Jianping Guo

Hong Kong Baptist University, Kowloon, Hong Kong

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Publications (12)28.8 Total impact

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    ABSTRACT: The metathesis reaction between two equivalents of [Ln(tpp)(H2O)3]Cl (Ln = Yb, Er; tpp2– = tetraphenylporphyrinate dianion) and one equivalent of cyanometallate in dmf at room temperature under nitrogen for 24 hours gave the cyanido-bridged d–f trinuclear complexes [{Ln(tpp)(dmf)n}2{(μ-NC)2M(CN)2}] (Ln = Yb, n = 2, M = Ni, 1; Ln = Er, n = 3, M = Ni, 2; Ln = Yb, n = 2, M = Pt, 3; Ln = Er, n = 3, M = Pt, 4), a trinuclear complex [{Er(tpp)(dmf)2}{(μ-NC)2Fe(CN)4}{Er(Htpp)(dmf)2}] (5), and a dinuclear complex [{Er(tpp)(dmf)(H2O)}(μ-NC)Ag(CN)] (6) when the cyanometallate used was the dianion [M(CN)4]2– (M = Ni, Pt), the trianion [Fe(CN)6]3–, and monoanion [Ag(CN)2]–, respectively. The solid-state structures of these complexes were ascertained by X-ray crystallography. Photoluminescence studies of complexes 1–4 showed that these complexes displayed photophysical properties characteristic of normal metal–porphyrinato complexes. Their absorption bands and emission peaks in the visible region are typical of the intraligand ππ* transitions of the porphyrinato ligand. Furthermore, these complexes also exhibited emission characteristic of the lanthanide(III) ion in the near-infrared (NIR) region, which was quenched by the cyanometallates. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
    Berichte der deutschen chemischen Gesellschaft 06/2008; 2008(22):3515 - 3523. · 2.94 Impact Factor
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    ABSTRACT: A series of 3d-4f heterobimetallic phenylene-bridged Schiff base complexes of the general formula [Zn(mu-L1)Ln(NO3)3(S)n] [Ln = La (1), Nd (2), Gd (3), Er (4), Yb (5); S = H(2)O, EtOH; n = 1, 2; H2L1 = N,N'-bis(3-methoxysalicylidene)phenylene-1,2-diamine] and [Zn(mu-L2)Ln(NO3)3(H2O)n] [Ln = La (6), Nd (7), Gd (8), Er (9), Yb (10); n = 1, 2; H(2)L(2) = N,N'-bis(3-methoxy-5-p-tolylsalicylidene)phenylene-1,2-diamine] were synthesized and characterized. Complexes 1, 2, 4, and 7 were structurally characterized by X-ray crystallography. At room temperature in CH(3)CN, both neodymium(III) (2 and 7) and ytterbium(III) (5 and 10) complexes also exhibited, in addition to the ligand-centered emission in the UV-vis region, their lanthanide(III) ion emission in the near-infrared (NIR) region. The photophysical properties of the zinc(II) phenylene-bridged complexes (ZnL1 and ZnL2) were measured and compared with those of the corresponding zinc(II) ethylene-bridged complexes (ZnL3 and ZnL4). Our results revealed that, at 77 K, both ligand-centered triplet (3LC) and singlet (1LC) states existed for the ethylene-bridged complexes (ZnL3 and ZnL4), whereas only the (1)LC state was detected for the phenylene-bridged complexes (ZnL1 and ZnL2). NIR sensitization studies of [Zn(mu-L')Nd(NO3)3(H2O)n] (L' = L1-L4) complexes further showed that Nd3+ sensitization took place via the 3LC and 1LC states when the spacer between the imine groups of the Schiff base ligand was an ethylene and a phenylene unit, respectively. Ab initio calculations show that the observed differences can be attributed to the difference in the molecular vibrational properties and electron densities of the electronic states between the ethylene- and phenylene-bridged complexes.
