Rhenium carbonyls containing pyridyl ligands incorporating an alkyne entity

Article abstract of DOI:10.1016/0022-328X(96)06167-0

Reactions of pyridyl ligands, 4,4′-dipyridylbutadiyne (DPB), 1,4-bis(4′-pyridylethynyl)benzene (BPEB), ferrocenyl-4-pyridylacetylene (FPA), 4-nitrophenyl-4′-pyridylacetylene (NPPA) and 4-aminophenyl-4′-pyridylacetylene (APPA), with Re(CO)₅X (X = Cl.Br), cis-Re(CO)₄(L)Cl (L = PPh₃, P(OMe)₃), and [Re(CO)₃(2,2′-bipy)(MeCN)][PF₆], provides fac-Re(CO)₃(η¹-DPB)₂Cl (1), fac-Re(CO)₃(PY)₂Br (2, PY = FPA; 3, L = NPPA; 4, L = APPA), [fac-Re(CO)₃(PPh₃)Cl]₂( μ-PY) (5, PY = BPEB; 6, PY = DPB), [fac-Re(CO)₃(P(OMe)₃)Cl]₂( μ-DPB) (7), fac-Re(CO)₃(PPh₃)(PY)Cl (8, PY = NPPA; 9, PY = FPA), [fac-Re(CO)₃(2,2′-bipy)(PY)][PF₆] (10, PY = NPPA; 11, PY = APPA; 12, PY = FPA), and [{fac-Re(CO)₃(2,2′-bipy)}₂( μ-PY)][PF₆]₂ (13, PY = DPB; 14, PY = BPEB). The energy of the metal to pyridyl π * charge-transfer (MLCT) is investigated by electronic absorption spectra and cyclic voltammetry. X-ray structural analyses for 2 · CH₂Cl₂ and 12 · 2H₂O were carried out. 2 · CH₂Cl₂: C₁₂H₂₈BrClN₂O₃P₂Fe₂Re; monoclinic; P2₁/n, Z=4; a =15.188(2), b= 15.100(2), c = 16.254(1) A; β = 102.22(1)°; R = 0.047; Rw = 0.040. 12 · 2H₂O: C₃₀H₂₁F₆N₃O₃PFeRe; monoclinic; P2₁/n, Z = 4; a = 19.022(4), b = 9.339(2), c = 21.111(3) A; β= 116.156(9)°; R = 0.043; Rw = 0.061.