Electron-deficient Pt2M2Pt2 hexanuclear clusters, [Pt4M2(μ-dpmp)4(XylNC)2](PF6)4 (M = Pt (7), Pd (8); dpmp = bis((diphenylphosphino)methyl)phenylphosphine), were synthesized by oxidation of hydride-bridged hexanuclear clusters [Pt4M2(μ-H)(μ-dpmp)4(XylNC)2](PF6)3 (M = Pt (2), Pd (3)) and were revealed to involve a linearly ordered Pt2M2Pt2 array joined by delocalized bonding interactions with 84 cluster valence electrons, which are discussed on the basis of DFT calculations. The central M–M distances of 7 and 8 are significantly reduced upon the apparent loss of a hydride unit from the M–H–M central part of 2 and 3, indicating that the bonding electrons in the adjacent M–Pt bonds migrate into the central M–M bond to result in a dynamic structural change during two-electron oxidation of the hexanuclear metal strings. A similar Pt6 complex terminated by two iodide anions, [Pt6I2(μ-dpmp)4](PF6)2 (9), was synthesized from [Pt6(μ-H)I2(μ-dpmp)4](PF6) (5) by treatment with [Cp2Fe][PF6]. Complexes 7 and 8 were readily reacted with the neutral two-electron donors XylNC, CO, and phosphines to afford the trinuclear complexes [Pt2M(μ-dpmp)2(XylNC)L](PF6)2 (M = Pt, L = XylNC (1a), CO (10), PPh3 (11); M = Pd, L = XylNC (1b)) through cleavage of the electron-deficient central M–M bond. When complex 7 was reacted with the diphosphines (PP) trans-Ph2PCHCHPPh2 (dppen) and Ph2P(CH2)2PPh2 (dppe), the diphosphine was inserted into the central M–M bond to afford [(XylNC)Pt3(μ-dpmp)2(PP)Pt3(μ-dpmp)2(XylNC)](PF6)4 (12), which was transformed by treatment with another 1 equiv of diphosphine into the asymmetric trinuclear complexes [Pt3(μ-dpmp)2(XylNC)(PP)](PF6)2 (13). A further ligand exchange reaction of 13a (PP = trans-dppen) provided the diphosphine-terminated symmetrical Pt3 complex [Pt3(μ-dpmp)2(L)2](PF6)2 (L = trans-dppen (14a)). Complexes 7 and 8 were also reacted with [AuCl(PPh3)] to yield the Pt2MAu heterotetranuclear complexes [Pt2MAuCl(μ-dpmp)2(PPh3)(XylNC)](PF6)2 (M = Pt (15), Pd (16)), in which the Pt2M trinuclear fragment is inserted into the Au–Cl bond in a 1,1-fashion on the central M atoms of the Pt2M2Pt2 string.

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The aim of this study is to clarify factors that support the work engagement of nurses, who bear the burden of extended day shifts, by focusing on the advantages of the variable shift system and workday break activities. Methods: Nurses who were working under a variable shift system were asked to complete a self-report questionnaire to examine the workload, work engagement, work stressors, stress-coping strategies, and stress-coping break time activities, as well as the advantages and disadvantages of the variable shift system. Nine break activities were classified into the following four categories: social activities, rest/relaxation, entertainment, and cognitive activities. The advantages or disadvantages of the variable shift system were scored by developing composite variables using principal component analysis. These variables were used to perform a multiple regression analysis with work engagement as the dependent variable. Results: The advantage score was the variable most strongly correlated with work engagement. In contrast, "Quantitative workload" was negatively correlated with work engagement. Among break activities, in the social activities category correlations were observed in "Both conversation and Email/SNS" and "Conversation only". Although in fact most nurses chose conversation as one of the break options, more than half of the nurses selected rest/relaxation as their ideal break activity. Conclusion: Our study suggested that the variable shift system supported the work engagement of nurses who worked extended day shifts. The results also suggested that it would be useful to arrange the employee lounge environment so that employees could freely choose between "conversation" or "taking a rest" depending on the circumstances.