Eric A. Maatta

A Diazoalkane Derivative of a Polyoxometalate: Preparation and Structure of [Mo6O18(NNC(C6H4OCH3)CH3)]2−

A new metathetical route to diazoalkane complexes is described which allows the introduction of such ligands into previously inaccessible environments. The method, which involves the exchange of oxo and [N2 CR2 ] ligands, is illustrated by the preparation of the first diazoalkane-polyoxometalate complex 1.

Functionalized heteropolyanions: high-valent metal nitrido fragments incorporated into a Keggin polyoxometalate structureElectronic supplementary information (ESI) available: general synthetic and characterization details. See http://www.rsc.org/suppdata/cc/b2/b209173a/

Three examples of nitrido-functionalized polyoxometalate species are reported, namely (n-Bu4N)4[PW11O39(OsN)] (1), (n-Bu4N)4[PW11O39(ReN)] (2), and (n-Bu4N)3[PW11O39(ReN)] (3), which feature the incorporation of [OsVI identical to N]3+, [ReVI identical to N]3+ and [ReVII identical to N]4+ fragments, respectively, into the framework of a Keggin-type heteropolyanion.

Organoimido-polyoxometalates as polymer pendants

The p-styrenyl substituent borne by the organoimido ligand in the Lindqvist derivative [NBu4]2[Mo6O18(NC6- H4CHCH2)] 1 allows the polyoxometalate complex to be introduced as a pendant group in polystyrene compositions via conventional free radical-induced copolymerization.

Organoimido and organodi-imido vanadium complexes

Abstract Reactions of the p-tolylimido vanadium(V) complex [V(NTol)Cl3], 1, with sodium dithiocarbamate salts Na[S2CNR2] yield an homologous series of organoimido vanadium(V) dithiocarbamate systems [TolNV(S2CNR2)xCl(3−x)] [x = 1:REt (2a), Me (3b); x = 3: REt (4a), Me (4b)]; the electronic and 51V NMR spectra of these complexes are described. Zn reduction of complexes 3 affords impure products whose ESR spectra are consistent with the presence of the V(IV) systems [V(NTol) (S2CNR2)2], 5. Reaction of VOCl3 with 0.5 equiv. of p-OCNC6H4-NCO yields the p-phenylenediimido complex [Cl3VNC6H4NVCl3], 6. Dissolution of 6 in THF produces an adduct [(THF)3Cl3VNC6H4NVCl3(THF)3], 7, whose THF ligands are weakly bound. VOCl3 reacts with an equimolar amount of p-OCNC6H4NCO to produce the mononuclear complex p-[Cl3VNC6H4NCO], 8. The reaction of 8 with OWCl4 in refluxing toluene affords an insoluble product analyzing as the expected heterobinuclear system [Cl3VNC6H4NWCl4], 9, but treatment of this product with THF yields a mixture shown by 1H NMR to contain both 7 and its ditungsten analogue [(THF)Cl4WNC6H4NWCl4(THF)], indicating that an unusual intermetallic exchange of imido ligands has occurred. The chloride ligands of 6 can be substituted by [S2CNEt2] or [OtBu] anions to afford [(Et2NCS2)3VNC6H4NV(S2CNEt2)3], 11, and [( t BuO ) 3 V  NC 6 H 4 N  V(O t Bu ) 3 ] ,, 12, respectively.

Polyoxometalate clusters as building blocks: preparation and structure of bis(hexamolybdate) complexes covalently bridged by organodiimido ligands

Covalently linked polyoxometalate clusters are produced in the reaction of organic diisocyanates with [Bu4N]2[Mo6O19], suggesting the development of extended interconnected networks incorporating polyoxometalate ions.

