The Thermal Reaction of the Tris(μ-Hydrido)-Dodecacarbonyltrirhenium (o) Cluster with Triphenylphosphine and Triphenylphosphite

The thermal reaction between the tris(μ-hydrido)dodecacarbonyltrirhenium (o) cluster and triphenylphosphine or triphenylphosphite results in a trisubstituted rhenium cluster as the major product. The results of an X-ray structural analysis of H₃Re₂(CO)₉(PPh₃) are: Mr=1597.57, Monoclinic, P₂₁/n, a=15.598(1), b=9.530(2), c=41.685(3) Å, β=80.60(1)°, V=6113.(1) ų, Z=4, D_c=1.736 g/cm³, CuK_e, λ-1.54056 Å, μ-121.23 cm^?1, F(000)=3059.17, room temperature, R=0.049 for 7361 reflections with I≥2.5σ(I). The molecule has a triangular Re₂ core coordinated propellerwise by three PPh₃ ligands in the molecular plane with virtual C_3k symmetry.     

A New Method to Investigate the Clustering Phenomena in Supercritical Fluids

EstimationoflocaldensityofsolventaboutthesoluteSolvatochromicbehaviorsofspectroscopicprobesarewidelyusedtoestimatethesol-ventstrengthofsupercriticalfluids(SCF,).i-3lnthiswork,thesolvatochrondcshiftofthen-n*transitionbandforacetone(O.o37mo1.L-')insupercrihcal(SC)CO2wasde-terminedbyUVspectroscopytostUdythesolvationeffect.TheMcRae-BaylissexpressionbasedonthedielectriccontinUUInmodelgivestherelahonshipbetWeenso1vatochromicshiftandpo1arizabilityofnonPolarsolvents4-5asfollows:wherevisthewave…     

Salting coefficients for gases in seawater from scaled-particle theory

Experimental values of the salting coefficients for He, Ne, Ar, O₂, and N₂ in seawater are compared with values calculated from scaled-particle theory. The agreement is reasonably good; the average difference between calculated and observed values at 25°C is 0.007. Scaled-particle theory predicts correctly thatk _s should decrease as the temperature increases and that this effect should be most pronounced at low temperatures. However, the predicted magnitude ofdK _s/dt is only about half of that observed.     

还原性的类立方烷型金属有机原子簇[M_4(μ~3-Se)_4(η-C_5H_4R)_4](M=Mo,R=Pr~i;M=Cr,R=Me)的合成、晶体结构和电子性质

类立方烷型金属原子簇化合物M_4E_4(M为过渡金属,E为硫属元素)的研究长期以来受到重视,其主要原因有二:(1)一些类立方烷型金属原子簇(如Fe_4S_4及Fe-Mo-S原子簇)在生物体系(如固氮酶、铁氧还蛋白)中有重要意义;(2)由于可以方便地对M或E作系列性的改变,因而M_4E_4成为研究原子簇化合物的电子结构及检测各种有关的理论假设的重要模型化合物。     

The First New Hydrogen-Bonded Heterohexanuclear Complex [(salen)Cu]4[(salen)Fe(H2O)2]2(ClO4)2: Molecular and Crystal Structure and Magnetic Properties

The preparation, magnetic properties, and crystal structure of [(salen)Cu]₄[(salen)Fe(H₂O)₂]₂(ClO₄)₂ via hydrogen bonding are described [salen=N,N-ethylenebis (salicylideneiminate)]. Crystals are triclinic, of space group , with cell constants a=12.853(3), b=13.921(3), c=14.251(3) Å, =68.68(3)°, =87.86(3)°, =86.82(3)°, and Z=1. The structure was solved and refined to R=0.064 and R=0.068. The structure comprises the hexanuclear units which result from the linking of four mononuclear fragments [(salen)Cu] and two mononuclear fragment [(salen)Fe(H₂O)]⁺, through Cu -O H -O -Fe -O -H O -Cu hydrogen bonds of coordinating H₂O. In this complex, Fe^III ions are in almost square-planar surroundings. The temperature dependences of the magnetic susceptibilities of the complex have been studied in the 4.2–300 K range, indicating the presence of an antiferromagnetic interactions between metal ions.     

