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1.
Six novel Ir(C^N)2(L^X)-type heteroleptic iridium complexes with deep-red and near-infrared region (NIR)-emitting coverage were constructed through the cross matching of various cyclometalating (C^N) and ancillary (LX) ligands. Here, three novel C^N ligands were designed by introducing the electron-withdrawing group CF3 on the ortho (o-), meta (m-), and para (p-) positions of the phenyl ring in the 1-phenylisoquinoline (piq) group, which were combined with two electron-rich LX ligands (dipba and dipg), respectively, leading to subsequent iridium complexes with gradually changing emission colors from deep red (≈660 nm) to NIR (≈700 nm). Moreover, a series of phosphorescent organic light-emitting diodes (PhOLEDs) were fabricated by employing these phosphors as dopant emitters with two doping concentrations, 5% and 10%, respectively. They exhibited efficient electroluminescence (EL) with significantly high EQE values: >15.0% for deep red light0 (λmax = 664 nm) and >4.0% for NIR cases (λmax = 704 nm) at a high luminance level of 100 cd m−2. This work not only provides a promising approach for finely tuning the emission color of red phosphors via the easily accessible molecular design strategy, but also enables the establishment of an effective method for enriching phosphorescent-emitting molecules for practical applications, especially in the deep-red and near-infrared region (NIR). 相似文献
2.
Cationic cyclometalated Ir(III) complexes (Ir1-Ir5) with fluorine-substituted 2-phenylpyridine (ppy) derivatives as C^N cyclometalating ligands and 2,2′-bipyridine (bpy) as the ancillary ligand, have been synthesized and fully characterized. The influences of the number and the position of fluorine atoms at the cyclometalating ligands on the photophysical, electrochemical and oxygen sensing properties of the Ir(III) complexes have been investigated systematically. The introduction of fluorine on the C^N cyclometalating ligands of the complexes results in blue-shifts of the maximum emission wavelengths, and increases in the photoluminescence quantum yields (ΦPL), phosphorescence lifetimes and energy gaps, compared to the non-fluorinated [Ir(ppy)2(bpy)]+PF6? (Ir0). Among them, 2-(2,4-difluorophenyl)pyridine-derived Ir4 shows the maximum blue-shift (514 nm vs. 575 nm for Ir0) and the highest ΦPL (50.8% vs. 6.5% for Ir0). The complex Ir3 with 2-(4-fluorophenyl)-5-fluoropyridine as C^N ligand exhibits the highest oxygen sensitivity and excellent operational stability in 10 cycles within 4000 s. 相似文献
3.
Vadapalli Chandrasekhar Bani Mahanti Kotamarthi Bhanuprakash 《Journal of organometallic chemistry》2011,696(14):2711-2719
The reaction of the cyclometalated chloro-bridged iridium(III) dimer, [(ppy)2 Ir(μ-Cl)]2 (ppy - 2-phenyl pyridine) with N-aryl picolinamides (LH, LH-NO2, LH-CH3, LH-l, LH-F) resulted in the formation of neutral heteroleptic complexes [Ir(ppy)2L] (1), [Ir(ppy)2L-NO2](2), [Ir(ppy)2L-CH3](3), [Ir(ppy)2L-Cl](4) and [Ir(ppy)2L-F] (5). These complexes contain a six-coordinate iridium with a 2C, 4N coordination environment. The N-aryl picolinamide ligands are deprotonated during complexation and the resulting amidates bind to iridium in a chelating manner (N, N). Optical spectroscopic studies revealed that the complexes 1-5 exhibited intense π→π∗ absorptions in the ultraviolet region. In addition low energy transitions due to 1MLCT, 1LLCT and 3MLCT are also seen. The emission spectra of 1-5, upon excitation at 450 nm, show a single emission with a λmax around 513 nm. The lifetimes of this emission are in between 7.4 and 9.6 μs while the quantum yields are quite high and range from 0.2 to 0.5. Based on density functional theory (DFT) calculations on 1 and 3, the three highest occupied orbitals are composed of ligand π orbitals mixed with Ir-d orbitals while the three lowest unoccupied orbitals are mostly π orbitals of the ligands. From the time dependent DFT calculations it is revealed that the lowest energy electronic singlet and triplet excitations are a mixture of MLCT and LLCT. 相似文献
4.
