Coordination Modes of a Series of Xylylene-Bridged Bis(1,4,7-triazacyclonon-1-yl) Ligands: Synthesis, Structure, and Properties of Nickel(II) and Copper(II) Complexes

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• 作者：Bim Graham ; Gary D. Fallon ; Milton T. W. Hearn ; David C. R. Hockless ; George Lazarev ; and Leone Spiccia
• 刊名：Inorganic Chemistry
• 出版年：1997
• 出版时间：December 31, 1997
• 年：1997
• 卷：36
• 期：27
• 页码：6366 - 6373
• 全文大小：222K
• 年卷期：v.36,no.27(December 31, 1997)
• ISSN：1520-510X

文摘

Three bis(1,4,7-triazacyclonon-1-yl) ligands,1,2-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene(L¹), 1,3-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene (L²), and1,4-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene(L³), have beensynthesized and their nickel(II) and copper(II) coordinationchemistry investigated. Reaction of L¹ withexcessNi²⁺ ions affords a mixture of mononuclear and binuclearcomplexes, which are readily separated by cationexchange chromatography and crystallized as their perchlorate salts,[NiL¹](ClO₄)₂ (1)and[Ni₂L¹(H₂O)₆](ClO₄)₄·4H₂O (2). Similar treatment ofL² and L³ with excess Ni²⁺ ionsaffords exclusively the binuclear complexes[Ni₂L²(H₂O)₆](ClO₄)₄(3) and[Ni₂L³(H₂O)₆](ClO₄)₄·3H₂O(4), respectively. Reaction of all three ligandswithexcess Cu²⁺ ions also yields binuclear complexes, whichmay be isolated as neutral species,[Cu₂LBr₄]·xDMF(5,L = L¹, x = 1; 6, L =L², x = 0; 7, L = L³,x = 0), or as perchlorate salts,[Cu₂L(H₂O)₄](ClO₄)₄·xH₂O(8, L =L¹, x = 5; 9, L = L²,x = 4; 10, L = L³, x= 5). The mononuclear copper(II) complex of L¹is prepared byreaction of L¹ with Cu²⁺ ions in a 1:1 moleratio and isolated as its perchlorate salt,[CuL¹](ClO₄)₂·2H₂O(11).The X-ray structures of complexes 1·H₂O,4, 5, and 11 have been determined.Compound 1·H₂O crystallizesinthe monoclinic space group P2₁/c (No.14) with a = 9.212(3) Å, b =17.805(8) Å, c = 16.501(6) Å, =103.36(3), V = 2633(1) ų, and Z= 4; 4, in the monoclinic space groupP2₁/c (No. 14) with a =9.108(4) Å, b =25.857(5) Å, c = 17.524(2) Å, =92.73(2), V = 4122(2) ų, andZ = 4; 5, in the trigonal space groupP3₁21(No. 152) with a = 10.889(5) Å, c =22.220(9) Å, V = 2281(1) ų, andZ = 3; and 11, in the monoclinicspacegroup P2₁/c (No. 14) witha = 9.45(1) Å, b = 19.51(2) Å,c = 15.10(1) Å, = 96.93(8),V = 2763(4) ų, andZ = 4. The nickel(II) and copper(II)centers in the mononuclear complexes, 1·H₂Oand 11, lie in distortedoctahedral environments, sandwiched by the two facially coordinatingtriamine rings of L¹. In complex 4,thetwo triamine rings of L³ coordinate to separatenickel(II) centers, with the distorted octahedral coordinationsphereabout each of the metal centers being completed by water molecules.Similarly, in complex 5, the two triaminerings of L¹ bind separate copper(II) centers, with thedistorted square pyramidal coordination sphere about eachof the metal centers being completed by bromide anions.