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A new Pb-II coordination complex [PbL(OAc)], which was readily synthesized from a mixture of Pb(OAc)(2)center dot 3H(2)O and 1-(pyridin-2-yl)benzylidene-4-phenyl-thiosemicarbazide (HL) is reported. The crystal structure analysis of [PbL(OAc)] showed that the Pb-II cation is N,N',S-chelated by the tridentate pincer-type ligand L and by the oxygen atoms of the acetate anion. In addition, the metal centre forms Pb center dot center dot center dot O and Pb center dot center dot center dot S tetrel bonds with an adjacent complex molecule, yielding a 1D zigzag polymeric chain, which is reinforced by N-H center dot center dot center dot O hydrogen bonds and pi center dot center dot center dot pi interactions. These chains are interlinked by C-H center dot center dot center dot py non-covalent interactions, realized between one of the acetate hydrogen atoms and the pyridine rings. According to the Hirshfeld surface analysis, the crystal packing is mainly characterized by intermolecular H center dot center dot center dot H, H center dot center dot center dot C and H center dot center dot center dot O contacts, followed by H center dot center dot center dot N, H center dot center dot center dot S, C center dot center dot center dot C, C center dot center dot center dot N, Pb center dot center dot center dot H, Pb center dot center dot center dot O and Pb center dot center dot center dot S contacts. The FTIR and H-1 NMR spectra of [PbL(OAc)] testify to the deprotonation of the parent ligand HL, while the acetate ligand exhibits an anisobidentate coordination mode as established by means of single-crystal X-ray diffraction and FTIR spectroscopy. Lastly, theoretical calculations at the PBEO-D3/def2-TZVP level of theory have been used to analyze and characterize the Pb center dot center dot center dot O and Pb center dot center dot center dot S tetrel bonds observed in the crystal of [PbL(OAc)], using a combination of QTAIM (Quantum Theory of Atoms in Molecules) and NCIPlot (N

A series of novel ONO ligands bearing an ionic pendant-armed (hereinafter indicated as ONONu, where Nu corresponds to an anionic nucleophile) were synthesized, characterized, and successfully coordinated to cobalt and manganese precursors. New air-stable cobalt (III) complexes (1-6) and manganese (II) complexes (7 and 8) were obtained and characterized. Single crystal X-ray diffraction analysis of the Co(III) compound 5 confirmed the presence of two quaternized ligands coordinated to the metal and iodide as counterion. These novel complexes were revealed to be active catalysts in the coupling reaction of carbon dioxide and propylene oxide (PO) in different degrees of success. Among these, the manganese complex 8 afforded the best results towards the formation of propylene carbonate (PC) with a productivity of 256 kg PC/(kg cat center dot h), achieving a TON of 4860.

A new supramolecular Pb(II) complex[PbL(NO2)](n)was synthesized from Pb(NO3)(2),N'-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide (HL) and NaNO2.[PbL(NO2)](n)is constructed from discrete [PbL(NO2)] units with an almost ideal N(2)O(3)square pyramidal coordination environment around Pb(II). The ligandL(-)is coordinated through the 2-pyridyl N-atom, one aza N-atom, and the carbonyl O-atom. The nitrite ligand binds in a kappa(2)-O,O coordination mode through both O-atoms. The Pb(II) center exhibits a hemidirected coordination geometry with a pronounced coordination gap, which allows a close approach of two additional N-atoms arising from the N=C(O) N-atom of an adjacent molecule and from the 4-pyridyl N-atom from the another adjacent molecule, yielding a N(4)O(3)coordination, constructed from two Pb-N and three Pb-O covalent bonds, and two PbMIDLINE HORIZONTAL ELLIPSISN tetrel bonds. Dimeric units in the structure of[PbL(NO2)](n)are formed by the PbMIDLINE HORIZONTAL ELLIPSISN=C(O) tetrel bonds and intermolecular electrostatically enforced pi+MIDLINE HORIZONTAL ELLIPSIS pi(-)stacking interactions between the 2- and 4-pyridyl rings and further stabilized by C-HMIDLINE HORIZONTAL ELLIPSIS pi intermolecular interactions, formed by one of the methyl H-atoms and the 4-pyridyl ring. These dimers are embedded in a 2D network representing a simplified uninodal 3-connectedfes(Shubnikov plane net) topology defined by the point symbol (4 center dot 8(2)). The Hirshfeld surface analysis of [PbL(NO2)] revealed that the intermolecular HMIDLINE HORIZONTAL ELLIPSISX (X = H, C, N, O) contacts occupy an overwhelming majority of the molecular surface of the [PbL(NO2)] coordination unit. Furthermore, the structure is characterized by intermolecular CMIDLINE HORIZONTAL ELLIPSISC and CMIDLINE HORIZONTAL ELLIPSISN interactions, corresponding to the intermolecular pi MIDLINE HORIZONTAL ELLIPSIS pi stacking interactions. Notably, intermolecular PbMIDLINE HORIZONTAL ELLIPSISN and, most interes

