure of complex IV is made up of the zigzag chains [Cu(HL)Cl]n and water molecules. The coordination polyhedron of the Cu atom is a distorted square pyramid (ClN2O2). The anion HL– acts as a chelating and bridging tetradentate ligand coordinated through the N atoms of the NH and NOH groups as well as through the O atoms of the COO–groups linking two adjacent Cu atoms together. The IR spectra of complexes I and II also provide evidence for the coordination of the functional COO–, NOH, and NH groups. In complex III, the coordination sphere of the Ag atom is made up of the O atoms of the COO–group. Complex III shows weak green photoluminescence (λmax = 530 nm).

The complex of the composition [Pd2(H2L1)Cl4] (I) (H2L1 is a chiral bis-α-sulfanyl oxime, a derivative of natural monoterpenoid (+)-3-carene) is synthesized. Single crystals of I and solvate [Pd2(H2L1)Cl4]•0.5CH2Cl2 (II) are grown. According to the X-ray crystallographic data, the crystal structure of I consists of acentric molecules of the binuclear [Pd2(H2L1)Cl4] complex. The structure of solvate II consists of the molecules of binuclear complex I and CH2Cl2 molecules. The PdCl2NS coordination sites are distorted squares (trapezia). In the structures of I and II, the PdCl2 fragments are in the transoid position. In I, the Cl2NS planes of the two coordination sites are nearly parallel (the angle between the planes is 7.7(1)°). The similar angle in solvate II is 22.0(1)°.

The complex Pd(HL)Cl2 (I) was obtained (HL is the anthracene-containing chiral α-amino oxime derived from the natural monoterpenoid (+)-3-carene). Single crystals of its solvate [Pd(HL)Cl2] · 0.33EtOH (II) were grown. According to X-ray diffraction data (CIF file CCDC no. 1008947), the crystals are built from mononuclear molecules of complex I and uncoordinated EtOH molecules. The coordination environment of the Pd atom in complex I (PdCl2N2) makes up a distorted square (trapezoid). The compound HL acts as a chelating bidentate ligand. The [Pd(HL)Cl2] and EtOH molecules are united into chains through weak hydrogen bonds. The photoluminescence (PL) of HL and the system ZnCl2-HL in acetonitrile was studied. The emission spectra show three bands at 394, 415, and 440 nm. The photoluminescence of the system ZnCl2-HL in solution is more intense than that of HL. A study of the system ZnCl2-HL by the molar ratio method in conjunction with emission spectroscopy suggests the formation of the complex Zn(HL)Cl2 in acetonitrile.

Five compounds of the composition Ln(2,2′-Bipy)(C4H8NCS2)3 · 0.5CH2Cl2 (Ln = Sm (I), Eu (II), Tb (III), Dy (IV), and Tm (V); 2,2′-Bipy = 2,2′-bipyridine) are synthesized. According to the X-ray diffraction data (CIF file CCDC 986259), the crystal structure of compound I consists of molecules of the mononuclear complex [Sm(2,2′-Bipy)(C4H8NCS2)3] and solvate molecules CH2Cl2 (2 : 1). The coordination polyhedron N2S6 of the Sm atom is a distorted tetragonal antiprism. The X-ray diffraction analysis shows that compounds I–V are isostructural. The magnetic properties of compounds I–V are analyzed in the temperature range from 2 to 300 K. At 300 K compounds I and III are photoluminescent in the visible spectral range. The photoluminescence intensity of compound I considerably exceeds that of complex III.

The [ZnLCl2] (1) and Cd2L2Cl4 (2) complexes, where L is ethyl 2-methyl-5-(prop-1-en-2-yl)pyrido[2,3-a]phenazine-3-carboxylate, were synthesized. The complexes were characterized by elemental analyses, 1H and 13C NMR spectroscopy, and X-ray powder diffraction. Single crystals of 1 and [Cd2L2Cl4]·4CH2Cl2 (3) have been grown. The structure of 1 consists of mononuclear molecules, while the structure of 3 is built up of centrosymmetrical binuclear [Cd2L2Cl4] complex molecules and uncoordinated CH2Cl2 molecules. In 1 and 3, L acts as a bidentate chelating ligand. There is five-membered ZnN2C2 chelate cycle in the [ZnLCl2] molecule. There are two five-membered CdN2C2 chelate cycles and a Cd2Cl2 dinuclear unit in the molecule of [Cd2L2Cl4]. The coordination polyhedra are distorted tetrahedron Cl2N2 (in the structure 1) and distorted tetragonal pyramid Cl3N2 (in the structure of 3). According to IR-spectroscopic data, complex 2 is binuclear. Complexes 1 and 2 display bright luminescence in CHCl3 solutions (λmax = 477 and 475 nm, respectively) and in the solid state (λmax = 510 and 529 nm, respectively). The free L ligand shows weak luminescence intensity (λmax = 441 and 467 nm in CHCl3 and solid state, respectively).

