Reaction of the dianion {p-[(CO)3MoC5H4C-(O)]2C6H4}2- with PhSnCl3 yields the tetranuclear heterodimetallic complex p-[(PhCl2Sn)(CO)3MoC5H4C-(O)]2C6H4 (1). Treatment of complex 1 with Na2S

The dianions {[p-(CO)3MC5H4C(O)]2C6H4}2 reacted with Ph2SnBr2 in a 1:2 or 1:1 ratio to give tetranuclear heterodimetalliccomplexes p-[(Ph2BrSn)(CO)3MC5H4C(O)]2C6H4 (M/Mo (1) or W (2), respectively), and with CH2(SnPhBr2)2 to yieldtetranuclear heterodimetallic metallamacrocycles {p-[(CO)3MC5H4C(O)]2C6H4}{(Ph2 nBrnSn)2CH2} (n/1, M/Mo (5) and W (6); n/0, M/Mo (7) and W (8), respectively). Only one bromide on the tin atom was replaced by the metallic anions owing to theelectron-withdrawing groups on the cyclopentadienyl rings greatly decreasing the nucleophilicity of the metallic anions. Treatmentof complexes 1 and 2 with Na2S/9H2O yielded the novel metallamacrocyclic complexes {p-[(CO)3MC5H4C(O)]2C6H4}{(Ph2Sn)2S}(M/Mo (3) and W (4), respectively). All compounds have been characterized by elemental analyses, IR and 1H-NMR spectra. Thecrystal structures of complexes 3 and 7 determined by X-ray crystallography indicate a novel 14-membered rganometallicmetallamacrocyclic ring system in which two Mo/Sn units are linked by the bridging cyclopentadienyl ligand and the sulfur orcarbon atom. In addition, the carbonyl group p-system is coplanar with the adjacent cyclopentadienyl ring system, but markedlydeviates from the bridging phenyl plane.

ngsten complexeshave one reversible couple corresponding to the ferrocenyl group and one irreversible oxidation process for the molybdenum ortungsten center. The crystal structures of 3-ferrocenylpyrazole pentacarbonyltungsten (3) and 3-methyl-5-ferrocenylpyrazolepentacarbonyltungsten (6) are determined by X-ray diffraction method, indicating that both 3(5)-ferrocenylpyrazole and3(5)-methyl-5(3)-ferrocenylpyrazole act as a monodentate ligand, and the central metal of W is six-coordinate with a quasi-octahedralcoordination geometry in both complexes. Complex 3 is linked into a one-dimensional chain in solid through intermolecularhydrogen bonds formed by metal carbonyl as hydrogen bond acceptors, while complex 6 forms a dimer by similarintermolecular hydrogen bond interactions. The N-H…O distances in complexes 3 and 6 are 2.932(11) and 2.900 A, respectively. All new compounds have been characterized by elemental analyses, IR, 1H-NMR. 13C-NMR spectra of molybdenum and tungstencomplexes have also been determined.

A series of new bis (pyrazol-1-yl)methane ligands with organogermyl and organosilyl groups on the methine carbon, MCHPz2(M/Ph3Ge, PhMe2Si, iPr3Si or Me3Si; Pz/3,5-dimethylpyrazole or 3,4,5-trimethylpyrazole), have been prepared by the reactionof bis (pyrazol-1-yl) methyllithium with triphenylgermanium bromide and organosilyl chloride. Treatment of these ligands withW (CO) 5 (THF) in refluxing THF resulted in new heterobimetallic complexes MCHPz2W (CO) 4 as major products, accompanied bypartial decomposition of ligands to yield a certain amount of PzW (CO) 5as by-products. These new ligands and complexes have beencharacterized by 1H-NMR, IR and elemental analysis. The molecular structures of complexes Ph3GeCHPz2W (CO) 4andMe3SiCHPz2W (CO)4 (Pz/3,5-dimethylpyrazole) have been determined by X-ray structure analysis, indicating that bis (pyrazol-1-yl)methanes act as chelating bidentate ligands in these complexes, and organometallic groups lie in the axial position of themethine carbon. # 2002 Elsevier Science B. V. All rights reserved.

The reaction of bis (3,5-dimethyl-1,2,4-triazol-1-yl) methane, CH2 (3,5-Me2Tz) 2, with M (CO) 6 (M=Cr, Mo or W) in refluxingDME produces CH2 (3,5-Me2Tz) 2M (CO) 4 in moderate yield. The crystal structures determined by X-ray analysis show thatbis (3,5-dimethyl-1,2,4-triazol-1-yl) methane acts as a chelating bidentate ligand with two endodentate nitrogen atoms in thesecomplexes. Reactions of complexes CH2 (3,5-Me2Tz) 2M (CO) 4 (M=Mo or W) with R2SnX2 (R=Ph or Me; X=Cl or Br) in a1:1 or 1:2 ratio, respectively, only yield 1:1 adducts. In these adducts, bis (3,5-dimethyl-1,2,4-triazol-1-yl)methane may coordinateto tin atom through exodentate nitrogen atoms on the 4-position of triazole rings to form linkage coordination polymers. Possiblyowing to weak donors of 4-position exonitrogen atoms on triazole rings to organotin acceptors, the dissociation of these adductsin solution could exist. Adduct of CH2 (3,5-Me2Tz) 2W (CO) 4