Acetylide, structure

The STM study provided microscopic evidence for the participation of added silver atoms in the chemisorbed acetylide structure. The Ag(110)-p(2x 1)0... 

M3(CO)9(CsCR)PPh2 and M3(CO)8(CsCR)PPh2 Clusters with /As-y -Acetylides. Structural data are available for both of the trimeric... 

A few simple beryllium acetylide structures are known. In one of these structures, illustrated as (112), the metal cation is symmetrically coordinated side-on to a triple bond. 

For example, the difference between the monoclinic CaC2 phases is the presence of only one type of acetylide ion in phase II and two distinct C2 species in phase III, as concluded from their crystal structures and from C-NMR studies (Fig. 8.3) [8]. The transformation between phases II and III is induced by heating phase II above 150°C until the metastable phase. III, is formed. Phase III remains stable even when being cooled down to room temperature. However, when the metastable phase III is ground in a mortar at room temperature, it transforms back into phase II. 

Metal-acetylide complexes including metal-poly(yne) polymers often show unique properties [21-23]. Thus, metal-acetylide dendrimers are of interest because amplification of the functionality due to metal-acetylide units based on three-dimensional assembly with a regular dendritic structure is expected. 

Luminescent gold(l) acetylide complexes. Photophysical and photoredox properties and crystal structure of [ Au(C = CPh) 2 (p-Ph2PCH2CH2PPh2)]. Journal of the Chemical Society, Dalton Transactions, 2929-2932 (d) Che, C.-M., Wong, W.-T., Lai, T.-F. and Kwong, H.-L. (1989) Novel luminescent binuclear gold(I) isocyanide complexes. Synthesis, spectroscopy, and X-ray crystal structure of Au2(dmh)(CN)2 (dmb = 1,8-di-isocyano-p-menfhane). Journal of the Chemical Society, Chemical Communications, 243-244. 

The ferrocenyldiphynylpropargyl cation, 77, has an intrinsic delocalization nature exhibiting a valence tautomerization band at 856 nm, and its nucleophilic trapping reactions give rise to the formation of ferrocenyldiphyenylallenes (173). The bis(acetylide) mixed-valence complexes of ferrocene and the Ru complex moiety, 78, also behave as a fulvene-cumulene structure, 79, showing a u(M=C = C—C) band at 1985 cm-1 (174). Related alleylidene and cumulenylidene complexes of transition metals have been reviewed by Bruce (175). 

Naturally, we thought our novel asymmetric acetylide addition on ketenimine 5 (Scheme 1.6) could also be applicable in the preparation of Efavirenz . The structure of 36 in Scheme 1.14 is somewhat misleading. We should expect that one of... 

The structure of the major aggregate was identified by labeling studies. Since the major set has two equal intensity 6Li signals, these signals could be assigned as a 1 1 complex 68 of lithium acetylide and lithium alkoxide or a dimer (such as 69) of the 1 1 complex 68 shown in Figure 1.9. Both structures have two different Li species. In order to discriminate between 68 and 69, a terminal acetylene carbon of 37 was labeled with 13C. In the case of 68, both lithium signals will be a doublet... 

Interaction of the acid with ammoniacal solutions of copperQ or silver salts gives precipitates which explode on warming or impact. The structures are not given, but may be amminemetal acetylide salts. 

Figure 36 The structure of the tetrameric acetylide complex [CpMg(/r3-C CPh)]4 70.

Figure 64 The structure of the barium acetylide complex M(C=CSiPh3)2(18-crown-6) 131.

A novel cadmate complex has been formed by the reaction of Cd(NH2>2 with I C=CH in the presence of acetylene in liquid ammonia.250 The potassium salt, K2Gd(CCH)4-2NH3 191, has been structurally characterized. The cadmium center is tetrahedrally coordinated to four acetylide units with which it forms Cd-C bonds of 2.23-2.25 A (Figure 29). The acetylide ligands are 7r-coordinated to two crystallographically distinct potassium ions whose coordination sphere is completed by two ammonia molecules. 

In addition to the types of compounds discussed so far, the group IVA elements also form several other interesting compounds. Silicon has enough nonmetallic character that it reacts with many metals to form binary silicides. Some of these compounds can be considered as alloys of silicon and the metal that result in formulas such as Mo3Si and TiSi2. The presence of Si22 ions is indicated by a Si-Si distance that is virtually identical to that found in the element, which has the diamond structure. Calcium carbide contains the C22-, so it is an acetylide that is analogous to the silicon compounds. 

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