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121.
122.
Bernd M. Rode 《Chemical physics letters》1974,26(3):350-355
A typical “chelate” effect is demonstrated by means of all-electron ab initio LCGO SCF calculations on the [Li(HCONH2)2]+ complex in different geometrical arrangements. Energetic factors and the electronic structure of the complexes are discussed, showing the chelate effect to be connected with striking changes in bonding, density distribution and electronic energy. 相似文献
123.
124.
Karl Krmer Hans U. Güdel Gerd Meyer Thorsten Heuer Norman N. Edelstein Bernd Jung Lukas Keller Peter Fischer Eugeniusz Zych Janusz Drozdzynski 《无机化学与普通化学杂志》1994,620(8):1339-1345
The ternary uranium(III) halides A2UX5 (A = K, Rb; X = Cl, Br, I) have been prepared from the binary components AX and UX3 in sealed tantalum containers. According to their Guinier X-ray powder patterns, they all crystallize with the K2PrCl5/Y2HfS5 type of structure. Lattice constants for ambient temperature are reported. Single-crystal structure refinemens were undertaken for K2UI5 and Rb2UCl5. Magnetic susceptibility data were recorded with a SQUID magnetometer from liquid helium to room temperature. One-dimensional (intrachain) and three-dimensional antiferromagnetic ordering occur at low temperatures dependent upon the U3+? U3+ distance. Absorption spectra were recorded between 4 000 and 28 000 cm?1. They show f—f transitions typical for U3+ and, depending on the halide, very strong f—d transitions above 14 000 to 15 000 cm?1, respectively. 相似文献
125.
Treatment of a solution of excess PCl(3) and PS (PS = "proton sponge" = 1,8-dimethylamino naphthalene) with arachno-4-CB(8)H(14) (1) in CH(2)Cl(2), followed by hydrolysis of the reaction mixture, resulted in the isolation of the eleven-vertex diphosphacarbaborane nido-7,8,9-P(2)CB(8)H(10) (2) (yield 34%) as the main product. Other products isolated from this reaction were the phosphacarboranes nido-7,8,9,10-P(3)CB(7)H(8) (3) (yield 5%) and closo-2,1-PCB(8)H(9) (4) (yield 15%). Compound 2 can be deprotonated by PS in CH(2)Cl(2) or NaH in diethyl ether to give the [nido-7,8,9-P(2)CB(8)H(9)](-) (2(-)()) anion, which gives back the original compound, 2, upon re-protonation. Thermal rearrangement of anion 2(-) (Na(+) salt) at 350 degrees C for 2 h produced the isomeric [nido-7,8,10-P(2)CB(8)H(9)](-) (5(-)()) anion, which was isolated as a PPh(4)(+) salt (yield 86%). Multinuclear ((1)H, (11)B, (31)P, and (13)C), two-dimensional [(11)B-(11)B] COSY, (1)H{(11)B(selective)}, (1)H{(31)P(selective)}, and gradient-enhanced ([(1)H-(13)C] HSQC) magnetic resonance measurements led to complete assignments of all resonances which are in excellent agreement with the structures proposed. Coupling constants, (1)J((31)P,(13)C), (2)J((31)P,C,(1)H), and (1)J((31)P,(31)P), were calculated using the DFT method B3LYP/6-311+G(d,p). The molecular geometries of all compounds were optimized ab initio at a correlated level of theory (RMP2(fc)) using the 6-31G basis set, and their correctness was assessed by comparison of the experimental (11)B and (13)C chemical shifts with those calculated by the GIAO-SCF/II//RMP2(fc)/6-31G method. The computations also include the structures and chemical shieldings of the still unknown isomers [nido-7,10,8-P(2)CB(8)H(9)](-) (6(-)) and [nido-7,9,8-P(2)CB(8)H(9)](-) (7(-)). 相似文献
126.
