SYNTHESIS AND PROPERTIES OF LIGAND-BRIDGED DINUCLEAR COMPLEXES CONTAINING -PHENYLENEBIS(DIMETHYLARSINE)]-CHLORORUTHENIMN(II) CENTERS

The series of mononuclear salts trans-[RuCl(pdma)(2)(L-L)]PF6 [pdma = o-phenylenebis(dimethylarsine); L-L = 4,4'-bipyridine (4,4'-bipy) 2, f umaronitrile (fmn) 4, di-4-pyridyl disulfide (dpds) 9 or trans-1,2-bis (4-pyridyl)ethylene (bpe) 11] have been synthesized by reaction of tra ns-[RuCl(pdma)(2)(NO)][PF6](2) with 1 equivalent of NaN3 in acetone at room temperature followed by reflux with an excess of L-L in butan-2- one. The salt trans-[RuCl(pdma)(2)(C5H5NS)]PF6 6 (C5H5NS = pyridine-4- thione) was prepared similarly by using pyridine-4-thiol, and trans-[R uCl(pdma)(2)(C5H4NSH)]PF6 8 (C5H4NSH = pyridine-4-thiol) was produced upon prolonged reflux of 9 in butan-2-one. Salts 6 and 8 are readily d eprotonated by aqueous NaOH to give trans-[RuCl(pdma)(2)(C5H4NS)] 7 an d 10. The dinuclear salts trans-[{(RuCl(pdma)(2)}(2)(mu-L-L)][PF6](2) [L-L = pyrazine (pyz) 1, 4,4'-bipy 3, fmn 5 or bpe 12] have been synth esized by reaction of trans-[RuCl(pdma)(2)(NO)][PF6](2) with 1 equival ent of NaN, followed by reflux with 1 equivalent of the monometallic s alts trans-[RuCl(pdma)(2)(pyz)]PF6, 2, 4 or 11, respectively, in butan -2-one. The dimer trans-[{RuCl(pdma)(2)}(2)(mu-dpds)][I-3](2) 13 was p repared by oxidation of 8 with iodine in Me(2)SO at room temperature. Single-crystal structures of 1, 3, 6 and 13 have been determined, and the extent of intermetallic electronic coupling in the dimers 1, 3, 5, 12 and 13 is assessed using cyclic voltammetry.