Reactions of the heterometallic MoRe complex [MoReCp(μ-PR*)(CO)6] and its MoMn analogue with some small molecules having N–N multiple bonds, such as diazoalkanes and organic azides, were investigated (R* = 2,4,6-C6H2 t Bu3). Reactions with excess ethyl diazoacetate proceeded slowly and with concomitant denitrogenation to give complexes [MoMCp(μ-η2 P,C:κ2 P,O-PR*CHCO2Et)(CO)5], which display a bridging phosphaalkene ligand in a novel μ-η2:κ2 coordination mode, while reactions with other diazoalkanes resulted only in the decomposition of the organic reagent. The MoRe complex reacted with benzyl- or p-tolyl azide at room temperature to give the green complexes [MoReCp(μ-η2 P,N:κP,N′ 2-PR*N3R)(CO)6] [R = Bn, p-tol], which display bridging phosphatriazadiene ligands in a novel 6-electron donor coordination mode as a result of a formal [2 + 1] cycloaddition of the terminal N atom of the azide to the Mo–P double bond of the parent complex, followed by coordination of the distal NR nitrogen to the rhenium center. Denitrogenation was only observed for the p-tolyl azide derivative, which upon heating at 333 K yielded [MoReCp{μ-κP:κN-PR*N(p-tol)}(CO)6], a molecule displaying a bridging phosphaimine ligand in a rare κP:κN coordination mode. Analogous reactions of the MoMn phosphinidene complex proceeded similarly at 273 K to give the phosphatriazadiene-bridged derivatives [MoMnCp(μ-η2 P,N:κ2 P,N′-PR*N3R)(CO)6], but these were thermally unstable and degraded at room temperature to give the mononuclear triazenylphosphanyl complexes [Mn2(κP,N-PR*NHNNR)(CO)3] as major products, along with small amounts of the phosphaimine-bridged complex [MoMnCp{μ-κP:κN-PR*N(p-tol)}(CO)6] in the case of the p-tolyl azide derivative. The structure of the new complexes was analyzed in light of spectroscopic data and single-crystal diffraction studies on selected examples of each type of complex.

Reactions of [MoReCp(μ-PMes*)(CO) 6 ] with internal alkynes RC�CR yielded the phosphapropenylidene-bridged complexes [MoReCp(μ-κ 2 P,C :η 3 -PMes*CRCR)(CO) 5 ] (Mes* = 2,4,6-C 6 H 2 t Bu 3 ; R = CO 2 Me, Ph). Terminal alkynes HC�CR 1 gave mixtures of isomers [MoReCp(μ-κ 2 P,C :η 3 -PMes*CHCR 1 )(CO) 5 ] and [MoReCp(μ-κ 2 P,C :η 3 -PMes*CR 1 CH)(CO) 5 ], with the first isomer being major (R 1 = CO 2 Me) or unique (R 1 = t Bu), indicating the relevance of steric repulsions during the [2 + 2] cycloaddition step between Mo�P and C�C bonds in these reactions. Similar reactions were observed for [MoMnCp(μ-PMes*)(CO) 6 ]. Addition of ligands to these complexes promoted rearrangement of the phosphapropenylidene ligand into the allyl-like μ-η 3 :κ 1 C mode, as shown by the reaction of [MoReCp(μ-κ 2 P,C :η 3 -PMes*CHC(CO 2 Me)}-(CO) 5 ] with CN(p-C 6 H 4 OMe) to give [MoReCp{μ-η 3 :κ 1 C -PMes*CHC(CO 2 Me)}-(CO) 5 {CN(p-CH 4 OMe)} 2 ]. The MoRe phosphinidene complex reacted with S�C� NPh to give as major products the phosphametallacyclic complex [MoReCp{μ-κ 2 P,S :κ 2 P,S -PMes*C(NPh)S}(CO) 5 ] and its thiophosphinidene-bridged isomer [MoReCp(μ-η 2 :κ 1 S -SPMes*)(CO) 5 (CNPh)].The first product follows from a [2 + 2] cycloaddition between Mo�P and C�S bonds, with specific formation of P�C bonds, whereas the second one would arise from the alternative cycloaddition involving the formation of P�S bonds, more favored on steric grounds. The prevalence of the μ-η 2 :κ 1 S coordination mode of the SPMes* ligand over the μ-η 2 :κ 1 p mode was investigated theoretically to conclude that steric congestion favors the first mode, while the kinetic barrier for interconversion between isomers is low in any case.

