Michael W. Bishop

Reactions of coordinated nitride to generate novel rhenium and molybdenum imido complexes: The crystal and molecular structures of [Mo(NCPh3)(S2CNMe2)3)]BF4 and [Mo(NSO2Ph)(S2CNMe2)3]PF6

Abstract The nitrido complexes [MoN(S 2 CNR 2 ) 3 ] (R 2  Me 2 , Et 2 ) and [ReN)S 2 CNR 2)2 -(PMe 2 Ph) n ] (R 2  Me 2 ; Et 2 ; n  0, 1) react with halides R′X (R′  PhCO, PhSO 2 , 2,4-(NO 2)2 C 6 H 3 , 2,4-(NO 2)2 C 6 H 3 S; X  Cl, R′  Me, X  I), [R′3 O ]BF 4 (R′  Me, Et) or [Ph 3 C]BF 4 to give the imido complexes [Mo(NR′)(S 2 CNR 2 ) 3 ]+ and [Re(NR′)(S 2 CNR 2 ) 2 (PME 2 Ph) n ] (R′  Me, Et, Ph 3 C + , PhSO 2 , PhCO, 2,4(O 2 N) 2 -C 6 H 3 , 2,4-(O 2 N) 2 C 6 H 3 S); the X-ray crystal structures of [Mo(NCPh 3 )(S 2 -CNMe 2 )3]BF 4 and [Mo(NSO 2 Ph)(S 2 CNMe 2 )3]PF 6 have been determined. Both complexes have approximately pentagonal bipyramidal geometries although the NSO 2 Ph complex is more distorted. The NCPh 3 and NSO 2 Ph complexes have MoNC and MoNS angles of 175.1(5) ° and 161.3(13)° and MoN distances of 1.731(2) and 1.70(2)A, respectively.

The preparation, structures and reactivity of complexes with molybdenum-nitrogen multiple bonds☆

Abstract Molybdenum(IV), (V) and (VI) nitrido complexes are prepared using trimethylsilylazide; the complexes [MoN(S 2 CNR 2 ) 3 ] ( R 2 = Me 2 , Et 2 , ( CH 2 ) 5 ) are precursors for the preparation of thionitrosyl and imido complexes and a trimeric species with two bridging nitride ligands. The X-ray crystal structures of [MoN(S 2 CNEt 2 ) 3 ], [MoN(S 2 CNMe 2 ) 3 ] and the trimeric complex [{MoN(S 2 CNEt 2 ) 3 } 2 Mo(S 2 CNEt 2 ) 3 ] [PF 6 ] 3 are reported. The preparation of mono- and bis-hydrazido(2-) complexes from molybdenum(IV) bis-oxo complexes and N,N-disubstituted hydrazines is also reported and their structures are compared with other analogous complexes.

Reactions of molybdenum oxo-complexes with substituted hydrazines. Part 3. The preparation and crystal and molecular structure of an oxo-[dimethylhydrazido(2–)]-complex

The oxo-complexes [MoO2L2][L = oxinate, S2CNMe2, S2CNEt2, S2CN(CH2)5, or S2CNPh2] react with the hydrazines R2NNH2[R2= Me2, (CH2)5, or Ph2] to give the hydrazido(2–)-complexes [Mo(NNR2)OL2]. The crystal and molecular structure of [Mo(NNMe2)O(S2CNMe2)2] has been determined by single-crystal X-ray diffraction methods. The complex crystallises in the monoclinic system, space group P21/c with a= 7.897, b= 13.854, c= 15.517 A, β= 103.1°, and Z= 4. The molecule has a distorted octahedral configuration with the hydrazido-ligand bonded linearly in a position cis to the oxo-group. The Mo–N and N–N distances of 1.799 and 1.288 A are consistent with a mode of bonding closer to the representation [graphic omitted][graphic omitted]N[graphic omitted]R2 than Mo[graphic omitted]N–NR2.

Reactions of molybdenum oxo-complexes with substituted hydrazines. Part 1. The preparation of molybdenum alkyl- and aryl-imido-complexes; the crystal and molecular structure of (N-benzoyl-N′-p-tolyldiazene-N′O)dichloro(dimethylphenylphosphine)(p-tolylimido)molybdenum

The molybdenum(IV) oxo-complexes [MoOCl2(PR″3)3](PR″3= PMe2Ph or PEt2Ph) react with the substituted hydrazines RCONHNHR′(R = Ph, p-ClC6H4, p-MeC6H4, p-MeOC6H4, Et, Prn, Pri, or CH2Ph; R′= Ph, p-ClC6H4,p-MeOC6H4, 1-C10H7, or Me) to give the imido-complexes [MoCl2(NR′)(R′N2COR)(PR″3)]. The crystal and molecular structure of the title complex has been determined from single-crystal X-ray diffractometer data. The crystals are monoclinic with a= 8.995, b= 19.090, c= 17.860 A, β= 104.15°, space group P21/c, and Z= 4. The structure has been solved by Patterson and Fourier methods, and least-squares refinement using 2 279 independent observed reflections has reached R= 0.066. The co-ordination geometry is distorted octahedral. The metal–diazene chelate system is quite planar and bond lengths indicate considerable delocalisation within the chelate ring. In particular, the Mo–N length [1.984(8)A] is shorter than the Mo–O length [2.110(7)A] and this is taken to indicate partial double-bond character in the Mo–N bond. The remaining metal–ligand distances are Mo–N(imido) 1.726(9), Mo–Cl 2.393(4)(trans to P) and 2.406(3)(trans to N in chelate ring), and Mo–P 2.528(4)A.