Flavio Sabatelli Jacopo Segato Leonardo Belpassi Alessandro Del Zotto Daniele Zuccaccia Paola Belanzoni 《Molecules (Basel, Switzerland)》2021,26(9)
The coordination ability of the [(ppy)Au(IPr)]2+ fragment [ppy = 2-phenylpyridine, IPr = 1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene] towards different anionic and neutral X ligands (X = Cl−, BF4−, OTf−, H2O, 2-butyne, 3-hexyne) commonly involved in the crucial pre-equilibrium step of the alkyne hydration reaction is computationally investigated to shed light on unexpected experimental observations on its catalytic activity. Experiment reveals that BF4− and OTf− have very similar coordination ability towards [(ppy)Au(IPr)]2+ and slightly less than water, whereas the alkyne complex could not be observed in solution at least at the NMR sensitivity. Due to the steric hindrance/dispersion interaction balance between X and IPr, the [(ppy)Au(IPr)]2+ fragment is computationally found to be much less selective than a model [(ppy)Au(NHC)]2+ (NHC = 1,3-dimethylimidazol-2-ylidene) fragment towards the different ligands, in particular OTf− and BF4−, in agreement with experiment. Effect of the ancillary ligand substitution demonstrates that the coordination ability of Au(III) is quantitatively strongly affected by the nature of the ligands (even more than the net charge of the complex) and that all the investigated gold fragments coordinate to alkynes more strongly than H2O. Remarkably, a stabilization of the water-coordinating species with respect to the alkyne-coordinating one can only be achieved within a microsolvation model, which reconciles theory with experiment. All the results reported here suggest that both the Au(III) fragment coordination ability and its proper computational modelling in the experimental conditions are fundamental issues for the design of efficient catalysts. 相似文献
5.
The electronic structures and spectroscopic properties of a series of mixed bis-cyclometalated iridium(III) complexes [Ir(ppy)2X2]− (X = CN, 1; X = NCS, 2; X = NCO, 3; ppy = 2-phenylpyridl) were investigated at the B3LYP/LANL2DZ and CIS/LANL2DZ levels. The calculated geometry parameters in the ground state are well consistent with the corresponding experimental values. The HOMO of 1 is dominantly localized on Ir atom and ppy ligand, but the HOMO of 2 and 3 have significant X ligand composition. Under the TD-DFT level with PCM model, the absorption and phosphorescence in CH2Cl2 media were calculated based on the optimized geometries in the ground and excited states, respectively. The lowest-lying absorption of 1 at 403 nm is attributed to {[dx2-y2(Ir)+dxy(Ir)+π(ppy)]→[π∗(ppy)]} transition with metal-to-ligand and intraligand charge transfer (MLCT/ILCT) transition characters, whereas those of 2 (449 nm) and 3 (475 nm) are related to {[dx2-y2(Ir)+dxy(Ir)+π(ppy)+π(NCS/NCO)]→[π∗(ppy)]} transition with MLCT/ILCT and ligand-to-ligand charge transfer (LLCT) transition characters. The phosphorescence of 1 at 466 nm can be described as originating from 3{[dx2-y2(Ir)+dxy(Ir)+π(ppy)][π∗(ppy)]} excited state, while those of 2 (487 nm) and 3 (516 nm) originate from 3{[dx2-y2(Ir)+dxy(Ir)+π(ppy)+π(NCS/NCO)][π∗(ppy)]} excited states. The calculated results showed that the transition character of the absorption and emission can be changed by adjusting the π electron-accepting abilities of the X ligands and the phosphorescent color can be tuned by altering the X ligands. 相似文献
6.