Chemiluminescence from the b 0+ → X1 0+ band system of AsI and of the b 0+ → X1 0+, X2 1 systems of SbI in the near-infrared spectral region has been observed in a discharge flow system. Analysis of the spectra led to the spectroscopic constants (in cm?1) of AsI: ωe(X1, X2) = 257 ± 2, ωexe(X1, X2) = 0.82 ± 0.2, Te(b 0+) = 11738 ± 5, ωe(b 0+) = 271 ± 2, ωexe(b 0+) = 0.66 ± 0.2, and of SbI: Te(X2 1) = 965 ± 10, ωe(X1, X2) = 206 ± 6, Te(b 0+) = 12328 ± 10, ωe(b 0+) = 211 ± 6. The intensity ratio of the two sub-systems b 0+ → X2 1 and b 0+→ X1 0+ was found to be ≈0.013 in the case of SbI and ? 0.01 for AsI. 相似文献
127.
The intramolecular dynamic behavior of the tetrahedrane-type cluster [Fe2(CO)6(μ-SNH)] 1 was studied by 13C NMR spectroscopy. The 57Fe chemical shift of 1 and the coupling constants 1
J(57Fe,13C) were measured. These NMR parameters, and also 1
J(57Fe,15N), were found to be in good agreement with data calculated by using density functional theory (DFT) methods (B3LYP), based on the geometry calculated at the 6-311+G(d,p) level of theory. The isolobal replacement of the Fe(CO)3 with BH fragments leads to the tetrahedranes [Fe(CO)3(BH)(μ-SNH)] 2 and [(HB)2(μ-SNH)] 3. Both were identified by calculations as minima on the respective potential energy surface (PES). However, the tetrahedrane-type structure of 3 is much higher in energy when compared with the planar cyclic isomers 3a and 3b. 相似文献
128.
Bernd G. Müller 《无机化学与普通化学杂志》1987,553(10):196-204
New Ternary Silver (II) Fluorides: Ag M F14 (MIV = Zr, Hf) Single crystals of deeply blue violet coloured fluorides Ag3IIM2IVF14 (MIV = Zr, Hf) have been obtained by heating powder samples under F2/N2 (1:2) at T ≈? 600°C. The isotypic compounds crystallizes monoclinic with a = 924.9, b = 668.6, c = 907.3 pm, β = 90.30° (Ag3Hf2F14) and a = 922.5, b = 667.6, c = 906.3 pm, β = 91.30° (Ag3Zr2F14) (Four circle diffractometer data, Philips PW 1100), spcgr. C2/m-C2h3 (No. 12), Z = 2. There are two different sorts of Ag2+:Ag(1) with coordination number C.N. [Ag(1)] = 4 + 2 and Ag(2) with C.N.[Ag(2)] = 4 + 4 against F?. Ag(1) can be substituted by Cu2+, Ni2+, Zn2+, Mg2+ (all of blue/red violet colour), Ag(2) by Ca2+, Cd2+, Hg2+ (bright green). From (preliminary) powder data CuAg2Zr2F14 with a = 912.3(4), b = 661.2(2), c = 899.4(2) pm, β = 90.70° (3) is isotypic, the other compounds seems to be of closely related type of structure. 相似文献
129.
130.
The reaction between arachno-4-CB(8)H(14) and PCl(3) in the presence of PS (PS = proton sponge = 1,8-dimethylamino naphthalene) (dichloromethane, rt, 24 h) produced the neutral phosphacarborane closo-2,1-PCB(8)H(9) (35% yield), while a similar reaction of nido-1-CB(8)H(12) gave the isomeric compound closo-6,1-PCB(8)H(9) (27% yield). The structures of both compounds were derived on the basis of the combined ab initio/GIAO/NMR ((1)H, (11)B, (13)C) approach. The optimized structures at a correlated level of theory (MP2) with 6-31G* basis set were used as a basis for calculations of the (11)B and (13)C chemical shifts at GIAO-SCF/II and GIAO-MP2/II, the latter showing excellent agreement with experimental data. 相似文献