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The preparation and characterization of two series of organotin(IV) complexes are reported, each series differing in the nature of the substituent bonded to the tin atom (cyclohexyl or bis(trimethyl)silylmethyl). The isosteric and bioisosteric approach was used as the strategy of molecular design. The ligand was 5-hydroxymethyl-4-[(2-hydroxyphenyl)iminomethyl]-2-methylpyridin-3-ol substituted at position 4 by methyl, halogeno (F, Cl), methoxy, nitro and tert-butyl; the synthesis of the organotin(IV) complexes was performed by a multi-component strategy in reasonable to high yields depending on the nature of the ligand. All new complexes were fully characterized by IR, MS, X-ray determinations and NMR (1H, 13C, 119Sn). Crystallographic data of complexes showed the geometries adopted around the metal tin center varied between square pyramidal in 2c and a trigonal bipyramidal in 3b-3d with the alkyl groups in the trigonal plane and the two oxygen atoms in the equatorial plane. Additionally, the in vitro cytotoxicity tests of the complexes towards six types of human cancerous cell lines U-251 (glioblastoma), K-562 (chronic myelogenous leukemia), HCT-15 (human colorectal), MCF-7 (human breast), MDA-MB-231(human breast) and SKLU-1 (non-small cell lung) showed the superior activity of the organotin complexes compared to the corresponding cisplatin used as positive control. The complexes containing fluorine exhibited excellent IC50 data indicating that both the bioisosteric replacement and the cyclohexyl ring bonded to the tin atom increased the potency of the cytotoxic activity towards the cancer cell lines tested.

A series of half-sandwich ruthenium(II) complexes of the type [Ru(η6-C6H6)(N∩C)L]PF6 (L = PPh3, P(n-Bu)3, SbPh3, MeCN), bearing cyclometalated N,N-dimethylbenzylamine (1a–d) and 2-phenylpyridine (2a–d) moieties, has been efficiently prepared by ligand substitution. The molecular structures of the new compounds were unequivocally determined by single-crystal X-ray diffraction. The catalytic activity of the complexes in the radical polymerizations of styrene and vinyl acetate was evaluated, and a comparative structure – activity analysis was performed.

The iminophosphorane ligands (Ph3P NC6H4SR) [R = CH3 (1) and C6H5 (2)] were easily synthesized from triphenylphosphine and 2-(methylthio)aniline or 2-(phenylthio)aniline respectively by the Horner and Oediger variation of the Kirsanov reaction. The reactivity of both ligands was explored with [Na2PdCl4] to afford the corresponding non-symmetric iminophosphorane pincer derivatives [PdCl{C6H4(Ph2P NC6H4SR-κ3-C,N,S)}] [R = CH3 (3) and C6H5 (4)]. A careful monitoring of the reaction by 31P{1H} NMR experiments revealed the N,S chelated species [PdCl2{C6H4(Ph2P NC6H4SR-κ2-N,S)}] [R = CH3 (5) and C6H5 (6)] to be stable intermediates through the formation of the pincer compounds. Thus, carrying out the reaction for the attaining of (4) at room temperature allowed the isolation and full characterization of the chelated complex [PdCl2{C6H4(Ph2P NC6H4SPh-κ-N,S)}] (6). All above mentioned species were unequivocally characterized by single crystal X-ray diffraction experiments. In addition, the newly synthesized pincer complexes [PdCl{C6H4(Ph2P NC6H4SR-κ3-C,N,S)}] [R = CH3 (3) and C6H5 (4)] were tested as catalyst, proven to be efficient in the Suzuki–Miyaura C–C cross coupling reactions of a series of para-substituted bromobenzenes.

A series of heterobimetallic complexes have been prepared by π-coordination of the [CpRu]+ fragment to the aromatic ring of POCOP pincer complexes of nickel, palladium and platinum. Their molecular structures were unequivocally determined by single-crystal X-ray diffraction, exhibiting the ruthenium moiety and the POCOP aromatic ring forming sandwich like species. The analysis in the solid state and in solution clearly showed that the coordination occurs in an orthogonal fashion and, as a consequence, both faces of the pincer complexes become non equivalent, thus conferring diastereotopicity to the isopropyl substituents. The electrochemical behavior of the new bimetallic complexes was studied and compared with that of the monometallic POCOP pincer precursors.

The reaction between the dihydride of decacarbonyltriosmium [H2Os3(CO)10] and phenyl arsine oxide (PAO) in benzene yields only one product [Os3(O)9(μ-H){μ-PhAs(O)OAsPh}] (1), which is characterized by high resolution mass spectrometry (HRMS), Fast Atomic Bombardment Mass Spectrometry (FAB)+, IR, 1H and 13C NMR, and single crystal X-ray diffraction. The solid state X-ray diffraction study of compound (1) shows that the molecule is polycyclic and has an osmium triangle with a bridging hydride bonded to a PhAs(O)-O-AsPh ligand.

