An Organometallic Methodology Affording Dinuclear Copper(I) Complexes (original) (raw)
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Inorganic Chemistry, 2010
The reaction of the multidentate Schiff base species TrenSal, TrenBrSal, and TEtSal with copper acetate is reported. The heptadentate ligands generate a tetrametallic L 2 Cu 4 OH motif that contains an internalized hydroxide anion. In contrast, the hexadentate TEtSal ligand is found to form an open trimetallic motif. The importance of L 2 Cu 4 OH to the family of copper complexes with an endohedral hydroxide anion is discussed. [(TrenBrSal) 2 Cu 4 OH][OAc] is analyzed by temperature-dependent magnetic measurements.
Auxiliary Part of Ligand Mediated Unique Coordination Chemistry of Copper (II)
ChemistrySelect, 2016
Six N,N,O-donor Schiff-base ligands, HL1-HL6, [HL1/HL2/HL3 = {2-(2-piperazin-1-yl)ethylimino)methyl)-4-(Cl/H/Me)-phenol}; HL4/HL5/HL6 = {2-(2-morpholine/piperidine/ pyrrolidine À1-yl) ethylimino)methyl)-4-chlorophenol}, have been designed by combining 5-R-2-hydroxy-benzaldehyde, (R=Cl/H/Me) and N-(2aminoethyl)-Y, (Y = piperazin/morpholine/ piperidine/pyrrolidine) with the view to explore the role of R and X (part of Y excluding coordinating N) on the coordination chemistry of Cu (II) in presence of bromide as counter anion. HL1-HL6 formed in situ on reaction with Cu(II)Br 2 produce complexes 1-6, respectively. Complex 1, [Cu(II) 2 Cu(I) 2 (L1)(MeOH) 2 Br 7.30 ], is a mixed valence Cu(I)-Cu(II) species having phenyl ring brominated at ortho position with 0.65 occupancy. Complexes 2-4 are mononuclear species with general formula [Cu{L2/L3/L4)}Br 2 ]. Complexes [Cu 3 (L5)Br 4 ] (5) and [Cu 3 (L6)Br 4 ] (6) are trinuclear species having similar structure but exhibit different magnetic property, 5 is ferro-(J = +16.64 cm À1) and 6 is antiferromegnetic (J =-11.76 cm À1). The influence of R and X on bromonation, magnetic property and nuclearity issues have been rationalized by DFT calculations.
Journal of Chemical Sciences, 2015
Equimolar reaction of copper(I) bromide with 2-thiouracil (tucH 2) in acetonitrile-methanol formed a light yellow solid which on subsequent treatment with a mole of triphenyl phosphine (PPh 3) in chloroform has yielded a sulfur-bridged dinuclear complex, [Cu 2 Br 2 (µ-S-tucH 2) 2 (PPh 3) 2 ]•2CHCl 3 1. A reaction of copper(I) bromide with two moles of 2,4-dithiouracil (dtucH 2) in acetonitrile-methanol followed by addition of two moles of PPh 3 , designed to form [Cu(µ-S,S-dtuc) 2 (PPh 3) 4 Cu] 2a, instead resulted in the formation of previously reported polymer, {CuBr(µ-S,S-dtucH 2)(PPh 3)} n 2. Reaction of copper(I) iodide with 2thiouracil (tucH 2) and PPh 3 in 1:1:2 molar ratio (Cu:H 2 tuc:PPh 3) as well as that of copper(I) thiocyanate with pyridine-2-thione (pySH) or pyrimidine-2-thione (pymSH) and PPh 3 in similar ratio, yielded an iodo-bridged unsymmetrical dimer, [(PPh 3) 2 (µ-I) 2 Cu(PPh 3)] 3 and thiocyanate bridged symmetrical dimer, [(PPh 3) 2 Cu(µ-N,S-SCN) 2 Cu(PPh 3) 2 ] 4, respectively. In both the latter reactions, thio-ligands which initially bind to Cu metal center, are de-ligated by PPh 3 ligand.