Preparation and X-ray crystal structure analysis of a novel, trinuclear nitrido complex [{Et2NCS2)3MoN}2Mo(S2CNEt2)3]3+[PF6–]3

The reaction of [MoN(S2CNEt2)3] with hydroxylamine-O-sulphonic acid and NaBF4 in methanol gives the title compound, the structure of which has been determined by X-ray diffraction.

The reactions of molybdenum oxo-complexes with substituted hydrazines. Part 5. The preparation of some organodiazenido-complexes of molybdenum

We describe a series of complexes [Mo(N2Q)(S2CNMe2)3](Q = alkyl, aryl, or alkoxycarbonyl) and [Mo(N2Q)2(S2CNMe2)2] prepared from [MoO2(S2CNMe2)2] and the appropriate hydrazine. Representative members of the former class of compounds can be protonated, alkylated, and arylated at the diazenido-nitrogen remote from the metal. The latter compounds are formed via intermediates which are probably [Mo(N2H2Q)(N2Q)(S2CNMe2)2]. The electrochemical properties of the new complexes are discussed.

Novel asymmetric benzoyldiazenido-bridged complex of molybdenum. X-Ray crystal structure of [Mo2O(PhCON2)2(S2CNEt2)2]

The product of the reaction between [MoO2(S2CNEt2)2] and benzoylhydrazine hydrochloride is shown by X-ray crystallography to be an asymmetric dinuclear complex [Mo2O(PhCON2)2(S2CNEt2)2], with bridging benzoyldiazenido-ligands.

Thionitrosyl complexes of molybdenum, rhenium, and osmium

The molybdenum nitrido-complexes [MoN(S2CNR2)3] react with elemental sulphur or propylene sulphide to give the thionitrosyl complexes [Mo(NS)(S2CNR2)3] in high yield. The rhenium nitrido-complexes [ReX2N(PR3)3](PR3= PMe2Ph, PEt2Ph, or PMePh2; X = Cl or Br) react with half an equivalent of S2Cl2 to give the pink thionitrosyl complexes [ReCl(X)(NS)(PR3)3] in yields of 60–70%. Use of an excess of S2Cl2 gives the purple complexes [ReCl2X(NS)(PR3)2] in good yields. The five-co-ordinate nitrido-complexes [ReCl2N(PRPh2)2](R = Ph or Prn) also give [ReCl3(NS)(PRPh2)2] on reaction with half an equivalent of S2Cl2. The osmium nitrido-complexes [OsX3NL2][L = AsPh3, PMe2Ph, ½ bipy (2,2′-bipyridyl), or py (pyridine); X = Cl or Br] react analogously with S2Cl2 to give [OsClX2(NS)L2]. ν(N–S) appears in the i.r. spectra in the range 1 120–1 280 cm–1, and the 1H n.m.r. spectra of the diamagnetic complexes show the phosphines to be mer in [ReCl2(NS)(PR3)3] and trans in [OsCl3(NS)(PMe2Ph)2]. Treatment of the thionitrosyls with tertiary phosphines regenerates the parent nitrido-complexes in high yields.

Reactions of molybdenum oxo-complexes with substituted hydrazines. Part 4. The preparation and structure of an anionic molybdenum oxo(diazene) complex

The complexes [MoCl(O)(P–P)2][MoCl3O(RCON2Ph)](R = Ph, p-ClC6H4,p-MeOC6H4, or Me; P–P = Ph2PCH2CH2PPh2 or Ph2PCHCHPPh2) have been prepared by reactions of the hydrazines RCONHNHPh with [{MoCl2O(P–P)}2] or [MoCl3O(P-P)] in refluxing methanol. The crystal and molecular structure of [MoCl(O)(Ph2PCH2CH2PPh2)2][MoCl3O(p-ClC6H4CON2Ph)] has been determined by single-crystal X-ray diffraction methods. The complex crystallises in the triclinic system, space group P with a= 14.87(1), b= 11.84(1), c= 18.37(1)A, α= 96.1(1), β= 98.8(1), γ= 97.2(1)°, and Z= 2. The geometry of the oxo(diazene) anion is distorted octahedral with the chloride atoms in a mer configuration and the oxygen atom of the diazene ligand is trans to the oxo-function. The Mo–Cl distances are 2.410(6), 2.412(6), and 2.334(7)A. The MoO terminal distance is 1.620(14)A and the bond lengths within the diazene ligand indicate considerable delocalisation.

Proton nuclear magnetic resonance study of electronic transmission effects and fluxional behaviour in aryldiazenidotris(dimethyldithiocarbamato)molybdenum

The rate of N-methyl exchange in a series of aryldiazenidomolybdenum complexes has been studied by 1H n.m.r. spectroscopy as a function of temperature and of substitution in the aromatic ring. The results indicate a fluxional rearrangement characterised by a single first-order rate constant. The aromatic-substituent effect shows a better Hammett correlation with σ than with σ+ values. The ρ factor is –0.64. Implications for the geometry of the system are discussed.