2,3-Diferrocenyl-1-morpholinocyclopropenylium tetrafluoroborate reacts with 1,3-diketones in the presence of triethylamine to give 3-diacylmethylidene-1,2-diferrocenylcyclopropenes (8a–d). Under similar conditions, 2,3-diferrocenyl-1-methylsulfanylcyclopropenylium iodide affords 8a–c (∼25–30%) and 1,1-diacyl-2,3-diferrocenyl-4-methylsulfanylbuta-1,3-dienes (10a–c) (∼50–60%). The structures of the products obtained were established based on the data from 1H (1D NOE) and 13C NMR spectra and X-ray diffraction analysis. Electrochemical properties of several (diacylmethylidene)diferrocenylcyclopropenes (8a–c) and 1,1-diacyl-2,3-diferrocenyl-4-methylsulfanylbuta-1,3-dienes (10a–c) are studied.

A series of palladium thiolate complexes of the type [Pd(dppf)(SRF)2] have been synthesized in good yields by metathetical reactions of [Pd(dppf)Cl2] with [Pb(SRF)2], (SRF=−SC6F5, −SC6F4-4-H, −SC6H4-2-CF3, −SC6H4-4-F, −SC6H4-3-F) and their crystal structures determined. The effect of the different thiolates in the structural properties of the complexes both in the solid state and in solution have been analyzed. Heck coupling reactions were carried out using the complexes [Pd(dppf)(SRF)2], SRF=−SC6F5 (1), −SC6F4-4-H (2), −SC6H4-2-CF3 (3), −SC6H4-4-F (4), −SC6H4-3-F (5) as catalysts in order to examine both the effect of the thiolates and the P–Pd–P bite angles in the reaction of bromobenzene and styrene. The results obtained indicate that electron-withdrawing substituents may favor higher yields in the Pd catalyzed Heck reaction using [Pd(dppf)(SRF)2] as catalysts.

The reactions of [Sn(Ph)2(Ph2PC6H4-2-S)2] with trans -[M(Cl)(CO)(PPh3)2] M=Ir, Rh afford the complexes [Rh(Ph2PC6H4-2-S)2(SnClPh2)] (1) and [Ir(CO)(Ph2PC6H4-2-S)2(SnClPh2)] (2) as final products of two processes, a transmetallation reaction and an oxidative addition process. The crystal structures of both complexes have been determined, showing the rhodium compound to be into a slightly distorted square base pyramidal geometry, while that of the iridium derivative can be described as a distorted octahedron.

The complexes cis -[M(Ph 2 PC 6 H 4 -2-S) 2 ] M=Ni, Pd, Pt were stereoselectively synthesized by transmetallation reactions of [M(Cl) 2 (NCC 6 H 5 ) 2 ] M=Pd, Pt or NiCl 2 ·6H 2 O with [Sn(R) 2 (Ph 2 PC 6 H 4 -2-S) 2 ] R=Ph, n Bu or t Bu. The conformation of the Pd and Pt derivatives being unequivocally confirmed by single crystal X-ray diffraction studies showing both metal centers to be into a slightly distorted square planar environment, the main distortion being due to the steric hindrance caused by the aromatic rings in the phosphine moiety.

Thermal reactions of [M(CO)6] with 1,2,3,4-tetrahydroquinoline (1) afford the corresponding (η6-arene)tricarbonylmetal complex (M=Cr, 3; M=Mo, 4; and M=W, 5). In contrast, thermolysis of the same hexacarbonyl complexes with 1,2,3,4-tetrahydroisoquinoline (2) affords the (σ-nitrogen)pentacarbonylmetal derivatives (M=Cr, 7; M=Mo, 8; and M=W, 9). For chromium the (η6-arene)tricarbonylmetal complex (6) was also isolated. X-ray crystal structures are reported for 3, 4, 7 and 9.

Two dithiocarbamate derivatives of stannolane, 2-nbutyl-2-(dimethyldithiocarbamate)-1,3,2-oxathiastannolane and 2-nbutyl-2-(piperidyldithiocarbamate)-1,3,2-oxathiastannolane have been obtained and full characterized. The X-ray single crystal diffraction studies show the presence of a dimer arrangement, through the formation of an inorganic ring. The bond lengths between the tin and all the S and O atoms are in the middle of covalent and secondary bonds, with a remarkable preference toward oxygen atoms. Both oxathiastannolane units present in solid state an equilibrium between conformations, while the arrangement of the three fused rings (oxathiastannolane–distannoxane–oxathiastannolane) is almost planar.