A new supramolecular Pb(II) complex[PbL(NO2)](n)was synthesized from Pb(NO3)(2),N'-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide (HL) and NaNO2.[PbL(NO2)](n)is constructed from discrete [PbL(NO2)] units with an almost ideal N(2)O(3)square pyramidal coordination environment around Pb(II). The ligandL(-)is coordinated through the 2-pyridyl N-atom, one aza N-atom, and the carbonyl O-atom. The nitrite ligand binds in a kappa(2)-O,O coordination mode through both O-atoms. The Pb(II) center exhibits a hemidirected coordination geometry with a pronounced coordination gap, which allows a close approach of two additional N-atoms arising from the N=C(O) N-atom of an adjacent molecule and from the 4-pyridyl N-atom from the another adjacent molecule, yielding a N(4)O(3)coordination, constructed from two Pb-N and three Pb-O covalent bonds, and two PbMIDLINE HORIZONTAL ELLIPSISN tetrel bonds. Dimeric units in the structure of[PbL(NO2)](n)are formed by the PbMIDLINE HORIZONTAL ELLIPSISN=C(O) tetrel bonds and intermolecular electrostatically enforced pi+MIDLINE HORIZONTAL ELLIPSIS pi(-)stacking interactions between the 2- and 4-pyridyl rings and further stabilized by C-HMIDLINE HORIZONTAL ELLIPSIS pi intermolecular interactions, formed by one of the methyl H-atoms and the 4-pyridyl ring. These dimers are embedded in a 2D network representing a simplified uninodal 3-connectedfes(Shubnikov plane net) topology defined by the point symbol (4 center dot 8(2)). The Hirshfeld surface analysis of [PbL(NO2)] revealed that the intermolecular HMIDLINE HORIZONTAL ELLIPSISX (X = H, C, N, O) contacts occupy an overwhelming majority of the molecular surface of the [PbL(NO2)] coordination unit. Furthermore, the structure is characterized by intermolecular CMIDLINE HORIZONTAL ELLIPSISC and CMIDLINE HORIZONTAL ELLIPSISN interactions, corresponding to the intermolecular pi MIDLINE HORIZONTAL ELLIPSIS pi stacking interactions. Notably, intermolecular PbMIDLINE HORIZONTAL ELLIPSISN and, most interes

The synthesis, structural elucidation and TD-DFT analysis of the self-assembly of a cobalt(II) complex with cyanuric acid is reported. The asymmetric unit in the crystal comprises a cobalt complex cation, [Co(H2CA)(H2O)5]+(H3CA = cyanuric acid), a cyanurate mono anion, and two lattice water molecules, which are assembled in the supramolecular network via pair-wise coupling of N-H···O type occurring between the ion pairs and additional hydrogen bonds involving aqua ligands and lattice water molecules.

info:eu-repo/semantics/published

info:eu-repo/semantics/published

Two new chiral, enantiomerically pure, hybrid P-N ligands, namely (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octan-4-one (1) and (2R,5S)-2phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octane (2), have been synthesized starting from L-proline. The two ligands differ in the presence or not of a carbonyl group in the diazaphosphane ring. Their coordination chemistry towards Pd(II) was studied by reacting them with [Pd(CH3)Cl(cod)]. A different behaviour was observed: ligand 2 shows the expected bidentate chelating behaviour leading to the mononuclear Pd-complex, while ligand 1 acts as a terdentate ligand giving a dinuclear species. The corresponding cationic derivatives were obtained from the palladium neutral complexes, both as mono-and dinuclear derivatives, and tested as precatalysts for styrene dimerization, yielding E-1,3-diphenyl-1-butene regio- and stereoselectively as the sole product. A detailed analysis of the catalytic behaviour is reported.

