Rhenium(I) Carbonyl Complexes of 2,4,6-Tris(2-pyridyl)-1,3,5-triazine(TPT).Rhenium(I)-Promoted Methoxylation of the Triazine Ring Carbon Atom in Dinuclear Rhenium Complexes

摘要

2,4,6-Tris(2-pyridyl)-1,3,5-triazine(TPT)bridged dinuclear rhenium(I) tricarbonyl halide complexes with the composition (#mu#-TPT)[ReX(CO)_3]_2(3,X=Cl;4,X=Br) can be made either by one-pot reaction of TPT with 2 equiv of [ReX(CO)_5](X=Cl and Br) in chloroform or by reacting mononuclear [ReX(CO)_3(TPT)]_2(1,X=Cl;2,X=Br) with an excess amount of [ReX(CO)_5]. Crystal data are as follows.1:monoclinic,P2_(1/c),a=11.751(1)A,b=11.376(1)A,c=15.562(2)A,#beta#=103.584(2)deg,V=2022.0(4)A~3,z=4.2:monoclinic,P2_(1/c),,a=11.896(1)A,b=11.396(1)A,c=15.655(1)A,#beta#=104.474(2)deg,V=2054.9(3)A~3,Z=4.3:triclinic,P1,a=11.541(2)A,b=12.119(2)A,c=13.199(2)A,#alpha#=80.377(2)deg,#beat#=76.204(3)deg,#gamma#66.826(2)deg,V=1642.5(4)A~3,Z=2.Crystals of 4 crystallized from acetone:triclinc,P1,a=11.586(5)A,b=12.144(5)A,c=13.364(6)A,#alpha#=80.599(7)deg,#beta#=76.271(8)deg,#gamma#=67.158(8)deg,V=1678.0(12)A~3,Z=2. Crystals of 4' are obtained from CH_2Cl_2-pentane solution:C2/c,a=17.555(4)A,b=15.277(3)A,c=13.093(3)A,#beta#=111.179(3)deg,V=3274.0(12)A~3,Z=4.By contrast, similar reactions in the presence of methanol yielded complexes with the composition [#mu#-C_3N_3(OMe)(py)_2(pyH)[ReX(CO)_3]_2(5,X=Cl;6,X=Br).Crystal data for 5:monoclinic,C2/c,a=26.951(2)A,b=16.602(1)A,c=14.641(1)A,#beta#=116.147(1)deg,V=5880.5(8)A~3,Z=8.6: monoclinic, C2/c,a=27.513(3)A,b=16.740(2)A,c=14.837(2)A,#beta#=116.925(2)deg,V=6092.8(10)A~3,Z=8.An unusual metal-induced methoxylation at the carbon atom of the triazine ring of the bridging TPT ligand was observed.The nucleophilic attack of MeO~- on C(3) results in a tetrahedral geometry around the carbon atom.Concomitantly. the uncoordinated pyridyl ring is protonated and rotated into a perpendicular orientation relative to the central C_3N_3 ring,Reaction of TPT with [NEt_4]_2[ReBr_3(CO)_3] in benzene-emthanol resulted in an unexpected dinuclear complex 7, with formulation[#mu#-C_3N_3(OMe)(py)_3][Re(CO)_3][ReBr(CO)_3].The methoxylated TPT ligand functions simultaneously as a tridentate and bidentate ligand with two fac-Re(CO)_3~+cores.Crystal data for 7:monoclinic,P2_(1),a=12.114(1)A,b=14.878(1)A,c=15.807(1)A,#beta#=104.601(1)deg,V=2756.9(3)A~3,Z=4.