    Inorganic Chemistry 12/2006; 45(23):9315-25. · 4.59 Impact Factor
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    ABSTRACT: The synthesis and structural characterisation of some new tetranuclear cadmium(II) Schiff-base complexes were described. Reaction of the hexadentate Schiff-base ligands (H2L) with an excess of cadmium(II) acetate, Cd(OAc)2, furnished novel tetracadmium complexes of the general formula [Cd4(L)2(OAc)4], which exhibit an interesting three-dimensional cage-like structure of four ligand-supported cadmium atoms. All of the complexes were fully characterised by spectroscopic (FTIR, NMR and FAB MS) methods and their molecular structures were confirmed by single-crystal X-ray analysis. The X-ray crystal structures of these tetranuclear Schiff-base complexes represent the first structurally characterised examples of this kind for the cadmium triad. These new complexes were found to display rich photophysical properties and they all exhibited low-temperature phosphorescence in the frozen state. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
    Berichte der deutschen chemischen Gesellschaft 08/2005; 2005(19):3950 - 3954. · 2.94 Impact Factor
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    ABSTRACT: Dimerization of monoporphyrinate lanthanide complexes [Yb(Por)(H(2)O)(3)]Cl, (Por = TTP(2-), TMPP(2-) and TPP(2-)) in the presence of sterically hindered tripodal ligand, zinc Schiff-base, dilute HCl, K(2)CO(3) solution, 4,4'-bipyridine (bipy), and basic 8-hydroxyquinaldine (HQ) solution was observed in CH(2)Cl(2) at room temperature. Six neutral dimeric lanthanide porphyrinate complexes, [Yb(TTP)(mu-OH)](2)(mu-THF) (1), [Yb(TMPP)(mu-OH)(H(2)O)](2) (2), [Yb(TPP)(mu-OH)(mu-H(2)O)](2) (4), [Yb(TMPP)(mu-Cl)(H(2)O)](2) (5), [Yb(TMPP)(mu-OH)](2)(THF) (6) and [Yb(TPP)](2)(mu-OH)(mu-Q) (7), were obtained. X-Ray diffraction studies showed that for the dimers, the two lanthanide ions were bridged by OH(-), Cl(-) or H(2)O. Photoluminescent studies showed that the porphyrinate dianion acted as an antenna, transferred its absorbed visible energy to the lanthanide ion and enabled the latter emitting in the near-infrared (NIR) region. In general, the NIR emission is more intense for the dimers than for the monomers, and the NIR emission intensity decreases as the number of O-H oscillators present in the molecule increases.
    Dalton Transactions 01/2005; · 3.81 Impact Factor
  • Jianping Guo, Wai-Kwok Wong, Wai-Yeung Wong
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    ABSTRACT: In the presence of air, the interaction of AgSO3CF3 with phosphorus–nitrogen π-electron-rich compounds ArC(NPPh2)[N(SiMe3)2] (Ar=phenyl, p-tolyl, 4-pyridyl, 3-pyridyl and 2-pyridyl) and 1,4-C6H4{C(NPPh2)[N(SiMe3)2]}2 in acetonitrile led to the formation of metallic silver and the oxidative cleavage product {[ArC(NH2)2](Ph2PO2)}n (Ar=phenyl, 1; p-tolyl, 2; 4-pyridyl, 3; 3-pyridyl, 4; 2-pyridyl, 5) and [{1,4-C6H4[C(NH2)2]2}(Ph2PO2)2]n (6), respectively. Structural analyses of compounds 1–6 revealed that these ionic salts are held together by charge-assisted hydrogen bonds forming 1D, 2D and 3D polymeric networks.
    Polyhedron 01/2005; 24(8):927-939. · 2.05 Impact Factor
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    ABSTRACT: Twelve neutral stable complexes of ytterbium(III) and erbium(III) coordinated by anionic hydridotris(pyrazol-1-yl)borate and meso-tetraphenylporphyrinate, and its derivatives with different substituents in the para position of the phenyl groups, were prepared and characterized. Crystal structure analyses revealed that seven nitrogen atoms, four from the porphyrinate dianion and three from the anionic tripodal ligand, are symmetrically coordinated to the lanthanide ions. Photophysical investigations of the complexes showed an enhancement of near-infrared photoluminescence as compared to aqua-coordinated monoporphyrinate lanthanide complexes. The solvent effect and substituent effects on the photoluminescent properties of the complexes were also investigated (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).
