Selenocyanates thiocyanates

Thiocyanate and selenocyanate. Thiocyanate complexes of dioxoneptunium(V) have been prepared. The species Cs4[Np02(NCS)5] and Np02(NCS)(urea)4 have been reported the latter complex has been structurally characterized." ... 

Thousands of compounds of the actinide elements have been prepared, and the properties of some of the important binary compounds are summarized in Table 8 (13,17,18,22). The binary compounds with carbon, boron, nitrogen, siUcon, and sulfur are not included these are of interest, however, because of their stabiUty at high temperatures. A large number of ternary compounds, including numerous oxyhaUdes, and more compHcated compounds have been synthesized and characterized. These include many intermediate (nonstoichiometric) oxides, and besides the nitrates, sulfates, peroxides, and carbonates, compounds such as phosphates, arsenates, cyanides, cyanates, thiocyanates, selenocyanates, sulfites, selenates, selenites, teUurates, tellurites, selenides, and teUurides. 

A number of compounds of the types RBiY2 or R2BiY, where Y is an anionic group other than halogen, have been prepared by the reaction of a dihalo- or halobismuthine with a lithium, sodium, potassium, ammonium, silver, or lead alkoxide (120,121), amide (122,123), a2ide (124,125), carboxylate (121,126), cyanide (125,127), dithiocarbamate (128,129), mercaptide (130,131), nitrate (108), phenoxide (120), selenocyanate (125), silanolate (132), thiocyanate (125,127), or xanthate (133). Dialkyl- and diaryUialobismuthines can also be readily converted to secondary bismuthides by treatment with an alkali metal (50,105,134) ... 

Thiocyanates and selenocyanates can be made by fusing the corresponding cyanide with S or Se. The SCN and SeCN ions are both linear, like OCN . (See p, 779 for TeCN ) Treatment of KSCN with dry KHSO4 produces free isothiocyanic acid HNCS, a white crystalline solid which is stable below 0° but which decomposes rapidly at room temperatures to HCN and a yellow solid H2C2N2S3. Thiocyanic acid, HSCN, (like HOCN) has not been prepared... 

Pseudohalides of Se in which the role of halogen is played by cyanide, thiocyanate or selenocyanate are known and, in the case of Se are much more stable with respect to disproportionation than are the halides themselves. Examples are Se(CN)2, Se2(CN)2, Se(SeCN)2, Se(SCN)2, Se2(SCN)2. The selenocyanate ion SeCN is ambidentate like the thiocyanate ion, etc., p. 325), being capable of ligating to metal centres via either N or Se, as in the osmium(IV) complexes [OsCl5(NCSe)], [OsCl5(SeCN)], and trans-[OsCU(NCSe)(SeCN)]2-.920) Tellurium and polonium pseudohalogen analogues include Te(CN)2 and Po(CN)4 but have been much... 

Coordination chemistry of cyanate, thiocyanate and selenocyanate ions. A. H. Norbury, Adv. Inorg. Chem. Radiochem., 1975,17,232-386 (825). 

The softer, less basic potassium bromide and iodide did not react with the thiirene dioxide 19b. The latter was also inert towards potassium thiocyanate, selenocyanate or nitrile. It did react, however, with potassium thiophenoxide in DMF at room temperature to yield, most probably, the vinyl sulfmate 138 isolated as the corresponding sulfone39 (equation 56). 

Coordination Chemistry of the Cyanate, Thiocyanate, and Selenocyanate Ions A. H. Norbury... 

In recent years research in the field of transition-metal thiocyanates and selenocyanates received a new impetus, because of the partly interesting physical properties of such crystalline species. A review on Cd and Hg thiocyanate systems collects and sorts results of this endeavor.371 The nonlinear optical (NLO) properties of Cd thiocyanate and selenocyanate systems and criteria for the design of NLO crystals (crystal engineering), especially, have been discussed afterwards.372 Further contributions to the field have also been described.37, 374 The structure of mercury chlorothiocyanate has been re-determined.375... 

Starting with 3-aminoselenophene, a thiocyano or a selenocyano group could be introduced in the ortho position using ammonium thiocyanate and potassium selenocyanate.136,137... 

The carbon-nitrogen triple bond of aryl thiocyanates acts as a dipolarophile in 1,3-dipolar cycloadditions. Reactions with nitrile oxides yield 5-arylthio-1,2,4-oxadiazoles 227 (X = O Y = S). Aryl selenocyanates behave similarly forming 5-arylseleno-l,2,4-oxadiazoles 227 (X = 0 Y = Se). Reactions of 5-aryl-... 

Many uranium(VI) sulfoxide complexes of the type [U02X2(Me2S0)B] (X = anionic ligand) have been synthesized, including chloride, bromide (322, 323), nitrate (41), and acetate (431) adducts. The thiocyanate (113,114) and selenocyanate (292) adducts [U02(XCN)2(Me2SO)2] have been synthesized, and infrared data indicate the presence of O-Me2SO and JV-NCX ligands. 

Therefore, if an acceptor coordinates thiocyanate and selenocyanate ions via their S and Se donor atoms, respectively, the selenocyanate complexes should be considerably stronger than the thiocyanate complexes, and moreover formed in considerably more exothermic reactions. If, on the other hand, an acceptor prefers to coordinate these ligands via their harder donor atom N, the bonds formed will be less covalent and the reactions much less exothermic than in the case of S or Se coordination. The strength of the bonds will be little influenced by an exchange of S for Se and much the same value of AH°n may therefore be expected for thiocyanate and selenocyanate complexes. 

Further papers in this section include the hydrosilylation of a-pinene and of j8-pinene, ° thiocyanation and selenocyanation of a-pinene, ° cationic polymerization of a- and /3-pinene epoxides,bromination of ( )-c/s-pinonic acid with dioxan dibromide, and straightforward myrtenol (224 R=CH20H) ° and tetrahydroperillyl alcohol syntheses from -pinene epoxide. 

The pseudohalides and related compounds have been investigated by a number of workers. Thallium(I) cyanate and thiocyanate are both known, and the latter has been shown to be ionic in the solid state 288 differing values have been reported for the stability constants in the T1/NCS system in aqueous or mixed water/non-aqueous systems, but the overall evidence is that the complexes are extremely weak.289 The ionic selenocyanate has been reported, but the chemistry has not been investigated.1... 

The group VIB cyanides, thiocyanates and selenocyanates and their complexes with species such as thiourea have been described.1,45 For example, the tellurium dithiocyanate complex has been prepared45 by treatment of tellurium dichloride or tellurium dibromide with ammonium thiocyanate. It seems that little information exists on the preparation of tellurocyanates and there is a sparsity of data on polonium derivatives. Indeed, the only known cyanide of polonium is probably a salt of the quadrivalent element.1... 

Triazines, azides, cyanates, thiocyanates, selenocyanates and related ligands 378... 

Zirconium and hafnium cyanate, thiocyanate, and selenocyanate complexes that contain N-heterocyclic ligands are discussed in Sections 32.4.2.5.iii, 32.4.2.5.iv and 32.4.2.5.V. 

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