A heteroligand complex [Sm(Biq)(iso-Bu2PS2)3]n (Biq = 6,6′-biquinoline) is synthesized. According to the X-ray diffraction data, the complex is one-dimensional coordination polymer. The crystal structure is built of chains consisting of fragments Sm(iso-Bu2PS2)3 and molecules of the bidentate-bridging ligand Biq. The coordination polyhedron N2S6 of the Sm atom is a distorted tetragonal antiprism. The complex exhibits red photoluminescence (λmax = 562, 598, 642, and 703 nm).

It is found that diffraction patterns of complexes I–V of the composition [Ln(Phen)(C4H8NCS2)3] (Ln = Sm, Eu, Tb, Dy, and Tm respectively) are similar. Single crystals of [Dy(Phen)(C4H8NCS2)3]·3CH2Cl2 (VI) obtained are. According to the X-ray crystallographic data, in the structure of VI the unit cell contains two crystallographically independent molecules of the [Dy(Phen)(C4H8NCS2)3] complex and six CH2Cl2 molecules. The N2S6 coordination polyhedron of the Dy atom is a distorted square antiprism. In the range of 2–300 K the magnetic properties of complexes I–V are studied. It is found that complex III passes to the magnetically ordered state; the spontaneous magnetization at 2 K is 24 600 G·cm3/mol. At 300 K compounds I–IV exhibit photoluminescence in the visible spectral range. It is found that the photoluminescence intensity of complex I is several times higher than the photoluminescence intensity of complexes II–IV.

3-(2-Methoxyphenylamino)caran-4-one and 2-(2-methoxyphenylamino)pinan-3-one E-oximes obtained from appropriate natural terpenes were transformed into 1: 1 complexes with PdCl2. The structures of the complexes were examined by X-ray diffraction.

Heteroligand complexes Tm(L)(iso-Bu2PS2)2(NO3) (L = 2,2′-Bipy (II), Phen (III)) are synthesized. According to the X-ray phase analysis data, complex III is isostructural to mononuclear compound [Dy(Phen)(iso-Bu2PS2)2(NO3)] including, according to the X-ray diffraction data, a coordination polyhedron DyN2O2S4 (distorted dodecahedron). Single crystals of compounds [Ln(2,2′-Bipy)(iso-Bu2PS2)2(NO3)] · C6H6 (Ln = Tm (IV), Tb (V)) are obtained. An X-ray diffraction analysis shows that the crystal structures of these isostructural compounds are formed by molecules of mononuclear complexes [Ln(2,2′-Bipy)(iso-Bu2PS2)2(NO3) and uncoordinated C6H6 molecules. In complexes IV and V, the ligands [Ln(2,2′-Bipy)(iso-Bu2PS 2 − , and NO 3 − are bidentate-cyclic. The coordination polyhedron LnN2O2S4 is a distorted dodecahedron. Complexes II and III possess photoluminescence in the visible spectral range (λmax = 478 and 477 nm, respectively).

The optically active complexes [Zn(L)2Cl2] (I) and [Zn(L1)2Cl2] (II) (L and L1 are thiosemicar-bazones of (+)-camphor and (−)-carvone, respectively) were obtained. The crystal structures of L and complex I were determined by X-ray diffraction. The structure of L consists of hydrogen-bonded molecules united into chains. The crystal structure of complex I is built from mononuclear molecules. The coordination polyhedron of the Zn atom is a distorted tetrahedron Cl2S2. The molecule L functions as a monodentate ligand. According to data from IR spectroscopy, complex II is structurally similar to complex I.

Coordination compounds Pd2(H2L2)Cl4 (I), Cu2(H2L2)Cl4 (II), Pd2(H2L3)Cl4 (III), and Cu2(H2L3)Cl4 (IV), where H2L2 and H2L3 are chiral bis-α-aminooxime ligands consisting of (+)-3-carene or (+)-limonene fragments and 4,4′-methylenedianiline linker, were synthesized and examined by NMR, ESR, and IR spectroscopy. The structure of [Cu(i-PrOH)CL2(μ-H2L3)CuCL2·H2O] (V) was determined by X-ray analysis.

The photoluminescence spectra of the known complexes, Sm(L)2(NO3)3 (I, II), Sm(L)(iso-Bu2PS2)3 (III, IV), Sm(L)(iso-Bu2PS2)2(NO3) (V, VI) (L = Phen, 2,2′-Bipy), and Sm(Phen)(C4H8NCS2)3 (VIII), and new compounds, Sm(Phen)((iso-PrO)2PS2)3 (VII), Sm(2,2′-Bipy)(C4H8NCS2)3 · 0.5CH2Cl2 (IX), are obtained and interpreted. Using the X-ray structure analysis data, the crystal structure of the [Sm(2,2′-Bipy)2(NO3)3] complex (II) is determined. Structure II consists of discrete mononuclear molecules having a ten-vertex coordination polyhedron N4O6. The ligands 2,2′-Bipy and NO 3 − are bidentate-cyclic. The influence of the composition of the complexes on the photoluminescence (PL) intensity in the series I–VI is considered. The dependence of the intensity of the band with λmax = 647 nm in the PL spectra of complexes III, VII, and VIII on the type of the sulfur-containing ligand in their composition is established. The band intensity changes in the series VIII > III > VII.

