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Casella G, Carlotto S, Mozzon M, Sgarbossa P, Bertani R, Casarin M. A DFT mechanistic study of the synthesis of trans-Z,Z-[PtIICl(NH3){HN = C(NH2)Me}2]Cl from addition of NH3 to trans-[PtIICl2(N CMe)2]. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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2
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N-Heterocyclic Carbene Platinum(IV) as Metallodrug Candidates: Synthesis and 195Pt NMR Chemical Shift Trend. Molecules 2020; 25:molecules25143148. [PMID: 32660104 PMCID: PMC7397185 DOI: 10.3390/molecules25143148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 11/24/2022] Open
Abstract
A series of octahedral platinum(IV) complexes functionalized with both N-heterocyclic carbene (NHC) ligands were synthesized according to a straightforward procedure and characterized. The coordination sphere around the metal was varied, investigating the influence of the substituted NHC and the amine ligand in trans position to the NHC. The influence of those structural variations on the chemical shift of the platinum center were evaluated by 195Pt NMR. This spectroscopy provided more insights on the impact of the structural changes on the electronic density at the platinum center. Investigation of the in vitro cytotoxicities of representative complexes were carried on three cancer cell lines and showed IC50 values down to the low micromolar range that compare favorably with the benchmark cisplatin or their platinum(II) counterparts bearing NHC ligands.
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3
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Zelenkov LE, Kuznetsov ML, Andrusenko EV, Avdontceva MS, Starova GL, Bokach NA, Kukushkin VY. Nickel( ii)-mediated cyanamide–pyrazole coupling highlights distinct reactivity of NCNR 2 and NCR nitrile ligands. NEW J CHEM 2020. [DOI: 10.1039/d0nj00704h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nickel(ii) center efficiently promotes the cyanamide–pyrazole coupling to give bis-chelate and tris-chelate products. The formation of the tris-chelate product for dialkylcyanamides is thermodynamically favorable.
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Affiliation(s)
- Lev E. Zelenkov
- Institute of Chemistry
- Saint Petersburg State University
- Saint Petersburg
- Russian Federation
| | - Maxim L. Kuznetsov
- Institute of Chemistry
- Saint Petersburg State University
- Saint Petersburg
- Russian Federation
- Centro de Química Estrutural
| | - Elena V. Andrusenko
- Institute of Chemistry
- Saint Petersburg State University
- Saint Petersburg
- Russian Federation
| | - Margarita S. Avdontceva
- Institute of Earth Sciences
- Saint Petersburg State University
- Saint Petersburg
- Russian Federation
| | - Galina L. Starova
- Institute of Chemistry
- Saint Petersburg State University
- Saint Petersburg
- Russian Federation
| | - Nadezhda A. Bokach
- Institute of Chemistry
- Saint Petersburg State University
- Saint Petersburg
- Russian Federation
| | - Vadim Yu. Kukushkin
- Institute of Chemistry
- Saint Petersburg State University
- Saint Petersburg
- Russian Federation
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Weetman C, Anker MD, Arrowsmith M, Hill MS, Kociok-Köhn G, Liptrot DJ, Mahon MF. Magnesium-catalysed nitrile hydroboration. Chem Sci 2016; 7:628-641. [PMID: 29896350 PMCID: PMC5952893 DOI: 10.1039/c5sc03114a] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/19/2015] [Indexed: 01/17/2023] Open
Abstract
A β-diketiminato n-butylmagnesium complex is presented as a selective precatalyst for the reductive hydroboration of organic nitriles with pinacolborane (HBpin). Stoichiometric reactivity studies indicate that catalytic turnover ensues through the generation of magnesium aldimido, aldimidoborate and borylamido intermediates, which are formed in a sequence of intramolecular nitrile insertion and inter- and intramolecular B-H metathesis events. Kinetic studies highlight variations in mechanism for the catalytic dihydroboration of alkyl nitriles, aryl nitriles bearing electron withdrawing (Ar(EWG)CN) and aryl nitriles bearing electron donating (Ar(EDG)CN) substitution patterns. Kinetic isotope effects (KIEs) for catalysis performed with DBpin indicate that B-H bond breaking and C-H bond forming reactions are involved in the rate determining processes during the dihydroboration of alkyl nitriles and Ar(EDG)CN substrates, which display divergent first and second order rate dependences on [HBpin] respectively. In contrast, the hydroboration of Ar(EWG)CN substrates provides no KIE and HBpin is not implicated in the rate determining process during catalysis. Irrespective of these differences, a common mechanism is proposed in which the rate determining steps are deduced to vary through the establishment of several pre-equilibria, the relative positions of which are determined by the respective stabilities of the dimeric and monomeric magnesium aldimide and magnesium aldimidoborate intermediates as a result of adjustments to the basicity of the nitrile substrate. More generally, these observations indicate that homogeneous processes performed under heavier alkaline earth catalysis are likely to demonstrate previously unappreciated mechanistic diversity.
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Affiliation(s)
- Catherine Weetman
- Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
| | - Mathew D Anker
- Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
| | - Merle Arrowsmith
- Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
| | - Michael S Hill
- Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
| | - Gabriele Kociok-Köhn
- Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
| | - David J Liptrot
- Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
| | - Mary F Mahon
- Department of Chemistry , University of Bath , Claverton Down , Bath , BA2 7AY , UK .
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Pelosi G, Ravera M, Gabano E, Fregonese F, Osella D. Unprecedented one-pot synthesis of an unsymmetrical cisplatin-based Pt(IV)-acetamidato complex. Chem Commun (Camb) 2015; 51:8051-3. [PMID: 25865106 DOI: 10.1039/c5cc02477c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe herein a novel Pt(IV)-acetamidato complex as a result of the one-pot reaction between cisplatin and the highly reactive peroxyacetimidic acid generated in situ. This is the first example of a Pt(IV) complex containing a N-donor ligand coordinated during the Pt(II) → Pt(IV) oxidation step. Remarkably, the Pt(IV)-amidato compound is highly soluble and stable in water; it represents an interesting building block for the further development of Pt(IV) antitumor prodrugs.
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Affiliation(s)
- Giorgio Pelosi
- Dipartimento di Chimica, Università di Parma, Parco Area delle Scienze, 17/A, 43124 Parma, Italy
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6
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Sinisi M, Gandin V, Saltarella T, Intini FP, Pacifico C, Marzano C, Natile G. Synthesis, characterization, and biological activity of platinum II, III, and IV pivaloamidine complexes. J Biol Inorg Chem 2014; 19:1081-97. [PMID: 24850131 DOI: 10.1007/s00775-014-1146-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 05/03/2014] [Indexed: 11/24/2022]
Abstract
Imino ligands have proven to be able to activate the trans geometry of platinum(II) complexes towards antitumor activity. These ligands, like aromatic N-donor heterocycles, have a planar shape but, different from the latter, have still an H atom on the coordinating nitrogen which can be involved in H-bond formation. Three classes of imino ligands have been extensively investigated: iminoethers (HN=C(R)OR'), ketimines (HN=CRR'), and amidines (HN=C(R)NR'R″). The promising efficacy of the platinum compounds with amidines (activity comparable to that of cisplatin for cis complexes and much greater than that of transplatin for trans complexes) prompted us to extend the investigation to amidine complexes with a bulkier organic residue (R = t-Bu). The tert-butyl group can confer greater affinity for lipophilic environments, thus potentiating the cellular uptake of the compound. In the present study we describe the synthesis and characterization of pivaloamidine complexes of platinum(II), (cis and trans-[PtCl2(NH3){Z-HN=C(t-Bu)NH2}] and cis and trans-[PtCl2{Z-HN=C(t-Bu)NH2}2]), platinum(III) ([Pt2Cl4{HN=C(t-Bu)NH}2(NH3)2]), and platinum(IV) (trans-[PtCl4(NH3){Z-HN=C(t-Bu)NH2}] and trans-[PtCl4{Z-HN=C(t-Bu)NH2}2]). The cytotoxicity of all new Pt complexes was tested toward a panel of cultured cancer cell lines, including cisplatin and multidrug resistant variants. In addition, cellular uptake and DNA binding, perturbations of cell cycle progression, induction of apoptosis, and p53 activation were investigated for the most promising compound trans-[PtCl2(NH3){Z-HN=C(t-Bu)NH2}]. Remarkably, the latter complex was able to overcome both acquired and intrinsic cisplatin resistance.
