Sulfur and Selenium Donors

Vibrational assignments for the electron-transfer series [M(CO)2(S2C2-Me2)3] , where M = Mo or W, = 0,1 or 2, are summarised in Table 14. Shifts in vCO are as expected. The dithiolene ligand modes show increasing enedithiolate character on reduction. The complexes 

W(S2C2R 2)2(S2CNR2)(SCNR2), where R = Me or Et, R = C02Me, give characteristic IR bands from the thiocarboxamido (1590 cm ) and dithiocarbamate (1540 cm ) ligands.  

The complexes [Pd(S2CNEt2) Ph2P(CH2)nPPh2 ], where n = 1, 3 or 4, show vCN bands in their IR spectra which are indicative of bidentate dithiocarba-mates (near 1525 For Pd[Ph2P(S)NP(S)Ph2]2, VasPNP is at 1161 cm-  

The IR spectra of Zn2(L)4(4,4 -bipy), where L = di(2-hydroxyethyl)dithiocar-bamate or AT-methyl-AT-ethanoldithiocarbamate, have vCS as a single band at 989 cm from the bidentate dithiocarbamate.  

The complex Me2Sn(S2PPh2)2 has a value of 106 cm for (VasPS2-VsPS2). This is consistent with an anisobidentate binding mode for the thiophosphinato ligands, (65)5  

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Complexes of Mercury(l) with Sulfur- and Selenium-Donor Ligands. 

Platinum(II) Complexes with Sulfur- and Selenium-donor Ligands 715... 

These methods are limited in scope. Direct thiation has been reported for the transformation of vicinal diketones to [3,4]-annelated thiophenes <1996CHEC-II(7)49>. Thionations and selenations of vicinal halomethyl ketones with thioacetamide or iV,iV-diethylselenopropionamide as sulfur and selenium donors, respectively, have also been reported <1996CHEC-II(7)49>. In a recent example, thieno[3,4-f]pyrazoles 160 were readily prepared from aryl 5-bromomethyl-l//-l-phenylpyrazole-4-yl ketones 159 by reaction with thioacetamide (Equation 35) <1998JHC71>. Additionally, an example of an amination cyclization by reaction of 161 with benzylamine to afford pyrrolo[3,4-i/ thiazole 162 has been described (Equation 36) <1998JHC71>. 

Complexes with sulfur and selenium donor ligands 1350... 

COMPLEXES OF GOLD(I) WITH SULFUR AND SELENIUM DONOR LIGANDS 872... 

Sulfur- and selenium-donor ligands stabilize several polynuclear zinc complexes, for example, the [E4Zii4(SPh)i6] (E = S or Se) anions, prepared as their Mc4N+ salts.The complex [Zn4(SPh)io] forms a ground-state charge transfer complex with methyl viologen. These... 

S). Similar compounds with bis(diphenylphoBphino)methane disulfide and the corresponding diselenide have also been prepared (Table X). These are the first examples of coordination of sulfur and selenium donors to actinide pentahalides and it will be interesting to see whether uranium pentahalides behave in a similar fashion since the analogous niobium(V) and tantalum(V) compounds are also known (43). 

Examples for square planar complexes of Se(II) and Te(II) with other sulfur and selenium donor ligands such as thio- and selenocarbamates are given (e.g., in 29,165, 205). When triarylphosphane ligands were introduced as two-electron donors by the reaction of triarylphosphane selenide with Br2, T-shaped Ar3PSeBr2 with the Br ligands in trans positions was prepared (435). Possibly, the molecules are dimerized via bromine bridges as in Se2(tmtu)2Br4 (445). 

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