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.

Treatment of triarylstannyl-bis (3,4,5-trimethylpyrazol-1-yl) methane, Ar3SnCH (3,4,5-Me3Pz)2 (Ar) phenyl or p-tolyl), with W (CO) 5THF results in the oxidative addition of the tin-carbon (sp3) bond to the tungsten (0) center to yield the heterodinuclear complexes CH (3,4,5-Me3Pz) 2 (CO) 3W-SnAr3, in which four-membered metallacycles are found and bis (3,4,5-trimethylpyrazol-1-yl) methide acts as a tridentate monoanionic 3-[N,C,N] chelating ligand. purity synthetic methods for poly (pyrazol-1-yl) alkanes have been explored. 5b, 7 In recent years, modification of the central carbon atom by the organic functional groups to form heteroscorpionate ligands has also been successful. These new heteroscorpionate ligands usually have asymmetric N2O, 8N2S, 9or N3O10 coordination environments. Recently, replacement of the central carbon atom by the silicon atom to form poly (pyrazol Poly (pyrazol-1-yl) alkanes were first reported to form transition-metal complexes by Trofimenko in 1970.1 After that, and especially after an improved synthetic method was developed by Julia et al.,2 the coordination chemistry of these ligands has received increasing attention. 3, 4 A number of main-group5 and transitionmetal6 complexes containing poly (pyrazol-1-yl) alkanes have been synthesized and characterized in recent years. To advance the development of poly (pyrazol-1-yl) alkane chemistry, some new higher yield and higher

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