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Affiliation(s)
- Marilù Sinisi
- Dipartimento di Chimica, University of Bari "Aldo Moro", via E. Orabona 4, 70125, Bari, Italy
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Zhang Z, Wu LZ, Geng ZR, Wang ZL. Cadmium(II) mediated addition of methanol to nitrile-functionalized 1,4,7-triazacyclononanes. Inorganica Chim Acta 2014. [DOI: 10.1016/j.ica.2014.02.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Lasri J, Kuznetsov ML, Guedes da Silva MFC, Pombeiro AJL. PtII-Mediated Imine–Nitrile Coupling Leading to Symmetrical (1,3,5,7,9-Pentaazanona-1,3,6,8-tetraenato)Pt(II) Complexes Containing the Incorporated 1,3-Diiminoisoindoline Moiety. Inorg Chem 2012; 51:10774-86. [DOI: 10.1021/ic301176b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Jamal Lasri
- Centro de Química Estrutural,
Complexo I, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon,
Portugal
| | - Maxim L. Kuznetsov
- Centro de Química Estrutural,
Complexo I, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon,
Portugal
| | - M. Fátima C. Guedes da Silva
- Centro de Química Estrutural,
Complexo I, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon,
Portugal
- Universidade Lusófona de Humanidades e Tecnologias, Av. Campo Grande 376,
ULHT Lisbon, 1749-024, Lisbon, Portugal
| | - Armando J. L. Pombeiro
- Centro de Química Estrutural,
Complexo I, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon,
Portugal
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Synthesis and hydrolysis of cis-octahedral nickel(II) complexes with C-racemic tetraaza macrocycles bearing two imidate ester pendant arms. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2012.05.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Wang Q, Gushchin PV, Bokach NA, Haukka M, Kukushkin VY. Facile base-free addition of methanol to PtII-activated nitriles. X-ray structure of a platinum(II) complex bearing unsymmetrical N-bound urea. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2011.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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11
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Bolotin DS, Bokach NA, Haukka M, Kukushkin VY. Platinum(IV)-Mediated Nitrile-Amidoxime Coupling Reactions: Insights into the Mechanism for the Generation of 1,2,4-Oxadiazoles. Chempluschem 2012. [DOI: 10.1002/cplu.201100047] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Chernyshev AN, Bokach NA, Gushchin PV, Haukka M, Kukushkin VY. Reactions of platinum(iv)-bound nitriles with isomeric nitroanilines: addition vs. substitution. Dalton Trans 2012; 41:12857-64. [DOI: 10.1039/c2dt30986f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Michelin RA, Sgarbossa P, Sbovata SM, Gandin V, Marzano C, Bertani R. Chemistry and biological activity of platinum amidine complexes. ChemMedChem 2011; 6:1172-83. [PMID: 21630470 DOI: 10.1002/cmdc.201100150] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 04/26/2011] [Indexed: 01/06/2023]
Abstract
Platinum amidine complexes represent a new class of potential antitumor drugs that contain the imino moiety HN=C(sp(2)) bonded to the platinum center. They can be related to the iminoether derivatives, which were recently shown to be the first Pt(II) compounds with a trans configuration endowed with anticancer activity. The chemical and biological properties of platinum amidine complexes, and more generally of platinum imino derivatives, can be rationally modified through suitable synthetic procedures with the aim of improving their cytotoxicity and antitumor activity. The addition of protic nucleophiles to nitriles coordinated to platinum in various oxidation states can offer a wide variety of complexes with chemical, structural, and physical properties specifically tuned for a more efficacious biological response.
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Affiliation(s)
- Rino A Michelin
- Department of Chemical Processes of Engineering, Padova University, Via F. Marzolo 9, 35131 Padova, Italy
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Turner DR, Chesman ASR, Murray KS, Deacon GB, Batten SR. The chemistry and complexes of small cyano anions. Chem Commun (Camb) 2011; 47:10189-210. [PMID: 21773626 DOI: 10.1039/c1cc11909e] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- David R Turner
- School of Chemistry, Monash University, Clayton, Vic 3800, Australia.
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15
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Zhdanov AP, Lisovsky MV, Goeva LV, Razgonyaeva GA, Polyakova IN, Zhizhin KY, Kuznetsov NT. Nucleophilic addition of alcohols to the C-N multiple bonds of the nitrilium substituent in the anion [2-B10H9(N≡CMe)]−. Russ Chem Bull 2010. [DOI: 10.1007/s11172-009-0234-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Kuznetsov ML, Bokach NA, Kharlampidi DD, Medvedev YN, Kukushkin VY, Dementiev AI. Theoretical study of nucleophilic addition of amines to organic nitriles. RUSS J GEN CHEM+ 2010. [DOI: 10.1134/s1070363210030151] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Chulkova TG, Gushchin PV, Haukka M, Kukushkin VY. 18-Crown-6 as a linker for (imino ester)2Pt centers providing their assembly into 1D arrays via hydrogen bonding. INORG CHEM COMMUN 2010. [DOI: 10.1016/j.inoche.2010.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Kuznetsov ML, Bokach NA, Kukushkin VY, Dement’ev AI. Theoretical study of ammonia nucleophilic addition to nitriles in platinum complexes. RUSS J GEN CHEM+ 2009. [DOI: 10.1134/s107036320902011x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Kuznetsov ML, Kukushkin VY, Pombeiro AJL. Reactivity of Pt- and Pd-bound nitriles towards nitrile oxides and nitrones: substitution vs. cycloaddition. Dalton Trans 2008:1312-22. [PMID: 18305843 DOI: 10.1039/b713425h] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Reactions of the nitrone CH3CH=N(CH3)O and the nitrile oxide CH3C[triple bond]NO with the nitrile complexes trans-[MCl2(N[triple bond]CCH3)2] (M = Pt, 1; Pd, 2) were investigated by theoretical methods at B3LYP and, for some processes, CCSD(T) levels of theory. The mechanisms of substitutions and cycloadditions were studied in detail. The former occur via a concerted asynchronous mechanism of dissociative type. The calculations of the metal-ligand bond energies in the starting complexes and substitution products and the analysis of structural features of the transition states indicate that the M-N bond dissociation (rather than M-O bond formation) is the step, which controls the reactivity of and in substitutions. The different chemical behaviours of the Pt and Pd complexes towards the 1,3-dipoles were investigated. The exclusive isolation of cycloaddition rather than substitution products in any solvents in the case of is both kinetically and thermodynamically controlled. The switch of the reaction mode from cycloaddition to substitution for 2 in CH2Cl2 solution is caused by the significantly lower Pd-N bond energy in comparison with the Pt-N bond energy, consistent with the higher lability of the Pd complexes. The different chemical behaviour of 2 in CH3CN and CH2Cl2 solvents is accounted for by the great excess of acetonitrile in the CH3CN solution rather than a different solvation character. The relative variation of Wiberg bond indices along the reaction path is proposed as a quantitative criterion for the classification of the reaction mechanism.