Heteroligand complexes Ln(L)(iso-Bu2PS2)2(NO3) (Ln = Sm, Tb, Dy; L = Phen, 2,2′-Bipy) (I–VI) are synthesized. The structure of Dy(Phen)(iso-Bu2PS2)2(NO3) (III) is determined from the data of X-ray structure analysis. The crystal structure of complex III is based on discrete mononuclear molecules in which the Dy atom has distorted dodecahedral coordination (polyhedron N2O2S4). The ligands Phen, iso-Bu2PS 2 − and NO 3 − are bidentate-cyclic. According to the X-ray diffraction analysis data, complexes I and II are isostructural to compound III. Complexes I–VI have photoluminescence in the visible spectral range. The photoluminescence spectra of solid samples of compounds I–VI exhibit bands corresponding to the radiative electron transitions of the Sm3+, Tb3+, and Dy3+ ions. Among the studied compounds I–VI, the Tb(III) complexes are characterized by the most intense photoluminescence.

Chiral sodium salts of N-derivatives of aminoacetic acid based on (+)-3-carene (HLNa) and (−)-α-pinene (HLNa) were synthesized. Complexes Zn(HL)Cl (1), Cd(HL)Cl·0.5H2O (3), Zn(HL′)Cl·0.5H2O (4), and Cd(HL′)Cl·0.5H2O (5) were obtained. The single crystals of the coordination polymer [Zn(HL)Cl·2H2O]n (2) were grown. According to the X-ray diffraction analysis, the crystal structure of 2 consists of 1D chains built of Zn(HL)Cl and water molecules. The coordination polyhedron ClN2O2 is a distorted square pyramid. The HL− ligand performs the chelating tetradentate-bridging function, and the COO− group binds two adjacent Zn atoms. The IR spectroscopy data for compounds 1 and 3–5 indicate the coordination of the COO−, NOH, and NH functional groups. The excitation and photoluminescence (PLM) spectra of the solid samples of compounds HLNa, HL’Na, 1, and 3–5 were recorded at room temperature. The compounds exhibit blue PLM. The intensity of PLM of the CdII complexes is higher than that of the ZnII complexes, which is a characteristic feature of PLM of the studied compounds.

Coordination compounds Cu2(H2L1)Cl4 (I), Pd2(H2L1)Cl4 (II), Cu2(H2L2)Cl4 (III), and Pd2(H2L2) Cl4 (IV) with chiral bis-α-sulfanyloximes, the derivatives of the monoterpenoid (−)-α-pinene, were obtained. The complexes I and III are paramagnetic (μeff = 2.45 and 2.67 μB, respectively), II and IV are diamagnetic. According to IR spectroscopy, in the compounds I–IV the nearest environment of Cu and Pd atoms includes N, S, and Cl atoms. The values of μeff and parameters of ESR spectra of the solid phase and solutions of I and III show a binuclear structure of the Cu(II) complexes. Parameters of the 1H and 13C NMR spectra of compounds II and IV indicate the formation of binuclear Pd(II) complexes of C2 symmetry and the closure of fivemembered chelate rings PdNSC2. The PdCl2 fragments are in transoid position. H2L1 and H2L2 are tetradentate bridging chelating ligands.

3,5-Dimethyl-1H-pyrazolide of 3-O-acetyl ursolic acid (II) is obtained in the course of the interaction of 3 O-acetyl ursolic acid acyl chloride (I) and 3,5-dimethyl-1H-pyrazole. The crystal structure of compound II is determined from the single crystal XRD data (150 K, Bruker X8 Apex CCD autodiffractometer, MoKα radiation). The crystals are rhombic, the unit cell parameters are as follows: a = 10.6034(2) A, b = 12.4096(2)A, c = 24.5972(5)A, P212121 space group. The structure consists of discrete acentric molecules. When pyrazolide II is boiled in the alcohol alkali solution, secondary hydroxyl is deacetylated and 3,5-dimethyl-1H-pyrazolide of ursolic acid IV is formed. Compounds II and IV are studied by NMR spectroscopy.

It is revealed that at 300 K Sm(Phen)(i-Bu2PS2)3 (I) and Sm(2,2′-Bipy)(i-Bu2PS2)3 (II) complexes have photoluminescence properties typical of the Sm3+ ion. In the spectra, three bands are observed with 7nmax = 564 nm, 600 nm, and 645 nm. Single crystals of Sm(Phen)(i-Bu2PS2)3·MeCN (III) are grown, and the structure of the compound is determined based on the X-ray diffraction data (X8 Apex diffractometer, MoK6h radiation, 7685 F hkl, R = 0.0258). Crystals of III are triclinic, unit cell parameters are a = 11.0554(3) A, b = 15.0446(3)A, c= 15.4849(4)A; 6h = 89.218(1)°, β = 75.555(1)°, γ = 73.484(1)°, V= 2386.6(1)A3, Z=2, ρcalc = 1.391 g/cm3, P1 space group. The structure of III is formed from the molecules of mononuclear complex I and MeCN molecules. A coordination polyhedron of the Sm atom is an N2S6 tetragonal antiprism. It is shown that the structure of III includes dimeric assemblies of the molecules of complex I.