Inorganic Chemistry, 2006
The use of a strategy combining ligand design and changes of reaction conditions has been investigated with the goal of directing the assembly of mononuclear, dinuclear, tetranuclear, and polymeric copper(II) complexes. As a result, closely related copper monomers, alkoxo dimers, and hydroxo cubanes, along with a carbonate-bridged polymeric species, have been synthesized using the rigid, aliphatic amino ligands cis-3,5-diamino-transhydroxycyclohexane (DAHC), cis-3,5-diamino-trans-methoxycyclohexane (DAMC), and the glutaryl-linked derivative glutaric acid bis-(cis-3,5-diaminocyclohexyl) ester (GADACE). The composition of the monomeric complex has been determined by X-ray crystallography as [Cu 2 ](ClO 4 ) 2 (1), the two dimers as [{Cu(DAHC)(OMe)} 2 ]-(ClO 4 ) 2 ‚MeOH (2) and [{Cu(DAMC)(OMe)(ClO 4 )} 2 ] (3), the three Cu 4 O 4 cubanes as [{Cu(DAHC)(OH)} 4 ](ClO 4 ) 4 ‚ 2.5MeOH (4), [{Cu(DAMC)(OH)} 4 ](ClO 4 ) 4 ‚H 2 O (5), and [{Cu 2 (OH) 2 (GADACE)} 2 ]Cl 4 ‚2MeOH‚6H 2 O (6), and an infinitechain structure as [{Cu(DAHC)(CO 3 )} n ] . Furthermore, the cubane structures 4 and 5 have been investigated magnetically. Our studies indicate that formation of the monomeric, dimeric, and tetranuclear DAHC and DAMC complexes can be controlled by small changes in reaction conditions and that further preorganization of the ligand moiety by linking the DAHC cores (GADACE) allows more effective direction of the self-assembly of the Cu 4 O 4 cubane core.
Inorganic Chemistry, 1998
The dinuclear copper(I) complex of 1,3-bis[N-(2-pyridylethyl)formimidoyl]benzene, [Cu 2 (H-BPB-H)(CH 3 CN) 2 ]-(BF 4) 2 , as well as the 5-nitro derivative, [Cu 2 (NO 2-BPB-H)(CH 3 CN) 2 ](BF 4) 2 , react with dioxygen to form phenolatebridged complexes as products. In a detailed kinetic study activation parameters of ∆H q) 47 (9 kJ/mol, ∆S q)-53 (11 J/(mol K), and ∆V q)-9.5 (0.5 cm 3 /mol for the reaction of [Cu 2 (H-BPB-H)(CH 3 CN) 2 ](BF 4) 2 with dioxygen were obtained which account, together with further kinetic findings, for the occurrence of an intermediate peroxo complex that cannot be observed spectroscopically. The crystal structures of the products of the reaction were determined. Crystal data: complex [Cu 2 (H-BPB-O)-OH(H 2 O)](BF 4) 2 , formula C 22 H 24 B 2-Cu 2 F 8 N 4 O 3 , monoclinic space group P2 1 /c, Z) 4, a) 10.122(2) Å, b) 28.711(6) Å, c) 9.283(2) Å, R) 90°,) 100.78(3)°, and γ) 90°; complex [Cu 2 (NO 2-BPB-O)-OH(H 2 O) 3 ](BF 4) 2 , formula C 22 H 27 B 2 Cu 2 F 8 N 5 O 7 , triclinic space group, P1 h, Z) 2, a) 10.144(2) Å, b) 10.7612(2) Å, and c) 16.000(4) Å.
Inorganic Chemistry, 1990
A Trinuclear Copper(1) Complex: Reaction with Dioxygen and the Formation of a Hexanuclear Copper(I1) Cluster Following our interest in the generation of lCuZ-Oj"+ moieties as models for copper protein Oz carriers (e.g. hemocyanin) and monooxygenases (e.g. tyrosinase),l we are currently expanding the scope of our studies to include the presence of a third (or fourth) copper(1) ion. Here, we report our initial attempts to develop new trinuclear wpper(1) structural chemistry and examine Cu(l),/O, reactivity? The impetus for this approach is the recent realization that "blue" multiwppcr oxidases contain such a unit. The copper ions in these proteins have previously been assigned by Malmstrom and co-workers as magnetically isolated type 1 (TI. "blue", high potential) and type 2 ("normal") and an EPRsilent coupled dinuclear pair (type 3)? Solomon and c-workers' first suggested that laccase actually possesses a trinuclear Center, and a recent X-ray structural study by Messerschmidt and coworkers' has confirmed the presence of such a cluster in the related