JP2006076972A - Multi-sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new compound having a vapochromic phenomenon and to provide a multi-sensor using the compound. <P>SOLUTION: The compound is composed of formula R<SB>4</SB>[Pt<SB>2</SB>(pop)<SB>4</SB>X] nH<SB>2</SB>O (wherein, Rs are each an alkali metal ion, an alkylammonium ion or an alkyldiammonium; X is a halide ion; and pops are each a P<SB>2</SB>O<SB>5</SB>H<SB>2</SB><SP>2-</SP>). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel compound and a multisensor using the same, and more particularly to a novel compound having a wepachromism phenomenon and a multisensor using the same.

  During the last decades, one-dimensional (1D) materials have received great attention in both chemical and physics fields. This is because they exhibit characteristic optical properties and magnetic and transfer properties resulting from 1D structures. Some 1D materials have been reported to show dramatic irreversible changes in color and / or fluorescence when exposed to volatile organic compounds (VOC) and water vapor. These spectral changes in the presence of vapor are called vapochromism and guarantee a phenomenon for chemical vapor sensor devices (CL Exstrom, JR Sowa, Jr., CADaws, D. Janzen, and KRMann, Chem. Mater. 1995, 7, 15-17; b) CA Daws, CL Exstrom, JR Sawa, Jr., and KR Mann, Chem. Mater. 1997, 9, 363-368. C) MA Mansour, WB Connick, RJ Lachicotte , HJ Gysling, and R. Eisenberg, J. Am. Chem. Soc. 1998, 120, 1329-1330; d) CE Buss and KR Mann, J. Am. Chem. Soc. 2001, 124, 1031-1039. ).

C.L.Exstrom, J.R.Sowa, Jr., C.A.Daws, D. Janzen, and K.R.Mann, Chem. Mater. 1995, 7, 15-17; C. A. Daws, C.L.Exstrom, J.R.Sawa, Jr., and K. R. Mann, Chem. Mater. 1997, 9, 363-368. M.A. Mansour, W.B.Connick, R. J. Lachicotte, H. J. Gysling, and R. Eisenberg, J. Am. Chem. Soc. 1998, 120, 1329-1330; C. E. Buss and K.R.Mann, J. Am. Chem. Soc. 2001, 124, 1031-1039.

However, a compound having a phenomenon in which the color is changed by desorbing moisture, that is, a so-called vapor chromism phenomenon has been found so far, but in addition to this phenomenon, a compound having a change in other physical characteristics or the like. Is not known so far.
There are many sensors that detect water vapor, but there are no sensors that change in conjunction with the magnetic and electronic states.

  Therefore, an object of the present invention is to provide a novel compound having a weep chromism phenomenon and a multisensor using the compound.

  In order to achieve the above object, the inventors have conducted extensive research on nanowire valence complexes, and as a result, have come to find the compound of the present invention and a multisensor using the compound.

That is, the compound of the present invention has the formula:
[Chemical 1]
R ₄ [Pt ₂ (pop) ₄ X] · nH ₂ 0
(Wherein R is an alkali metal ion, alkylammonium ion, walking rudiammonium, X is a halogen ion, pop is P ₂ O ₅ H ₂ ²⁻ ).

In a preferred embodiment of the compound of the present invention, R ₄ is [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ .

  In a preferred embodiment of the compound of the present invention, X is I.

  The multisensor of the present invention is characterized by using the compound according to claim 1.

  The compound of the present invention can be applied at a bulk crystal level or at a nano-size level, and has an advantageous effect that the application range is wide.

  In addition, the sensor using the compound of the present invention can sense not only a change in color but also a change in magnetism and electronic state at the same time, and has an advantageous effect that the application range as a multisensor is wide.

The compounds of the present invention have the formula:
[Chemical formula 2]
R ₄ [Pt ₂ (pop) ₄ X] · nH ₂ 0
(Wherein R is an alkali metal ion, alkylammonium ion, walking rudiammonium, X is a halogen ion. Pop is P ₂ O ₅ H ₂ ²⁻ ). Preferably, R ₄ is [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ . Preferably, X is I.

From the viewpoint that the novel compound of the present invention can provide a multisensor capable of recognizing color, magnetism and the like with higher sensitivity, [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ [Pt ₂ (pop) ₄ I] _{· 4H 2 0 (pop = P} 2 O 5 H 2 2-) is preferably made of. As will be described later, such a compound can adsorb and desorb water molecules with changes in temperature or humidity, and consequently changes in color (for example, green and gold), magnetic properties. It can be used as a multi-sensor based on desorption of water vapor by utilizing changes (paramagnetism and diamagnetism) and changes in electronic state (for example, charge polarization phase and charge density wave state).