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Affiliation(s)
- Maxim L Kuznetsov
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
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Orto P, Selby HD, Ferris D, Maeyer JR, Zheng Z. Alcohol Addition to Acetonitrile Activated by the [Re6(μ3-Se)8]2+ Cluster Core. Inorg Chem 2007; 46:4377-9. [PMID: 17458960 DOI: 10.1021/ic7004985] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The addition of methanol and ethanol to the previously reported cluster solvates [Re6(mu3-Se)8(PEt3)5(MeCN)](SbF6)2 and trans-[Re6(mu3-Se)8(PEt3)4(CH3CN)2][SbF6]2 afforded three cluster complexes with imino ester ligands: {Re6(mu3-Se)8(PEt3)5[HN=C(OCH3)(CH3)]}(SbF6)2, {Re6(mu3-Se)8(PEt3)5[HN=C(OCH2CH3)(CH3)]}{SbF6}2, and trans-{Re6(mu3-Se)8(PEt3)4[HN=C(OCH3)(CH3)]2}{SbF6}2. In all cases, predominant formation of the Z isomers was observed.
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Affiliation(s)
- Peter Orto
- Department of Chemistry, The University of Arizona, Tucson, Arizona 85721, USA
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Scaffidi-Domianello YY, Nazarov AA, Haukka M, Galanski MS, Keppler BK, Schneider J, Du P, Eisenberg R, Kukushkin VY. First Example of the Solid-State Thermal Cyclometalation of Ligated Benzophenone Imine Giving Novel Luminescent Platinum(II) Species. Inorg Chem 2007; 46:4469-82. [PMID: 17451237 DOI: 10.1021/ic062414k] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The (benzophenone imine)platinum(II) compounds trans-[PtCl2(Ph2C=NH)(RR'SO)] [R, R'=Me, Me (2); n-Pr, n-Pr (3); (CH2)4 (4); Me, Ph (5); Me, p-MeC6H4 (6)] were prepared by the reaction of Ph2C=NH with K[PtCl3(RR'SO)], obtained in situ from K2[PtCl4] and the corresponding sulfoxide, giving 2-6 as well as cis-[PtCl2(Ph2C=NH)2] (1) as a minor product. The complexes were characterized by 1H, 13C, and 195Pt NMR and IR spectroscopy, electrospray ionization mass spectrometry, and C, H, and N elemental analysis. The X-ray crystallography of 1 enables confirmation of the cis configuration of the complex, while in 2 and 4.1/2CHCl3, the imine and sulfoxide ligands are mutually trans. The solid-state structure of 4.1/2CHCl3 consists of two dimeric Pt moieties representing a rather weak Pt...Pt interaction. The dimeric architecture of 4.1/2CHCl3 is enhanced by the hydrogen bonding between imine H atoms and O atoms. The orthometalation of 1 and 2-6 proceeds both in the solid phase and in a toluene suspension, leading to the formation of [PtCl{Ph(C6H4)C=NH}(Ph2C=NH)] (7) and [PtCl{Ph(C6H4)C=NH}(RR'SO)] (8-12), respectively, isolated in nearly quantitative yields. Complexes 8-12 are emissive at room temperature both in solution (lambdaemmax approximately 535 nm) and in the solid state (lambdaemmax 560-610 nm), with excited-state lifetimes of ca. 300-600 ns, representing a new family of PtII-based luminescent complexes. Compounds 8 and 10 have been characterized by X-ray analysis, confirming the square-planar coordination geometry of the metal center with the almost planar platinacycles. In 8, the asymmetric unit contains two independent Pt molecules, while in 10, it includes four Pt molecules linked by the intermolecular hydrogen-bonding network between the NH group and Cl atoms.
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Gushchin PV, Bokach NA, Luzyanin KV, Nazarov AA, Haukka M, Kukushkin VY. PtII-Mediated Nitrile−Tetramethylguanidine Coupling as a Key Step for a Novel Synthesis of 1,6-Dihydro-1,3,5-triazines. Inorg Chem 2007; 46:1684-93. [PMID: 17266300 DOI: 10.1021/ic061884b] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The coupling between tetramethylguanidine, HN=C(NMe2)2, and coordinated organonitriles in the platinum(II) complexes cis/trans-[PtCl2(RCN)2] (R = Me, Et, Ph) proceeds rapidly under mild conditions to afford the diimino compounds containing two N-bound monodentate 1,3-diaza-1,3-diene ligands [PtCl2{NH=C(R)N=C(NMe2)2}2] (R = Et, trans-1; R = Ph, trans-2; R = Me, cis-3; R = Et, cis-4), and this reaction is the first observation of metal-mediated nucleophilic addition of a guanidine to ligated nitrile. Complexes 1-4 were characterized by elemental analyses (C, H, N), X-ray diffraction, FAB mass spectrometry, IR, and 1H and 13C{1H} NMR spectroscopies; assignment of signals from E/Z-forms of 1,3-diaza-1,3-diene ligands and verification of routes for their Z right harpoon over left harpoon E isomerization in solution were performed using 2D 1H,1H-COSY, 1H,13C-HETCOR, and 1D NOE NMR experiments. The newly formed and previously unknown 1,3-diaza-1,3-dienes NH=C(R)N=C(NMe2)2 were liberated from the platinum(II) complexes [PtCl2{NH=C(R)N=C(NMe2)2}2] (1-3) by substitution with 2 equiv of 1,2-bis-(diphenylphosphino)ethane (dppe) to give the uncomplexed HN=C(R)N=C(NMe2)2 species (5-7) in solution and the solid [Pt(dppe)2](Cl)2. The former were utilized in situ, after filtration of the latter, in the reaction with 1,3-di-p-tolylcarbodiimide, (p-tol)N=C=N(tol-p), in CDCl3 to generate (6E)-N,N-dimethyl-1-(4-methylphenyl)-6-[(4-methylphenyl)imino]-1,6-dihydro-1,3,5-triazin-2-amines) (8-10) due to the [4 + 2]-cycloaddition accompanying elimination of HNMe2. The formulation of 8-10 is based on ESI-MS, 1H, 13C{1H} NMR, and X-ray crystal structures determined for 9 and 10. The reaction of 1,3-diaza-1,3-dienes with 1,3-di-p-tolylcarbodiimide, described in this article, constitutes a novel synthetic approach to a useful class of heterocyclic species like 1,6-dihydro-1,3,5-triazines.