protein ascorbate oxidase.lb These and other biochemical studies suggest that substrates such as ascorbate reduce the TI copper ion and electrons are then transferred to the Cu, cluster where the 4e-/4H* reduction of Oz to H,O is effected. T i Cu -T3 Cu= 12.2 A TI Cu -R Cu-14.8 A ( I ) TyeklHr, 2.; Karlin, K. D. Ace. Chcm. Res. 1989, 22, 241-248 and references cited therein. (b) Tyeklar, Z.; Ghosh. P.; Karlin. K. D.: Fsrooq. A,: Cohen. B. 1.; Cruse, R. W.; Gultneh. Y.; Haka, M. S.; Jawbron. R. R.; Zubieta. ACS S y m p i u m Series 372: American Chemical Society: Washington, DC, 1988: pp 116-150. (c) Cole, J. L.; Tan, G. 0.; Yang. E. K.; Hcdgsan. K. 0.; Solomon. E. 1. J . Am. C h m . Soe. 1990.112, 2243-2249. (5) (a) Msscrschmidt, A.; Rossi. A.; Ladenstein. R.; H u k , R.; Bolagnesi, M.; Gatti. C.; Marchesini, A,; Petruuclli. R.; Fimzzi-Agr6, A. 1. Mol. Bid. 1989, 206. 513-529. (b) The X-ray analysis" indicats that a His-Cys-His peptide sequence is ligated to the T3 and TI eoppcr ions, as shown in the insert figure. Scheme I 6 + 2% (X =OH-) 2b (X = N<) Ligand L (Scheme I, PY = 2-pyridyl) readily forms the trinuclear Cu(1) complex
Copper(II) Mediated Anion Dependent Formation of Schiff Base Complexes
Inorganic Chemistry, 2005
A tetranuclear mixed ligand copper(II) complex of a pyrazole containing Schiff base and a hydroxyhexahydropyrimidylpyrazole and copper(II) and nickel(II) complexes of the Schiff base having N-donor atoms have been investigated. A 2 equiv amount of 5-methyl-3-formylpyrazole (MPA) and 2 equiv of 1,3-diamino-2-propanol (1,3-DAP) on reaction with 1 equiv of copper(II) nitrate produce an unusual tetranuclear mixed ligand complex [Cu 4-(L 1) 2 (L 2) 2 (NO 3) 2 ] (1), where H 2 L 1) 1,3-bis(5-methyl-3-formylpyrazolylmethinimino)propane-2-ol and HL 2) 5-methyl-3-(5-hydroxyhexahydro-2-pyrimidyl)pyrazole. In contrast, a similar reaction with nickel(II) nitrate leads to the formation of a hygroscopic intractable material. On the other hand, the reaction involving 2 equiv of MPA and 1 equiv each of 1,3-DAP and various copper(II) salts gives rise to two types of products, viz. [Cu(T3-porphyrinogen)(H 2 O)]X 2 (X) ClO 4 , NO 3 , BF 4 (2)) (T 3-porphyrinogen) 1,6,11,16-tetraza-5,10,15,20-tetrahydroxy-2,7,12,17-tetramethylporphyrinogen) and [Cu(H 2 L 1)X]X‚H 2 O (X) Cl (3), Br (4)). The same reaction carried out with nickel(II) salts also produces two types of compounds [Ni(H 2 L 1)(H 2 O) 2 ]X 2 [X) ClO 4 (5), NO 3 (6), BF 4 (7)] and [Ni(H 2 L 1)X 2 ]‚H 2 O [X) Cl (8), Br (9)]. Among the above species 1, 3, and 5 are crystallographically characterized. In 1, all four copper atoms are in distorted square pyramidal geometry with N 4 O chromophore around two terminal copper atoms and N 5 chromophore around two inner copper atoms. In 3, the copper atom is also in distorted square pyramidal geometry with N 4 Cl chromophore. The nickel atom in 5 is in a distorted octahedral geometry with N 4 O 2 chromophore, where the metal atom is slightly pulled toward one of the axial coordinated water molecules. Variable-temperature (300 to 2 K) magnetic susceptibility measurements have been carried out for complex 1. The separations between the metal centers, viz., Cu(1)‚‚‚Cu(2), Cu(2)‚‚‚Cu(2A), and Cu(2A)‚‚‚Cu(1A) are 3.858, 3.89, and 3.858 Å, respectively. The overall magnetic behavior is consistent with strong antiferromagnetic interactions between the spin centers. The exchange coupling constants between Cu(1)‚‚‚Cu(2) and Cu(2)‚‚‚Cu(2A) centers have turned out to be −305.3 and −400.7 cm-1 , respectively, resulting in a S) 1/2 ground state. The complexes are further characterized by UV−vis, IR, electron paramagnetic resonance, and electrochemical studies.