  That is, the present invention senses the color change (green and gold) due to desorption of water vapor in the nanowire platinum mixed valence complex and the accompanying magnetic change (paramagnetism = charge polarization phase and diamagnetism = charge density wave state). It can be applied as a sensor. The phenomenon of color change upon desorption of moisture is called vapor chromism.In addition to this phenomenon, the novel compound of the present invention is accompanied by changes in the electronic state (charge polarization phase and charge density wave state), and the magnetism also changes. This is an unprecedented phenomenon that will become a fundamental technology as a molecular device.

The compound of the present invention has water molecules at (room temperature), and cross-linking ions (X) such as iodine ions are displaced in one direction from the center between platinum, so that Pt ^II -Pt ^III -X. . . The electric polarization phase of Pt ^II -Pt ^III -X can be taken.

For example, the complex of [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ [Pt ₂ (pop) ₄ I] · 4H ₂ 0 is green because it has a charge transfer absorption band at 2.37 eV. It is paramagnetic because it has unpaired electrons on Pt ^II -Pt ^III . In Raman scattering, v (Pt ^II -Pt ^III ) is also observed at 98 cm ⁻¹ . On the other hand, when the temperature is raised to 340 K (66 degrees Celsius) or higher, water molecules are desorbed. Accompanying this desorption, the bridging ions (X) were shifted symmetrically in a double cycle. . . Pt ^II -Pt ^II. . . X-Pt ^III -Pt ^III -X. It becomes a charge density wave state. For this reason, there are no unpaired electrons and diamagnetism occurs. Moreover, since the charge transfer absorption band shifts to the low energy side up to 1.12 eV, it becomes gold. Raman scattering is v (Pt ^II -Pt ^II) is to ^{86cm -1, v (Pt III -Pt} III) is observed 94cm ^-1.

  Such color changes, magnetic changes, and electronic state changes are repeatedly observed. Therefore, it can be seen that it can be applied as a sensor.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not intended to be interpreted as being limited to the following examples.

  One-dimensional electronic systems have received considerable attention from both basic science and application concerns. From an application point of view, these systems are very promising in the fields of nonlinear optics and nanoelectronic devices, while from a basic science point of view many characteristic physical properties such as spin electron wave (SDW), charge Electronic waves (CDW) and metallic states in organic conductors, isolation in π-conjugated polymers, polarons, bipolarons, etc. are observed. Among these compounds, quasi-one-dimensional halogen-bonded binuclear Pt complexes are attractive targets due to the large variety of their electronic state wavelength variability, optical and magnetic properties. These binuclear Pt complexes have four oxidation states depending on the position of the bound halogen ion and the binuclear Pt ion, for example, (1) average balance state, (2) CDW state, (3) charge polarization state, and (4 ) Selective charge polarization state can be taken.

  Therefore, we studied the first novel vapochromic phenomenon associated with the phase transition between charge polarization and CDW state at increased temperatures in the MMX (metal-metal-halogen) chain.

A typical vapor chromic material is a planar square PtII compound that forms a linear chain that selects the Pt (CNR) ₄ ²⁺ direction and the Pt (CN) ₄ ^2- direction [Pt (CNR) ₄ ] [Pt (CN) ₄ ] (R = p-CN-C ₆ H ₄ -C _n H _{2n + 1} ; n = _{1, 2, 6, 10, 12, 14} ). The bapochromism of these complexes is suggested to be due to changes in the Pt-Pt distance that are unrelated to 1D electronic structural instabilities such as Peierls and Spin-Peierls instabilities.

  We have discovered a new type of vapor chromism that is performed through the phase transition property to the 1D system. The compounds of the present invention are 1D halogen-bonded dinuclear platinum compounds that significantly change in structure and optical properties and exhibit a reversible phase transition with vapor. This compound has a 1D chain structure compound repeating metal-metal-halogen (M-M-X) units with M = Pt and X = I, and is called MMX chain.

In MMX chain compounds, the 1D electronic structure is formed by M d _z2 orbitals and X p _z orbitals. The normal balance of M is _2.5+ , with 3 electrons present per 2 d _z2 orbitals. Four charge order (CO) states are theoretically expected in this system as shown below.