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Affiliation(s)
- Pavel V Gushchin
- Saint Petersburg State University, 198504 Stary Petergof, Russian Federation, Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Avenida Rovisco Pais, 1049-01 Lisbon, Portugal
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Kuznetsov ML, Kozlova LV, Dement’ev AI. Theoretical study of 1,3-dipolar cycloaddition of nitrones to doubly activated nitriles. RUSS J INORG CHEM+ 2006. [DOI: 10.1134/s0036023606100147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Khripun AV, Kukushkin VY, Selivanov SI, Haukka M, Pombeiro AJL. Unusual Reaction between (Nitrile)Pt Complexes and Pyrazoles: Substitution Proceeds via Metal-Mediated Nitrile−Pyrazole Coupling Followed by Elimination of the Nitrile. Inorg Chem 2006; 45:5073-83. [PMID: 16780329 DOI: 10.1021/ic0602300] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The reaction of platinum(IV) complex trans-[PtCl4(EtCN)2] with pyrazoles 3,5-RR'pzH (R/R' = H/H, Me/H, Me/Me) leads to the formation of the trans-[PtCl4{NH=C(Et)(3,5-RR'pz)}2] (1-3) species due to the metal-mediated nitrile-pyrazole coupling. Pyrazolylimino complexes 1-3 (i) completely convert to pyrazole complexes cis-[PtCl4(3,5-RR'pzH)2] by elimination of EtCN upon reflux in a CH2Cl2 solution or upon heating in the solid state; (ii) undergo exchange at the imino C atom with another pyrazole different from that contained in the pyrazolylimino ligand. The reaction of trans-[PtIICl2(EtCN)2] and 3,5-RR'pzH, conducted under conditions similar to those for trans-[PtIVCl4(EtCN)2], is much less selective, and the composition of the products strongly depends on the pyrazole employed: (a) with pzH, the reaction gives a mixture of three products, i.e., [PtCl2NH=C(Et)pz-kappa2N,N}] (4), [PtCl(pzH){NH=C(Et)pz-kappa2N,N}]Cl (5), and [Pt(pzH)2{NH=C(Et)pz-kappa2N,N}]Cl2 (6) (complexes 5 and 6 are rather unstable and gradually transform to trans-[PtCl2(pzH2] and [Pt(pzH)(4)]Cl(2) and free EtCN); (b) with 3,5-Me(2)pzH, the reaction leads to the formation of [PtCl2NH=C(Et)(3,5-Me2pz)-kappa2N,N}] (7) and [PtCl(3,5-Me2pzH)3]Cl (8); (c) in the case of asymmetric pyrazole 3(5)-MepzH, which can be added to EtCN and/or bind metal centers by any of the two nonequivalent nitrogen sites, a broad mixture of currently unidentified products is formed. The reduction of 1-3 with Ph3P=CHCO2Me in CHCl3 allows for the formation of corresponding platinum(II) compounds trans-[PtCl2{NH=C(Et)(3,5-RR'pz)}2] (9-11). Ligands NH=C(Et)(3,5-RR'pz) (12-14) were almost quantitatively liberated from 9-11 with 2 equiv of 1,2-bis-(diphenylphosphino)ethane in CDCl3, giving free imines 12-14 in solution and the precipitate of trans-[Pt(dppe)2](Cl)2. Pyrazolylimines 12-14 undergo splitting in CDCl3 solution at 20-25 degrees C for ca. 20 h to furnish the parent propiononitrile and the pyrazole 3,5-RR'pzH, but they can be synthetically utilized immediately after the liberation.
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Affiliation(s)
- Anatoly V Khripun
- Department of Chemistry, St. Petersburg State University, 198504 Stary Petergof, Russian Federation
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27
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Boccarelli A, Intini FP, Sasanelli R, Sivo MF, Coluccia M, Natile G. Synthesis and in vitro antitumor activity of platinum acetonimine complexes. J Med Chem 2006; 49:829-37. [PMID: 16420068 DOI: 10.1021/jm050986t] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cis- and trans-dichloro- and diiodo-platinum(II) complexes containing two acetonimines (cis- and trans-[PtX(2){HN=C(CH(3))(2)}(2)], 1 and 2 for X = Cl and 1' and 2' for X = I, respectively) or one acetonimine and one ammine (cis- and trans-[PtX(2)(NH(3)){HN=C(CH(3))(2)}], 3 and 4 for X = Cl and 3' and 4' for X = I, respectively) have been prepared from platinum-ammine precursors by condensation with acetone. Except for the cis-diiodo species, in all other cases the presence of a base was required. A crucial role of the ligand trans to the ammine undergoing condensation with acetone has been disclosed: the greater the trans effect the greater the reactivity. In a panel of human tumor cell lines representative of ovarian, colon, lung, and breast cancers, cis complexes 1 and 3 are less active than cis-DDP (mean IC(50) = 20, 12.5, and 2.8 microM, respectively), whereas trans complexes 2 and 4 are more active than trans-DDP (mean IC(50) = 10.6, 26, and 164 microM, respectively), thus indicating that substitution of acetonimine for one or two ammine ligands determines strikingly different effects depending upon the complex geometry.
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Affiliation(s)
- Angelina Boccarelli
- Dipartimento di Scienze Biomediche ed Oncologia Umana, University of Bari, 70124 Bari, Italy
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Liu F, Chen W. Oxidative Addition of Cl2, HClO to Square-Planar PtII Complexes: Synthesis and Structural Characterization of Platinum(II) and Platinum(IV) Bis(amidate) Complexes. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200500878] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Ghumaan S, Kar S, Mobin SM, Harish B, Puranik VG, Lahiri GK. 2,4,6-Tris(2-pyridyl)-1,3,5-triazine (tptz)-Derived [RuII(tptz)(acac)(CH3CN)]+ and Mixed-Valent [(acac)2RuIII{(μ-tptz-H+)-}RuII(acac)(CH3CN)]+. Inorg Chem 2006; 45:2413-23. [PMID: 16529460 DOI: 10.1021/ic0514288] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mononuclear [Ru(II)(tptz)(acac)(CH3CN)]ClO4 ([1]ClO4) and mixed-valent dinuclear [(acac)2Ru(III){(mu-tptz-Eta+)-}Ru(II)(acac)(CH3CN)]ClO4 ([5]ClO4; acac = acetylacetonate) complexes have been synthesized via the reactions of Ru(II)(acac)2(CH3CN)2 and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), in 1:1 and 2:1 molar ratios, respectively. In [1]ClO4, tptz binds with the Ru(II) ion in a tridentate N,N,N mode (motif A), whereas in [5]ClO4, tptz bridges the metal ions unsymmetrically via the tridentate neutral N,N,N mode with the Ru(II) center and cyclometalated N,C- state with the Ru(III) site (motif F). The activation of the coordinated nitrile function in [1]ClO4 and [5]ClO4 in the presence of ethanol and alkylamine leads to the formation of iminoester ([2]ClO4 and [7]ClO4) and amidine ([4]ClO4) derivatives, respectively. Crystal structure analysis of [2]ClO4 reveals the formation of a beautiful eight-membered water cluster having a chair conformation. The cluster is H-bonded to the pendant pyridyl ring N of tptz and also with the O atom of the perchlorate ion, which, in turn, makes short (C-H- - - - -O) contacts with the neighboring molecule, leading to a H-bonding network. The redox potentials corresponding to the Ru(II) state in both the mononuclear {[(acac)(tptz)Ru(II)-NC-CH3]ClO4 ([1]ClO4) >> [(acac)(tptz)Ru(II)-NH=C(CH3)-OC2H5]ClO4 ([2]ClO4) > [(acac)(tptz)Ru(II)-NH2-C6H4(CH3)]ClO4 ([3]ClO4) > [(acac)(tptz)Ru(II)-NH=C(CH3)-NHC2H5]ClO4 ([4]ClO4)} and dinuclear {[(acac)2Ru(III){(mu-tptz-H+)-}Ru(II)(acac)(NC-CH3)]ClO4 ([5]ClO4), [(acac)2Ru(III){(mu-tptz-H+(N+-O-)2)-}Ru(II)(acac)(NC-CH3)]ClO4 ([6]ClO4), [(acac)2Ru(III){(mu-tptz-H+)-}Ru(II)(acac)(NH=C(CH3)-OC2H5)]ClO4 ([7]ClO4), and [(acac)2Ru(III){(mu-tptz-Eta+)-}Ru(II)(acac)(NC4H4N)]ClO4 ([8]ClO(4))} complexes vary systematically depending on the electronic nature of the coordinated sixth ligands. However, potentials involving the Ru(III) center in the dinuclear complexes remain more or less invariant. The mixed-valent Ru(II)Ru(III) species ([5]ClO4-[8]ClO4) exhibits high comproportionation constant (Kc) values of 1.1 x 10(12)-2 x 10(9), with substantial contribution from the donor center asymmetry at the two metal sites. Complexes display Ru(II)- and Ru(III)-based metal-to-ligand and ligand-to-metal charge-transfer transitions, respectively, in the visible region and ligand-based transitions in the UV region. In spite of reasonably high K(c) values for [5]ClO4-[8]ClO4, the expected intervalence charge-transfer transitions did not resolve in the typical near-IR region up to 2000 nm. The paramagnetic Ru(II)Ru(III) species ([5]ClO4-[8]ClO4) displays rhombic electron paramagnetic resonance (EPR) spectra at 77 K (g approximately 2.15 and Deltag approximately 0.5), typical of a low-spin Ru(III) ion in a distorted octahedral environment. The one-electron-reduced tptz complexes [Ru(II)(tptz.-)(acac)(CEta3CN)] (1) and [(acac)2Ru(III){(mu-tptz-Eta+).2-}Ru(II)(acac)(CH3CN)] (5), however, show a free-radical-type EPR signal near g = 2.0 with partial metal contribution.
