1. Synthesis and characterization of octaacetonitriledimolybdenum(II) tetrafluoroborate
2. Synthesis and characterization of molybdenum species: dinuclear and mononuclear species of the molecular formulas [Mo2(O2CCH3)2(LL)2][BF4]2 and [Mo(O)(F)(LL)2][BF4] where LL=bis-phosphine. The use of [Mo2(NCCH3)10][BF4]4 as a source for the [Mo2]4+ core
3. Synthesis and structure of W2Cl4(μ-dppm)2(η2-μ-CH3CN)
4. Compounds1and2were crystallized by layering solutions of the compounds in acetonitrile/methanol or acetonitrile, respectively, with hexanes and then diethyl ether. Within a week bright dark green (1) or bluish green (2) crystals formed at room temperature.1crystallizes in the triclinic space groupP1̄ (No. 2) witha= 15.292(3) Å,b= 15.654(6) Å,c= 18.145(7) Å, α = 75.95(2)°, β = 75.35(2)°, γ = 70.42(3)°. Cell volume = 3899(2) Å3. The data were collected on an Enraf-Nonius Fast diffractometer (Mo Kα radiation, λ = 0.71073 Å) at −100 °C. All non-hydrogen atoms were anisotropically refined; in calculating Fc values, H atoms of all nonsolvent molecules were included in ideal positions. A common temperature factor was refined for all H atoms. 7663 unique data were collected with 6874 > 4s(I), R1(obs)= 8.0, wR2(obs)= 18.4. We believe that these relatively high values are the result of severe disorder of some of the included solvent molecules and BF4-ions. Spectroscopic data: 1H-NMR (200.1 MHz, CD3CN, 22.2 °C) δ (ppm) = 8.58−8.70 (m, 3H, aromat. H), 8.10−8.17 (m, 3H, aromat. H), 7.54−7.67 (m, 12H, aromat. H), 6.80−7.36 (m, 22H, aromat. H), 4.74 (dd, 1H,2JP(1,2)-H= 17 Hz, N−H), 3.85 (d, 3H,2JP(4)-H= 29 Hz, P(4)−C−CH3), 3.46 (s, 3H, bridging NCCH3), 1.95 (s, 15H, terminal NCCH3);31P{1H}-NMR(CH3CN, 22 °C, 81 Hz) δ (ppm) = 81.5 (d,2JP(2)-P(1)= 53 Hz, P(2)), 80.6 (dd,2JP(1)-P(2)= 53 Hz,2JP(1)-P(3)= 34 Hz, P(1)) 52.3 (t,2JP(3)-P(1)= 34 Hz,2JP(3)-P(4)= 33 Hz, P(3)), 21.4 (d,2JP(4)-P(3)= 33 Hz, P(4)); IR (KBr) ν (cm-1) = 3055 w, 2963 m, 2313 w, 2280 m, 1636 m, 1481 m, 1436 m, 1261 s, 1084 vs, 803 s, 742 m, 696 s, 531 m, 505 m; UV−vis (acetonitrile) ν (nm) = 715 b; +FAB/DIP-MS (Nitrobenzyl alcohol (NBA))m/z= 1170 ([M − 2 CH3CN]+, Mo-98, rel. int. 4%), 1129 ([M − 3CH3CN]+, 4%), 1104 ([M − C2H6− CH3CN − C6H5]+, 5%), 1088 ([M − 4CH3CN]+, 8%), 1082 ([M − C12H10− CH4]+, 13%), 1047 ([M − 5CH3CN]+, 4%), 1041 [M − (C6H5)2P − CN]+, 3%), 1026 [M − (C6H5)2P − CH3CN]+, 12%), 980 ([M − 6CH3CN − CN]+, 14%), 537 ([(C6H5)2PN(C6H5)2P(C6H5)2]+, 20%), 468 ([(CH3)CN−(C6H5)2PN(H)2(C6H5)2−NC(CH3)]+, 20%), 427 ([(C6H5)2PN(H)2P(C6H5)2−C(CH3)N]+, 28%), 386 [(C6H5)2PN(H2)P(C6H5)2]+, 100%); χmol= 7 × 10-5cm3mol-1(298 K); Elemental analysis for Mo2C62H62N9P4B3F12(1509.40 g/mol) calcd C, 49.34; H, 4.14; N, 8.35; found C, 49.21; H, 4.41; N, 8.09.2crystallizes in the orthorhombic space groupCmcm(No. 63), witha= 13.804(1) Å,b= 22.629(2) Å,c= 24.862(2) Å; volume = 7766(1) Å3. The data were collected on a CAD4 diffractometer (Mo Kα radiation; λ = 0.71073 Å) at room temperature with the crystal mounted in a capillary. All non-hydrogen atoms were anisotropically refined. Hydrogen atoms on the ligands were placed in calculated positions. Peaks representing interstitial hexane molecules were refined as partially occupied carbon sites, but since they represent a mixture of several isomers no single molecular model for the solvent molecule is implied. The presence of hexanes in the crystals was confirmed by1H-NMR spectroscopy. 3652 unique data were collected with 2766 > 2s(I), R1(obs)= 4.7, wR2(obs)= 12.6. Spectroscopic data: 1H-NMR (200.1 MHz, CD3CN, 22.2 °C) δ (ppm) = 7.33−8.17 (m, 40H, aromat. H), 5.53 (b, 1H, N−H), 5.15 (b, 1H, N−H), 3.43 (s, 3H, bridging NCCH3), 1.95 (s, 12H, terminal NCCH3);31P{1H}-NMR (CH3CN, 22.2 °C, 81 MHz), AA‘BB‘ system, multiplets centered at δ (ppm) = 74.6, 67.0; IR (KBr) ν (cm-1) = 3052 w, 2963 m, 2315 m, 2286 s, 1684 m, 1633 m, 1572 w, 1482 m, 1435 s, 1262 s, 1054 vs, 802 st, 752 m, 705 s, 504 m, 521 m; UV−vis (acetonitrile) ν (nm) = 725 b; χmol= 3 × 10-5cm3mol-1(298 K); Elemental analysis for Mo2C58H57N7P4OB2F8(1357.50 g/mol) Calcd C, 51.29; H, 4.20; N, 7.22; found C, 51.08; H, 4.47; N, 6.93. [Mo2(m,h2-CH3CN)(m-O)(m-dppma)2(CH3CN)4](BF4)2: 31P{1H}-NMR (81 MHz, CH3CN) AA‘BB‘ system, multiplets centered at δ (ppm) = 96.2 and 86.4;1H-NMR (200.1 MHz, CD3CN, 22.2 °C) δ (ppm) = 7.35−8.22 (m, 40H, aromat. H), 4.40 (dd, 3H,2JP-H= 15 Hz, 45 Hz, N-CH3), 3.43 (d, 3H,2JP-H= 10 Hz, N−CH3), 3.37 (s, 3H, bridging NCCH3), 1.95 (s, 12H, terminal NCCH3); IR (KBr) ν (cm-1) = 3052 w, 2962 m, 2315 m, 2285 m, 1685 m, 1572 w, 1482 m, 1300 m, 1262 m, 1053 vs, 875 s, 803 m, 751 m, 701 s, 640 m, 614 w, 505 m, 525 m; UV−vis (CH3CN) ν (nm) = 723 b; χmol= 4 × 10-5cm3mol-1(298 K); Elemental analysis for Mo2C60H61N7OP4B2F8(1385.55 g/mol) calcd C, 52.01; H, 4.44; N, 7.08; found C, 51.82; H, 4.54; N, 6.97. Crystal yield: ca. 54%.