Ling-Yang Hsu Qiumin Liang Zhiheng Wang Hsin-Hung Kuo Wun-Shan Tai Shi-Jian Su Xiuwen Zhou Yi Yuan Yun Chi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(67):15375-15386
Iridium complexes bearing chelating cyclometalates are popular choices as dopant emitters in the fabrication of organic light-emitting diodes (OLEDs). In this contribution, we report a series of blue-emitting, bis-tridentate IrIII complexes bearing chelates with two fused five-six-membered metallacycles, which are in sharp contrast to the traditional designs of tridentate chelates that form the alternative, fused five-five metallacycles. Five IrIII complexes, Px-21 – 23 , Cz-4 , and Cz-5 , have been synthesized that contain a coordinated dicarbene pincer chelate incorporating a methylene spacer and a dianionic chromophoric chelate possessing either a phenoxy or carbazolyl appendage to tune the coordination arrangement. All these tridentate chelates afford peripheral ligand–metal–ligand bite angles of 166–170°, which are larger than the typical bite angle of 153–155° observed for their five-five-coordinated tridentate counterparts, thereby leading to reduced geometrical distortion in the octahedral frameworks. Photophysical measurements and TD-DFT studies verified the inherent transition characteristics that give rise to high emission efficiency, and photodegradation experiments confirmed the improved stability in comparison with the benchmark fac-[Ir(ppy)3] in degassed toluene at room temperature. Phosphorescent OLED devices were also fabricated, among which the carbazolyl-functionalized emitter Cz-5 exhibited the best performance among all the studied bis-tridentate phosphors, showing a maximum external quantum efficiency (EQEmax) of 18.7 % and CIEx,y coordinates of (0.145, 0.218), with a slightly reduced EQE of 13.7 % at 100 cd m−2 due to efficiency roll-off. 相似文献
7.
The ground and the lowest-lying triplet excited state geometries, electronic structures, and spectroscopic properties of a novel series of neutral iridium(III) complexes with cyclometalated alkenylquinoline ligands [(C^N)2Ir(acac)] (acac = acetoylacetonate; C^N = 2-[(E)-2-phenyl-1-ethenyl]pyridine (pep) 1; 2-[(E)-2-phenyl-1-ethenyl]quinoline (peq) 2; 1-[(E)-2-phenyl-1-ethenyl]isoquinoline (peiq) 3; 2-[(E)-1-propenyl]pyridine (pp) 4; 2-[(E)-1-fluoro-1-ethenyl]pyridine (fpp) 5) were investigated by DFT and CIS methods. The highest occupied molecular orbital is composed of d(Ir) and π(C^N) orbital, while the lowest unoccupied molecular orbital is dominantly localized on C^N ligand. Under the TD-DFT with PCM model level, the absorption and phosphorescence in CH2Cl2 media were calculated based on the optimized ground and triplet excited state geometries, respectively. The calculated lowest-lying absorptions at 437 nm (1), 481 nm (2), 487 nm (3), 422 nm (4), and 389 nm (5) are attributed to a {[dx2-y2(Ir) + dxz(Ir) + π(C^N)] → [π∗(C^N)]} transition with metal-to-ligand/intra-ligand charge transfer (MLCT/ILCT) characters, and the calculated phosphorescence at 582 nm (1), 607 nm (2), 634 nm (3), 515 nm (4), and 491 nm (5) can be described as originating from the 3{[dx2-y2(Ir) + dxz(Ir) + π (C^N)] [π∗(C^N)]} excited state with the 3MLCT/3ILCT characters. The calculated results revealed that the phosphorescent color of these new Ir(III) complexes can be tuned by changing the π-conjugation effect strength of the C^N ligand. 相似文献
8.