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Affiliation(s)
- Sandeep Ghumaan
- Department of Chemistry, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India
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30
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Luzyanin KV, Kukushkin VY, Kuznetsov ML, Ryabov AD, Galanski MS, Haukka M, Tretyakov EV, Ovcharenko VI, Kopylovich MN, Pombeiro AJL. Kinetic and Thermodynamic Aspects of the Regioselective Addition of Bifunctional Hydroxylaminooxime-type HO-Nucleophiles to Pt-Complexed Nitriles. Inorg Chem 2006; 45:2296-306. [PMID: 16499396 DOI: 10.1021/ic051909r] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The coupling between coordinated propiononitriles in trans-[PtCln(EtCN)2] (n = 2, 4) and the 1,2-hydroxylaminooximes HON(H)CMe2C(R)=NOH (R = Ph 1, Me 2) proceeds smoothly in CHCl(3) at ca. 40-45 degrees C and gives trans-[PtCln{NH=C(Et)ON(H)CMe2C(R)=NOH}2] (n = 2, R = Ph 5, Me 6; n = 4, R = Ph 7, Me 8) in 80-85% isolated yields. The reaction is highly regioselective, and both spectroscopic (IR; FAB+-MS; 1D 1H, 13C{1H}, and 195Pt NMR; and 2D 1H,13C HMQC, 1H,13C HMBC, and 1H,15N HMQC NMR) and X-ray data for 6-8 suggest that the addition proceeds exclusively via the hydroxylamine moiety of the 1,2-hydroxylaminooxime species; the existence of an oxime group remote from the nucleophile was also confirmed. Heating of 6 in air leads to its conversion to the unusual nitrosoalkane complex [PtCl2{HON=C(Me)C(Me)2N=O}] (9), whereas in the case of 5, only the metal-free salt [H3NC(Me)2C(Ph)=NOH]2(NO3)Cl.H2O (10) was isolated. To compare the kinetic aspects and trends in the addition of both types of nucleophiles (oximes and hydroxylamines; for the latter, see our recent work: Inorg. Chem. 2005, 44, 2944) to coordinated nitriles, a kinetic study of the addition of HON=C(CH2Ph)2 to [Ph3PCH2Ph][PtCl5(EtCN)] (11) to give [Ph(3)PCH(2)Ph][PtCl(5){NH=C(Et)ON=C(CH2Ph)2}] (12) was performed. The calculated rate constant k2 of 3.9 x 10(-6) M(-1) s(-1) at -20 degrees C for the addition of the oxime indicates that the hydroxylamine is, by a factor 1.7 x 10(4), more reactive toward the addition to nitriles than the oxime. Results of the synthetic, kinetic, and theoretical (at the B3LYP level of theory) studies have demonstrated that the high regioselectivity of the reactions of the 1,2-hydroxylaminooximes with ligated nitriles is both kinetically and thermodynamically controlled.
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Affiliation(s)
- Konstantin V Luzyanin
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Avenida Rovisco Pais, 1049-001 Lisbon, Portugal
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31
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Le Hénanf M, Le Roy C, Pétillon FY, Schollhammer P, Talarmin J. Nitrate‐ and Nitrite‐Assisted Conversion of an Acetonitrile Ligand Into an Amidato Bridge at an {Mo
2
(Cp)
2
(μ‐SMe)
3
} Core: Electrochemistry of the Amidato Complex [Mo
2
(Cp)
2
(μ‐SMe)
3
{μ‐η
1
,η
1
‐OC(Me)NH}]
+. Eur J Inorg Chem 2005. [DOI: 10.1002/ejic.200500315] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Marc Le Hénanf
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, 6 Av. V. Le Gorgeu, CS 93837, 29238 Brest cedex 3, France
| | - Christine Le Roy
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, 6 Av. V. Le Gorgeu, CS 93837, 29238 Brest cedex 3, France
| | - François Y. Pétillon
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, 6 Av. V. Le Gorgeu, CS 93837, 29238 Brest cedex 3, France
| | - Philippe Schollhammer
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, 6 Av. V. Le Gorgeu, CS 93837, 29238 Brest cedex 3, France
| | - Jean Talarmin
- UMR CNRS 6521 Chimie, Electrochimie Moléculaires et Chimie Analytique, Université de Bretagne Occidentale, 6 Av. V. Le Gorgeu, CS 93837, 29238 Brest cedex 3, France
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32
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Kuznetsov ML, Nazarov AA, Pombeiro AJL. Protic Conversion of Nitrile into Azavinylidene Complexes of Rhenium, a Mechanistic Theoretical Study. J Phys Chem A 2005; 109:8187-98. [PMID: 16834205 DOI: 10.1021/jp0527913] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mechanism of the protonation of the rhenium nitrile chloro-complexes [ReCl(NCCH3)(PH3)4] (2), taken as models of the real systems [ReCl(NCR)(dppe)(2)] (dppe = Ph2PCH2CH2PPh2), leading to the azavinylidene products [ReCl(NC(H)CH3)(PH3)4]+ (3) was investigated by theoretical methods at the B3LYP level of theory. Electrostatic and molecular orbital arguments and thermodynamic, kinetic, and steric factors are analyzed and indicate that the chlorine atom is the most probable site of the initial proton attack, although the direct protonation of the nitrile carbon atom is also possible as a concurrent process. For the cis-isomer of 2, the initially formed chloro-protonated species cis-[Re(ClH)(NCCH3)(PH3)4]+ further converts to the azavinylidene cis-3 via either an acid-independent 1,4-proton shift or an acid-base catalyzed pathway involving a second protonation of the nitrile carbon atom to give cis-[Re(ClH)(NC(H)CH3)(PH3)4]2+ followed by elimination of the proton from the chlorine atom.