    Berichte der deutschen chemischen Gesellschaft 01/2004; 2004(4):837 - 845. · 2.94 Impact Factor
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    ABSTRACT: In the presence of Ln3+ (Ln = La, Eu, Gd, Tb, Dy, Ho, Er, Tm or Lu), tris(2-aminoethyl)amine condensed with three equivalents of 3-(2′-pyridyl)-5-tert-butyl-2-hydroxybenzaldehyde in methanol to give the neutral Schiff-base complex LnIIIL (Ln = La 1, Eu 2, Gd 3, Tb 4, Dy 5, Ho 6, Er 7, Tm 8 and Lu 9; H3L = tris{[3′-(2′′-pyridyl)-5′-tert-butyl-2′-hydroxybenzylidene-2-imino]ethyl}amine). The structures of compounds 4−7 were determined by X-ray crystallography. The crystal structure analyses revealed that the Schiff base behaves as a tri-deprotonated heptadentate ligand encapsulating the lanthanide metal ion within the N4O3 cavity, with all the pyridyl groups being pendant. Solution spectroscopic data suggest that the LnIIIL complexes remain intact in methanol and exist as nine-coordinate non-electrolytes with the lanthanide metal ions coordinated to the N4O3 cavity of the tripodal Schiff base and two solvent molecules. The solution photoluminescent properties of these lanthanide Schiff-base complexes were also examined. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
    Berichte der deutschen chemischen Gesellschaft 01/2004; 2004(4):829 - 836. · 2.94 Impact Factor
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    ABSTRACT: A series of new 3d–4f heterobimetallic Schiff base complexes of the general formula [Zn(μ-L2)Ln(NO3)3(H2O)n] (Ln=La 1, Nd 2, Gd 3, Er 4 and Yb 5; n=1 or 2; H2L2=N,N′-bis(3-methoxy-5-p-tolylsalicylidene)ethylene-1,2-diamine) are synthesized and characterized. Complexes 1, 2, 4 and 5 are structurally characterized by X-ray crystallography. The photophysical properties of these complexes are also investigated. At room temperature, complexes 1–5 exhibit similar solution absorption and emission spectra in the UV–Vis region. Furthermore, compounds 2, 4 and 5 exhibit solution emission corresponding to the lanthanide(III) ion in the near-infrared region at room temperature. The triplet state emission of the 3d–4f bimetallic complexes without energy transfer is also determined through the photophysical study of complex 3.
    Inorganica Chimica Acta - INORG CHIM ACTA. 01/2004; 357(15):4510-4521.
  • Australian Journal of Chemistry - AUST J CHEM. 01/2004; 57(8).
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    ABSTRACT: A series of monoporphyrinate neodymium (III) complexes stabilized by anionic tripodal ligand (cyclopentadienyl)tris(dimethylphosphito)cobaltate(I) were prepared and characterized by IR, ESI-HRMS, UV–Vis and X-ray diffraction studies. Structural analyses revealed that the Nd3+ ion was seven-coordinate, surrounded by four nitrogen atoms from the porphyrinate dianion and three oxygen atoms from the anionic tripodal ligand. Photoluminescence studies showed that the porphyrinate dianion acting as a sensitizer absorbed the light and transferred the energy to the Nd3+ center, which then allowed the metal ion to emit efficiently at 885 and 1071 nm. The luminescent intensity of the complexes increases when there are strong electronic donating groups on the porphyrin rings but decreases with increasing polarity of the solvents.
    Inorganica Chimica Acta - INORG CHIM ACTA. 01/2004; 357(15):4379-4388.
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    ABSTRACT: The reaction of LiN(SiMe3)2 with arylnitrile, followed by the addition of anhydrous NiCl2 gives ionic complexes of the general formula [Ni{H2NC(Ar)=NH}4]Cl2 (Ar = Ph 1, p-tolyl 2). When the above reaction is carried out with cyanopyridine instead of arylnitrile under the same reaction conditions, neutral complexes of the general formula [{HN=C(Py)N=C(Py)NH}2Ni] (Py = 4-pyridyl, 3; 3-pyridyl, 4] are obtained. Compound 1 undergoes a metathesis reaction with sodium benzoate to give the neutral complex [(PhCO2)2Ni {H2NC(Ph)=NH}4] (5). Magnetic susceptibility measurements show that 1−4 are diamagnetic and that 5 is paramagnetic with two unpaired electrons. These results suggest that 1−4 are d8 square-planar complexes and 5 is an octahedral complex. The solid state structures of compounds 1−5 were determined by X-ray crystallography. Structural analyses reveal that 1 and 2 form a one-dimensional network through charge-assisted hydrogen bonds; whereas 5 forms a one-dimensional network through hydrogen bonds only. In complexes 3 and 4, the 2,4-dipyridyl-1,3,5-triazapentadienyl ligand behaves as a bidentate ligand forming a six-membered ring with the metal ion. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
    Berichte der deutschen chemischen Gesellschaft 11/2003; 2004(2):267 - 275. · 2.94 Impact Factor
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    ABSTRACT: The interaction of cationic lanthanide complexes [Ln(porp)(H2O)3]+ (Ln = Er or Yb; porp = porphyrinate) with sodium (cyclopentadienyl)tris(diethylphosphito)cobaltate (NaLOEt) gives the neutral 3d–4f bi-metallic porphyrinate complexes, [(LOEt)Ln(porp)]. X-Ray structural analyses reveal that these complexes are seven-coordinate with the three oxygen atoms of the O3-tripodal ligand, LOEt, coordinated to the lanthanide metal behaving as a 6-electron donor. Photophysical measurements show that the porphyrinate ligand behaves as a sensitizer by absorbing visible light to excite the Ln(III) metal ions, producing near-infrared emission.
    Journal of the Chemical Society Dalton Transactions 10/2001; · 3.65 Impact Factor