The thermal behaviors of the chelate Ni(iso-Bu2PS2)2 (I) and the mixed-ligand complexes Ni(2,2′-Bipy)(iso-Bu2PS2)2 (II) and Ni(Phen)(iso-Bu2PS2)2 (III) in air are reported. These compounds can pass into the gas phase, as was demonstrated by vacuum sublimation for I and by vacuum distillation for II and III in a gradient furnace. The mass spectra of I–III are presented and discussed. The temperature dependence of the saturation vapor pressure over I and ΔHT0 and ΔST0 and of evaporation of I determined by the vapor transport method are reported.

A reaction of CuCl2 with a chiral Schiff base (H2L) derived from (+)-6h-pinene leads to paramagnetic complex Cu(HL)Cl (1) (fueff = 2.03 fuB) and solvate Cu(HL)Cl•MeCN (2) (fueff = 1.87 fuB). Monocrystals of hydrate [Cu(HL)Cl]•H2O (3) were grown for the X-ray diffraction study, which showed that the crystal structure of 3 consists of the molecules of a mononuclear complex [Cu(HL)Cl] containing tridentate chelating ligand HL—, and water molecules. Coordination polyhedron ClNO2 is a distorted tetrahedron. Intermolecular con- tacts in the structure 3 lead to the formation of supramolecular chains, parallel to the axis -6h. Compounds 1 and 2 were studied by ESR and IR spectroscopy.

The reaction of Cu(II) complex with 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotet-radeca-4,11-diene (L) and iso-Bu2PS2− or iso-BuOCS2− anions gave stable paramagnetic compounds [CuL](iso-Bu2PS2)2 (I) (μeff = 1.77 μB) and [CuL](iso-BuOCS2)2 (II) (μeff = 1.76 μB). According to X-ray diffraction, the crystal structure of I is composed of discrete centrosymmetric complex cations [CuL]2+ and iso-Bu2Ps2− anions. The CuN4 coordination unit is a square. The Cu...S distance (iso-Bu2PS2−) equal to 3.047 A attests to possible S-coordination. Compounds I and II were studied by EPR.

Heteroligand complexes [Co2(HMTA)(iso-Bu2PS2)4] (I) (μeff = 4.67 μB) and [Cd2(HMTA)(iso-Bu2PS2)4] (II) have been synthesized. Single crystals of compounds I and II have been obtained. The crystals are monoclinic: a = 32.622(2) A, b = 9.4891(6) A, c = 21.7570(13) A, β = 125.774(1)o, V = 5464.3(6) A,3, Z = 4, ρcalcd = 1.331 g/cm3 for I; a = 34.6092(7) A, b = 9.5595(2) A, c = 22.3473(5) A, β = 127.144(1)o, V = 5893.5(2) A, Z = 4, ρcalcd = 1.355 g/cm3 for II; space group for both complexes C2/c. Structures I and II are based on discrete binuclear molecules. The coordination polyhedra of the Co and Cd atoms are distorted tetragonal pyramids NS4, with the bases formed by four S atoms of two bidentate chelating ligand iso-Bu2PS2− and the axial vertices occupied by N atoms of bidentate bridging HMTA ligand. The character of interaction of the molecules in structures I and II is considered.

The Cu2LCl4 complex (I) with chiral bis{(E)-[(1S,4R)-Δ7,8-1-amino-2-para-menthalidene]aminohydroxy} methane (L — a derivative of natural monoterpenoid (R)-(+)-limonene) is synthesized. The crystal structure of the solvate of complex I[Cu(L)(μ-Cl)CuCl3] · iso-PrOH (II) is determined by X-ray diffraction analysis. Structure II is based on molecules of the [Cu(L)(μ-Cl)CuCl3] binuclear complexes in which L is the tetradentate cycleforming ligand. One Cl atom manifests the bridging function. The CuN4 Cl coordination unit is a square pyramid, and CuCl4 is a distorted tetrahedron. The iso-PrOH molecules are localized in cavities between the layers of structure II. The μeff value for complex I is 2.56 μB and indicates the absence of an appreciable interaction between the Cu2+ ions in the Cu(II)-Cl-Cu(II) exchange cluster. The compound CuLCl2· H2O (III) is synthesized. The μeff value for compound III is 1.6 μB. Complexes I and III are studied by EPR and IR spectroscopy.