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Affiliation(s)
- Maxim L Kuznetsov
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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33
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Luzyanin KV, Kukushkin VY, Ryabov AD, Haukka M, Pombeiro AJL. Kinetic and Mechanistic Study of the Pt(II) versus Pt(IV) Effect in the Platinum-Mediated Nitrile−Hydroxylamine Coupling. Inorg Chem 2005; 44:2944-53. [PMID: 15819582 DOI: 10.1021/ic048388c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The metal-mediated coupling between coordinated EtCN in the platinum(II) and platinum(IV) complexes cis- and trans-[PtCl(2)(EtCN)(2)], trans-[PtCl(4)(EtCN)(2)], a mixture of cis/trans-[PtCl(4)(EtCN)(2)] or [Ph(3)PCH(2)Ph][PtCl(n)(EtCN)] (n = 3, 5), and dialkyl- and dibenzylhydroxylamines R(2)NOH (R = Me, Et, CH(2)Ph, CH(2)C(6)H(4)Cl-p) proceeds smoothly in CH(2)Cl(2) at 20-25 degrees C and the subsequent workup allowed the isolation of new imino species [PtCl(n){NH=C(Et)ONR(2)}(2)] (n = 2, R = Me, cis-1 and trans-1; Et, cis-2 and trans-2; CH(2)Ph, cis-3 and trans-3; CH(2)C(6)H(4)Cl-p, cis-4 and trans-4; n = 4, R = Me, trans-9; Et, trans-10; CH(2)Ph, trans-11; CH(2)C(6)H(4)Cl-p, trans-12) or [Ph(3)PCH(2)Ph][PtCl(n){NH=C(Et)ONR(2)}] (n = 3, R = Me, 5; Et, 6; CH(2)Ph, 7; CH(2)C(6)H(4)Cl-p, 8; n = 5, R = Me, 13; Et, 14; CH(2)Ph, 15; CH(2)C(6)H(4)Cl-p, 16) in excellent to good (95-80%) isolated yields. The reduction of the Pt(IV) complexes 9-16 with the ylide Ph(3)P=CHCO(2)Me allows the synthesis of Pt(II) species 1-8. The compounds 1-16 were characterized by elemental analyses (C, H, N), FAB-MS, IR, (1)H, (13)C{(1)H}, and (31)P{(1)H} NMR (the latter for the anionic type complexes 5-8 and 13-16) and by X-ray crystallography for the Pt(II) (cis-1, cis-2, and trans-4) and Pt(IV) (15) species. Kinetic studies of addition of R(2)NOH (R = CH(2)C(6)H(4)Cl-p) to complexes [Ph(3)PCH(2)Ph][Pt(II)Cl(3)(EtCN)] and [Ph(3)PCH(2)Ph][Pt(IV)Cl(5)(EtCN)] by the (1)H NMR technique revealed that both reactions are first order in (p-ClC(6)H(4)CH(2))(2)NOH and Pt(II) or Pt(IV) complex, the second-order rate constant k(2) being three orders of magnitude larger for the Pt(IV) complex. The reactions are intermolecular in nature as proved by the independence of k(2) on the concentrations of added EtC triple bond N and Cl(-). These data and the calculated values of Delta H++ and Delta S++ are consistent with the mechanism involving the rate-limiting nucleophilic attack of the oxygen of (p-ClC(6)H(4)CH(2))(2)NOH at the sp-carbon of the C triple bond N bond followed by a fast proton migration.
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Affiliation(s)
- Konstantin V Luzyanin
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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Makarycheva-Mikhailova AV, Tronova EA, Kukushkin VY. Synthesis of amidine complexes by metal-mediated addition of amino acid esters to coordinated nitriles. Russ Chem Bull 2005. [DOI: 10.1007/s11172-005-0330-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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35
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Westra AN, Bourne SA, Koch KR. First metallamacrocyclic complexes of Pt(iv) with 3,3,3′,3′-tetraalkyl-1,1′-phenylenedicarbonylbis(thioureas): synthesis by direct or electrolytic oxidative addition of I2, Br2 and Cl2. Dalton Trans 2005:2916-24. [PMID: 16094481 DOI: 10.1039/b507188g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Elemental I(2) and Br(2) cleanly react with the 3:3 Pt(ii) metallamacrocycle of 3,3,3',3'-tetra(n-butyl)-1,1'-terephthaloylbis(thiourea)(cis-[Pt(II)(3)(L(p)(1)-S,O)(3)]3), in chloroform at room temperature, to yield oxidative addition products; (195)Pt NMR studies reveal that a stepwise oxidative addition readily occurs to each of the Pt(ii) centres in the metallamacrocycle to yield the mixed valence species cis-[Pt(II)(2)Pt(IV)I(2)(L(p)(1)-S,O)(3)] and cis-[Pt(II)Pt(IV)(2)I(4)(L(p)(1)-S,O)(3)], and the fully oxidised cis-[Pt(IV)(3)I(6)(L(p)(1)-S,O)(3)] in solution, depending on the mole ratio I(2):3. Similar results are obtained on treatment of solutions of 3 with elemental Br(2). Treatment of the corresponding 2:2 Pt(ii) complex of 3,3,3',3'-tetraethyl-1,1'-isophthaloylbis(thiourea)(cis-[Pt(II)(2)(L(m)(1)-S,O)(2)]4) with iodine, results in facile oxidative addition to yield cis-[Pt(IV)(2)(L(m)(1)-S,O)(2)I(4)], with a trans-Pt(iv)-iodo arrangement. Molecules in the crystal structure of 5 have their trans-Pt(iv)-iodo axes essentially aligned, with very close intermolecular iodide contacts (3.775(1)A), resulting in chains of weakly bound metallamacrocycles in the solid. An alternative electrolytic synthesis method, using a simple two-compartment glass cell containing 4 and a chosen halide salt in dichloromethane, led to the formation of cis-[Pt(IV)(2)(L(m)(1)-S,O)(2)Br(4)] 6 and cis-[Pt(IV)(2)(L(m)(1)-S,O)(2)Cl(4)] 7, completing characterization of a series of first-reported trans-Pt(iv)-X (X=I, Br, Cl) metallamacrocyclic complexes.
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Affiliation(s)
- Arjan N Westra
- Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
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36
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Makarycheva-Mikhailova AV, Selivanov SI, Bokach NA, Kukushkin VY, Kelly PF, Pombeiro AJL. Nucleophilic addition of bifunctional sulfimidosulfides to platinum(IV)-coordinated nitriles. Russ Chem Bull 2004. [DOI: 10.1007/s11172-005-0017-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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37
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Kuznetsov ML. Is the charge on the nitrile carbon atom a driving force of the nucleophilic addition to coordinated nitriles? ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2003.12.042] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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38
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Bokach NA, Pakhomova TB, Kukushkin VY, Haukka M, Pombeiro AJL. Hydrolytic metal-mediated coupling of dialkylcyanamides at a Pt(IV) center giving a new family of diimino ligands. Inorg Chem 2004; 42:7560-8. [PMID: 14606852 DOI: 10.1021/ic034800x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Addition of excess R(2)NCN to an aqueous solution of K(2)[PtCl(4)] led to the precipitation of [PtCl(2)(NCNR(2))(2)] (R(2) = Me(2) 1; Et(2) 2; C(5)H(10) 3; C(4)H(8)O, 4) in a cis/trans isomeric ratio which depends on temperature. Pure isomers cis-1-3 and trans-1-3 were separated by column chromatography on SiO(2), while trans-4 was obtained by recrystallization. Complexes cis-1-3 isomerize to trans-1-3 on heating in the solid phase at 110 degrees C; trans-1 has been characterized by X-ray crystallography. Chlorination of the platinum(II) complexes cis-1-3 and trans-1-4 gives the appropriate platinum(IV) complexes [PtCl(4)(NCNR(2))(2)] (cis-5-7 and trans-5-8). The compound cis-6 was also obtained by treatment of [PtCl(4)(NCMe)(2)] with neat Et(2)NCN. The platinum(IV) complex trans-[PtCl(4)(NCNMe(2))(2)] (trans-5) in a mixture of undried Et(2)O and CH(2)Cl(2) undergoes facile hydrolysis to give trans-[PtCl(4)[(H)=C(NMe(2))OH](2)] (9; X-ray structure has been determined). The hydrolysis went to another direction with the cis-[PtCl(4)(NCNR(2))(2)] (cis-5-7) which were converted to the metallacycles [PtCl(4)[NH=C(NR(2))OC(NR(2))=NH]] (11-13) due to the unprecedented hydrolytic coupling of the two adjacent dialkylcyanamide ligands giving a novel (for both coordination and organic chemistry) diimino linkage. Compounds 11-13 and also 14 (R(2) = C(4)H(8)O) were alternatively obtained by the reaction between cis-[PtCl(4)(MeCN)(2)] and neat undried NCNR(2). The structures of complexes 11, 13, and 14 were determined by X-ray single-crystal diffraction. All the platinum compounds were additionally characterized by elemental analyses, FAB mass-spectrometry, and IR and (1)H and (13)C[(1)H] NMR spectroscopies.