A complete series of dppfMX2 (M=Pt, Pd; X=Cl, Br, I) compounds have been synthesized using different routes, and characterized fully. The synthesis of dppfPdI2 has been achieved by reacting Pd(COD)Cl2 with dppf in the presence of NaI. X-ray structures of dppfPdBr2 and dppfPdI2 have also been reported for the first time in this study. A preliminary Suzuki coupling screening study reveals that dppfPdX2 compounds are superior to the conventional Ph3P-based catalysts and bidentate phosphine-based ligands. Reactions carried out under in situ conditions also gave a similar trend, but their respective activities were much lower than that of the fully formed catalysts.

The synthesis of the organotellurium(IV) compounds [C4H8TeI(S2PMe2)] (2), [C4H8TeI(S2PEt2)] (3), [C4H8TeI(S2CNC4H6)] (4) and [C4H8TeI(SOCNC5H10)] (6) was achieved. All of them were characterized by IR, 1H-, 13C-, 31P- and 125Te-NMR, mass spectroscopy, elemental analyses and single-crystal X-ray diffraction. In addition, the crystal and molecular structures of the previously known 1,1-diiodotetrahydrotellurophene and [C4H8TeI(S2CNEt2)] (5) were obtained. The geometry around Te(IV) is that of a sawhorse structure in which the lone pair is apparently stereochemically active and occupying an equatorial position in a distorted trigonal bipyramid. All the structures exhibit different supramolecular associations. The intermolecular Te⋯S and Te⋯I interactions result in the formation of dimeric species in 4, and in 1 and 6, respectively. The intermolecular Te⋯S bonds in 2, 3 and 5 lead to formation of one-dimensional polymers.

The reaction between a new ( η 4 )- trans -1,2-α,β-unsaturated diketone-Fe(CO) 3 complex derived from trans -1,2-dibenzoylethylene or the corresponding ( η 2 )-Fe(CO) 4 complex with MeLi under a CO atmosphere leads to the formation of an ( η 4 )-α-pyrone-Fe(CO) 3 complex 3 via the respective ( η 4 )-ketene-Fe (O) complex. The structure of the complex was determined by mass spectrometry, IR, 1 H and 13 C NMR spectroscopies and was confirmed by X-ray diffraction studies.

Reaction of the appropriate R2SnCl2 with the potassium salt of the imidobis(diphenylselenophosphinate-Se,Se') ligand (1c) in 1:2 stoichiometry yields n-Bu2Sn[{N(SePPh2}(2)-Se,Se')(2)] (2) and Ph2ClSn[N(SePPh2)(2)-Se,Se']. H2O (3). The crystal and the molecular structures of both compounds were determined by X-ray diffractometry. The core geometry in compound 2 is a quasi perfect octahedron. Two selenide ligands are coordinated symmetrically to the tin atom forming a spiro-bicyclic NP2Se2SnSe2P2N system [Sigma(Se-Sn-Se) = 360 degrees]. Both organo substituents are in trans positions [(C'-Sn-C'A) = 180.0(1)degrees] and they are almost perpendicular to the SnSe4 plane. In derivative 3 only one selenium-based ligand is coordinated asymmetrically to the tin atom and unexpectedly a chlorine atom remains attached to the metal center. The geometry around the tin atom corresponds to a distorted trigonal bipyramid with the Se(1) and Cl atoms at the axial positions.

Mn(CO) 4 [(SPPh 2 ) 2 N] was prepared by allowing [Mn(CO) 5 ]Br to react with K[SPPh 2 ) 2 N], in THF. The compound was characterized by IR, mass and NMR ( 1 H, 13 C, 31 P) spectroscopy, and its crystal and molecular structure was determined by single-crystal X-ray diffraction. The lattice contains two independent, monomeric molecules, ( 1 ) and ( 1a ). The metal atom has a distorted octahedral coordination geometry (C ax MnC ax 175.9(3)° in ( 1 ), 176.9(3)° in ( 1a )), with two carbonyl groups and the two sulfur atoms of the symmetric monometallic bidentate (mean PS 2.021(2) A in ( 1 ), 2.020(2) A in ( 1a )) dithio ligand unit in equatorial positions (mean MnS 2.420(2), MnC eq 1.804(4), MnC ax 1.855(5) A in ( 1 ), MnS 2.417(2), MnC eq (2) MnC ax 1.862(5) A in ( 1a )). The main difference between the two independent molecules is the conformation of the inorganic MnS 2 P 2 N chelate ring.