The novel nitrosyl-bridged complex [W 2 Cp 2 (μ-P t Bu 2 )(μ-κ:η-NO)(CO)(NO)](BAr 4 ) [Ar = 3,5-C 6 H 3 (CF 3 ) 2 ] was prepared in a multistep procedure starting from the hydride [W 2 Cp 2 (μ-H)(μ-P t Bu 2 )(CO) 4 ] and involving the new complexes [W 2 Cp 2 (μ-P t Bu 2 )(CO) 4 ](BF 4 ), [W 2 Cp 2 (μ-P t Bu 2 )(CO) 2 (NO) 2 ](BAr 4 ), and [W 2 (μ-κ:η 5 -C 5 H 4 )Cp(μ-P t Bu 2 )(CO)(NO) 2 ] as intermediates, which follow from reactions with HBF 4 ·OEt 2 , NO, and Me 3 NO·2H 2 O, respectively. The nitrosyl-bridged cation easily added chloride upon reaction with [N(PPh 3 ) 2 ]Cl, with concomitant NO rearrangement into the terminal coordination mode, to give [W 2 ClCp 2 (μ-P t Bu 2 )(CO)(NO) 2 ], and underwent N–O and W–W bond cleavages upon the addition of CN t Bu to give the mononuclear phosphinoimido complex [WCp(NP t Bu 2 )(CN t Bu) 2 ](BAr 4 ). Another N–O bond cleavage was induced upon photochemical decarbonylation at 243 K, which gave the oxo- and phosphinito-bridged nitrido complex [W 2 Cp 2 (N)(μ-O)(μ-OP t Bu 2 )(NO)](BAr 4 ), likely resulting from a N–O bond cleavage step following decarbonylation.

Reactions of [MoReCp(μ-PR*)(CO)6] with S8 were strongly dependent on experimental conditions (R* = 2,4,6-C6H2 t Bu3). When using 1 equiv of sulfur, complex [MoReCp(μ-η2:κ1 S-SPR*)(CO)6] was slowly formed at 313 K, with a thiophosphinidene ligand unexpectedly bridging the dimetal center in the novel μ-κ1 S:η2 coordination mode, as opposed to the μ-κ1 P:η2 mode usually found in related complexes. The latter underwent fast decarbonylation at 363 K to give [MoReCp(μ-η2:η2-SPR*)(CO)5], with a six-electron donor thiophosphinidene ligand rearranged into the rare μ-η2:η2 coordination mode. Depending on reaction conditions, reactions with excess sulfur involved the addition of two or three S atoms to the phosphinidene ligand to give new complexes identified as the dithiophosphinidene-bridged complex [MoReCp(μ-η2:κ2 S,S′-S2PR*)(CO)5], its dithiophosphonite-bridged isomer [MoReCp(μ-κ2 S,S′:κ2 S,S′-S2PR*)(CO)5], or the trithiophosphonate-bridged derivative [MoReCp(μ-κ2 S,S′:κ2 S,S′-S3PR*)(CO)5], all of them displaying novel coordination modes of their PRS2 and PRS3 ligands, as determined by X-ray diffraction studies. In contrast, the related MoMn complex yielded [MoMnCp(μ-η2:η2-SPR*)(CO)5] under most conditions. A similar output was obtained in reactions with gray selenium for either MoRe or MoMn phosphinidene complexes, which under different conditions only gave the pentacarbonyl complexes [MoMCp(μ-η2:η2-SePR*)(CO)5] (M = Re, Mn), these providing a new coordination mode for selenophosphinidene ligands.

Las abejas son un grupo extremadamente diverso con más de 1000 especies descritas en la península ibérica. Además, son excelentes polinizadores y aportan numerosos servicios ecosistémicos fundamentales para la mayoría de ecosistemas terrestres. Debido a los diversos cambios ambientales inducidos por el ser humano, existen evidencias del declive de algunas de sus poblaciones para ciertas especies. Sin embargo, conocemos muy poco del estado de conservación de la mayoría de especies y de muchas de ellas ignoramos cuál es su distribución en la península ibérica. En este trabajo presentamos un esfuerzo colaborativo para crear una base de datos de ocurrencias de abejas que abarca la península ibérica e islas Baleares que permitirá resolver cuestiones como la distribución de las diferentes especies, preferencia de hábitat, fenología o tendencias históricas. En su versión actual, esta base de datos contiene un total de 87 684 registros de 923 especies recolectados entre 1830 y 2022, de los cuales un 87% presentan información georreferenciada. Para cada registro se incluye información relativa a la localidad de muestreo (89%), identificador y colector de la especie (64%), fecha de captura (54%) y planta donde se recolectó (20%). Creemos que esta base de datos es el punto de partida para conocer y conservar mejor la biodiversidad de abejas en la península ibérica e Islas Baleares. Se puede acceder a estos datos a través del siguiente enlace permanente: https://doi.org/10.5281/zenodo.6354502