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Affiliation(s)
- Nadezhda A Bokach
- Department of Chemistry, St Petersburg State University, 198504 Stary Petergof, Russian Federation
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39
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Theoretical study on reactivity of coordinated nitriles: structure, bonding and reactivity of [ReCl4(NCCH3)2]. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2003.11.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bokach NA, Kukushkin VY, Haukka M, da Silva JJRF, Pombeiro AJL. Pop-the-cork strategy in synthetic utilization of imines: stabilization by complexation and activation via liberation of the ligated species. Inorg Chem 2003; 42:3602-8. [PMID: 12767199 DOI: 10.1021/ic034086j] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Treatment of trans-[PtCl(4)(RCN)(2)] (R = Me, Et) with ethanol allowed the isolation of trans-[PtCl(4)[E-NH[double bond]C(R)OEt](2)]. The latter were reduced selectively, by the ylide Ph(3)P[double bond]CHCO(2)Me, to trans-[PtCl(2)[E-NH[double bond]C(R)OEt](2)]. The complexed imino esters NH[double bond]C(R)OEt were liberated from the platinum(II) complexes by reaction with 2 equiv of 1,2-bis(diphenylphosphino)ethane (dppe) in chloroform; the cationic complex [Pt(dppe)(2)]Cl(2) precipitates almost quantitatively from the reaction mixture and can be easily separated by filtration to give a solution of NH[double bond]C(R)OEt with a known concentration of the imino ester. The imino esters efficiently couple with the coordinated nitriles in trans-[PtCl(4)(EtCN)(2)] to give, as the dominant product, [PtCl(4)[NH[double bond]C(Et)N[double bond]C(R)OEt](2)] containing a previously unknown linkage, i.e., ligated N-(1-imino-propyl)-alkylimidic acid ethyl esters. In addition to [PtCl(4)[NH[double bond]C(Et)N[double bond]C(Et)OEt](2)], another compound was generated as the minor product, i.e., [PtCl(4)(EtCN)[NH[double bond]C(Et)N[double bond]C(Et)OEt]], which was reduced to [PtCl(2)(EtCN)[NH[double bond]C(Et)N[double bond]C(Et)OEt]], and this complex was characterized by X-ray single-crystal diffraction. The platinum(IV) complexes [PtCl(4)[NH[double bond]C(Et)N[double bond]C(R)OEt](2)] are unstable toward hydrolysis and give EtOH and the acylamidine complexes trans-[PtCl(4)[Z-NH[double bond]C(Et)NHC(R)[double bond]O](2)], where the coordination to the Pt center results in the predominant stabilization of the imino tautomer NH[double bond]C(Et)NHC(R)[double bond]O over the other form, i.e., NH(2)C(Et)[double bond]NC(R)[double bond]O, which is the major one for free acylamidines. The structures of trans-[PtCl(4)[Z-NH[double bond]C(Et)NHC(R)[double bond]O](2)] (R = Me, Et) were determined by X-ray studies. The complexes [PtCl(4)[NH[double bond]C(Et)N[double bond]C(R)OEt](2)] were reduced to the appropriate platinum(II) compounds [PtCl(2)[NH[double bond]C(Et)N[double bond]C(R)OEt](2)], which, similarly to the appropriate Pt(IV) compounds, rapidly hydrolyze to yield the acylamidine complexes [PtCl(2)[NH[double bond]C(Et)NHC(R)[double bond]O](2)] and EtOH. The latter acylamidine compounds were also prepared by an alternative route upon reduction of the corresponding platinum(IV) complexes. Besides the first observation of the platinum(IV)-mediated nitrile-imine ester integration, this work demonstrates that the application of metal complexes gives new opportunities for the generation of a great variety of imines (sometimes unreachable in pure organic chemistry) in metal-mediated conversions of organonitriles, the "storage" of imino species in the complexed form, and their synthetic utilization after liberation.
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Affiliation(s)
- Nadezhda A Bokach
- St. Petersburg State University, 198504 Stary Petergof, Russian Federation
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Vallina AT, Stoeckli-Evans H, Neels A, Ensling J, Decurtins S. Iron-promoted nucleophilic additions to diimine-type ligands: a synthetic and structural study. Inorg Chem 2003; 42:3374-82. [PMID: 12739980 DOI: 10.1021/ic026079l] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here three examples of the reactivity of protic nucleophiles with diimine-type ligands in the presence of Fe(II) salts. In the first case, the iron-promoted alcoholysis reaction of one nitrile group of the ligand 2,3-dicyano-5,6-bis(2-pyridyl)-pyrazine (L1) permitted the isolation of an stable E-imido-ester, [Fe(L1')(2)](CF(3)SO(3))(2) (1), which has been characterized by spectroscopic studies (IR, ES-MS, Mössbauer), elemental analysis, and crystallographically. Compound 1 consists of mononuclear octahedrally coordinated Fe(II) complexes where the Fe(II) ion is in its low-spin state. The iron-mediated nucleophilic attack of water to the asymmetric ligand 2,3-bis(2-pyridyl)pyrido[3,4-b]pyrazine (L2) has also been studied. In this context, the crystal structures of two hydration-oxidation Fe(III) products, [Fe(L2')(2)](ClO(4))(3).3CH(3)CN (2) and trans-[FeL2"Cl(2)] (3), are described. Compounds 2 and 3 are both mononuclear Fe(III) complexes where the metals occupy octahedral positions. In principle, L2 is expected to coordinate to metal ions through its bipyridine-type units to form a five-membered ring; however, this is not the case in compounds 2 and 3. In 2, the ligand coordinates through its pyridines and through the hydroxyl group attached to the pyrazine imino carbon after hydration, that is, in an N,O,N tridentate manner. In compound 3, the ligand has suffered further transformations leading to a very stable diamido complex. In this case, the metal ion achieves its octahedral geometry by means of two pyridines, two amido N atoms, and two axial chlorine atoms. Magnetic susceptibility measurements confirmed the spin state of these two Fe(III) species: compounds 2 and 3 are low-spin and high-spin, respectively.