(a) ―M ^{2.5 +} −M ^2.5+ ―x−M ^2.5+ −M ^2.5+ -X- (Average balance (AV) state)
(b) ――― M ²⁺ -M ²⁺ --- XM ³⁺ -M ³⁺ -X --- (Charge Density Wave (CDW) state)
(c) ――― M ²⁺ -M ³⁺ -X --- M ²⁺ -M ³⁺ -X --- (Charge polarization (CP) state)
(d) ――― M ²⁺ -M ³⁺ -XM ³⁺ -M ²⁺ --- X --- (Selective charge polarization (ACP) state)

Two families of MMX chain compounds, namely R ₄ [Pt ₂ (pop) ₄ X] nH ₂ O (pop = p ₂ O ₅ H ₂ ^2- ; R = K, NH ₄ ; X = Cl, Br) and M ₂ (dta) ₄ I (M = Pt, Ni, dta = CH ₃ CS ₂ ⁻ ) was found in the early stages of the study. The former ground condition was revealed to be CDW. For Pt ₂ (dta) ₄ I, the transition from CP to ACP is suggested to occur at 80K, while Ni ₂ (dta) ₄ I is thought to have an AV state. I-bonded compounds have greater hybridization between the X p-orbitals and M d-orbitals than Cl or Br-bonded compounds, and various CO states are expected to be stabilized. We have alkali metals (R = Na, NH ₄ , Rb and Cs) and alkali ammonium [R = C _n H _{2n + 1} NH ₃ , (C _n H _{2n + 1} ) ₂ NH ₂ and R ′ = NH ₃ ( About 20 compounds of R ₄ [Pt ₂ (pop) ₄ I] nH ₂ O and R ′ ₂ [Pt ₂ (pop) ₄ I] nH ₂ O with different counter cations of C _n H _2n ) NH ₃ ] These substitutions are such that the Pt-I-Pt distance (d (Pt-I-Pt) varies widely and the electronic structure of the PtPtI chain is controlled between the diamagnetic CDW and paramagnetic CP states. The resulting phase diagram is shown in Fig. 1 where the lowest charge transfer (CT) energy Ect is plotted as a function of d (Pt-I-Pt) The phase boundary is approximately d (Pt -I-Pt) = 6.1 angstroms, and we have CP in [(C ₂ H ₅ ) ₂ NH ₂ ] ₄ [Pt ₂ (pop) ₄ I] (material 17 in FIG. 1) and Reported pressure and light-induced phase transition between CDW states Target material in the present study indicates a novel Weserblick Pas electrochromic effect with metastasis between the paramagnetic CP states and diamagnetic CDW state _{[NH 3 (C 4 H 8} ) NH 3] 2 [Pt 2 (pop) 4 I] · 4H ₂ 0 (material 18 in FIG. 1).

Example 2
Next, [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ [Pt ₂ (pop) ₄ I] · 4H ₂ 0 exhibiting a favorable wepachromism phenomenon was examined in detail.

FIG. 2 shows a perspective view of the crystal structure of [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ [Pt ₂ (pop) ₄ I] · 4H ₂ 0 (hereinafter referred to as 1) at 296K. Two Pt atoms are joined by four pop ligands to form a Pt ₂ (pop) ₄ unit. Two adjacent Pt ₂ (pop) ₄ units are joined by an I ion to form a PtPtI linear chain along the c-axis. As represented in the figure, the binding I ions are disordered in the semi-occupied state from the middle of adjacent Pt-Pt unitization. This is because substitution of I ions is not defined three-dimensionally. From x-ray structural analysis, it is therefore difficult to determine if one ground state is CDW or CP. The Pt-Pt distance is 2.837 angstroms, that of [Pt ₂ ^II (pop) ₄ I] · 2H ₂ 0 (2.925 angstroms) and [Pt ₂ ^III (pop) ₄ I ₂ ] (2 .755 angstroms) in between. The shorter and longer distances are 2.722 angstroms and 4.249 angstroms, respectively. The counter cation NH ₃ (C ₄ H ₈ ) NH ₃ ²⁺ is located in the space between the four chains and forms an H bond to the pop ligand. Four H ₂ O molecules are located in space.

The Raman spectrum was measured to obtain information about the CO structure of 1. FIG. 3 is a polar Raman spectrum of 1. A strong signal of 80-100 cm ⁻¹ contributes to the Pt—Pt stretching mode v (Pt—Pt) of the Pt—Pt unit. At 296K, the signal v (Pt-Pt) band is observed at 98 cm-1, indicating the formation of only one type of Pt-Pt unit. A relatively weak band was also observed at about 115 cm- ¹ . This band can be assigned to the Pt-I stretching mode activated by substitution of I ions from the middle between adjacent Pt-Pt units. This fact is consistent with the crystal structure of 1 described above. From these results, therefore, a ground state of 1 at 296K is considered to be CP. When the temperature is increased from 296K to 340K, the v (Pt-Pt) band clearly splits into two components, and two types of Pt-Pt units, in this case Pt ^II -Pt ^II (86 cm ^-1 ) and while some ^{Pt III -Pt III (94cm -1)} , Pt = stretching mode is still seems to be activated. Therefore, the electronic phase at 340K is classified as CDW.