Guoyun Meng Lijie Liu Zhechang He David Hall Xiang Wang Tai Peng Xiaodong Yin Pangkuan Chen David Beljonne Yoann Olivier Eli Zysman-Colman Nan Wang Suning Wang 《Chemical science》2022,13(6):1665
Multi-resonant thermally activated delayed fluorescence (MR-TADF) materials have attracted considerable attention recently. The molecular design frequently incorporates cycloboration. However, to the best of our knowledge MR-TADF compounds containing nitrogen chelated to boron are still unknown. Reported herein is a new class of tetracoordinate boron-containing MR-TADF emitters bearing C^N^C- and N^N^N-chelating ligands. We demonstrate that the replacement of the B–C covalent bond in the C^N^C-chelating ligand by the B–N covalent bond affords an isomer, which dramatically influences the optoelectronic properties of the molecule. The resulting N^N^N-chelating compounds show bathochromically shifted absorption and emission spectra relative to C^N^C-chelating compounds. The incorporation of a tert-butylcarbazole group at the 4-position of the pyridine significantly enhances both the thermal stability and the reverse intersystem crossing rate, yet has a negligible effect on emission properties. Consequently, high-performance hyperfluorescent organic light-emitting diodes (HF-OLEDs) that utilize these molecules as green and yellow-green emitters show a maximum external quantum efficiency (ηext) of 11.5% and 25.1%, and a suppressed efficiency roll-off with an ηext of 10.2% and 18.7% at a luminance of 1000 cd m−2, respectively.A new class of tetra-coordinate boron-containing MR-TADF emitters and their corresponding high-performance hyperfluorescent organic light-emitting diodes have been successfully achieved. 相似文献
9.
Chen Chen Meng-hui Wang Lin-Yan Feng Lian-Qing Zhao Jin-Chang Guo Hua-Jin Zhai Zhong-hua Cui Sudip Pan Gabriel Merino 《Chemical science》2022,13(27):8045
The occurrence of planar hexacoordination is very rare in main group elements. We report here a class of clusters containing a planar hexacoordinate silicon (phSi) atom with the formula SiSb3M3+ (M = Ca, Sr, Ba), which have D3h (1A1′) symmetry in their global minimum structure. The unique ability of heavier alkaline-earth atoms to use their vacant d atomic orbitals in bonding effectively stabilizes the peripheral ring and is responsible for covalent interaction with the Si center. Although the interaction between Si and Sb is significantly stronger than the Si–M one, sizable stabilization energies (−27.4 to −35.4 kcal mol−1) also originated from the combined electrostatic and covalent attraction between Si and M centers. The lighter homologues, SiE3M3+ (E = N, P, As; M = Ca, Sr, Ba) clusters, also possess similar D3h symmetric structures as the global minima. However, the repulsive electrostatic interaction between Si and M dominates over covalent attraction making the Si–M contacts repulsive in nature. Most interestingly, the planarity of the phSi core and the attractive nature of all the six contacts of phSi are maintained in N-heterocyclic carbene (NHC) and benzene (Bz) bound SiSb3M3(NHC)6+ and SiSb3M3(Bz)6+ (M = Ca, Sr, Ba) complexes. Therefore, bare and ligand-protected SiSb3M3+ clusters are suitable candidates for gas-phase detection and large-scale synthesis, respectively.The global minimum of SiSb3M3+ (M = Ca, Sr, Ba) is a D3h symmetric structure containing an elusive planar hexacoordinate silicon (phSi) atom. Most importantly, the phSi core remains intact in ligand protected environment as well.Exploring the bonding capacity of main-group elements (such as carbon or silicon) beyond the traditional tetrahedral concept has been a fascinating subject in chemistry for five decades. The 1970 pioneering work of Hoffmann and coworkers1 