{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T03:06:50Z","timestamp":1775099210432,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,2,6]],"date-time":"2019-02-06T00:00:00Z","timestamp":1549411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/MULTI\/00612\/2013"],"award-info":[{"award-number":["UID\/MULTI\/00612\/2013"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"CICECO \u2013 Aveiro Institute of Materials","award":["UID\/CTM\/50011\/2013"],"award-info":[{"award-number":["UID\/CTM\/50011\/2013"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Three new complexes [Mo(\u03b73-C3H5)Br(CO)2{iPrN=C(R)C5H4N}], where R = H (IMP = N-isopropyl 2-iminomethylpyridine), Me, and Ph, were synthesized and characterized, and were fluxional in solution. The most interesting feature was the presence, in the crystal structure of the IMP derivative, of the two main isomers (allyl and carbonyls exo), namely the equatorial isomer with the Br trans to the allyl and the equatorial with the Br trans to one carbonyl, the position trans to the allyl being occupied by the imine nitrogen atom. For the R = Me complex, the less common axial isomer was observed in the crystal. These complexes were immobilized in MCM-41 (MCM), following functionalization of the diimine ligands with Si(OEt)3, in order to study the catalytic activity in olefin epoxidation of similar complexes as homogeneous and heterogeneous catalysts. FTIR, 13C- and 29Si-NMR, elemental analysis, and adsorption isotherms showed that the complexes were covalently bound to the MCM walls. The epoxidation activity was very good in both catalysts for the cis-cyclooctene and cis-hex-3-en-1-ol, but modest for the other substrates tested, and no relevant differences were found between the complexes and the Mo-containing materials as catalysts.<\/jats:p>","DOI":"10.3390\/molecules24030578","type":"journal-article","created":{"date-parts":[[2019,2,6]],"date-time":"2019-02-06T11:51:12Z","timestamp":1549453872000},"page":"578","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["New Molybdenum(II) Complexes with \u03b1-Diimine Ligands: Synthesis, Structure, and Catalytic Activity in Olefin Epoxidation"],"prefix":"10.3390","volume":"24","author":[{"given":"Maria","family":"Vasconcellos-Dias","sequence":"first","affiliation":[{"name":"Centro de Qu\u00edmica e Bioqu\u00edmica, DQB, Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"}]},{"given":"Jo\u00e3o","family":"Marreiros","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica e Bioqu\u00edmica, DQB, Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"}]},{"given":"Rita","family":"Sales","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica e Bioqu\u00edmica, DQB, Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"}]},{"given":"Vitor","family":"F\u00e9lix","sequence":"additional","affiliation":[{"name":"Department of Chemistry, CICECO\u2014Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"given":"Paula","family":"Brand\u00e3o","sequence":"additional","affiliation":[{"name":"Department of Chemistry, CICECO\u2014Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"given":"Carla D.","family":"Nunes","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica e Bioqu\u00edmica, DQB, Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"},{"name":"Centro de Qu\u00edmica Estrutural, DQB, Faculdade de Ci\u00eancias, Universidade de Lisboa, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6872-3569","authenticated-orcid":false,"given":"Maria Jos\u00e9","family":"Calhorda","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica e Bioqu\u00edmica, DQB, Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"},{"name":"BioISI\u2014Biosystems &amp; Integrative Sciences Institute, DQB, Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2019,2,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1016\/j.ica.2012.01.029","article-title":"Epoxidation of olefins using a dichlorodioxomolybdenum(VI)-pyridylimine complex as catalyst","volume":"387","author":"Balula","year":"2012","journal-title":"Inorg. Chim. Acta"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/S0022-328X(02)01778-3","article-title":"Allyl complexes of molybdenum with Schiff base ligands. The crystal structures of [MoCl(CO)2{N(C6H4-2-OMe)=C(Me)C5H4N}(\u03b73-C3H5)] and [MoCl(CO)2{N(Me)=C(Ph)C5H4N}(\u03b73-C3H5)] are described","volume":"660","author":"Mentes","year":"2002","journal-title":"J. Organomet. Chem."},{"key":"ref_3","first-page":"41","article-title":"Syntheses and structure determination of allyl complexes of molybdenum","volume":"25","author":"Gilani","year":"2003","journal-title":"J. Chem. Soc. Pak."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1007\/s11243-007-9011-5","article-title":"Synthesis of water-soluble Mo(0) tetracarbonyl complexes containing nitrogen donor ligands and polymerization of methyl methacrylate","volume":"33","author":"Mentes","year":"2008","journal-title":"Transit. Met. Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3543","DOI":"10.1016\/j.jorganchem.2011.07.040","article-title":"Epoxidation of cyclooctene using soluble or MCM-41-supported molybdenum tetracarbonyl\u2013pyridylimine complexes as catalyst precursors","volume":"696","author":"Gomes","year":"2011","journal-title":"J. Organomet. Chem."