One of the most impressive features is that the transition from CP to CDW is accompanied by a significant color change of the crystal. The polarization reflection spectrum of the sample and the corresponding microscopic image are shown in FIG. 4a). 296K, 1 is yellow green. When the temperature is raised to about 340K, the color of the sample changes to red-brown. The peak at 2.37 eV at 296K changes to a yellow-green color, while the red-brown color at 340K is mainly due to a strong reflection band from the near-infrared region to about 2 eV. Such color chromism is also confirmed from the optical conductivity spectrum (σ) of FIG. As evidenced by the figure, Ect is dramatically increased from 2.37 eV (520 nm) to 1.12.
Shift to eV (1110 nm). This spectral change is much greater than that of previously reported vapor chromic materials. The lowest CT band observed at 2.37eV in CP phase from previous theoretical studies in the optical excitation of MMX chain ^{compounds, [- I --- Pt 2+ -P} 3+ -I --- Pt 2+ While assigned to internal dimer CT excitation from -Pt ³⁺ -I-] to [-I-Pt ³⁺ -P ²⁺ --- I --- Pt ²⁺ -Pt ³⁺ -I-] , the CT band at 1.12eV in CDW ^{phase, [- I --- Pt 2+ -P} 2+ -I --- Pt 3+ -Pt 3+ -I-] from [-I-Pt ²⁺ -P3 ⁺ -I --- Pt2 ⁺ -Pt3 ⁺ contributes to the external dimer to -I-]. That is, changes resulting from the CP-CDW transition and the origin of the optical gap are responsible for the observed chromism. The gap energy Ect = 1.12 eV at 340 K is almost equal to that of the compound in the CDW phase as shown in FIG. Therefore, it is natural to think that the observed CP-CDW transition is caused by a decrease in d (PT-I-Pt).

  To gain insight into the phase transition mechanism, thermal mass spectrometry (TGA) was performed in a dry nitrogen atmosphere. The result of TGA is shown in FIG. When the temperature was raised from room temperature, 1 showed moderate weight loss, releasing 5.450% at 395K. This value is in good agreement with that calculated for the loss of 4 H2O molecules per blending unit (5.365%). The compound then shows a low mass loss up to approximately 500 K (<0.5%). The red-brown phase (CDW) changes the background to the original yellow-green (CP) phase by cooling the crystals to room temperature and / or exposing them to water vapor. These results demonstrate that the vapor chromic reaction is irreversible and the transition between CP and CDW is triggered by the absorption and desorption of water molecules. Powder X-ray diffraction measurement was also conducted to investigate the change in the vapor chromic structure. A collected X-ray pattern of 1 heated at 353 K in vacuum indicates that some solids change to a new but still unidentified crystal structure. Further structural studies may be necessary to determine the details of this structural transition.

In conclusion, we have found that in the MMX compound, [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₄ [Pt ₂ (pop) ₄ I] · 4H ₂ 0, between the paramagnetic CP state and the diamagnetic CDW state. A novel reversible vaporomic effect associated with the phase transition has been found. The results presented here anticipate that MMX chain compounds are candidates for additional chemical vapor sensor devices.

The starting compounds, K ₄ [Pt ₂ (pop) ₄ ] · 2H ₂ 0 and K ₄ [Pt ₂ (pop) ₄ I ₂ ] were prepared by the method described previously. That is, in the synthesis method, K ₄ [Pt ₂ (pop) ₄ ] · 2H ₂ 0 is obtained by dissolving K ₄ Pt ₂ Cl ₄ and phosphorous acid in water and heating at 120 ° C. for 2 hours. When this is dissolved in water and oxidized by adding I ₂ , K ₄ [Pt ₂ (pop) ₄ I ₂ ] is obtained. One single crystal was grown by standard diffusion using an H-shaped glass cell. [NH ₃ (C ₄ H ₈ ) NH ₃ ] SO ₄ in 2 ml aqueous solution (2 mg) and the required molar amounts of K ₄ [Pt ₂ (pop) ₄ ] · 2H ₂ 0 (20 mg) and K ₄ [Pt ₂ (pop ) A 2 ml aqueous solution of ₄ I ₂ ] (20 mg) was placed at both ends of the cell and allowed to diffuse slowly in water at room temperature. One week later, yellow green needle crystals were obtained. Elemental analysis is as follows.