initiated the field of planar tetracoordinate carbons (ptCs), or more generally, planar hypercoordinate carbons. The past 50 years have witnessed the design and characterization of an array of ptC and planar pentacoordinate carbon (ppC) species.2–14 However, it turned out to be rather challenging to go beyond ptC and ppC systems. The celebrated CB62− cluster and relevant species15,16 were merely model systems because C avoids planar hypercoordination in such systems.17,18 In 2012, the first genuine global minimum D3h CO3Li3+ cluster was reported to have six interactions with carbon in planar form, although electrostatic repulsion between positively charged phC and Li centers and the absence of any significant orbital interaction between them make this hexacoordinate assignment questionable.19 It was only very recently that a series of planar hexacoordinate carbon (phC) species, CE3M3+ (E = S–Te; M = Li–Cs), were designed computationally by the groups of Tiznado and Merino (Fig. 1; left panel),20 in which there exist pure electrostatic interactions between the negative Cδ− center and positive Mδ+ ligands. These phC clusters were achieved following the so-called “proper polarization of ligand” strategy.Open in a separate windowFig. 1The pictorial depiction of previously reported phC CE3M3+ (E = S–Te; M = Li–Cs) clusters and the present SiE3M3+ (E = S–Te and N–Sb; M = Li–Cs and Ca–Ba) clusters. Herein the solid and dashed lines represent covalent and ionic bonding, respectively. The opposite double arrows illustrate electrostatic repulsion.The concept of planar hypercoordinate carbons has been naturally extended to their next heavier congener, silicon-based systems. Although the steric repulsion between ligands decreases due to the larger size, the strength of π- and σ-bonding between the central atom and peripheral ligands dramatically decreases, which is crucial for stability. Planar tetracoordinate silicon (ptSi) was first experimentally observed in a pentaatomic C2v SiAl4− cluster by Wang and coworkers in 2000.21 Very recently, this topic got a huge boost by the room-temperature, large-scale syntheses of complexes containing a ptSi unit.22 A recent computational study also predicted the global minimum of SiMg4Y− (Y = In, Tl) and SiMg3In2 to have unprecendented planar pentacoordinate Si (ppSi) units.23 Planar hexacoordinate Si (phSi) systems seem to be even more difficult to stabilize. Previously, a C2v symmetric Cu6H6Si cluster was predicted as the true minimum,24 albeit its potential energy surface was not fully explored. A kinetically viable phSi SiAl3Mg3H2+ cluster cation was also predicted.25 However, these phSi systems24,25 are only local minima and not likely to be observed experimentally. In 2018, the group of Chen identified the Ca4Si22− building block containing a ppSi center and constructed an infinite CaSi monolayer, which is essentially a two-dimensional lattice of the Ca4Si2 motif.26 Thus, it is still an open question to achieve a phSi atom to date.Herein we have tried to find the correct combination towards a phSi system as the most stable isomer. Gratifyingly, we found a series of clusters, SiE3M3+ (E = N, P, As, Sb; M = Ca, Sr, Ba), having planar D3h symmetry with Si at the center of the six membered ring, as true global minimum forms. Si–E bonds are very strong in all the clusters, and alkaline-earth metals interact with the Si center by employing their d orbitals. However, electrostatic repulsion originated from the positively charged Si and M centers for E = N, P, and As dominates over attractive covalent interaction, making individual Si–M contacts repulsive in nature. This makes the assignment of SiE3M3+ (E = N, P, As; M = Ca, Sr, Ba) as genuine phSi somewhat