簇离子Mo_3S_4M~（n＋）中M与Mo成键作用及电子光谱（M＝Fe、Ni，n＝4；M＝Cu，n＝5）

应用ＩＮＤＯ／Ｓ半经验量子化学方法，对簇合物离子Ｍｏ３Ｓ和Ｍｏ３Ｓ４Ｍｎ＋（Ｍ＝Ｆｅ、Ｎｉ，ｎ＝４；Ｍ＝Ｃｕ，ｎ＝５）分别进行分子轨道计算。根据计算得到的簇离子中的原子表观电荷和成键指标，说明Ｆｅ、Ｎｉ、Ｃｕ＋与Ｍｏ３Ｓ成键作用的相对强度依次是Ｆｅ－Ｍｏ＞Ｎｉ－Ｍｏ＞Ｃｕ＋－Ｍｏ。比较了用含组态作用的ＩＮＤＯ／Ｓ方法计算得到的电子跃迁能与实验得到的电子吸收光谱值，并讨论了吸收峰归属情况。对于Ｍ为Ｆｅ、Ｎｉ的簇离子Ｍｏ３Ｓ４Ｍ４＋，最低能量的电子跃迁吸收峰起源于异金属间电荷转移跃迁（ＭＭ’ＣＴ）；而Ｍｏ３Ｓ４Ｃｕ（５＋）簇离子观察到的吸收峰主要是Ｍｏ３Ｓ芯的局域内电荷转移跃迁。根据理论计算结果，由Ｃｕ＋离子到Ｍｏ３Ｓ的电荷转移跃迁谱线，大约在４６０００ｃｍ－１以上才能观察到吸收峰。从Ｍｏ３Ｓ４Ｆｅ４＋次低能量吸收峰的实验值１６６００ｃｍ－１和理论值１６５００ｃｍ－１与Ｍｏ３Ｓ的最低能量吸收峰的实验值１６６００ｃｍ－１和理论值１６９００ｃｍ－１比较，表明无论从理论上或实验上都能证实簇离子Ｍｏ３Ｓ４Ｆｅ４＋在能量为１６６００ｃｍ－１处的吸收峰是起因于Ｍｏ３Ｓ芯的局域内电荷转移跃迁。     

The magnetic behaviour of [NnBu4]4[Ni16Pd16(CO)40]: an even-electron homoleptic carbonyl-metal cluster anion displaying a J = 2 ground state

The magnetic behaviour of the even-electron [Ni16Pd16(CO)40]4- cluster, in its [NnBu4]+ salt, has been investigated by magnetometry and muon spin rotation/relaxation (muSR) spectroscopy. The susceptibility measurements show an exceptionally high magnetic moment corresponding to a total spin value J=2. This suggests a Hund filling of a quadruplet ground state, quite unique in carbonyl-metal clusters. SQUID magnetometry shows a departure from the Curie-Weiss law, for T>150 K, and strong deviation from a Brillouin behaviour of the magnetisation curves. muSR spectroscopy in zero applied field shows a temperature independent decay of the muon spin polarisation, similar to that of a purely paramagnetic system. The observed muon spin repolarisation in a moderate external longitudinal field, however, invalidates this simple picture and suggests the presence of a local anisotropy field acting on the cluster's magnetic moment. A consistent interpretation of magnetometry and muSR results implies the occurrence of an additional interaction of the cluster spin with an effective crystalline field. The inclusion of this interaction in a model Hamiltonian allows us to successfully reproduce both the susceptibility and magnetisation data.     

十八元环多钒硼酸盐的水热合成及其氧化还原性质研究

在水热条件下合成了[Ni(en)2]6[(VO)12O6B18O39(OH)3].6H2O多钒硼酸盐,X射线衍射分析表明,该晶体属三方晶系,R-3空间群.测试了晶体的IR光谱和TG曲线,用循环伏安法详细研究了合成化合物的氧化还原性质及电子转移机理,结果表明该化合物具有两对氧化还原峰,其电子转移数分别为单电子和三电子.     

室温和低热固相反应在合成化学中的应用

介绍了室温和低热固相反应的监测手段和影响因素。总结了它在金属原子簇化合物、多酸、简单配位化合物、亚稳态化合物合成以及材料化学和生产实际中的应用。     

Topological analysis of some special graphs: III. Regular polyhedra

A regular polyhedron is isomorphic to a cluster on which every face has same number of bonds and every atom has an equal number of coordinating atoms. A general strategy for generating the eigenvectors and the eigenvalues of regular polyhedra is given. Not sign analyses are also performed on the eigenvectors of regular polyhedra. The results provide us a quick way to grasp the topological feature of the electronic structure of clusters having interesting topology.