Calculated for C ₁₀ H ₄₈ IN ₄ O ₂₄ P ₈ Pt ₂ (%): C7.14; H3.30; N4.16
Theoretical value: C7.15; H3.20; N4.13

  X-ray structural analysis of 1 was performed using a Rigaku RAXIS-RAPID image plate diffractometer with graphite monochromatic Mo-Kα radiation (λ = 0.7107 Å). Crystal data of 1 at 296K: Mr = 1343.31, tetragonal, space group I4 / m, α = 13.3473 (8) angstrom, c = 9.8091 (7) Ongstrom, V = 1747.5 (2) angstrom 3, Z = 2, ρcal = 2.553 gcm−3, final R = 0.0351, wR = 0.138, I> 3.00ρ (I) and GOF = 1.588. CCDC 245189 contains supplemental crystal graphic data for this paper.

  The polar Raman spectrum of 1 was measured using a Renishow Ramanscope 1000B Raman spectrometer with a cwHe-Ne laser (1.96 eV) and an optical microscope. Polar reflection spectra are obtained by using a specially designed spectrometer with a 25 cm grating monochromator and an optical microscope. TGA was performed in a dry nitrogen gas atmosphere using Rigaku Thermo Plus 2TG 8120.

To summarize these results, at 296K, the compound of the present invention has 4H ₂ O molecules and takes a charge polarization state. In the Raman spectrum, it shows a single PtII-PtIII mode at 98 cm-1 and a charge transfer band from PtII to PtIII at about 2.4 eV. At 340K, the compounds of the invention release 4H ₂ O and change to the CDW state. After this rearrangement, the Pt-Pt band in the Raman spectrum splits into the Pt II-Pt II mode at 86 cm-1 and the PtIII-PtIII mode at 94 cm-1, and the charge transfer band shows a significant red shift to 1.1 eV. Show. This vapochromic action is repeated by changing the temperature and / or exposing to vaporized water.

From these results, the compounds of the present invention, room temperature, or under ^{steam, [- I --- Pt 2+ -P} 3+ -I --- Pt 2+ -Pt 3+ -I-] charge It takes a density wave state, and since there is one unpaired electron on Pt2 ⁺ -Pt3 ⁺ , it takes paramagnetism and shows a green color. Also, high temperature, or in the vapor state ^{without, Pt 2+ -P 2+ --- I-} Pt 3+ -Pt 3+ -I shows a charge density wave state of, all e will create a pair Therefore, it is diamagnetic and gold.

  In other words, it has been found that if the compound of the present invention is used, the degree of vapor can be detected by a change in color and a change in magnetism, and it can be used as a so-called multisensor.

  In the nanowire platinum mixed valence complex, the phenomenon in which vapor chromism and the accompanying change in electronic state and change in magnetism are linked is the first in the world and is a very innovative invention. It can be applied as a multi-sensor / molecular device that simultaneously senses color changes, magnetic changes and electronic state changes due to the adsorption and desorption of water vapor.

FIG. 1 shows the peak energy of the CT band E _CT as a function of the distance d (Pt-I-Pt) between two Pt ions bound by iodine ions. FIG. 2 shows the crystal structure of the [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ [Pt ₂ (pop) ₄ I] · 4H ₂ 0 compound. The H atom was omitted for clarity. FIG. 3 shows polarization Raman spectra for the polarization of z (xx) z (x parallel c-axis) at a) 296K and b) 340K. FIG. 4 shows a) polarization with light polarization parallel to the c-axis in [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ [Pt ₂ (pop) ₄ I] · 4H ₂ 0 compounds at 296K and 340K. Reflectance, b) Photoconductivity spectrum. FIG. 5 shows a TGA transmission of [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ [Pt ₂ (pop) ₄ I] · 4H ₂ 0 compound with 5 K / min dry nitrogen purification.

Claims (4)

formula,
[Formula 1]
R ₄ [Pt ₂ (pop) ₄ X] · nH ₂ 0
(Wherein R is an alkali metal ion, alkylammonium ion, walking rudiammonium, X is a halogen ion, pop is P ₂ O ₅ H ₂ ²⁻ ). The compound according to claim 1, wherein R ₄ is [NH ₃ (C ₄ H ₈ ) NH ₃ ] ₂ . The compound according to claim 1 or 2, wherein X is I. A multisensor using the compound according to any one of claims 1 to 3.

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