The hydroxo complex cis-[L2Pt(í-OH)]2(NO3)2, (L ) PMePh2, 1a), in CH3CN solution, deprotonates the NH2 group of 9-methyladenine (9-MeAd) to give the cyclic trinuclear species cis-[L2Pt{9-MeAd(-H)}]3(NO3)3, (L ) PMePh2, 2a), in which the nucleobase binds the metal centers through the N(1), N(6) atoms. In solution at room temperature, 2a slowly reacts with the solvent to form quantitatively the mononuclear azametallacycle cis-[L2PtNHdC(Me){9- MeAd(-2H)}]NO3 (L ) PMePh2, 3a), containing as anionic ligand the deprotonated form of molecule N-(9-methyl- 1,9-dihydro-purin-6-ylidene)-acetamidine. In the same experimental conditions, the hydroxo complex with PPh3 (1b) forms immediately the insertion product 3b. Single-crystal X-ray analyses of 3a and 3b show the coordination of the platinum cation at the N(1) site of the purine moiety and to the N atom of the inserted acetonitrile, whereas the exocyclic amino nitrogen binds the carbon atom of the same CN group. The resulting six-membered ring is slightly distorted from planarity, with carbon-nitrogen bond distances for the inserted nitrile typical of a double bond [C(3)- N(2) ) 1.292(7) Å in 3a and 1.279(11) Å in 3b], while the remaining CN bonds of the metallocycle are in the range of 1.335(8)-1.397(10) Å. A detailed multinuclear 1H, 31P, 13C, and 15N NMR study shows that the nitrogen atom of the inserted acetonitrile molecule binds a proton suggesting for 3a,b an imino structure in solution. In DMSO and chlorinated solvents, 3a slowly releases the nitrile reforming the trinuclear species 2a, whereas 3b forms the mononuclear derivative cis-[L2Pt{9-MeAd(-H)}]NO3 (L ) PPh3, 4b), in which the adeninate ion chelates the metal center through the N(6) and N(7) atoms. Complex 4b is quantitatively obtained when 1b reacts with 9-MeAd in DMSO and can be easily isolated if the reaction is carried out in CH2Cl2. In CH3CN solution, at room temperature, 4b slowly converts into 3b indicating that the insertion of acetonitrile is a reversi

The hydroxo complex cis-[L2Pt(í-OH)]2(NO3)2, (L ) PMePh2, 1a), in CH3CN solution, deprotonates the NH2 group of 9-methyladenine (9-MeAd) to give the cyclic trinuclear species cis-[L2Pt{9-MeAd(-H)}]3(NO3)3, (L ) PMePh2, 2a), in which the nucleobase binds the metal centers through the N(1), N(6) atoms. In solution at room temperature, 2a slowly reacts with the solvent to form quantitatively the mononuclear azametallacycle cis-[L2PtNHdC(Me){9- MeAd(-2H)}]NO3 (L ) PMePh2, 3a), containing as anionic ligand the deprotonated form of molecule N-(9-methyl- 1,9-dihydro-purin-6-ylidene)-acetamidine. In the same experimental conditions, the hydroxo complex with PPh3 (1b) forms immediately the insertion product 3b. Single-crystal X-ray analyses of 3a and 3b show the coordination of the platinum cation at the N(1) site of the purine moiety and to the N atom of the inserted acetonitrile, whereas the exocyclic amino nitrogen binds the carbon atom of the same CN group. The resulting six-membered ring is slightly distorted from planarity, with carbon-nitrogen bond distances for the inserted nitrile typical of a double bond [C(3)- N(2) ) 1.292(7) Å in 3a and 1.279(11) Å in 3b], while the remaining CN bonds of the metallocycle are in the range of 1.335(8)-1.397(10) Å. A detailed multinuclear 1H, 31P, 13C, and 15N NMR study shows that the nitrogen atom of the inserted acetonitrile molecule binds a proton suggesting for 3a,b an imino structure in solution. In DMSO and chlorinated solvents, 3a slowly releases the nitrile reforming the trinuclear species 2a, whereas 3b forms the mononuclear derivative cis-[L2Pt{9-MeAd(-H)}]NO3 (L ) PPh3, 4b), in which the adeninate ion chelates the metal center through the N(6) and N(7) atoms. Complex 4b is quantitatively obtained when 1b reacts with 9-MeAd in DMSO and can be easily isolated if the reaction is carried out in CH2Cl2. In CH3CN solution, at room temperature, 4b slowly converts into 3b indicating that the insertion of acetonitrile is a reversi

Four new M3L2 molecular cages (CA1-CA4) have been synthesized in excellent yield via coordination driven self -assembly of flexible tri-imidazole donors based on triazine (L1) and tri-phenyl benzene (L2) core with 90 degrees cis-blocked metal acceptors of Pd(II). Two of them CA1 and CA2 are highly soluble in water. All the cages were characterized by spectroscopic studies and ESI-MS; CA3 and CA4 also by X-ray diffraction. Selective formation of two separate cages CA3 and CA4 was noticed instead of a hetero-ligand cage, when the metal acceptor (dppf)Pd(OTf)(2) was treated with a mixture of ligands L1 and L2.