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Affiliation(s)
- Ana Tesouro Vallina
- Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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Makarycheva-Mikhailova AV, Kukushkin VY, Nazarov AA, Garnovskii DA, Pombeiro AJL, Haukka M, Keppler BK, Galanski MS. Amidines derived from Pt(IV)-mediated nitrile-amino alcohol coupling and their Zn(II)-catalyzed conversion into oxazolines. Inorg Chem 2003; 42:2805-13. [PMID: 12691592 DOI: 10.1021/ic034070t] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The reaction between the platinum(IV) complex trans-[PtCl(4)(EtCN)(2)] and the amino alcohols NH(2)CH(2)CH(2)OH, NH(2)CH(2)CH(Me)OH-(R)-(-), NH(2)CH(Ph)CH(2)OH-(R)-(-), NH(2)CH(Et)CH(2)OH-(R)-(-), NH(2)CH(Et)CH(2)OH-(S)-(+), and NH(2)CH(Pr(n)())CH(2)OH proceeds rapidly at room temperature in CH(2)Cl(2) to furnish the amidine complexes [PtCl(4)(HN=C(Et)NH(arcraise;)OH)(2)] (1-6) in good yield (70-80%). The related reaction between the platinum(II) complex trans-[PtCl(2)(EtCN)(2)] and monoethanolamine in a molar ratio of 1:2 in CH(2)Cl(2) results in the addition of 4 equiv of NH(2)CH(2)CH(2)OH per mole of complex to give [Pt(HN=C(Et)NHCH(2)CH(2)OH)(2)(NH(2)CH(2)CH(2)OH)(2)](2+) (7). Formulation of 1-6 is based upon satisfactory C, H, N elemental analyses, electrospray mass spectrometry, IR spectroscopy, and (1)H, (13)C((1)H), (15)N, and (195)Pt NMR spectroscopies, while the structures of trans-[PtCl(4)((Z)-NH=C(Et)NHCH(2)CH(2)OH)(2)] (1), trans-[PtCl(4)((Z)-NH=C(Et)NHCH(2)CH(Me)OH-(R)-(-))(2)] (2), and trans-[PtCl(4)((Z)-NH=C(Et)NHCH(Et)CH(2)OH-(R)-(-))(2)] (4) were determined by X-ray single-crystal diffraction. The Z-amidine configuration of the ligands is preserved in CDCl(3) solutions as confirmed by gradient-enhanced (15)N,(1)H-HMQC spectroscopy and NOE experiments. The amidines, formed upon Pt(IV)-mediated nitrile-amino alcohol coupling, were liberated from their platinum(IV) complexes 1, 3, and 4 by reaction with Ph(2)PCH(2)CH(2)PPh(2) (dppe) giving free NH=C(Et)NHCHRCH(2)OH (R = H 8, Et 9, Ph 10), with the substituents R of different types, and dppe oxides; the P-containing species were identified by (31)P((1)H) NMR spectroscopy. NOESY spectroscopy indicates that the liberated amidines retained the same configuration relative to the C=N double bond, i.e., syn-(H,Et)-NH=C(Et)NHCHRCH(2)OH. The liberated hydroxo-functionalized amidines 8-10 were converted into oxazolines (11-13) in the presence of a catalytic amount of ZnCl(2). A similar catalytic effect has also been reached using anhydrous MSO(4) (M = Cu, Co, Cd), CdCl(2), and AlCl(3).
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Affiliation(s)
- Anastassiya V Makarycheva-Mikhailova
- Department of Chemistry, St. Petersburg State University, 198504 Stary Petergof, Russian Federation, Institute for Inorganic Chemistry, University of Vienna, Währinger Strasse 42, A-1090 Vienna, Austria
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Bokach NA, Khripoun AV, Kukushkin VY, Haukka M, Pombeiro AJL. A Route to 1,2,4-oxadiazoles and their complexes via platinum-mediated 1,3-dipolar cycloaddition of nitrile oxides to organonitriles. Inorg Chem 2003; 42:896-903. [PMID: 12562205 DOI: 10.1021/ic026103v] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A significant activation of the Ctbd1;N group in organonitriles upon their coordination to a platinum(IV) center has been found in the reaction of [PtCl(4)(RCN)(2)] (R = Me, Et, CH(2)Ph) with the nitrile oxides 2,4,6-R'(3)C(6)H(2)CNO (R' = Me, OMe) to give the (1,2,4-oxadiazole)platinum(IV) complexes (R = Me, R' = Me (1); R = Et, R' = Me (2); R = Et, R' = OMe (3); R = CH(2)Ph, R' = Me (4)); the [2 + 3] cycloaddition was performed under mild conditions (unless poor solubility of [PtCl(4)(RCN)(2)] precludes the reaction) starting even from complexed acetonitrile and propionitrile, which exhibit low reactivity in the free state. The reaction between complexes 2-4 and 1 equiv of Ph(3)P=CHCO(2)Me in CH(2)Cl(2) leads to the appropriate platinum(II) complexes (5-7); the reduction failed only in the case of 1 insofar as this complex is insoluble in the most common organic solvents. All the platinum compounds were characterized by elemental analyses, FAB mass spectrometry, and IR and (1)H, (13)C((1)H), and (195)Pt NMR spectroscopies, and three of them also by X-ray crystallography. The oxadiazoles formed in the course of the metal-mediated reaction were liberated almost quantitatively from their Pt(IV) complexes by reaction of the latter (complexes 2-4) with an excess of pyridine in chloroform, giving free 1,2,4-oxadiazoles and trans-[PtCl(4)(pyridine)(2)]; the sequence of the Pt(IV)-mediated [2 + 3] cycloaddition and the liberation opens up an alternative route for the preparation of this important class of heterocycles.
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Ferreira CMP, C. Guedes da Silva MF, Michelin RA, Kukushkin VY, Fraústo da Silva JJR, Pombeiro AJL. 2-Amino-2-oxazoline and trialkylisourea Pt(ii) complexes derived from organocyanamides. Dalton Trans 2003. [DOI: 10.1039/b306690h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Adília Januário Charmier M, Kukushkin VY, Pombeiro AJL. Microwave-assisted [2 + 3] cycloaddition of nitrones to platinum-(ii) and -(iv) bound organonitriles. Dalton Trans 2003. [DOI: 10.1039/b301892j] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bokach NA, Selivanov SI, Kukushkin VY, Vicente J, Haukka M, Pombeiro AJL. Synthesis of the First Family of Platinum(IV) Complexes with Phosphorus Ylide Ligands. Organometallics 2002. [DOI: 10.1021/om020113m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nadezhda A. Bokach
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal, Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation, Department of Chemistry, Grupo de Química Organometálica, Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Apartado 4021, 30071-Murcia, Spain, and Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland
| | - Stanislav I. Selivanov
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal, Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation, Department of Chemistry, Grupo de Química Organometálica, Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Apartado 4021, 30071-Murcia, Spain, and Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland
| | - Vadim Yu. Kukushkin
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal, Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation, Department of Chemistry, Grupo de Química Organometálica, Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Apartado 4021, 30071-Murcia, Spain, and Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland
| | - Jose Vicente
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal, Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation, Department of Chemistry, Grupo de Química Organometálica, Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Apartado 4021, 30071-Murcia, Spain, and Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland
| | - Matti Haukka
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal, Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation, Department of Chemistry, Grupo de Química Organometálica, Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Apartado 4021, 30071-Murcia, Spain, and Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland
| | - Armando J. L. Pombeiro
- Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisbon, Portugal, Department of Chemistry, St. Petersburg State University, 198904 Stary Petergof, Russian Federation, Department of Chemistry, Grupo de Química Organometálica, Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Apartado 4021, 30071-Murcia, Spain, and Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland
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