The complex [Fe(Phen)3][iso-Bu2PS2)2 (I) was synthesized and the single crystals of [Fe(Phen)3](iso-Bu2PS2)2 · 5H2O (II) were grown. The disulfan {iso-Bu2P(S)S}2 (III) was isolated. Compound II consists of the complex cations [Fe(Phen)3]2+, the outer-sphere anions iso-Bu2PS2−, and the molecules of water of crystallization. The coordination polyhedron of the Fe atom is a distorted N6 octahedron. Complex I is diamagnetic, and thus, the full spin of the Fe2+ ion S = 0. The structure of III is built of the molecules containing the S-S bridge 2.061(1) A in length.

Heteroligand complexes [Pb(Phen)2(iso-Bu2PS2)2] (I) and [Pb(4,4′-Bipy(iso-Bu2PS2)2] n (II) were synthesized, and their crystal structures were determined. The crystals of complex I are monoclinic: a = 17.2011(9) A, b = 14.1695(7) A, c = 19.8727(12) A; β = 115.644(1)°, V = 4366.5(4) A3, Z = 4, ρcalcd = 1.500 g/cm3, space group C2/c. The crystals of complex II are triclinic: a = 11.9283(2)A, b = 12.3814(2) A, c = 14.0917(3) A; α = 74.705(1)°, β = 87.240(1)°, γ = 61.448(1)°, V = 1755.86(6) A3, Z = 2, ρcalcd = 1.479 g/cm3, space group P $$ \bar 1 $$ . The structure of complex I consists of mononuclear molecules. The coordination polyhedron of the Pb atom is a distorted tetragonal antiprism N4S4 formed by the bidentate chelating ligands Phen and iso-Bu2PS 2 − . Continuous zigzag ribbons along the c axis are formed through contacts of the peripheral atoms of the Phen molecules of the adjacent complexes. Polynuclear complex II has a chain structure. The coordination polyhedron of the Pb atom is a distorted octahedron N2S4 formed by the bidentate chelating iso-Bu2PS 2 − ligands and bidentate bridging 4,4′-Bipy molecules. Short intermolecular contacts between the Pb and S atoms of the adjacent chains in structure II result in the formation of supramolecular two-chain assemblies as volume columns parallel to the b axis. The environment of the Pb atoms in the assembly is formed by pentagonal bipyramids N2S4 + 1.

The paramagnetic complex Cu(HL)Cl2(I) (μeff = 1.88 μB) and the diamagnetic complex Pd(HL)Cl2(II) with chiral α-thiooxime, a derivative of natural terpenoid (−)-α-pinene (HL), were synthesized. The crystal structures of these complexes were determined from single-crystal X-ray diffraction data (X8 APEX diffractometer, MoK α radiation, 2975 F hkl , R = 0.0258 for I and 3270 F hkl , R = 0.0222 for II). The crystals of complex I are monoclinic, a = 9.3376(3) A, b = 6.8619(2) A, c = 14.6540(5) A, β = 97.814(1)°, V = 930.22(5) A3, Z = 2, ρcalc = 1.513 g/cm3, space group P21. The crystals of complex II are orthorhombic, a = 7.0084(6) A, b = 9.2113(9) A, c = 29.081(3) A, V = 1877.4(3) A3, Z = 4, ρcalc = 1.651 g/cm3, space group P212121. The structures are composed of mononuclear molecules. The coordination cores MNSCl2 (M = Cu, Pd) are tetrahedrally distorted squares. According to NMR data, complex II has a similar structure in a CDCl3 solution. The intermolecular contacts in structure I generate supramolecular polymeric ribbons lying parallel to axis b. No short intermolecular contacts are present in complex II.

Diamagnetic Pd(II) complexes with the chiral ethylenediaminodioxime (H 2 L) and bis-α-thiooxime (H2L1), the derivatives of monoterpenoid (+)-3-carene, of the composition Pd2(H2L)Cl4(I), Pd2(H2L1)Cl4 (II), and the solvate Pd2(H2L1)Cl4·3DCl3 (III) were synthesized. The crystal structures of complex I and solvate III were determined from X-ray diffraction data. The structures consist of acentric binuclear molecules with the coordination cores PdN2Cl2 (in I) and PdNSCl2 (in III) in the form of the distorted squares. In complex I, each Pd atom coordinates two N atoms of the tetradentate bridge-cyclic ligand H2L and two Cl atoms; in compound III, one N and one S atom of the tetradentate bridge-cyclic ligand H2L1, and 2 Cl atoms. The CDCl3 molecules in compound III lie in the cavities formed by the molecules of complex II. In both structures, the PdCl2 fragments are in the trans-positions. The 1H NMR spectra indicate that the structures of complexes I, II in solutions are similar to the structures of compounds I, III in the solid state.