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/S0020-1693(00)90117-8","article-title":"A paramagnetic 1H NMR study of tetrabromo(N-alkyl-methylpyridine-2-carbaldimine)tungsten(IV) and related complexes","volume":"161","author":"Matsubayashi","year":"1989","journal-title":"Inorg. Chim. Acta"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Haddleton, D.M., Duncalf, D.J., Kukulj, D., Crossman, M.C., Jackson, S.G., Bon, S.A.F., Clark, A.J., and Shooter, A.J. (1998). [N-Alkyl-(2-pyridyl)methanimine]copper(I) complexes: Characterisation and application as catalysts for atom-transfer polymerisation. Eur. J. Inorg. Chem., 1799\u20131806.","DOI":"10.1002\/(SICI)1099-0682(199811)1998:11<1799::AID-EJIC1799>3.3.CO;2-Y"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1016\/j.jorganchem.2017.07.003","article-title":"Pd nanoparticles on reverse phase silica gel as recyclable catalyst for Suzuki-Miyaura cross coupling reaction and hydrogenation in water","volume":"846","author":"Shabbir","year":"2017","journal-title":"J. Organomet. Chem."},{"key":"ref_9","first-page":"1","article-title":"Cationic ruthenium(II) complexes supported on mesoporous silica as catalyst precursors in the selective oxidative cleavage of 1-octene","volume":"31","author":"Kotze","year":"2016","journal-title":"Appl. Organomet. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"11704","DOI":"10.1021\/acs.inorgchem.8b01847","article-title":"Accurate description of low-lying excited states in a series of photoreactive clusters [Os3(CO)10(\u03b1-diimine)] by DFT calculations","volume":"57","author":"Hartl","year":"2018","journal-title":"Inorg. Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/j.jcat.2008.03.023","article-title":"Heptacoordinate tricarbonyl Mo(II) complexes as highly selective oxidation homogeneous and heterogeneous catalysts","volume":"256","author":"Nunes","year":"2008","journal-title":"J. Catal."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1016\/S0022-328X(01)00988-3","article-title":"Synthesis, bonding and dynamic behavior of fac-[Mo(II)(CO)2(\u03b73-allyl)] derivatives","volume":"632","author":"Ascenso","year":"2001","journal-title":"J. Organomet. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.jorganchem.2003.08.004","article-title":"Mono- and binuclear bipyridyl derivatives of the Mo(\u03b73-C3H5)(CO)2 fragment: Structural studies and fluxionality in solution","volume":"687","author":"Costa","year":"2003","journal-title":"J. Organomet. Chem."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Saraiva, M.S., Nunes, C.D., F\u00e9lix, V., Ribeiro, A.P.C., Nieto de Castro, C., and Calhorda, M.J. (2018). Molybdenum(II) complexes with \u03b1-diimines: Catalytic activity in organic and ionic liquid solvents. Eur. J. Inorg. Chem., 3922\u20133932.","DOI":"10.1002\/ejic.201800700"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"5548","DOI":"10.1021\/om700348w","article-title":"Molybdenum \u03b73-allyl dicarbonyl complexes as a new class of precursors for highly reactive epoxidation catalysts with tert-butyl hydroperoxide","volume":"26","author":"Alonso","year":"2007","journal-title":"Organometallics"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/j.jorganchem.2014.01.015","article-title":"Spectroelectrochemical study of complexes [Mo(CO)2(\u03b73-allyl)(\u03b1-diimine)(NCS)] (\u03b1-diimine = bis(2,6-dimethylphenyl)-acenaphthenequinonediimine and 2,2\u2032-bipyridine) exhibiting different molecular structure and redox reactivity","volume":"760","author":"Tory","year":"2014","journal-title":"J. Organomet. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1735","DOI":"10.1039\/b109678h","article-title":"MCM-41 functionalized with bipyridyl groups and its use as a support for oxomolybdenum(VI) catalysts","volume":"12","author":"Nunes","year":"2002","journal-title":"J. Mater. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"10834","DOI":"10.1021\/ja00053a020","article-title":"A new family of mesoporous molecular sieves prepared with liquid crystal templates","volume":"114","author":"Beck","year":"1992","journal-title":"J. Am. Chem. Soc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1016\/0927-6513(96)00016-8","article-title":"Influence of the sorbate type on the XRD peak intensities of loaded MCM-41","volume":"6","author":"Marler","year":"1996","journal-title":"Microporous Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/S1387-1811(98)00222-4","article-title":"Structure factor for the periodic walls of mesoporous MCM-41 molecular sieves","volume":"27","author":"Hammond","year":"1999","journal-title":"Microporous Mesoporous Mater."},{"key":"ref_21","unstructured":"Gregg, S.J., and Sing, K.S.W. (1982). Adsorption, Surface Area and Porosity, Academic Press. [2nd ed.]."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"849","DOI":"10.1039\/ft9969200849","article-title":"Pore structure analysis of the mesoporous titanosilicate molecular sieve MCM-41 by 1H NMR and N2 sorption","volume":"92","author":"Alba","year":"1996","journal-title":"J. Chem. Soc. Faraday Trans."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"5294","DOI":"10.1021\/jp970077i","article-title":"Synthesis and Characterization of the Mesoporous Silicate Molecular Sieve MCM-48","volume":"101","author":"Romero","year":"1997","journal-title":"J. Phys. Chem. B"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"5410","DOI":"10.1021\/la990136e","article-title":"Standard Nitrogen Adsorption Data for Characterization of Nanoporous Silicas","volume":"15","author":"Kruk","year":"1999","journal-title":"Langmuir"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"7874","DOI":"10.1002\/chem.200700310","article-title":"Vibrational study on the local structure of post-synthesis and hybrid mesoporous materials: Are there fundamental distinctions?","volume":"13","author":"Vaz","year":"2007","journal-title":"Chem. Eur. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1007\/BF00938727","article-title":"Preparation of some silyl esters and study of their vibration spectra in gas and condensed phases","volume":"111","author":"Bett","year":"1980","journal-title":"Monatshefte Chem."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.ica.2015.03.018","article-title":"Molybdenum(II) catalyst precursors in olefin oxidation reactions","volume":"431","author":"Nunes","year":"2015","journal-title":"Inorg. Chim. Acta"},{"key":"ref_28","unstructured":"Parr, R.G., and Yang, W. (1989). Density Functional Theory of Atoms and Molecules, Oxford University Press."},{"key":"ref_29","unstructured":"SCM (2013). Theoretical Chemistry, Vrije Universiteit."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1016\/S0022-328X(00)87677-9","article-title":"\u00dcber \u03c0-Allyl-Komplexe des Molybd\u00e4ns II. Die bildung von \u03c0-Allyldicarbonylmolybd\u00e4n-Komplexen aus Molybd\u00e4n-hexacarbonyl und seinen Derivaten","volume":"14","author":"Friedel","year":"1968","journal-title":"J. Organomet. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1016\/S0022-328X(00)99633-5","article-title":"The synthesis and spectral properties of some highly reactive new seven-coordinate molybdenum(II) and tungsten(II) bisacetonitrile dihalogenotricarbonyl complexes","volume":"309","author":"Baker","year":"1986","journal-title":"J. Organomet. Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"P1","DOI":"10.1016\/S0022-328X(00)88846-4","article-title":"A new route to \u03c0-allyl complexes of molybdenum and tungsten","volume":"13","author":"Hayter","year":"1968","journal-title":"J. Organomet. Chem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/j.progsolidstchem.2005.11.012","article-title":"Hybrid mesoporous MCM-41 type material containing 1,4-diazobutadiene chelate ligand in the walls","volume":"33","author":"Ferreira","year":"2005","journal-title":"Prog. Solid State Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"670","DOI":"10.1016\/j.micromeso.2008.08.012","article-title":"Activity of Mo(II) allylic complexes supported in MCM-41 as oxidation catalysts precursors","volume":"117","author":"Saraiva","year":"2009","journal-title":"Microporous Mesoporous Mater."},{"key":"ref_35","first-page":"3","article-title":"SHELXT-Integrated space-group and crystal-structure determination","volume":"A71","author":"Sheldrick","year":"2015","journal-title":"Acta Cryst."},{"key":"ref_36","first-page":"3","article-title":"Crystal structure refinement with SHELXL","volume":"C71","author":"Sheldrick","year":"2015","journal-title":"Acta Cryst."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1107\/S0021889807067908","article-title":"Mercury CSD 2.0\u2014New features for the visualization and investigation of crystal","volume":"41","author":"Macrae","year":"2008","journal-title":"J. Appl. Cryst."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1200","DOI":"10.1139\/p80-159","article-title":"Accurate spin-dependent electron liquid correlation energies for local spin density calculations: A critical analysis","volume":"58","author":"Vosko","year":"1980","journal-title":"Can. J. Phys."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2092","DOI":"10.1063\/1.476722","article-title":"A new inhomogeneity parameter in density-functional theory","volume":"109","author":"Becke","year":"1998","journal-title":"J. Chem. Phys."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"8822","DOI":"10.1103\/PhysRevB.33.8822","article-title":"Density-functional approximation for the correlation energy of the inhomogeneous electron gas","volume":"33","author":"Perdew","year":"1986","journal-title":"Phys. Rev. B"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"7406","DOI":"10.1103\/PhysRevB.34.7406","article-title":"Erratum: Density-functional approximation for the correlation energy of the inhomogeneous electron gas","volume":"34","author":"Perdew","year":"1986","journal-title":"Phys. Rev. B"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"8943","DOI":"10.1063\/1.478813","article-title":"Geometry optimizations in the zero order regular approximation for relativistic effects","volume":"110","author":"Ehlers","year":"1999","journal-title":"J. Chem. Phys."},{"key":"ref_43","unstructured":"(2018, November 23). Chemcraft Program. Available online: http:\/\/www.chemcraftprog.com\/index.html."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.ccr.2016.12.010","article-title":"Structure, bonding and reactivity of seven-coordinate allylic Mo(II) complexes","volume":"344","author":"Calhorda","year":"2017","journal-title":"Coord. Chem. Rev."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/24\/3\/578\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:31:16Z","timestamp":1760185876000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/24\/3\/578"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,2,6]]},"references-count":44,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2019,2]]}},"alternative-id":["molecules24030578"],"URL":"https:\/\/doi.org\/10.3390\/molecules24030578","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,2,6]]}}}