Bimetallic complexes of platinum, rhodium, or copper bridged by Ph2PCH2PPh2 or Ph2PC(CH2)PPh2 to diazenidorhenium groups; crystal structure of [(4-MeC6H4N2)ClRe(µ-dppm)2(µ-CO)PtCl]·2Me2CO

Abstract

Treatment of [ReCl(CO)(N₂C₆H₄Me-4)(dppm-PP′)(dppm-P)][PF₆](dppm = Ph₂PCH₂PPh₂) with trans-[PtH(Cl)(PPh₃)₂] gave the neutral, rhenium–platinum complex [(4-MeC₆H₄N₂)ClRe(µ-dppm)₂(µ-CO)PtCl](2a); the analogous vdpp complex (2b) was made similarly [vdpp = Ph₂PC(CH₂)PPh₂]. Complex (2b) was methylated on treatment with trimethyloxonium tetrafluoroborate to give the hydrazidorhenium complex [{(4-MeC₆H₄)MeNN}ClRe(µ-vdpp)₂(µ-CO)PtCl][BF₄](3). Treatment of complex (2b) with HBF₄·Et₂O gave [{(4-MeC₆H₄)HNN}ClRe(µ-vdpp)₂(µ-CO)PtCl][BF₄](4). The complex [ReCl(CO)(N₂C₆H₄Me-4)(vdpp-PP′)(vdpp-P)][BF₄] reacted with [Rh₂Cl₂(CO)₄] to give [(4-MeC₆H₄N₂)(OC)ClRe(µ-vdpp)₂(µ-Cl)Rh(CO)][BF₄](5a); the analogous 4-fluorophenyldiazenido-(5b) and 4-methoxyphenyldiazenido-(5c) complexes were prepared similarly. Treatment of trans-[ReCl(CO)(vdpp-PP′)₂] with [Rh₂Cl₂(CO)₄] gave a mixture of two complexes, which when treated with toluene-p-diazonium tetrafluoroborate gave, eventually, (5a) in essentially quantitative yield via a mixture of three complexes, one of which was (5a). Treatment of [ReCl(CO)(N₂C₆H₄Me-4)(vdpp-PP′)(vdpp-P)][PF₆] with CuCl gave a rhenium–copper complex [(4-MeC₆H₄N₂)(OC)Re(µ-vdpp)₂(µ-Cl)CuCl][PF₆](6a). Corresponding complexes were made containing the 4-fluoro- and the 4-methoxy-phenyldiazenido groups, and [(4-FC₆H₄N₂)(OC)Re(µ-vdpp)₂(µ-Cl)Cu(CN)][PF₆] was made using CuCN. ³¹P-{¹H}, ¹H-{³¹P}, and ¹H n.m.r. and i.r. data are given; some of the AA‘XX’³¹P-{¹H} n.m.r. spectra showed 18–20 peaks (or 9–10 for the half pattern) and were analysed fully. Crystals of complex (2a) were orthorhombic, space group P2₁2₁2₁, a= 1 187.5(1), b= 1 898.2(2), c= 2 664.2(4) pm, and Z= 4; final R factor 0.0353 for 3 972 observed reflections.