Organoimido complexes of Mo(IV), Mo(V) and Mo(VI): preparation, structure and reactivity

Abstract Two series of p-tolylimido (Ntol) complexes of Mo(VI), Mo(V) and Mo(IV) are described. One series, containing diethyldithiocarbamate ligands, is formed via oxygen atom abstraction from Mo(VI)O(Ntol)(S2CNEt2)2 using tertiary phosphines which affords the oxo-bridged Mo(V) dimer [Mo(Ntol)(S2CNEt2)2]2O and the Mo(IV) species Mo(Ntol)(S2CNEt2)2. In solution, the Mo(V) dimer participates in a disproportionation equilibrium affording the Mo(VI) and Mo(IV) complexes. Mo(Ntol)(S2CNEt2)2 reacts with O2 to regenerate MoO(Ntol)(S2CNEt2)2, thus completing a catalytic phosphine oxidation cycle. Mo(Ntol)(S2CNEt2)2 also reacts with Me2SO to yield the Mo(VI) complex and Me2S, and with dimethylacetylenedicarboxylate to yield the alkyne complex, Mo(Ntol)(DMAC)(S2CNEt2)2. The second series of p-tolylimido complexes contains chloride and phosphine co-ligands and derives from the Mo(VI) species Mo(Ntol)Cl4(THF). In the presence of tertiary phosphines, this complex undergoes reduction to afford monomeric Mo(V) complexes of the form Mo(Ntol)Cl3L2 (L = Ph3P, EtPh2P and Me3P; L2 = Ph2PC2H4PPh2). The bis(monodentate phosphine) complexes possess the trans, mer-geometry while the diphos complex is assigned the cis, mer-configuration. Reduction of Mo(Ntol)Cl3(Me3P)2 by NaHg in the presence of Me3P affords the Mo(IV) complex cis, mer-Mo(Ntol)Cl2(Me3P)3 whose molecular structure is described.

An alkyne derivative of an organoimido molybdenum(IV) complex: molecular structure of the acetone hemi-solvate of bis(diethyldithiocarbamato)-dimethylacetylenedicarboxylate(p-tolylimido)molybdenum(IV), Mo(Ntol)(DMAC)-(S2CNEt2)2· 1/2Me2CO

Abstract The molecular structure of the dimethylacetylenedicarboxylate adduct of bis(diethyldithiocarbamato)- (p-t olylimid o)molybdenum(IV), Mo(Ntol)(DMAC)- (S2CNEt2)2, is described. The complex represents a rare example of an unsaturated organic molecule ligated to an organoimido species. Crystals suitable for X-ray diffraction were obtained as the acetone hemi-solvate. The complex crystallizes in space group P21/c with the following parameters: a = 17.680(3), b = 8.860(1), c = 20.497(3) A, β = 106.97(1)°, Z = 4. Least-squares refinement based on all 4039 unique intensities converged to R = 0.042 and Rw = 0.054. The complex displays a distorted pentagonal bi-pyramidal structure with the imido ligand occupying an apical position and the alkyne lying in the pentagonal plane. Analysis of the metrical parameters of the complex leads to the conclusion that the alkyne successfully contributes a slight amount of pi-electron density to the Mo atom in competition with the imido ligand.

A superoctahedral complex derived from a polyoxometalate: thehexakis(arylimido)hexamolybdate anion[Mo6(NAr)6O13H]-

Reaction of [Mo 6 O 19 ] 2- with an excess of 2,6-diisopropylphenyl isocyanate (ArNCO) affords the title anion in which the hexamolybdate framework serves as an octahedral nexus for six terminal arylimido ligands.

Organoimido ligands with remote functionality: a p-pyridylimido complex of vanadium(V) and its use as a metalloligand

The exposed nitrogen atom of the p-pyridylimido ligand in the vanadium(V) species [(N3N)VN-C5H4N]1{N3N =[(Me3SiNCH2CH2)3N]3–} provides a reactive site capable of complexing a second metal fragment, enabling the construction of new types of heterobimetallic complexes linked by a compact conjugated bridge.

Dealkylation of an organoimido ligand leading to a binuclear (µ-nitrido) complex of molybdenum(IV): structure of the [Cl3(py)2MoNMo(py)2Cl3]– anion

Pyridine abstracts an allyl group from the MoVI allylimido complex [CH2CH–CH2–NMoCl4(thf)], leading to the ultimate formation of the N-allylpyridinium salt of an unusual µ-nitrido binuclear MoIV species, [CH2CH–CH2-py][Cl3(py)2MoNMo(py)2Cl3].