New organometallic compounds containing the cis-Grignard reagents to give [MoO(NNPhR)Me 2 (o-phen)] [R =Me (4), R = Ph (5) Much of the current interest in coordination of the hy-anthroline, [15] hydridotris(pyrazolyl)borate, [23,24] hydridotris(3,5-dimethylpyrazolyl)borate, [23] and mercaptobendrazido ligand, NNH 2 , at transition-metal centers stems from the expectation that its geometric and electronic struc-zoate.[25] However, recent work in our laboratories has focused on the synthesis of organometallic molybdenum comture, as well as its reactivity, may provide some insight into the mechanism of metal-catalysed reduction of dinitrogen pounds containing these cores; the new piano-stool compounds formulated as [(η 5 -C 5 H 5 )Mo(NNPhR) 2 -into ammonia.[1Ϫ6] Organohydrazido ligands, NNRRЈ (RRЈ ϭ alkyl and/or aryl; H and alkyl/aryl), are considered (PPh 3 )] ϩ CF 3 SO 3 Ϫ (R ϭ Me, Ph) represent the first two members of this new class of organometallic compounds. [26] as potential models of NNH 2 because of their structural similarities. Accordingly, in the last few years increasing at-This paper deals with a convenient synthesis of the first members of a new class of organometallic molybdenum tention has been paid to transition-metal complexes containing NNRRЈ ligands and, consequently, several studies compounds containing the cis-[ MoO(NNPhR) [10,12] pro-phen)] (1) with neutral organohydrazines leads to the stable intermediates [MoO(NNMePh)Br 2 (o-phen)] (2) and tonationϪdeprotonation reactions, [13,14] and hydrolysis of the MoϪNNRRЈ group. We also report the X-ray crystal and molecular structures azene character to NNH 2 and NNRRЈ groups (RRЈ ϭ alkyl and/or aryl) in coordination compounds. [16] of compounds 5 and 7. As part of an ongoing investigation into (organohydrazido)molybdenum complexes, we have previously described the synthesis, characterization, and the chemical properties of a number of inorganic complexes containing the cis-[Mo(NNPhR) 2 ] 2ϩ and cis-[MoO(NNPhR)] 2ϩ cores with a wide range of ancillary ligands, e.g. acetylacetonate, [14,17Ϫ21] tertiary phosphanes, [14,21,22] 2,2Ј-bipyridine, [15] 1,10-phen- [a]
The π-donor imido functional group gives rise to a chemistry that is generally dominated by medium to high metal oxidation states; also showing a variety of coordination modes such as terminal metal-nitrogen multiple bond or bridging disposition. This chemistry is interesting not only because of their structural features, and their remarkable reactivity, as well, nowadays it is well recognized the importance of imido compounds in industrial processes, organic synthesis and catalysis. [1] The most reactive of imido compounds occur within group 4. As an example, titanium imides react with many organic substrates including alkenes, allenes, alkynes, heterocumulenes, nitriles, isonitriles, isocyanates, and phosphaalkynes, and in many cases these reactions result in the formation of both novel organic products and metalcontaining species. [2] Our studies are focused on species containing imido ligands which possess functionalized substituents as we are interested in analysing the effect of the additional functionality on the coordination behaviour of these derivatives and on their reactivity. As well the presence of an additional donor atom in the ligand would enhance the capacity of the species synthesized to behave as metalloligands for the construction of ordered supramolecular structures.The treatment of the complexes [Ti(NR 2 ) 4 ], [Ti(C 5 Me 5 )Cl 3 ] and [Ti(C 5 Me 5 )(NR 2 ) 3 ] with functionalized aromatic amines leads to the formation of new amido complexes. To achieve the double deprotonation it is necessary to introduce in the reaction an additional base such as alkyl lithium or magnesium derivates. In these conditions it is possible to attain the formation of imido species as the one show in fi gure 1. This compound crystallizes as a triclinic in the space group P-1; only half of the molecule is found in the asymmetric unit, through an inversion centre is generated the titanium (IV) dinuclear species. Interestingly not many titanocenes with bridging imido arene ligands have been described. Mono-and bis(cyclopentadienyl) complexes of early transition metals have received an increased attention stimulated by their use in understanding the chemistry of important catalytic processes, in particular those related to olefi n and ring-opening polimerization metathesis.[1] Many aryl tantalum compounds are labile and tend to decompose via β-H elimination reactions forming benzyne complexes, for example, TaCp*Me 3 Ph.[2] However, ancillary ligands capable of π-bonding have a stabilizing infl uence on σ-bonded aryl ligands in high oxidation state early transition metal chemistry. For it, a possible approach to overcome complications caused by β-H elimination is to prepare derivatives by employing an aryl ligand that has an ortho-substituted C,N-chelating arylamine ligands form an additional coordinative bond (σ-donor N) to the metal center and thereby enhance the kinetic stability of the organometallic complex formed.[3] These bidentated ligands possess a hard anionic carbon (C i ) atom and a neutral tertiary ...
New organometallic compounds containing the cis‐[MoO(NNPhR)]2+ core have been synthesized by means of a two‐step procedure involving: (i) functionalization of the precursor [MoO2Br2(o‐phen)] (1) with MePhNNH2 and Ph2NNH2 to afford the intermediates [MoO(NNMePh)Br2(o‐phen)] (2) and [MoO(NNPh2)Br2(o‐phen)] · MeCN (3), respectively, and (ii) reaction of these intermediates with Grignard reagents to give [MoO(NNPhR)Me2(o‐phen)] [R = Me (4), R = Ph (5)], [MoO(NNPhMe)Ph2(o‐phen)] (6), and [MoO(NNPh2)Ph2(o‐phen)] · CH2Cl2 (7). These compounds have been characterized by 1H‐NMR, IR, and UV/Vis spectroscopy and the crystal and molecular structures of 5 and 7 have been determined by X‐ray diffraction analysis.
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