Abbreviations Used in This Review

764 (b) Biedenbach, B. Ph.D. Thesis, Universitat Kaiserslautern, 1988 (c) Haas, J. Ph.D. Thesis, Universitat Kaiserslautern, 1990 (d) Haas, J. Diplomarbeit, Universitat Bonn, 1988. 

Synthesis and Reactions of Polynuclear Cobalt-Alkyne Complexes 

Department of Chemistry University of Kent Canterbury. Kent CT2 7NH, United Kingdom 

In 1974, Dickson and Fraser reviewed the already substantial area of cobalt-alkyne complexes.1 Since then the number of examples and applications of this class of organometallic compounds, especially dinuclear complexes, has increased enormously. This review will present the chemistry of polynuclear cobalt-alkyne complexes, with emphasis on the more recent developments. Although there have been many exciting fundamental discoveries, this is a maturing area of research that is finding many important applications in organic synthesis,2 such as the use of [Co2(jU-alkyne)(CO)6] complexes in the synthesis of enediyne antitumor antibiotics.3-4 

Although many metal-alkyne complexes are known, probably the most thoroughly studied are those in which the alkyne is coordinated with a dicobalt unit. When this area was reviewed in 1974, more than 170 examples 

---

Table 2. Abbreviations used in this review for some of the commonest olefinic group V ligands...

MCD and TDDFT each has their own extensive system of notation. We have tried to make the symbols used distinct through choice of font and context. As an additional aid we have included a list of the symbols and abbreviations used in this review along with their meaning ... 

It is convenient to list initially those abbreviations used in this review which are not self-explanatory bipy, 2,2 -bip3Tidyl py, pyridine dien, diethylenetriamine diphos, 1,2-bisdiphenylphosphinoethane and en, ethylenediamine. 

Abbreviations used in this review APL, acute promyelocytic leukaemia CEF, chick embryo fibroblasts CRABP, cellular retinoic acid-binding protein ODC, ornithine decarboxylase RA, retinoic acid RARE, retinoic acid responsive element RAR, retinoic acid receptor RXR, retinoid X receptor TEMPO, 2,2,6,6-tetramethylpiperidine Y-oxide TOC, tracheal organ culture TPA, 12-<2-tetradecanoylphorbol-13-acetate TTNN, 6-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)-2-naphthanoic acid TTNPB, 4-((.Q-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthyl)propenyl)benzoic acid. 

Other abbreviations used in this review ACE, angiotensin converting enzyme ANP, atrial natriuretic peptide DADL, (D-Ala -D-Leu)-enkephalin DAP, dipeptidylaminopeptidase GABA, gamma-aminobutyric acid PTC-amino acid, phenylthiocarbamyl-amino acid. 

II. Sugar Nomenclature and Abbreviations Used in this Review. 197... 

Abbreviations Standard abbreviations as recommended by IUPAC-1UB Commission are used in this review (1). Other abbreviations include Acm, acetamidomethyl Bn, benzyl Boc t-butyloxycarbonyl Bom, benzyloxymethyl BHA, benzhydrylamine Cbz, benzyloxycarbonyl cHx, cyclohexyl DCC, N,N-dicyclohexylcarbodiimide DCM, dichloromethane Die, N,N-diisopropylcarbodiimide DMF, N,N-dimethylformamide DMSO, dimethyl sulphoxide For, formyl Fmoc, 9-fluorenylmethyloxycarbonyl HMP, 4-hydroxymethylphenoxyacetyl HOAt,... 

The following abbreviations have been used in this review ... 

The parameters described in the previous sections are collected for convenience in Table 1, which also summarizes the abbreviations used throughout this review for the various methods of structure determination. In most of the tabulations in this review, mean values are presented in the form, e.g., d cr, n). Thus the value 1.474 (1, 88) indicates a mean bond length of 1.474 A and a standard deviation of 0.001 A obtained from a distribution of 88 observations. In some cases, the value of n is constant for all entries in a given line of a table and here, to conserve space, mean values are given only in the form, e.g., d o), with the value of in a separate column. 

For convenience, a number of abbreviations will be used in this review. These are given here alphabetically ... 

A special nomenclature for the cyclopentadienyl metal compounds has grown up because of the complexity of their chemical names. The dicyclo-pentadienyl metal compounds, (CsH5)2M, are called ferrocene, cobaltocene, vanadocene, ruthenocene, etc., and these names will be used in this review. Furthermore, the abbreviation Cp will be used to represent C5H5, the cyclopentadienyl radical. 

In this review, drug concentrations or doses are assumed to be IC50 or ED50 values unless indicated otherwise. Abbreviations for routes of administration are p.o. (oral), i.p. (intraperitoneal) and i.v. (intravenous). The following abbreviations are used for common biological testing systems ... 

The examples that are presented in this section are not rigorous reviews of reactive intermediates but highlight instead the application of picosecond-resolved methods to selected problems. The symbols and abbreviations used herein may be different from those in the original publications, but if they have been changed, it is to achieve a uniformity of meaning for which they are used in this chapter. 

The generally accepted numbering schemes for 1,2,3-triazoles, thiatriazoline-5-thiones, and 8-azapurines, which are used throughout this section of the review, are given in (7), (8), and (9), respectively. Abbreviations used throughout this section to indicate neutral and anionic forms of the 1,2,3-triazole and benzotriazole ligands are taH/ta and btaH/bta, respectively. 

---