Mixed-ligand complex compounds [Pb(Phen)(i-Bu2PS2)]2 (I) and [Pb(2,2′-Bipy)(i-Bu2PS2)]2 (II) were synthesized. Their structures were determined from X-ray diffraction data (X8 APEX diffractometer, MoK α radiation, 6392 Fhkl , R = 0.0233 for I and 3937 F hkl , R = 0.0252 for II). Crystals I are triclinic: a = 10.2662(3) A, b = 12.3037(2) A, c = 14.8444(4) A; α = 92.054(1)°, β = 103.473(1)°, γ = 105.561(1)°, V = 1746.89(8) A3, Z = 2, ρcalc = 1.532 g/cm3, space group P $$\bar 1$$ . Crystals II are monoclinic: a = 9.3462(3) A, b = 26.3310(12) A, c = 28.5345(13) A; β = 96.436(1)°, V = 6977.9(5) A3, Z = 8, ρcalc = 1.489 g/cm3, space group P21/n. The structures are built from mononuclear molecules. In both structures, the intermolecular contacts between the Pb and S atoms of the neighboring mononuclear molecules form supramolecular assemblies involving two molecules. The environment of the Pb atoms in the assemblies is a pentagonal bipyramid, N2S4+1. The assemblies are joined into ribbons by π-π interactions of the Phen rings in I and C…C short contacts between the pyridine rings in II.

A chelate compound Pb[(iso-C4H9)2PS2]2 is synthesized. Using X-ray diffraction data, the crystal structures of two modifications of this compound are determined (X8 APEX diffractometer, MoK α radiation, 14169 F hkl , R = 0.0480 for the low temperature α-form and 6261 F hkl , R = 0.0387 for the β-form studied at ambient temperature). The crystals are triclinic: a = 11.047(2) A, b = 14.486(3) A, c = 32.048(6) A; α = 91.30(3)°, β = 99.73(3)°, γ = 101.61(3)°, V = 4942.9(17) A3, Z = 8, ρcalc = 1.682 g/cm3 (α-modification) and a = 11.2124(5) A, b = 14.6989(7) A, c = 17.1644(6) A; α = 109.393(1)°, β = 94.989(2)°, γ = 101.649(1)°, V = 2576.83(19) A3, Z = 4, ρcalc = 1.613 g/cm3 (β-modification), space group $$P\bar 1$$ for both polymorphs. The structures are molecular, coordination cores of PbS4 are tetragonal pyramids with Pb atoms in the vertices and S atoms in the base. In both structures intermolecular Pb...S contacts yield supramolecular ensembles comprising by four molecules, where PbS4+2 cores form planar aggregates of edge-sharing octahedra. The ensembles are joined by weak intermolecular S...S interactions resulting in the development of polymeric chains along the a axis.

Chiral bis-α-thiooxime (H2L1), the derivative of the natural monoterpenoid (+)-3-carene, was synthesized and used to prepare paramagnetic complexes of the composition M(H2L1)Cl2 (M=Ni, Cu). The crystal structures of [Ni(H2L1)Cl2] (I) and [Cu(H2L1)Cl2] (II) were determined by X-ray diffraction analysis. Crystals I and II consist of mononuclear acentric molecules. The Ni2+ ion in a molecule of complex I coordinates two N atoms and two S atoms of a tetradentate chelating ligand (the H2L1 molecule) and two Cl atoms. The NiCl2N2S2 coordination core forms octahedron compressed along the apical N atoms. In a molecule of complex II, the Cu2+ ion coordinates two S atoms and the N atom of a tridentate chelating H2L1 ligand and two Cl atoms. The CuCl2NS2 coordination core forms a trigonal bipyramid.

A paramagnetic (µef = 3.86 BM) complex Cr(i-Bu2PS2)3 (I) has been synthesized. Single crystals I were grown, and the crystal structure of the compound was determined from X-ray diffraction data (X8 APEX diffractometer, MoK α radiation, 4516 F hkl , R = 0.0604). Monoclinic crystals, space group P21/n, unit cell parameters a = 14.2665(5) A, b = 11.4400(4) A, c = 23.1299(8) A, β = 90.245(1)°, V = 3775.0(2) A3, Z = 4, d calc = 1.196 g/cm3. The structure is based on discrete mononuclear molecules. The coordination polyhedron of the Cr atom is a distorted S6 octahedron formed from the S atoms of three cyclic bidentate ligands — i-Bu2PS 2 − ions. Electron spectroscopy data correspond to the octahedral structure of the CrS6 chromophore.