skeptical. SiSb3M3+ (M = Ca, Sr, Ba) clusters are the sole candidates which possess genuine phSi centers as both electrostatic and covalent interactions in Si–M bonds are attractive. The d orbitals of M ligands play a crucial role in stabilizing the ligand framework and forming covalent bonds with phSi. Such planar hypercoordinate atoms are, in general, susceptible to external perturbations. However, the present title clusters maintain the planarity and the attractive nature of the bonds even after multiple ligand binding at M centers in SiSb3M3(NHC)6+ and SiSb3M3(Bz)6+. This would open the door for large-scale synthesis of phSi as well.Two major computational efforts were made before reaching our title phSi clusters. The first one is to examine SiE3M3+ (E = S–Po; M = Li–Cs) clusters, which adopt D3h or C3v structures as true minima (see Table S1 in ESI†), being isoelectronic to the previous phC CE3M3+ (E = S–Po; M = Li–Cs) clusters. In the SiE3M3+ (E = S–Po; M = Li–Cs) clusters, the Si center always carries a positive charge ranging from 0.01 to +1.03|e|, in contrast to the corresponding phC species (see Fig. 1). Thus, electrostatic interactions between the Siδ+ and Mδ+ centers would be repulsive (Fig. 1). Given that the possibility of covalent interaction with an alkali metal is minimal, it would be a matter of debate whether they could be called true coordination. A second effort is to tune the electronegativity difference between Si and M centers so that the covalent contribution in Si–M bonding becomes substantial. Along this line, we consider the combinations of SiE3M3+ (E = N, P, As, Sb; M = Be, Mg, Ca, Sr, Ba). The results in Fig. S1† show that for E = Be and Mg, the phSi geometry has a large out-of-plane imaginary frequency mode, which indicates a size mismatch between the Si center and peripheral E3M3 (E = N–Bi; M = Be, Mg) ring. On the other hand, the use of larger M = Ca, Sr, Ba atoms effectively expands the size of the cavity and eventually leads to perfect planar geometry with Si atoms at the center as minima. In the case of SiBi3M3+, the planar isomer possesses a small imaginary frequency for M = Ca. Although planar SiBi3Sr3+ and SiBi3Ba3+ are true minima, they are 2.2 and 2.5 kcal mol−1 higher in energy than the lowest energy isomer, respectively (Fig. S2†). Fig. 2 displays some selected low-lying isomers of SiE3M3+ (E = N, P, As, Sb; M = Ca, Sr, Ba) clusters (see Fig. S3–S6† for additional isomers). The global minimum structure is a D3h symmetric phSi with an 1A1′ electronic state for all the twelve cases. The second lowest energy isomer, a ppSi, is located more than 49 kcal mol−1 above phSi for E = N. This relative energy between the most stable and nearest energy isomer gradually decreases upon moving from N to Sb. In the case of SiSb3M3+ clusters, the second-lowest energy isomer is 4.6–6.1 kcal mol−1 higher in energy than phSi. The nearest triplet state isomer is very high in energy (by 36–53 kcal mol−1, Fig. S3–S6†) with respect to the global minimum.Open in a separate windowFig. 2The structures of low-lying isomers of SiE3M3+ (E = N, P, As, Sb; M = Ca, Sr, Ba) clusters. Relative energies (in kcal mol−1) are shown at the single-point CCSD(T)/def2-TZVP//PBE0/def2-TZVP level, followed by a zero-energy correction at PBE0. The values from left to right refer to Ca, Sr, and Ba in sequence. The group symmetries and electronic states are also given.Born–Oppenheimer molecular dynamics (BOMD) simulations at room temperature (298 K), taking SiE3Ca3+ clusters as case studies, were also performed. The results are displayed in Fig. S7.