The interaction of the Co(iso-Bu2PS2)2 chelate with 4-NH2Py afforded a paramagnetic complex [Co(4-NH2Py)(iso-Bu2PS2)2] (µeff = 4.53 BM). Single crystals of [Ni(4-NH2Py)2(iso-Bu2PS2)2] (I) and [Co(4-NH2Py)(iso-Bu2PS2)2] (II) were grown and used for X-ray diffraction investigation (X8 APEX diffractometer, MoKα radiation). Crystals I are monoclinic with unit cell parameters a = 12.5336(5) A, b = 9.4356(4) A, c = 16.4095(6) A; β = 111.351(1)°; V = 1807.4(1) A3; Z = 2, ρ = 1.223 g/cm3, space group P21/n. Crystals II are triclinic with unit cell parameters a = 8.7572(4) A, b = 9.6934(6) A, c = 18.665(1) A; α = 79.374(2)°, β = 87.049(2)°, γ = 75.640(2)°; V = 1508.6(1) A3; Z = 2, ρ = 1.259 g/cm3; space group \(P\bar 1\). The structures of I and II are formed by isolated mononuclear molecules. The coordination unit is NiN2S4 (octahedron) in I and CoNS4 (tetragonal pyramid) in II. The 4-NH2Py molecule is coordinated through the N atom of the heterocycle. Electronic spectroscopy data for II agree with the symmetry of the NS4 polyhedron found by X-ray diffraction (XRD) analysis. The noncoordinated amine groups link the complex molecules via N-H...S hydrogen bonds.

Single crystals of a mononuclear mixed-ligand complex [Mn(Phen)(i-Bu2PS2)2] were grown and used for X-ray diffraction structural study of the material (diffractometer CAD-4, MoK α -radiation, 1205 F hkl , R = 0.0351). The crystals are monoclinic: a = 15.602(2) A, b = 20.914(3) A, c = 11.419(2) A; β = 111.36(1)°, V = 3470.1(9) A3, Z = 4, ρ(calc) = 1.251 g/cm3, space group P21/c. Coordination polyhedron of Mn is a distorted octahedron N2S4. Molecular and crystal structures of mixed-ligand coordination compounds ML(i-Bu2PS2)2 (M= Zn, Cd, Mn, Co, Ni; L = Phen, 2,2′-Bipy) are considered on the basis of XRD data (automated diffractometers CAD-4 and X8-APEX). The analysis of intermolecular distances in the structures of ten mixed-ligand coordination compounds revealed in nine of them the presence of short contacts made by carbon atoms of the N-heterocycles. These contacts correspond to π-π interactions of Phen or 2,2′-Bipy molecules of two neighboring complexes giving rise to dimeric molecular ensembles.

Crystal structures of chelate compounds Ni[(iso-C4H9)2PS2]2 (I) and Pd[(iso-C4H9)2PS2]2 (II) have been determined by X-ray diffraction: diffractometer X8-APEX, MoK α∔ -radiation, 1048 F hkl , R = 0.0544 for I and CAD-4 diffractometer, MoK α∔ -radiation, 1283 F hkl , R = 0.0347 for II. The crystals are rhombic: a = 12.921(5) A, b = 17.094(5) A, c = 22.971(5) A; V = 5074(3) A3, Z = 8, calc = 1.250 g/cm3, space group Pbca for I and a = 13.312(3) A, b = 16.130(7) A, c = 23.171(5) A; V = 4975(3) A3, Z = 8, ρcalc = 1. 208 g/cm3, space group Pbca for II. The structures of I and II are formed by discrete mononuclear molecules. Coordination cores MS4 (M = Ni, Pd) approach planar square configurations.

X-ray photoelectron and voltammetry studies of the charged state of the metal atom in nickel(II) chelate complexes with ligands containing CS 2 − and PS 2 − groups and in heteroligand complexes on their basis were carried out. It is shown that the degree of formal oxidation of the nickel atom in the complexes corresponds to Ni(II). In the case of heteroligand complexes, addition of nitrogen heterocycles causes an increase in the electron density on the atoms of the coordination center. Theoretical data obtained in ab initio quantum chemical model calculations correlate with the experimental results.

Mixed-ligand complexes [Ni(4-NH2Py) (i-Bu2PS2)2] (I) and Ni(4-NH2Py)2(i-Bu2PS2)2 (II) have been synthesized. Single crystals were grown and X-ray diffraction data (CAD-4 diffractometer, MoK α radiation, 1477 F hkl , R = 0.0320) were used to determine the structure of I. The crystals are orthorhombic: a = 10.675(1) A; b = 21.681(2) A; c = 26.302(4) A, V = 6087.5(12) A3, Z = 8, ρ(calc) = 1.247 g/cm3, space group Pbca. Complex I possesses a mononuclear molecular structure. The coordination polyhedron of the Ni atom is a tetragonal pyramid NS4 whose base is formed by four S atoms of two cyclic bidentate ligands i-Bu2PS 2 − and the axial position is occupied by the N atom of the 4-NH2Py cycle. According to electron spectroscopy data, complex II has an octahedral N2S4 environment of the Ni atom.

Paramagnetic compounds [Ni(Phen)(i-Bu2PS2)2] (I), [Ni(Phen)2(i-Bu2PS2)](i-Bu2PS2) (II), and [Ni(Phen)3](i-Bu2PS2)2 (III) (μeff = 3.03–3.14 μB) were synthesized by reacting Ni(i-Bu2PS2)2 chelate with Phen. Their single crystals were grown. X-ray diffraction analysis of II was performed (CAD4 diffractometer, МоKα radiation, 1181 Fhkl, R = 0.0378). The crystals are monoclinic: a = 14.039(2) A, b = 18.030(2) A, c = 18.118(2) A β = 105.52(1)°, V = 4418.9(9) A3, Z = 4, ρ(calcd) = 1.259 g/cm3, space group P21/c. The structure is built of individual [Ni(Phen)2(i-Bu2PS2)]+ cations and i-Bu2PS2- anions. The coordination polyhedron of NiN4S2 is a distorted octahedron with four N atoms of two bidentate chelate ligands (Phen molecules) and with two S atoms of a bidentate cyclic ligand i-Bu2PS2-. The electronic spectroscopy data for molecular complex I and ionic complex III suggest the octahedral structure of the NiN2S4 and NiN6 chromophores, respectively.

The paramagnetic compounds [Ni2(HMTA)(i-Bu2PS2)4] (I) and [Ni2(TEDA)(i-Bu2PS2)4] (II) (μeff = 3.11 and 3.23 μB, respectively) were synthesized by reacting diamagnetic Ni(i-Bu2PS2)2 with hexamethylenetetramine (HMTA) and triethylenediamine (TEDA) in ethanol. The crystal structure of I was established by single-crystal X-ray diffraction analysis (CAD4 diffractometer, MoKα radiation, 1483 Fhkl, R = 0.0648). The crystals are monoclinic: a = 35.212(7) A, b = 9.313(2) A, c = 22.622(5) A; β = 129.97(3)°, V = 5685(2) A3, Z = 4, ρ(calcd) = 1.281 g/cm3, space group C2/c. The structure is built of discrete binuclear molecules. The coordination polyhedron of the Ni atom is a distorted tetragonal pyramid with four S atoms of two bidentate cyclic ligands i-Bu2PS2– in the base and the N atom of the bidentate bridging ligand HMTA at the axial vertex. Complexes I and II have similar electronic reflection spectra, which agrees with the C4v symmetry of the ligand field.

The reaction of Ni{(i-C4H9)2PS2}2 with imidazole and 3,5-dimethylpyrazole in ethanol gave paramagnetic (μef = 3.02 and 3.11 BM) mixed-ligand complex compounds [Ni(Im)2{(i-C4H9)2PS2}2] (I) and [Ni(Pyr){(i-C4H9)2PS2}2] (II). Single crystals were grown and the crystal structures of I and II were determined from X-ray diffraction data (CAD-4 diffractometer, Mo\(K_\alpha \) radiation, 1483 \(F_{hkl} \), R = 0.0344 for I and 2630 \(F_{hkl} \), R = 0.0486 for II). The crystals are monoclinic with cell dimensions a = 12.845(2), b = 10.250(1), c = 13.431(1) A, β = 115.89(1)°, V = 1591(1) A3, Z = 2, dcalc = 1.281 g/cm3, space group \(P2_{1/c} \) (for I); a = 11.152(3), b = 12.483(2), c = 23.389(4) A, β = 100.78(1)°, V = 3199(2) A3, Z = 4, dcalc = 1.191 g/cm3, space group \(P2_{1/n} \) (for II). The structures consist of discrete monomer molecules. The coordination polyhedron of the Ni atom is a compressed octahedron NiN2S4 (in I) and a tetragonal pyramid NiNS4 (in II) formed by four S atoms of the two cyclic bidentate ligands i-Bu2\(PS_{2^\_ } \) and the N atoms of two monodentate ligands (Im molecules in trans-positions) or the N atom of the monodentate Pyr ligand in complexes I and II, respectively. The character of interaction between molecules I and II and molecular packing modes are considered. The electronic spectra of the complexes are consistent with the symmetry of chromophores found from X-ray data.

Diamagnetic [Ni(i-Bu2PS2)2] compound (I) in ethanol reacts with 2,2"-bipyridine or pyrazine to give the paramagnetic complexes [Ni(2,2"-Bipy)(i-Bu2PS2)2] (II), [Ni(Pz)2(i-Bu2PS2)2] (III), and [Ni(Pz)(i-Bu2PS2)2] n (IV) (μeff= 2.91–3.12 μB). Single crystals of IIwere grown for X-ray diffraction study. The crystals are monoclinic, a= 14.669(3) A, b= 19.693(4) A, c= 12.155(2) A, β = 107.51(3)°, V= 3348(1) A3, Z= 4; ρcalcd= 1.257 g/cm3, space group P21/c. The structure is built from monomeric molecules. The coordination polyhedron of the Ni atom is a distorted octahedron formed by four S atoms of two bidentate chelating i-Bu2PS– 2ligands and by two N atoms of bidentate cyclic 2,2"-Bipy. Preliminary data for complexes IIIand IVindicate that they also contain an octahedral NiN2S4fragment. The structures of complexes I(square planar) and ofII–IV(octahedral) were confirmed by data from electron spectroscopy. Electronic absorption spectra were used to determine the rankings of the i-Bu2PS– 2ions and Pz on a spectrochemical scale.