† All trajectories show no isomerization or other structural alterations during the simulation time, as indicated by the small root mean square deviation (RMSD) values. The BOMD data suggest that the global minimum also has reasonable kinetic stability against isomerization and decomposition.The bond distances, natural atomic charges, and bond indices for SiE3Ca3+ clusters are given in † for M = Sr, Ba). The Si–E bond distances are shorter than the typical Si–E single bond distance computed using the self-consistent covalent radii proposed by Pyykkö.27 In contrast, the Si–M bond distance is almost equal to the single bond distance. This gives the first hint of the presence of covalent bonding therein. However, the Wiberg bond indices (WBIs) for the Si–M links are surprisingly low (0.02–0.04). We then checked the Mayer bond order (MBO), which can be seen as a generalization of WBIs and is more acceptable since the approach of WBI calculations assumes orthonormal conditions of basis functions while the MBO considers an overlap matrix. The MBO values for the Si–M links are now sizable (0.13–0.18). These values are reasonable considering the large difference in electronegativity between Si and M, and, therefore, only a very polar bond is expected between them. In fact, the calculations of WBIs after orthogonalization of basis functions by the Löwdin method gives significantly large bond orders (0.48–0.55), which is known to overestimate the bond orders somewhat. The above results indicate that the presence of covalent bonding cannot be ruled out only by looking at WBI values.Bond distances (r, in Å), different bond orders (WBIs) {MBOs} [WBI in orthogonalized basis], and natural atomic charges (q, in |e|) of SiE3Ca3+ (E = N, P, As, Sb) clusters at the PBE0/def2-TZVP level
Open in a separate windowOur following argument regarding the presence of covalent Si–M bonding is based on energy decomposition analysis (EDA) in combination with natural orbital for chemical valence (NOCV) theory. We first performed EDA by taking Ca and SiE3Ca2 in different charge and electronic states as interacting fragments to get the optimum fragmentation scheme that suits the best to describe the bonding situation (see Tables S6–S9†). The size of orbital interaction (ΔEorb) is used as a probe.28 For all cases, Ca+ (D, 4s1) and SiE3Ca2 (D) in their doublet spin states turn out to be the best schemes, which give the lowest ΔEorb value. Energy term Interaction Ca+ (D, 4s1) + SiN3Ca2 (D) Ca+ (D, 4s1) + SiP3Ca2 (D) Ca+ (D, 4s1) + SiAs3Ca2 (D) Ca+ (D, 4s1) + SiSb3Ca2 (D) ΔEint −192.9 −153.0 −144.9 −129.9 ΔEPauli 139.8 115.2 115.7 110.9 ΔEelstata −162.0 (48.7%) −116.4 (43.4%) −113.0 (43.4%) −100.9 (41.9%) ΔEorba −170.7 (51.3%) −151.8 (56.6%) −147.6 (56.6%) −140.0 (58.1%) ΔEorb(1)b SiE3Ca2–Ca+(s) electron-sharing σ-bond −89.2 (52.3%) −79.4 (52.3%) −74.3 (50.3%) −66.9 (47.8%) ΔEorb(2)b SiE3Ca2 → Ca+(d) π‖-donation −32.9 (19.3%) −32.0 (21.1%) −31.8 (21.5%) −30.8 (22.0%) ΔEorb(3)b SiE3Ca2 → Ca+(d) σ-donation −13.1 (7.7%) −11.9 (7.8%) −12.0 (8.1%) −11.9 (8.5%) ΔEorb(4)b SiE3Ca2 → Ca+(d) π⊥-donation −12.3 (7.2%) −12.2 (8.0%) −12.5 (8.5%) −12.5 (8.9%) ΔEorb(5)b SiE3Ca2 → Ca+(d) δ-donation −8.1 (4.7%) −9.9 (6.5%) −10.9 (7.4%) −11.8 (8.4%) ΔEorb(rest)b −15.1 (8.8%) −6.4 (4.2%) −6.1 (4.1%) −6.1 (4.4%)
r Si–E | r Si–Ca | r E–Ca | q Si | q E | q Ca | |
---|---|---|---|---|---|---|
E = N | 1.669 | 2.555 | 2.246 | 1.57 | −1.93 | 1.74 |
(1.14) {1.23} [1.84] | (0.02) {0.13} [0.51] | (0.22) {0.67} [0.84] | ||||
E = P | 2.180 | 2.935 | 2.640 | 0.25 | −1.42 | 1.67 |
(1.34) {1.11} [1.52] | (0.03) {0.14} [0.54] | (0.27) {0.74} [1.05] | ||||
E = As | 2.301 | 3.004 | 2.721 | 0.07 | −1.34 | 1.65 |
(1.33) {1.10} [1.45] | (0.03) {0.15} [0.55] | (0.29) {0.71} [1.12] | ||||
E = Sb | 2.538 | 3.155 | 2.896 | −0.39 | −1.16 | 1.62 |
(1.29) {1.01} [1.33] | (0.04) {0.18} [0.48] | (0.30) {0.78} [1.14] |